Saturday, February 28, 2009

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"Hold on for one more day..."
- from the 1990 single Hold On by Wilson Phillips

BIG KAHUNA ALERT: SAT FEB 28 - 12:00 PM. NWS has issued a Winter Storm Watch for central Maryland - central and southwestern Virginia - Philadelphia metro - portions of northern DelMarVa. View map. Sterling, VA NWS projects 5 or more inches by Monday AM: Forecast discussion - HPC snow probability map - HPC short range discussion. Widespread school closings on Monday and delays Tuesday are a near certainty.

MY QUICK TAKE: While 6 to 10 inches may fall, a warm ground and higher sun angle may also negate much of that so actual accumulations on untreated secondaries/sidewalks/parking lots will be closer to 5 inches, with main roads receiving 3 inches or less. Closest comparison is the Feb 28-Mar 1 Kahuna of 2005: Heavy snow warnings of 6 - 10 inches in the Baltimore metro region yielded 5 or less for the same reasons.

PREVIOUS SYNOPSIS: FRI FEB 27 - 2:45 PM. I hope you're able to hold on for one more day, because if you want snow...things may be turning your way. A breakdown of weather impacts for eastern Mid-Atlantic/ I-95 corridor from DC to Philly:
FRIDAY: Mild windy conditions give way to showers this evening ahead of a cold front crossing the area overnight.
SATURDAY: Cold afternoon rain mixes with wet snow toward evening and changes to snow/sleet overnight.
SUNDAY: Colder air arrives by Sunday morning, with periods of snow and sleet that could accumulate 5 or more inches by evening on untreated secondaries and sidewalks, with up to 3 inches on main roads.
MONDAY: Sub-freezing temperatures throughout the day wind-driven snow on top of ice may produce widespread school closings from Virginia to DC and Baltimore into the Philly metro area. Cold winds in wake of the storm will deliver an unpleasant and disruptive start to the Spring sports season, so coaches, players and athletic directors alike should plan accordingly.
To stay current on storm developments, I encourage you to visit the following links: HPC probabilistic snow/ice, yesterday's prelim extended discussion, and the Baltimore/Washington forecast discussion. For comparison, here is Accuweather's take. A quick glance at the current precip timing charts for the GFS and NAM show roughly .50" of liquid equivalent snow, which for the Baltimore region could translate to a ballpark 2" by Sunday evening. A bigger picture of moisture potential is shown via the current QPF day 1-5 map (see all the purples and reds?) The current European model provides a general snapshot of 5000 foot temps and the storm's projected path. Taking all this into account, I hope you can plainly see it's worth holding on for one more day, even if it's barely enough to cover the grass.

Thursday, February 26, 2009

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"I keep working my way back to you, babe."
- Frankie Valli and the Four Seasons

UPDATED SYNOPSIS: THU FEB 26 - 6:45 AM. The period Saturday through Monday will feature several low pressure systems moving northeast from the Tennessee valley. As is being reflected in your NWS local forecasts, any or all of these systems have the potential to deliver rain, snow or both. The KEY factor raising concern is PLACEMENT OF THE HIGH. As quoted many times on this site, "predict the High and you predict the storm" a rule attributed to a legendary Penn State meteorology professor. Indications are that one of several high pressure cells in southern Canada may be positioned to supply adequate cold air as this projected system moves from the US southeast.

The forecasting rule to be applied for this storm is called "short range" which is a fancy term for "nowcasting" which is a euphemism for "we're not really sure what will happen, so just keep your eyes on the radar." I can understand the consternation facing NOAA forecasters, as this transition period into Spring is a historically tough time to accurately nail down snow potential. My analysis will have to wait until I complete several coursework projects this week. Until then, perhaps you can interpret these snippets from the HPC discussions of Feb 24-25 on our storm potential (edited for clarity):
PREVIOUS SYNOPSIS: FRI FEB 20. No doubt takes some of our readers back a ways, and I select it to represent what this winter seems to keep doing. For the past 3 winters in the Mid-Atlantic, computer models (and indeed, the atmospheric trends which drive them) in an almost sadistic way keep throwing bones to the powderhounds... only to have those dream storms live on, but only in our dreams. While it's obvious winter conditions have returned, a never-say-die La Nina coupled with an unfavorable North Pacific trend compounded by a sporadically negative NAO mean the general rule still applies. What's the "general rule?" Easy: If there is potential for a storm to quench the Mid-Atlantic snowdrought, once curtain time arrives, the atmosphere will find a way to "misalign" and truncate that potential. I'm certain to be in good company with this philosophy among the skeptics! Of course if the PNA/NAO trend reverses, we're back in business.

WANT THE ONE SENTENCE SUMMARY? Except for the Saturday night-Sunday tease, there are no snow or rain threats on the horizon until next Friday: Just cold and windy trending to mild between now and then.

Powderhounds (a term coined here several years ago) are right to remain doubtful of any storm possibility right until they see the whites of it's eyes, er flakes. That said, the GFS and European models are again advertising another trip to Fantasyland from Friday 2/27 to Monday 3/01. Taken literally, the outcome would be no different than many PREVIOUS fantasy storms: The usual 24-36" of interior snow, with oh say 12 inches in the big cities. As with all previous storm monitoring this season, I'll take a closer look on Monday. Until then, you are welcome to track, analyze and comment accordingly on these comparable projections from the GFS, European.

In conclusion, Spring-a-lings know the true meaning of today's title: Regardless of what distractions winter continues to bring up, SPRING is working it's way back to you, babe.

Tuesday, February 17, 2009

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A repeat of Wednesday?

