Sunday, February 25, 2007

"SUPPOSE YOU'RE WRONG THIS TIME?"
-Comment made by Kenneth Welsh, playing the Vice President in Day After Tomorrow to paleoclimatologist Jack Hall, played by Dennis Quaid when he suggests the climate is changing.

2:30 PM Update - SUNDAY 2/25

If you reside in the Mid-Atlantic area near the DC-Baltimore-Philly Metro areas, obviously what you see out your window would indicate a few changes to the forecast are in order.
And you would be correct. First, the current radar:

Surprise Snow on 2-25..at least it's not ice


The unexpectedly heavier snow is occuring due to a couple factors. The wedge of cold air was more entrenched across the coastal plain than computer models had indicated. Despite overnight temperatures not falling to far, the orientation of the airmass was more widespread in a north to south arrangement (along the East Coast) than in the East-West setup in the Valentine's Day Storm. As a professional meteorologist dutifully noted in the chat feature last night... we were concerned about the marginal aspect of surface temperatures. He made a point that has rung loud and clear today. Upward motion. The strong onshore flow into the Northeast and Mid-Atlantic caused by the tandem combination of the decaying Midwest low and the High pressure ridge setup from Canada down to the south east provided ample moisture. For simplicity sake, let me explain it this way by saying Atlantic moisture is riding in along the coastal plain, striking the pervasive dome of "cool" air, (not really cold) forcing it upward quickly.


The moisture then falls through the cool air at upper levels, crystallizing into snow. As it falls, the snow slowly evaporates, creating what I discussed yesterday...evaporative cooling. This in turn chills the atmosphere and brings the air temperature near the surface "down with the snow." It is a perfect example of micro- to mesoscale atmospheric dynamics. Proof is in thermometer at your house..dropping all day when climatology this time of year suggests sun angle among other things should send that temperature up. The result? A chilled air mass which can produce a hefty amount of snow in a short time even during maximum daytime heating, overcoming subpar temperatures at the surface.


HOW LONG WILL THE SNOW LAST ?
WILL A SECONDARY LOW FORM ALONG THE COAST ?


Surface Observations 130 PM 2-25


Review with me the current surface observations from Penn State's e-Wall. Notiee position of that teensy high around the Delaware Bay? I think that's inhibiting development of the secondary. You cannot have a surface Low forming in the same place as a Surface High. That's the Theory of Reciprocity, right Physics teachers? There can be an upper level low contaminating a surface High, or a weak Low next to a weak High, but not both in the same place at the same time. Momentum from the eastward pivoting dry line behind the cold/occluded front associated with the maturing Midwest low is simply flushing all the moisture to the coast. There it meets enhancement from Atlantic moisture being sent onshore by the double-barrel nature of air flow around both pressure systems. (Counterclockwise for the Low, clockwise for the High). So where is the Secondary Low to form? If it does, it will probably be weak, and have little or no effect on the final outcome of the precip in the Mid-Atlantic right now. Perhaps it will form under the High somewhere in North Carolina, but certainly not along the DelMarVa coast, at least not until pressure falls can indicate the High has decayed enough to allow for a pressure difference.


THE SNOW? WELL, THE BAD NEWS IS IT WON'T LAST LONG. Once that sharp back edge works it's way to the coast, that's probably it for those of you in northern/central Maryland. Redevelopment of a secondary isn't going to happen quickly enough to wrap a lot of energy back around and keep the snow going....there's too great of a north-northeastward motion for that I think. Energy for an explosive coastal low has basically been sapped out. What about the freezing rain that was originally predicted? That may still happen, but I am thinking not anywhere to the extent that was first believed, which is a good thing. There are still many nuances yet to uncover in this drama, and I may have to come back and re-unexplain myself if it changes again. Just remember the headline up top.


