Wednesday, January 31, 2007

WHAT GOES AROUND, COMES AROUND


No the wheels are not coming off the wagon. Yes I know, you've seen or read your latest TV or online forecast and are wondering "what happened to the storm?" Look, I forecast different than most others, because I'm going to make a call and stick with it. If it ends up being wrong, I'll explain the reasoning, admit the errors and move on. If you follow winter storms this time of year, you are no doubt conditioned to expect that forecasters will be non-committal about storms sometimes right to the onset of precipitation. This is happening yet again because there is tremendous disparity between a number of computer models on exactly what the 2 different low pressure systems will do once near the East Coast. The reason for this is a heavy reliance on the US-favored model, the GFS (Global Forecast System) and the recent moisture or "QPF" guidance from HPC (the Hydrometeorological Prediction Center). The GFS has been drifting back and forth with this storm for several days now, and with just ONE or TWO runs, now everyone starts to backtrack their forecasts. In reality, there is an equal chance the next two computer simulations (or "runs") will reverse that trend and you'll see everyone lean back toward a snowier forecast on Thursday, overnight and into Friday. I've seen it before and wouldn't be surprised if this time tomorrow night there's snow on the ground, and the local NWS (which has so far refused to go beyond a "Hazardous Weather Outlook" will be forced to raise a Winter Weather Advisory seemingly out of nowhere.

More importantly, for those who know some of the history behind this website, you should also know the most critical forecast model just completed it's on and only run for this storm earlier today: the FCFM. The results are in! The "Fruit Cup Forecast Model" (currently located at Sparrows Point High School in SE Baltimore County) predicts the following:

"Enjoy your long weekend." I am not making this up. The fruit cup has made it's case, and the science to me seems sound and credible. Forget the billion dollar government servers, I'm sticking with the fruit cup on this storm. We shall find out who wins soon enough. Next update Thurs AM.

Tuesday, January 30, 2007

WHEN THE MOMENT IS RIGHT...
WILL YOU BE READY ?

Feb Storm 1

Storm #2 featured above is just a prelude to what's coming later in February. Though I will end up one day off for the projected arrival time (original call January 13 was for Storm # 2 to occur in the 1/29-31 time frame), it will be nice to finally have enough snow to cover the grass.

I know you want the full story on this storm, but a brief update is all I can do for now until tomorrow morning and then more tomorrow evening. But here's what it looks like to me:

1. CLIMATE TELECONNECTIONS point to a coastal storm: The Pacific North American (PNA) Index is positive, the North Atlantic Oscillation (NAO) is in a negative phase but driftly slowly toward neutral. That as some of you know is a key indicator for me, because when the NAO (a measure of air mass movement in the North Atlantic Ocean) backs off from strongly negative, it means there will be sufficient, if not fresh, cold air available as a coastal storm turns north.

2. ALL ABOUT THE TIMING. For the I-95 corridor from DC to Philly, the timing of this is terrible for commuters but wonderful for students and teachers hoping on a snow day, or at least some kind of something to give you a little time off. The NWS has been backing the temps down all day for Thursday, off from a high of 40 to now just 34 in the Dundalk area. I use my town as a gauge because we are southeast Baltimore County, right along the Chesapeake just east of 95. If the forecast HERE calls for snow/sleet/freezing rain, you can bet the rest of the Baltimore Metro area will see all frozen precip and coming at just the right (wrong) time.

3. WHERE'S THE HIGH? Some of you know the old rule: "Predict the High and you predict the storm." Problem this time around is there won't be a High Pressure system in the right place (SE Canada or upstate New York) to deliver fresh cold air. Instead the high moves off the Mid-Atlantic coast Wednesday, and the storm arrives on leftover cold air Thursday. Combine that with the expectation this will be a fast moving system, and you can see why snow amounts will stay on the low side, and this may wind up more of an ice event for many than snow.