UPDATED SYNOPSIS: THU FEB 19 - 7:15 AM. For residents of the Mid-Atlantic from West Virginia eastward to the Baltimore-Washington Metro areas, today will be ANOTHER study in contrasts. Between 7AM and lunch, weather conditions for many of us will go from clear to cloudy to more rounds of scattered light snow throughout the day. More information later today about the possible Kahuna or Kanona next week.
ORIGINAL REPORT: TUE-WED FEB 17-18. This event is a "lakes cutter" which by definition means we are on the east side of the counter-clockwise flow. While light snow is expected across the region between 7 AM and 10 AM tomorrow, it is not likely to accumulate enough for school delays. What does fall will stick, but with traffic getting underway at the same time, roads should be just wet. Before noon, all snow will have changed over to rain, and warm frontal passage late in the day will prevent a change back to snow. There is also little chance for a re-freezing overnight into Thursday, with temps staying above 32 F.

For "towel-throwers" who believe winter is over, I learned a lesson several years in a row when I too would throw the towel in mid-February. Since 2006 in the Mid-Atlantic, late winter and early Spring snow has continued to crop up. In 2007, measureable snow at BWI occured on the "bookends" of astronomical winter (though in 2 different seasons, the dates were: March 16, April 7, December 5). Even last year, some Maryland school systems were delayed or closed as late as February 22 on just one inch or less. With return of the cold, we can all agree winter has officially relaunched and may even be returning to a more December-like pattern of clippers. Indications are the next several clippers could "dive" far enough south to produce scattered light snow this coming weekend. For powderhounds, hope is alive, but spring-a-lings and naysayers alike know time is on their side with each passing day. The battle is joined! What do you think?

Sunday, February 15, 2009

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"Memory...all alone in the moonlight."
- From the Broadway Musical CATS

SUN FEB 15 - 12:45 PM Some families celebrate holiday traditions such as watching Polar Express or It's A Wonderful Life at Christmas, making angels at the first snowfall, and giving Valentine's chocolate. In the Foot household we take a few moments to relive the memories of that other lifetime event: The President's Weekend Blizzard of February 2003. Below is a slideshow I developed to record our perilous journey back to Dundalk, MD from a central PA ski trip, as well as the exhausting after-effects throughout our town. Six years ago this weekend, all of us in the Northeast became a band of brothers and sisters to dig out from this monster. For powderhounds, it was the quintessential example of what a weak El Nino/negative NAO/positive PNA combination can produce on the East Coast given the right environment. That arrangement is not present now... but someday it will come back.

But diligent weather watchers are probably seeing through this nostalgic attempt to distract them away from the failing potential for snow this coming week. While the winter weather pattern is still in place for a stormy 10 day period from the 18th forward, it is not showing a "snow"stormy look.. at least for next Wednesday. Granted one cannot say this means "absolutely zero snow rest of the winter" (unless you are speaking with authority on the subject, like Brig. Weather General Andy from Southern York County)

While the North Atlantic Oscillation (NAO) may be negative, so also is the Pacific-North American Index (PNA) at present. Going into next week it appears the Atlantic ridge will make a comeback, while La Nina looks to persist at least into the Spring. As nicely pointed out by commentator Gary from Towson in an earlier post, nearly neutral Nino/Nina signals (within -0.5 C) are often times just as unfavorable for East coast snow as strong signals. Some notable exceptions to that rule are Feb 1983 (extremely strong Nino) and January 1996 (strong Nina). If you head is now spinning with all this terminology, just glance at this quick overview of Nino/Nina impacts on North American weather. This should either clarify or confuse further, depending on your preference for reading about climate teleconnection analyses on Sunday mornings.

If this winter has pushed you to make snow your new anti-friend, just remember that for the previous 2 years over this week, the Mid-Atlantic was dealing with terrible ice Kahunas, notably the Valentine's Day Massacre of 2007 and the February 2008 ice storms. Also of mention is that both years featured followup events from late Feb all the way to early favorite of course being in 2007 when we had more snow the day on "Easter Eve" than "Christmas Eve." With that I turn the floor over for your memories, but know you're not alone in the moonlight here, because many of us still secretly yearn for that next big one.

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Saturday, February 14, 2009

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"Seven days, so many ways..."
- Lyrics from a single of the same title in Sting's 1993 album Ten Summoner's Tales.

UPDATED SYNOPSIS: SAT FEB 14 - 6:45 AM. Spring-a-lings no doubt reveled in our February thaw this week, but powderhounds know that paybacks are coming. Climate indications and computer models alike are advertising a relaunch of winter weather by next Wednesday. From the 18th to the 28th, atmospheric factors will be in alignment for some Mid-Atlantic snow. The next 5 days are the prologue to that period, so let's call it the "three steps back to winter":