BUT THE REAL ANSWER YOU WANT TO KNOW: SCHOOL ON MONDAY?
If snow ends this afternoon, and air behind it is not cold or below 32, and DC-Baltimore metro areas get cut off from the High pressure source region, I could see this snow starting to melt right away. Crews would have many hours to clean up, overnight temps are not projected to sink into the 20's regionwide, all of which makes me lean towards a delay rather than closed for many schools in affected counties of Maryland.

I'll take a look at things again later this afternoon after I get some snow cleared off the sidewalks. Enjoy it now while it lasts. This time of year it'll start falling off the trees quickly and become clumpy and wet before long. If you have a digital camera, snap some nice pictures from your area and I'll be introducing a photo sharing feature on here using flickr.com (that is.. if school closes tomorrow!) Meanwhile, our weather spotters across the land of education... I guess it's time we start the traditional scientifically based speculation on school tomorrow. What are your thoughts on it?

"BABY, BABY...
LOOKS LIKE IT'S GONNA HAPPEN."
-artist and title unknown, maybe the Stray Cats?

The Sickest radar you've ever seen


Ready or not, here it comes. With a projected liquid equivalent of anywhere from .5 to 1.25 inches, this will be a juicy event for Maryland, Virginia, the Del-Mar-Va, Pennsylvania and New Jersey. Be sure to check your local NWS sites for changes in the advisories. I have no major changes to my forecast except to say that temperatures today will determine extent of frozen vs. liquid precip. If northern Maryland receives the widespread icing indicated by NWS, (up to 1/2 inch freezing rain) then school Monday is in jeopardy for those areas (Frederick, Carroll, Baltimore, Harford, Cecil counties). More information later. Please post your observations in the comments or the storm chat center. I will not be able to participate in either until this afternoon, so will talk to you all then.


Special note of thanks to Mr. B in Greencastle, PA for providing this link to the neatest looking radar program I've ever seen, the image above of which is a capture from this morning. Bookmark that one for sure and I'll be adding it in the links soon.

79 comments:

Linda said...

Good Morning you all! Local weather says 3 to 6 inches in Bucks county, while the weather channel says 1 inch. Also ice. I don't quite know where I am situated in all this, but I am sure to find out soon enough. According to local news I am situated in major storm catagory.

kristine said...

Linda-
Where are you inucks County? My family is in Montgomery County and I went to college in Kutztown...

kristine said...

Sorry- that was Bucks County...

E.H. Boston said...

Hey all...

Still trying to get acclimated to this time change. Last night I fell asleep at 7 and woke up this morning at 3:30. Gotta love it.

Looks like this storm will be a mostly miss for my area. Maybe way down south in SNE will see some "good" snows, 3-5"...

Since I'm outta this one, hoping all of you get all the snow and ice you can handle.

Linda said...

Right outside of Doylestown. Jamison.

kristine said...

ok...I grew up in Lansdale...very close to Doylestown.

kristine said...
This comment has been removed by the author.
Mr. Foot said...

Good morning(afternoon) EH..

What a flop of a winter so far. What do you have up there, 8" max. Incredible snow drought compared to recent years, huh?

No precip in Dundalk though radar is looking impressive.

37 up 2 deg from early this AM.

wvmommyof4 said...

snowing with 3 1/2 inches on the ground so far. temp is 31

Katie said...

Beautiful light fluffy snow covering the ground in Silver Spring! I wish it wasn't supposed to change to a freezing rain mix later...

Mr. Foot said...

Holy smokes mommyof4, you are hogging all the snow out there! Mr. B that should be an indication of what you'll get.

E.H. Boston said...

At my house in Woburn...I've recorded a meager 10.5" for the entire season so far...

Boston's Logan Airport I think just surpassed the 4" mark for the season.

If BOS breaks 10" for the season, that will be a MIRACLE!

Least snowy winter I think is 8".

We may come close.

Mrs. Burke said...
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kristine said...

10:15- snow has started...

kristine said...

oh yeah- that would be in Sparks..

Russ said...