WHAT ABOUT SCHOOL? For DC/Northern VA area schools, it looks more likely you'll be closed Friday due to the ice potential. For Baltimore Metro schools, this will be a tricky call at two different times:

- Thursday afternoon: Precip (mostly snow/some frozen mixed in) will start after lunch and spread northeast. Travel will deteriorate from 1PM on. Early dismissal? Don't count on it, because I doubt the radar will look so ominous so as to suggest school officials should pull the plug at 11AM based on a projection of something that's 2 hours away.

- Friday morning: Considering what the map above indicates, this will be a tough call. For everyone along I-95 and then to the north or west, snow will probably mix with sleet and freezing rain for a few hours overnight, then change back to snow in the morning. We are not talking much more than 3 inches for anyone. In fact, I'm leaning closer to 2 inches for most areas south of Mason-Dixon given that mixed precip will lower amounts. The kicker will be that blob of green you see wrapping back around the storm. For many Maryland districts: Balt Co, Harford, Baltimore City, Anne Arundel and Howard, I can see a scenario where everyone calls for a 2 hour delay, then 15 minutes later says they will reevaluate at 6:45 AM. If that band of wrap-around snow starts up right at the time of "reevaluation" you'll see schools change to closed. This happened twice in recent years...January 4, 2003 (snow) and February 6, 2004 (ice).

Finally, what is the point of my headline? No it has nothing to do with Cialis. It means that this storm will present only a few precious moments where the right decision can be made quickly and easily. Official forecasts will probably flucuate more in the next 24 hours, driving you crazy when you're looking for consistency and there is none to be found. A special note of warning to my teacher colleagues: A lot of things have to come together just right for this storm to deliver a day off, so maybe the headline should really say: "If the moment is NOT right, will YOU be ready?" (for class on Friday).

Next update in the comments feature Wed 5:45 AM, followed by Pre-Storm Report Wed evening after 9 PM.

Tuesday, January 23, 2007

IF YOU WANT SNOW...
YOU'RE GOING TO LIKE THIS

Cold Blast 1

The following statement and maps are directly from the Climate Prediction Center, posted today (1/23) and is not edited or altered in any way. This agency provides routine hazard assessments for the country on 6-10 and 8-14 day projections. I found this particular statement elsewhere on the internet and had to locate the source before I felt comfortable bringing it here. But I find it interesting how forth-right and confident this prediction is for a government forecasting agency which rarely issues such headline grabbing hitters.


"SYNOPSIS: Repeated surges of cold air from Canada will overspread most of the lower 48 states east of the Continental Divide throughout most of the Assessment Period. With little available moisture in these Arctic/Polar air masses to work with, storm activity will diminish across the country during most of this period, although there is a chance for a significant wintry mix event across the interior of the Gulf and South Atlantic states sometime between Jan 31 and Feb 3, with a risk of heavy snow along the Atlantic Seaboard from Virginia to New England as this system turns northeastward. Several periods of locally heavy Lake Effect snows are likely due to the very cold Arctic air crossing the still mostly unfrozen lakes."

- Valid for the period Friday, January 26 to Tuesday, February 6.


BUT FIRST, WE HAVE TO HITCH A RIDE ON THE POLAR EXPRESS

Remember friends, I did promise you a "Very Fabulous February." It's nice to see that long range government forecasts are starting to move in that direction. But before the big blockbuster events of next month, some verrry cold air is going to park itself over the eastern third of the nation. Most of you know quite well that in order to have a good honking Nor-easter snowstorm, there needs to be a persistent and pervasive cold air mass in place well in advance of the storm. For now, it appears those elements are slowly coming together, and when they do, your patience will be rewarded.


Cold Blast 2

ABOUT THE FREQUENCY OF POSTS: Until January 30, I will be generally either preparing, issuing or grading midterms and quarter grades. This is the last post until after I have turned my grades on time, so I'll see you all back here on the 31st and we'll find out together if this projection pans out.