Step 1: THU-FRI Wednesday's warmth was replaced by a dangerous cold front sweeping to the East Coast, delivering sustained strong winds in it's wake into Friday.
Step 2: SAT-SUN High pressure settles across the Northeast, as waves of weak low pressure move along an active southern jet stream, bringing scattered rain and wet snow to the Ohio valley on Saturday. Light and intermittent rain is expected from Maryland south, while Pennsylvania may see brief light snow showers.
Step 3: MON-WED This launches the 10-day period which I have marked as from Feb 18 to 28. To start, a second, stronger High pressure reinforces cold air across the Northern US while a low pressure system from the California/Oregon coast moves over the central plains by Tuesday and near Ohio-West Virginia by Wednesday. This setup suggests potential for some accumulating snow on Wednesday-Thursday of next week. (Sat 2:30 PM edit-- Note the slight change in wording there.) For the Mid-Atlantic region of PA, MD, VA, WV this is trending toward a "snow changing to rain" scenario.
Since we are nearing the 5-day prior point, a more formal estimate of storm impacts will be posted over the weekend. Diligent weather watchers know the computer models have shown possibilites ranging from a "March 1962" to a January 22, 2005 type event to "off the coast-out to sea." Hence the reasoning of today's seven days, there are so many ways this could evolve.
This next phase, lasting approximately 10 days, may be the final act for major winter storm potential in the Mid-Atlantic. Skeptics correctly point out that with the ground having warmed and softened, and an increasing sun angle with each passing day, ingredients for an accumulating snow event will have to be absolutely perfect. That said, you can sure more than a few of us will be searching for those ingredients, and if found, we will not hesistate to gleefully report our discoveries here!
Snowstorm aficionadoes may feel a strange alignment with history this week, as it is the 26th anniversary of the February 11-12, 1983 East Coast blizzard. It was the one time in my life and never since have I witnessed thunder and lightning in snow so incredibly heavy it obscured the neighbor's house just 20 feet away. Scroll through this link for some amazing pictures taken in several cities the morning after, including Baltimore. If you have a moment, read through some amazing stories in the comments section below...if you're a true powderhound, then these tales of thundersnow are sure to warm (cool?) your heart.

Wednesday, February 11, 2009

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The "one screen approach"
Seeking your input on website content

SITE DISCUSSION: MON FEB 9 - 8:45 AM. In advance of the next weather pattern change, your input is needed to assure this site delivers the content you seek in an appropriate and effective manner. Changes made in recent years to provide ready-access of weather trends include:
1) Addition of "self-updating" features such as radar, temps, conditions, big picture trends;
2) Time-sensitive re-arrangement of links and maps tailored to current or impending events;
3) Direct links to scientific weather data, discussions of reporting agencies,
One specific improvement is what I term the "one screen" approach. The objective is for all pertinent information you seek to appear on one screen..the first screen at which you land. I realize many of you are busy professionals, parents, students, teachers who don't have time to sift through a comglomeration of gobbly-gook to "just get the weather." Obviously, if you want more details, or wish to revel yourself in an excruciating dissection of every possible weather trend (real or imagined), the just scroll down at your own risk.
In the comments, I welcome your input on the following site presentation issues, as I always look to stay current with what readers want. A more efficient design not only streamlines the forecasting and increases time with family, it helps both of us make informed decisions about approaching weather hazards. At your convenience, comment on the following (and any other suggestions or changes):
(1) Location and content of the snapshots: Do you prefer the Mid-Atlantic/National quick glance as they current appear, or is it too much information on one screen?
(2) What's the one feature of most importance to you: Radar, satellite, regional/local temps, links to your local forecast, or something else?
(3) The SpringWidgets dilemma: Some school servers block this feature. I prefer it for a quick glance, but maybe it is too unwieldy for everyone else. Should it be kept or cut?
Thanks for the feedback provided already, and keep it coming. Knowing your preferences helps make this a more useful information source for everyone. Comment reminder: Your post may not appear right away, so no need to retype if after you click "publish."

Friday, February 6, 2009

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"What would a slumdog know?"
- Indian police officer, interrogating Jamal in Slumdog Millionaire
Jamal, the 18-year old main character, quietly responds: "The answers."

REVISED UPDATE: SUN FEB 8 - 1:45 PM. I don't claim to have all the answers here about the weather, but I can make this educated guess based on my analysis of climate patterns and upper level atmospheric data:

1. Arrival of the false warmup will permit Mid-Atlantic residents a five to seven day break to regroup, (if you started Saturday) to get outside and pretend that Spring is on the way.

2. Climate indicators (our good friends the NAO, PNA et al.) are hinting this is a false warmup, and from February 13 forward to end of the month, the East Coast could be headed back into a cold, stormy and snowy pattern. Fellow teachers: My suggestion is if you have a major project/lab/multi-day activity in the works, don't wait to get it moving. If there's another interruption, at least your goals are in motion. This is not hype, but prudence.

3. Despite the impending warmup, are also headed into the snowiest period of the entire year for central Maryland, according to climate records: The time frame of early to mid February is replete with big snowstorms in the Mid-Atlantic. Notable storms in that time criteria since 1899 as recored at BWI include Feb 15-18, 2003 (28") ; Feb 1996 (2 storms in early month, not incl. Jan 96 blizzard); The Ice Nightmares of February 1994 [who could ever forget that one! ] ; Feb 11-12, 1983 (23") ; Feb 18-19, 1979 (20") ; Feb 15-17, 1958 (15"), Feb 11-14, 1899 (21") Summary: At BWI airport, seven of the top twenty snowstorms since 1891 occurred during a tiny 13-day slice of the calendar: Feb 5 to 18. My elbows get sore just LOOKING at that list.

Source: "Maryland Winters" by Barbara McNaught Watson, published by the National Weather Service, Sterling, VA,

SYNOPSIS: THU FEB 5 - 11:00 AM. Some residents of Lancaster County PA and the Philadelphia region discovered 6 to 12 INCHES of snow on their front step yesterday morning. Can you imagine the surprise in Lititz, PA when their residents went to bed expecting LIGHT SNOW ACCUMULATING UP TO TWO INCHES. I am not making this up. Some areas of Delaware County across Philly and into New Jersey received 8 to 10 inches. If you have the time, are a serious weather watcher, and want to see something just amazing, start on this page from the Mount Holly, NJ NWS. It shows the "Zone Forecasts" for the Philly region. Now go forward or backward from the page # to see how the snowfall forecast kept changing..(in less than 24 hours mind you). Chester County, PA started with 1 to 3, then 2 to 4, then 4 to 6. The Lancaster situation was even more incredible. Take a look at the last sentence of the 1:09 AM Wed Feb 4 Discussion, it's currently denoted as "version 18" in their archives. Now fair is fair, I busted on the last storm too. Which would you prefer..a "non-storm" bust, or to wake up with an extra 12 inches on the car? Oh to have been a student in that school district on that particular morning!