Just started in Perry Hall. I've been checking on capitalweather.com and those people down in that area say they are getting heavy to moderate snow. Capital weather gus are saying Montgomery Co. could see 4-8"? Mr. Foot, could this be the same for us? What's happening?

terpguy said...

1046 local-33.4F


...it beginneth.


Fallston

TQ said...

Keep track of surface data from COOP observers, various State Departments of Transportation, and METARs @

http://www-frd.fsl.noaa.gov/mesonet/?center_lon=-78.255¢er_lat=39.22467&scale=220

Set 'Show Special' to 'show values.'

Set 'Overlays' to 'Geopolitical,' 'US counties,' and 'Airports.'

Click on a station to see observation history.

Mess around with slider bars at bottom of display to increase / decrease station plot density.

Parent URL:
http://www-frd.fsl.noaa.gov/mesonet/

Newton said...

Snowing nicely here in Bel Air with 33.6 F on the old thermometer.

DerbsATerp said...

12:15 here in College Park, temp around 32, snowing rather heavily right now, grass is covered underneath the trees.
Looking like a fun walk to see the Terps beat UNC.

terpguy said...

1233 local

About 0.5" so far, temp down 3.4F (to 30.0) in 105 minutes.

cgoodnight said...

29* here in Fells Point, snowing since 10am, about .5" on the deck, roads mostly wet.

ScienceGuy said...

Hey Chad!

Still snowing here in Bel Air, but it can't last. Where is the changeover to sleet and freezing rain?

wvmommyof4 said...

7 inches of snow in Inwood WV. The snow is now mixed with sleet.

Mr. Foot said...

I am blown away mommyof4. You must have been in the dark blues there a while. Would rather have the snow than anything else though.

To all..I was at church from 10:45 to 12:30, figures things would change during that time.

Am working on an update now. No hype, just some thoughts on why the change. Don't get too excited about school closed tomorrow, not yet. Issue is roads are just wet and there's a lot of heat to be given up still despite what your temp is at home. Let's see what overnight trends bring.

chip said...

Hi all, a little over 2 inches of snow in Towson so far, and continuing to snow pretty steadily. NWS pulled back from Warning to Advisory this morning, but as of now, they have gone back to Warning, saying 3-6" and also ice possible. Any thoughts on school tomorrow, Mr. Foot? My knuckles aren't itching much, so I think we will be in school...

Chris said...

I'm in Hereford and we have about an inch and half covering our driveway and it is still coming down steadily. So what do you think are we getting a delay/ will we be off. I wouldn't mind a Hereford Zone.

Linda said...

Not doing anything here yet. 32 and am waiting with baited breath!!

Chris said...
This comment has been removed by the author.
Chris said...

Hereford is up to 2+

Julee said...

Mr. Foot

I 'Comcasted" you a photo of the (unplowed) main road where I live.
Still snowing hard ... cars driving sloooooooooooooooooowly.

Mr.S said...
This comment has been removed by the author.
runner said...

Check Accuweather for Parkton, MD. Seven inches possible. Snowing madly now in Shrewsbury. I'm still completing essays and interims for tomorrow, nonetheless. I even went to Wal-Mart to buy supplies for my classes tomorrow. It just doesn't seem real because of the lack of hype and anticipation on this one!

Mr.S said...

Well it's definatly interesting outside. Down here in AA county we're closer to the 3.5 inches already, and still coming down strong. I was just out running some errands and the streets were horrible, no plows out yet. When I got home I shoveled the driveway, and in 15 minutes it is already covered again. I hope it stops soon and doesn't change over to ice. Rain would be good b/c then it would melt all this, as long as it doesn't freeze overnight.
My predictions for tomorrow, AA county closed (being announced tonight on 11pm news), Balt County open on time, with Hereford Zone 1hr delay b/c it's Hereford. So Mr. Foote I'll see you at work tomorrow. I also sent you a pic of my neighborhood down here in AA County. I sent it to your email.
Mr. S

Richard said...