Sunday, January 21, 2007

MIDTERM MAYHEM...RIGHT ON TARGET


For those true old-time powderhounds of the Foot's Forecast community, this weekend hold special meaning for us in several regards. Number 1..it is the Dundalk Adventure Club's traditional weekend ski & snowboard trip to the fabulous mountain resort of Seven Springs in Somerset County, PA. That's the reason behind no posts since last week, so for all those who felt dissed or ignored, it's not you, I was simply busy skiing with students on fresh powder. Sorry, when duty calls, I have to respond, no matter how challenging or unpleasant the job may be (sike.) Now in all fairness to my frequent readers, I owe you an apology for the last post. Some had asked what happened to the storm update that was supposed to follow the maps I displayed 1/18. I can tell you it existed for a short time on my computer. During breakfast that morning as I am trying to feed my two little angels, and get the forecast uploaded, and make my wife's coffee, I must have erroneously hit some key and shazam! update deleted! It's been a maelstrom since this is my first time on a keyboard since Thurs AM. Sorry that got lost, but at least it wasn't for a real big storm.


Number 2...it is the second Anniversary of the Great New England Blizzard of January 2005, which I bet will always live in the memory of Mr. EH Boston as the best snowstorm of all time for his family.


Number 3...if measureable snowfall occurs at BWI airport in the next 24 hours, it will be my first forecast victory of the season. January 13 I targetedthe time period of the 22nd to the 25th for the first snow, and sure enough, here it comes.


A SPECIAL REPORT FOR BALTIMORE METRO AREA READERS

For those school districts with high schools scheduled to hold midterms this week, it appears the Monday 1/22 exam program will be disrupted in some manner. Before I depart Seven Springs this afternoon, I will post an overview of my projections for this minor but noticeable winter weather event. For all those outside the Baltimore Metro area, please excuse my lack of attentiveness to your weather situation, but time constraints prevent me from going into extensive detail on this storm. I can tell you that the eastern third of the country will reall go into the deep freeze following this storm and stay that way from the 23rd right on through to the 6th of February.


CAREER PROTECTION DISCLAIMER: Since my wife and I are blessed with wonderful jobs that truly we enjoy (I am not being sarcastic), in no way should any forecast, comment or statement about my employer (Baltimore County Schools) be misconstrued as critical in nature. I am merely providing analysis to educate readers in the affected areas of a weather event as to how difficult the decision making process can be for school officials. This is so when someone wants to complain about why school was open or closed due to the weather, we can give them reasonable answers grounded in scientific fact.

THAT HAVING BEEN SAID: The challenge of this forecast for those in the Baltimore Metro Schools and surrounding counties is that the northern fringe of this storm SHOULD be mostly snow. A light coating of snow up to perhaps 1.5" south of Towson will be easier to deal with than if freezing rain and sleet mix in, glaze over secondaries and sidewalks, then a light dusting of snow on top of that. From Towson on north, expect only light snow and flurries. Anyone north of Philly, sorry. You'll wait out this one.

The tricky part is going to be when the precip arrives and how long it stays. If it ends prior to 1AM, that gives road crews a few hours to prep main roads and start working on secondaries. If by 4AM, the snow is continuing, albeit light in nature, and temperatures in the mid 20's, the morning commute will be difficult and I would anticipate a delay. We have most of the elements in place..cold ground, a moistening atmosphere and a slow moving system that will graze the DC-Baltimore areas. The general rule is, farther south you are, the more you will receive. The unknown is if your precip will be mostly snow, or a mix of frozen fun that cuts down on snow accumulation but increases the mayhem. We are departing Seven Springs now as it is already snowing lightly so we are going to head out early. The next update this evening once I am home safely.