How could this happen? What went wrong with the forecast? (A plug for my teacher colleagues, wouldn't all this make for an intriguing lesson?) Much like the storyline of Slumdog Millionaire, the answers might have been with us all along: a product of our "knowledge and intuition" as remarked by Justin Berk, a meteorologist for whom I have great respect, and is with ABC2 News in Baltimore. The "why" behind this surprise snow might be just as "plausibly bizarre" as a young man from the slums of Mumbai, India appearing on Who Wants To Be A Millionaire?

As promised, I will be presenting a brief evaluation of the January ice event and the Groundhog storm. That includes the What Went Right/What Went Wrong analysis of my forecasts. But I emphasize "brief" because my father likes to say: "Asking the other Mr. Foot about the weather is like going to a fire hydrant for a sip of water." I'll let Dad take the credit for an accurate call on that one, don't you think? ;-)

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Tuesday, February 3, 2009

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WED FEB 4 - 10:45 AM. I thought you all would be encouraged by the fact that my Mom in Chester County called to say they received 7 INCHES! as a result of the Groundhog Storm, topped off by last night's surprise. Don't believe me...scroll down through the Philly/Mount Holly snow report in their Public Information Statement. Incredible totals! A few of Mom's photos are posted below showing a true "powderhound" enjoying the snow. Although commuters this morning were not celebrating in the slightest, at least we can say someone benefitted from this storm. Teachers and students, take heed and get as much instruction moving as possible, because we have a LOT of February yet to accomplish. :::insert sound of exasperated exhale here::: And then there is the long slog through March. But I digress, now everybody, back to work! Enough of this weather business for now.

Note: The picture below is just a montage of the family canine in suburban Philly reveling in his surprise snow. If not viewable on your screen, tt will be here to see when you get home!

WED FEB 4 - 9:45 AM. Actually, had I been paying closer attention last night, I might have found this and it would not have been a surprise at all. A map to be posted shortly to show you what caused our little spritz of snow. UPDATE: Several MD Eastern Shore districts had to pull surprise last minute closings. There must be a new NWS category called "Heavy Flurries" developed by the Mount Holly, NJ Office. With the advisory expanded to 10:00 AM, it indicates NWS had trouble identifying where the trailing edge of the shortwave was located! Either widened in it's route to here from Syracuse, or it's their way of saying: "Yeah, we don't use those old fashioned techniques anymore, that's for paper and pencil types."

Surprise Shortwave

Look, I am not tooting my horn, because I did not initially take the time to locate the shortwave last night. But I'm not the certified meteorologist here. It took me all but 5 minutes to identify it on the 850 mb map shown above, and do the calculations. No computer model. I used a map that was posted by NOAA overnight, so it was 4-5 hour old data. Had I been watching at 11:00 PM, I would have noticed and at least said, "hmmm. Better take a closer look." So I say it is a mini-bust for BOTH parties involved here (myself included.)

Previous post 11:00 PM Wed 2-3-09

OPENER: WED FEB 4 - 6:00 AM. As we bid farewell to the much-maligned and long predicted Groundhog Storm, attention naturally turns to the other question on many reader's minds: "What's in store for the rest of February?" After a wrapup of both the late January ice storm and our currently departing one, I will spend some time pin-pointing the indicators that could lead to an active storm pattern for this month. The false warmup this weekend will give many the impression that the potential for serious winter weather has ended. Their remain two or possibility three periods coming up for February that could deliver a traditional East Coast snowstorm. After the 28th..climatology and sun angle conspire to generally end any speculation or hope of good snow after March 1. So enjoy what could be a "Fabulous February" for I believe the atmosphere still has many more surprises lurking.

ABOUT COMMENT DELAY: Your post may not appear immediately, so don't think it was "missed" or needs re-typing. The number shown below may also not reflect the current total.

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MON FEB 3 - 9:45 AM. The next set of 850 mb shortwaves are easy to identify on the map below published by NOAA a little after 8 AM and 8 PM each day I've posted this for those teachers who are conducting a storm followup discussion. Based on wind barb indicators (calculating the flow direction, speed of the shortwave and distance to a location) you can peg the arrival of precipitation down to the hour. The map displays upside down, so you'll have to cut/paste.

As an example, my estimated arrival time for another round of snow showers in the Carolinas would be by noon today, lasting perhaps 4 hours, then tapering off. For the Mid-Atlantic, it looks like a very small embedded shortwave as of 8AM was located in western PA. As of 10:30 AM, it is represented on the surface map as a weak trough, the trailing edge of which should exit central Maryland by noon. If you see your snow intensity increase, then decrease between 10AM and Noon, that's the reason. (Teachers and students: Don't get excited, it's just light snow touched off by the shortwave.) In addition to a weak upper level and surface low in southern Ohio, there was another strong shortwave over central Albany, NY that will take longer to rotate around the 850 mb low. That second wave should arrive over central Maryland by dusk, about the same time as the surface low. These two will touch off another round of light snow during the evening commute, but ending by 7PM. This timing suggests that afternoon or evening activities should be able to go forward as planned.. but ultimately that decision is up to you!