Thursday, January 18, 2007

WHAT DO YOU EXPECT?...
IT'S A GLOBAL WARMING WINTER
What else can I say...but welcome to your future. For those of us who love frolicking in snow and seeing the sun rise and set over a crisp white landscape sparkling with little twinkly crystals…you’re in the wrong country from now on. The media loves to blame our recent warm weather on El Nino, and that’s a nice easy answer for a less-than-patient public. It is also the wrong answer in my opinion. Previous El Nino winters which had readings very close to this year did not produce the long warm spells we have seen across the country. A close match for current conditions is the winter of 02-03, which featured a weak to moderate El Nino ( a seasonal warming of Equatorial waters in the East Pacific of .5 to 1.5 degrees C over a period of several months), but instead of weeks of warm weather, my school district (Baltimore County, Maryland) had 9 snow days. If we use that some unscientific data set, my district has seen our snowday count the past 5 years drop from 9 to 4 in 2004-05 to just 1 last year. Do you think there is any correlation between that and the well-known fact that the important “September Arctic sea ice” count has decreased every year for the past 4 years. Each September NOAA makes a comprehensive assessment of the amount, thickness and extent of floating Arctic sea ice. Each successive year since 2001, the measure of this ice has decreased, which means this September, there was less Arctic sea ice than last September, and so on. Two images from the Earth Observatory System Satellite:


Arctic Sea Ice

The theory as it relates to snow cover and weather in the United States is simple. As the amount of ice in the Arctic circle decreases, it leaves behind a larger and larger area of darker water, which continues to absorb more of the sun’s energy. This in turn warms the water, the adjacent coastal areas as well as the low atmospheric levels above the water. In fact, since 1970 there has been a decrease of roughly 670,000 THOUSAND square miles of Arctic sea ice. Don’t you find that significant? Wouldn’t it seem plausible that with the Arctic losing more and more ice each year, it becomes increasingly difficult for the Ice cap to provide the “cooling effect” it does on the planetary climate patterns. Continental Polar air masses (read: High Pressure) in turn take longer to become the customary “Cold Canadian Highs” that charge southward in our winter because there is less ice providing a cooling effect on the air. The air simply takes longer to cool down, and the effect in increasing, perhaps geometrically.
So what WE in the U.S. are seeing is the results of that effect: A prolonged fall interspersed with warm spells, and a significant delay in the traditional arrival time of winter-like weather. Since the Arctic is not providing the influx of cold air from the Northern jet stream, and El Nino is weak to moderate, IT becomes the more dominant factor, but NOT because El Nino is simply "so strong it is controlling the weather pattern." My take on this pattern is that the lack of cold air has ALLOWED El Nino to take a larger role for a longer period of time because the customary "clash" of air masses this time of year has been delayed for at least a month.

OKAY FINE, OUR WEATHER IS BEING INFLUENCED BY GLOBAL WARMING. THANKS FOR CLEARING THAT UP, AS IF I DIDN'T KNOW. So what about the snow already?

Oh yeah, I was going to do some analysis of that on here sometime. Here it is:

Storm # 1: Projected for the January 22-25 time frame. Computer models continue to advertise some kind of Tennessee Valley system moving to the coast, which a moderately cold High placed to the north. Not the perfect setup when you consider the NAO is going Negative and that will tend to push storms more to the south. The following set of graphics are three models that indicate what is anticipated for 7AM January 22. First,the GFS:

1-22-07 GFS

You can see the 540 thickness line (a good indicator of the general rain/snow line) is right over DC. Sorry Boston, this one will more than likely miss you altogether. Next the JMA:


1-22-07 JMA

What's significant about these two maps is they both show a storm reaching the Mid-Atlantic coast fairly juicy with a potential for rapid development once there. The culprit for this lies with the sea surface temperatures in that same area.

1-10-07 East Coast SST

Saturday, January 13, 2007

START YOUR ENGINES

for the Mid-Altantic and Northeast
Storm # 1
Target time: January 22-25.
Storm # 2
Target time: January 29-February 1
Data and analysis to back up this forecast in progress..post expected early Thursday AM.