REGARDING AVAILABILITY OF "COMMENTS" AT SCHOOL: Although our evening scientific discussions have been engaging, please do not to pester your friendly neighborhood school Internet security department with requests to unblock the comments. (No, I wasn't contacted by them or are otherwise "in trouble.") They have perfectly valid reasons for leaving things just where they are, and I wholeheartedly support their decision.

Let's just be eternally grateful that educational systems permit this weather news source to be viewed in the first place! You all would agree, having the comments available in school would be a terrible distraction or worse. For true weather enthusiasts, it gives you something to look forward to when you get home: reading the day's comments! If something cataclysmic develops, that information will be posted on the main page. Thank you everyone for your support and understanding!

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After all, it's only the weather. We'll all survive somehow.

TUE FEB 3 - 7:00 AM.
Office supplies to track shortwaves: $5.00
Extra bold Colombian coffee to get up early: $6.75.
A picture of yourself wearing a bag holding two little girls in their pajamas: PRICELESS.
Watching snow while sitting in class tired because you stayed up all night: AGGRAVATING.

More humor coming to help dull your pain, a brief "during-storm" analysis, as well as the true story of my worst call ever, which isn't this one because hey, at least it IS snowing, like somewhere. For my esteemed colleagues (and students) in the school systems, I know that ONE question will be gnawing at you all day like a patch of ice that just won't melt:

ARE WE GETTING OUT EARLY ? My answer to students on that one is always: "Well, I'm not going to stay here all night." The simple's not likely. The culprit is warm road surfaces, though temps have dropped significantly since yesterday at this time. But in honor of your disappointment, I will keep a close eye on conditions today, because the so-called "Fish Storm" is still somehow managing to produce crystalline precipitation over a large area of land. In deference to parents and especially my elementary school compatriots, if there's any meteorological evidence suggesting a surprise early dismissal in the Baltimore Metro region, I'll post accordingly. For now, just enjoy the snow out your window, focus on your day and don't crash this site checking multiple times in an hour! Do not expect an update at least 11:00 AM. Later, I'll do my own version of Justin Berk's "What Went Right" and "What Went Wrong" with my forecast, but that is after the storm departs the Northeast region.

P.S. My worst ever call goes back to my days at Conestoga High School in the mid-late 1980's. I'm not sure of the year, might have been 1988. I remember making grand proclamations for 4-8" of snow overnight, on the morning announcements no less. I woke up to... FOG. I didn't understand how double-barrel lows can actually shut off the precip if they pass over you. Boy that was a rough next day at school.

Monday, February 2, 2009

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EVENING UPDATE: MON FEB 2 - 10:15 PM. The map above is my final snowfall forecast, and the one on which we will grade the storm. If it busts, I wear a bag and life goes on.

OPENING STATEMENT: The arrival of snow in the Baltimore Metro region Monday evening as predicted days ago is a vindication for many readers on this site who have been loyally following all the round-about twists and turns of our "Groundhog Storm." Incidentally, Punxsutawney Phil did see his shadow today thanks to the bright sunshine, so it's back to the regularly scheduled program: Lots of winter still to overcome in the next 6 weeks. Your devotion to faithfully providing observations is sincerely appreciated.

SCHOOL IMPACTS: (5:30 am - LOOKS BUSTED!) My general take on this unique storm situation is that Tuesday's school schedule will be affected in some way, but will vary by district based on their location. That sounds obvious, but is not as clear cut. The best projection I can make based on current indications of precip, temperature trends, and likely duration of incoming moisture:

CLOSED: Frederick, Carroll, Loudon, Montgomery. MAY ATTEMPT A 2-HOUR DELAY: Baltimore County, Howard, Anne Arundel, Harford, Cecil, Prince Georges. 1-HOUR DELAY: Baltimore City, DC Schools. If snow continues into the early morning hours (as in still snowing by 4AM, then what was going to be an attempt at a delay may be announced as a closing.)

SNOW AND RADAR: Yes, I know many powderhounds like you out there are all stressed out over the radar hole. It is probably caused by "subsidence" of the air from the front passing so quickly. It's almost a "gust front" like we see in the summer on weather maps. As the front moved in, it pushed lots of air away ahead of it. We are talking extremely huge volumes of air being moved around here, and as the air subsides or sinks, it becomes more dry. This creates a hurdle for the incoming moisture to saturate, and that's what we're seeing over the Chesapeake Bay. Give it time, and this will eventually fill in. Hey, someone in the comments said it best earlier today. Despite all the computer model mayhem, the very fact that we have this fairly huge mid-latitude cyclone that has all but popped out of nowhere is in of itself truly amazing. Consider that the snow shield as of 11:00 PM Groundhog Day 2009 extends from North Carolina to Maine. What computer model foresaw that? Just one, it's called the "LOW" model.. which stands for "Look Out Window."

REGARDING COMMENTS: I want to make clear that we need to keep the discussion focused on the storm and not one-line itty-bitty statements. The students who have joined us here know what I'm talking about. We all love snow, but we don't need to sift through excessive one-liners that are not weather observations, valid questions or scientific concerns. Humor is welcome, but don't let it get out of hand. This discussion feature is not Twitter, nor a chat room. Keep those things in mind when you post a comment. Last statement on this: Students, if I wake up to find dozens of comments or more that are mostly one-line blurbs and of little value, the comments will be suspended. I had to do it before, let's not have that happen again.

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UNDERSTATEMENT OF THE EVENING UPDATE: MON FEB 2 - 7:00 PM. As aptly quoted by some of our commentators: "Something Wicked This Way Comes." I figured it was time to start a new round of comments and observations. When you post, try to answer me this: WHERE do you suppose all that moisture is going if it's not going off the coast? Oh wait, it is going off the coast. Maybe those are false radar echoes. Someone call a friend in South Carolina to find out if it's really raining, because it seems like we're back to good ole' "ground truth, and the best prediction method of all: NOWCASTING.

REGARDING COMMENTS: STUDENTS..Please post only worthwhile questions that pertain to this event. I can not answer specific requests for "how much in my backyard" or "will school be closed." The answers for that information is already published in previous posts. Like I tell my students who used to ask in class alot, I'd say: "Um, read the site. It's why I put it there." In a earlier storm a few years back, we had to remove comments and a chat feature due to abuse. Let's not have that happen again.

Sincerely, Mr. Foot

Sunday, February 1, 2009

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CURRENT SYNOPSIS: MON FEB 2 - 3:45 PM. A TOTAL OF FOUR OR MORE inches across the Baltimore Metro region, with possibly higher amounts first in far western counties of the Blue Ridge, and then later in areas adjacent to the Chesapeake Bay.

The cold front in central Maryland, which may shortly go stationary, will usher in colder air by the evening commute. What little rain that occurs will quickly mix with and change to all snow before midnight. Snow may be intermittent into Tuesday morning, until moisture from one or more waves of low pressure developing along this front moves along the Mid-Atlantic coast. Despite today's warm temperatures, dynamic cooling coupled with evaporative cooling will provide an upper level environment conducive for snow. The bulk of accumulation should occur Tuesday, but could extend into the evening hours. Little or no risk of frozen precipitation until the very end of the event. Below normal temperatures will be in place Wednesday and Thursday, causing overnight re-freezing of standing water on sidewalks, bridges, overpasses and untreated roads.

MON FEB 2 - 1:45 PM. This is a quick update to let you know there are no changes to my forecast for amount and timing of snow. However as you can all tell just by looking out the window, things are not working out today as many forecasters had planned (That could be a good thing for powderhounds). Even I had to take an umbrella with me this morning to shield against the uh, rain er, um the blazing sunshine. I've been watching a variety of data just briefly, and what I see suggests the Mid-Atlantic is still in for a surprise tonight and tomorrow. Question is, will the surprise be a picture of me wearing a grocery bag? Or will it be a "children sleeping, snow is softly falling" kind of surprise? DISCLAIMER FOR STUDENTS AND TEACHERS: None of my forecasts are a suggestion to discard preparation for school the following day. Just adhere to the rule set forth by my esteemed colleague Mr. Terpguy (a Baltimore County science teacher for 39 years) : Be prepared (also known as the Boy Scout motto.)

Observations since 12 noon today: Deep convection in the Gulf and over Florida; There's a ton of moisture headed this way, and it is NOT just happily flowing into the Atlantic, an 850 mb upper low in northern Gulf; Where is the rain for Maryland? The front is almost on top of Baltimore; For concerns the ground is "warm" I decided to check. Here's what I found:

1:30 PM Mon 2-2: The ground on my south facing yard in Dundalk was so hard I had trouble inserting a thermometer. At last check the subsurface temp about 1/2 inch down is ::get this :: 37 F! This is in FULL SUN with no shade and it's been there over an hour now. That tells me once the front arrives as sun angle dips lower, temps will tumble. i was walking on another large field in town a few hours ago. The top 1/2 inch was moist, but you could feel under that a rock solid layer of basically semi-permafrost.

Lastly.. how about the surface lows currently on the live, real, actual, in-front-of-our face maps that ARE NOWHERE TO BE FOUND ON THE HPC SURFACE LOW TRACKING MAP? I guess a low that pops in Pennsylvania and delivers several inches of snow, snarling traffic, is not significant?

Previous discussion from 5:45 AM follows:

SCHOOL: If my snow forecast of 4 inches verifies, then most Maryland districts from Frederick County, MD eastward to the MD-DE line will close once snow is falling Tuesday morning. The same will be true for Northern Virginia, the WV panhandle, and York County, PA eastward to Philadelphia. Wednesday may bring school delays due to re-freezing, black ice and the added potential for a shortwave touching off more snow showers. For Thursday and Friday, roads will be clear and thus, it is expected that schools open on time both days.

ANALYSIS: My research indicates the potential for several inches remains unchanged, despite inconsistencies in computer models. I calculated the amount by taking just the general liquid equivalent projected by an average of the QPF map and the models, but I added the likelihood of "Bay-effect enhancement" if banding sets up from northeast to southwest. With this approach, you arrive at roughly .50 inches of liquid. Translated directly by the standard snow-to-liquid ratio of 10:1, (lowered to 8:1 due to marginal temps) delivers a general 4 inches across Central Maryland, lesser amounts west of Baltimore, higher totals near the Chesapeake Bay and northeast toward Elkton and Philly.


ME: I'm not looking at ANY computer model. I'm relying on that which Justin Berk suggested we all do.. (read next section for context) use my own knowledge, intuition and experience.

If NWS and TV forecasters have seemed unwilling to commit on amounts until now, it may have been due not only to misguided model data, but the memory of embarrassing outcomes in the past decade: (Too low-January 25, 2000) (played catchup-February 14, 2003); (Too high-March 3, 2001). (Caveat: I've had a number of them myself, and will relate those stories to you because none of us are immune to making vast, catastrophic mistakes.) There is more discussion of this in my "statement on the models" below.

Since it's been 5 years from when this site began, perhaps it is time you get some background on "the man behind the curtain" so you can better understand the methods behind the madness. Scroll to the next post for three true stories of life without computer models.

STATEMENT ABOUT "THE MODELS." Expecting more "GoDaddy" goofiness during the Superbowl, my wife and I conveniently blocked the TV during commercials for sake of the children. Oh, sorry, that was the wrong intro. I meant to talk about computer models.

The other game may be over, but the real game in town is just starting. I wonder if the computer model whiplash confounding forecasters is from data so corrupted for this event that NOAA would rather let it go than admit they're unwilling to rely on traditional meteorological techniques. Justin Berk of ABC2 News said it best in his post earlier today, with regard to the possible data gap caused by diverted air traffic over Alaska's Mount Redoubt: "many forecasters have relied too much on computers and not enough on their own knowledge and intuition. I often say that if computers were perfect, we would be out of work." I for one appreciate his candor, and if I had a choice between laying off meteorologists, or shutting off computer models, he'd be among the ones I'd keep!

Case in point from the Baltimore/Washington NWS at 8:50 PM Sunday. Note that I've converted the abbreviated text to full words for clarity:


I still have a lot of misgivings with the picture being painted by NWS and higher offices. There is so much erroneous information scattered throughout the playing field, and I think they realize this to the point that even though the computer projections "appear" to have settled on a solution, doesn't mean the programs have initialized all the pieces to make an informed decision. That last critical part is up to US, the CREATORS of the program.

(1) Radar shows convection and thunderstorm cells in the Gulf of Mexico. This was NOT predicted by the models. It is clear some of the models did not even include this data in their most recent runs.
(2) Moisture is feeding into the upper level flow already ahead of the cold front sliding south across the Midwest. This moisture cannot be ignored and will be involved in the end game.
(3) Upper level low at 500 mb is moving out of southern Canada. The models do not have a good handle on it's direction and destination.
(4) The very unusual precipitation forecasts for the Mid-Atlantic suggest there will be this "hang-back" of moisture from Baltimore north to Philly and New York. There is also odd placement of convective activity off the Carolina/Florida coast.
(5) Finally, it appears that the placement, strength and destination of several shortwaves have been so problematic that no one can figure out what they're going to do once they encounter the base of the trough over the Mid-Atlantic by Monday night.

In conclusion, if I'm wrong, then there will be a full accounting on this site, and you will thoroughly enjoy the way in which we do this. It is the same technique I've had to use in class in previous years for failed forecasts: I wear a brown paper bag over my head, with the forecasted amount written next to the actual amount. If it happens this time, I'll post that picture of myself here for all to see!

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"25 years ago..."


It all started in the Fall of 1986. I along with a few friends my high school created the "Conestoga Weather Service." I had been practicing TV weather forecasts with our school studio and district news cable program, T/E TV News. (That's Tredyffrin/Easttown School District in Berwyn, PA). Starting that January, we began preparing forecasts for the morning announcements. On Wednesday, January 21, 1987.. a weather forecast changed my life.

My friend Chris and I met in the library each day before school from about 6:45 to 7:30, and typed our forecast. We also had a unique little computer program I ordered seen in a magazine. It was contained on a 5 1/4" floppy disk program, and inserted into an IBM PC 2 with a whopping 30 meg of memory. We plugged in just standard observations from that morning taken from ABC'S "Action News" on Channel 6 and The Weather Channel, then still in it's infancy. I'll never forget what happened next.

The computer whirred and churned for a minute or so, then began spitting out the 3-day forecast on the glacially slow dot-matrix printer. For the Philadelphia area the following day, it said: "heavy snow, windy and cooler." My friend and I were stunned and amazed. We quickly checked the daily newspapers for any evidence of this. We listened to NOAA weather radio, and he ran back to the TV studio to check The Weather Channel. Nothing. Even Accu-Weather's forecast for the following day was "Partly Cloudy, high of 40." Time was running out, as the 7:25 bell had rung and we needed to finish the forecast, print it, and get to the main office in time for the announcements. Chris and I said to each other, "How do we explain this to people who will ask us why?"  We decided the real answer was simply that a giant Arctic high would nose in to the area right before the storm strikes, and other agencies were not picking up on this.

I grabbed a file of NWS pamphlets on Winter Storms. As my friend Chris typed, I read their description of heavy snow: "4 or more inches in a 12-hour period." So it was settled. That Wednesday in January 1987, as a Junior in high school, I went on the air with 1,400 listeners, and announced a forecast that probably remains the most memorable one of my life: "...and for Thursday: 6 to 12 inches of snow, windy and much colder." The entire school was electrified the rest of the day, and the administration was not pleased in the slightest. I'll never forget the shocked expression on our AP's face as soon as I handed him back the microphone.

Thursday morning, right on schedule, the snow began. Most schools had learned of the impending storm overnight, and closed on the first sign of snow. We were closed again Friday. The total accumulation at my house in Paoli, PA: Fourteen wonderful inches. A second snowstorm (a Miller B for you powderhounds) developed on the heels of that one  and smacked the Mid-Atlantic again Sunday night, closing schools on  MONDAY. Well, you can imagine what happened when Chris and I got finally back to school. 

Thus began this weather forecasting adventure that led to an internship at the Philadelphia National Weather Service (before it moved to Mount Holly, NJ), acceptance to Penn State in where I worked the 5AM Monday shift at the PSU Campus Weather Service, teaching Weather Merit Badge at Boy Scout camps, writing articles for PSU student newspapers and gaining Science Teacher Certification in 1999 from West Chester University. A June 2001 phone call changed everything. A Dr. Kim Stephanic of  "Dundalk High School" said in the voicemail message: "I'm trying to contact Rich Foot, I have a one-year old resume here but was wondering if you would like to come down for an interview..."  

And here we are.

# 2 - FEBRUARY 2003 
THE PRESIDENT'S DAY STORM 2003  FORECAST. Two years later, at Dundalk High School, a fellow science teacher asked me if our class would be preparing a  snowfall forecast for President's Weekend. I was reluctant, but knew the liquid equivalents were tremendous, so I put the student to the task. To this day, there are still countless  witnesses in Baltimore County, MD to that impromptu request, the  forecast and the results. Some of them are still employees in the Baltimore County school system and could attest to what was said and posted that historical day. So what DID we say?

On Thursday, February 13, 2003, my 10th grade Earth Science classes and I settled on 18-24" of snow for Baltimore by Monday. Observed by 2/17/2003 in Dundalk was 24" exactly, with 28.2" at BWI airport. Even if NOAA and the NWS revise those numbers downward in the 10-year climate data reanalysis, hard to argue with history.

# 3 - SEPTEMBER 2003 
 HURRICANE ISABEL: ORIGIN OF THE FIRST "FOOT'S  FORECAST" WHICH BECAME A LIFE LESSON.  The details of this story, and the February 2003 storm are related in a PowerPoint which we will post via a link in this section. A preview: Many coastal dwellers in the Mid-Atlantic, who had survived or heard tales of previous tropical cyclone impacts on the East coast, knew that someday, "the one" would take aim again. My family had a small and quaint cottage on the Elk River in Cecil County, and the property had been in the Foot name since 1934. On Saturday, September 12, 2003 we randomly turned on The Weather Channel, and saw a giant orange ball in the Atlantic  that was then Category 5 Isabel. I called my Aunt at the cottage and said, "We're coming up tomorrow to take pictures...because this is 'The One.' "   Stay tuned for the powerpoint...
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PRE-GAME UPDATE: SUN FEB 1 - 6:45 PM. There is much going both in atmospheric analysis and in the Foot household. I have reviewed some data, HPC discussion and current upper air 500 mb charts. There's no change to the forecast posted below, the game is still on, but I have one suggestion: send someone from your household to the store DURING the Superbowl. Why? No NWS office is anywhere close to raising a Watch, and today's false warmup will completely remove any suspicion of significant snow in less than 48 hours. This will not be similar to March 1993 as originally feared, but it could be quite a surprise to some on Tuesday morning! Especially those who plowed through their food supply at the ballgame party. Teachers: Lesson plan info posted, links to be added shortly, thanks for being patient.

KICKOFF STATEMENT: SUNDAY, FEB 1 - 6:45 AM. Welcome to the start of what may be a "Fabulous February" for powderhounds and storm watchers alike. Changes in official forecasts over the past 2 days demonstrate the value of relying on the laws of physics, because despite what mathematical formulas may project about the future, one must never abandon the most important source of data: reality. That being said, I believe that physics has turned in our favor. Result: the GAME is ON, and I'm not talking about that other game.

WEATHER AND IMPACT SYNOPSIS: Several upper level factors are converging on a solution that many on this site have been anticipating for some time:
(1) Deep tropical moisture ejecting from the East Pacific into the Gulf of Mexico (could this in fact be the arrival of the MJO Phase 1 that I never explained?)
(2) A negatively-tilted upper level trough over the Eastern seaboard US, due in part to a decreasing North Atlantic Oscillation, a slightly rising Pacific-North American Index.
(3) Several short-waves embedded in the upper level flow moving southeast from western Canada. These short-waves will travel the flow, and begin interacting with a surface low which has formed in the Oklahoma panhandle.

The combined effect of these three factors will use the Gulf moisture to moisten the surface low that was touched off by the short-wave. (6:45 PM update: I realize some forecasters are discounting the Gulf moisture, I but think based on even just general cyclonic can this moisture go anywhere but up into the flow. It's not just going to sit there. Indeed, I believe you can see it interacting with the flow already on the water vapor. )
6:45 PM clarifications: A new low pressure should take shape in the northern Gulf of Mexico Monday, and direct newly energized moisture into the upper level flow. With the base of the trough located over the coastal Mid-Atlantic, ANOTHER new surface low should form there as a reflection of the short-wave and incoming moisture. Just like an old Joe Paterno play, this low goes "straight up the middle" but in the process dumps moisture westward in doing so, partly because is caught at base of the trough.

Result: Slow-moving and localized coastal storm. Thus, my original forecast posted yesterday remains intact: Rain Monday mixes with and changes to snow, becoming heavy overnight before ending Wednesday. Liquid equivalents could be anywhere between .75 and 1.00 inches for much of the region. You can do the math to determine snow amounts. As for school, this scenario suggests Tuesday may have to be punted, but I would not put Wednesday on the bench just yet.

WHY THE BIG CHANGES? It has been hypothesized by Accuweather forecasters that an air traffic restriction over parts of Alaska due to an impending volcano eruption may have led to a gap in data. Concurrently, shortwaves that would be responsible for spawning the storm in the Gulf were moving across this area at the very same time. It is coincidence? Certainly other factors could explain the huge 300 mile shift in many computer models since Friday, but there do not seem to be any the NWS is willing to acknowledge. I guess we can just chalk it up to physics. Note to the analysis team: I am out today until at least 12:30 PM, so no updates until after that. So enjoy THIS game, and the "other one!"