EXPECTING LOTS OF SNOW AND ICE HERE

runner said...

OOPS, NOAA.gov has the 3-7 inch prediction for northern Baltimore County, not Accuweather. I'm thinking about the offshore low --that's probably accountable for the prediction into the evening. I'm so sick of running on a treadmill. The NCR trail is my tonic, so I have mixed feelings about all this. Snow days are nice, but I miss my trail miles!

cgoodnight said...

Temps steady at 29* in Fells, just got back from Patterson Park with Lily, and we have about 1.5", only had .5" when we left here an hour and a half ago. Reminds me of home... Amazingly there were no kids sledding on this perfect snow! Stupid ghetto kids sled on ice, and snow that brushes away, but not on the good stuff!

cgoodnight said...

ScienceGuy, are you Tom M.?

chip said...

Just checked WBAL, and Tom T. or whoever is saying 4-8" and not stopping until tonight, maybe even late tonight. Mr. Foot, you're seeing the precip stopping earlier, and temps getting high enough to melt? Another site, I think Weather.com, said lows tonight around 31, and highs only 38 tomorrow... well, all this science aside, the lack of itchy knuckles tells me that the best I can hope for is a delay.

Julee said...

Weather Channel and NWS still predicting freezing rain for tonight until 4 a.m.
WHAT?

runner said...

The HZ will definitely be below freezing tonight. Remember, Tom T. makes predictions for the city. I always take about five degrees off of that for a Zone prediction. Meanwhile, I'm all over this site with a stack of essays to grade in my lap!!!!!

Chris said...

NWS still saying 5-10" and saying we should get freezing rain till midnight. Plus there saying its going to be cloudy and stay right around or below freezing. I would think there be at the very least a lot of issues on bridges and overpasses.

Chris said...
This comment has been removed by the author.
runner said...

Five to ten? There'll be issues everywhere with five to ten--not just bridges and overpasses!!

Chris said...

I realize that but when we are talking about melting and road temps it could make it easier to clean up the roads but you still have the cold air under the bridges and overpasses which will make them more of an issue

Linda said...

Finally SNOOOWING!!!

Mr. Foot said...

Sounds like lots of inconsistencies with the models and predictions. 4-8" that would be over the top. I have to get some clearing done before my neighbors do it all. Be back later.

Rachael said...

here in ellicott city its 30 and there is A LOT of snow i just had to shovel
while i was out there freezing rain was starting as well
that was within the last 30 minutes

Mr.B said...

Hey guys come over to my page while Foot is away. It's the Mr. B page on foot's friends. I have a chat at the bottom of the home page.

Julee said...

Snow stopped about an hour ago in Pikesville.
As if on cue, everyone came out to shovel ... but if there is going to be ICE, I'd rather clear ice-covered snow off of my car than chip ice.

Uh OHHHHHHHHHHHHHH ... what is that PLINKING noise I'm hearing??????

Anonymous said...

Sleet just hit the window... and now raining...

Mr. Foot said...

I've read the newest WSW from Balto-DC NWS. 5-10"?? Okay. I don't think so. That moisture plume is going to miss us to the SE. I would love to see it hit, we'd have another 5" quickly. But I just don't see that happening. Look at the radar, you can tell the vectors of that dry slot are NNE and there's not enough moisture to Baltimore's SW to warrant accums up to 10"

Now in Philly that might happen. Areas east of the Bay up to NYC could get hammered.

From here on out it is sleet/fz rain south of the Mason Dixon Line, and light amounts at that.

Mr.S said...

Well it stopped snowing at about 3:15 down here in AA county. There was a nice quitness for a while, then everyone came out and started shoveling. A few kids were sledding down a hill out front. Then at about 4:00 I heard that plinking on my windows like Julee heard. That's right we have a mix of sleet and rain. Large pellets of sleet though, about the size of a pencil eraser. I remember how long it took to shovel out after the last storm with the ice on top of the snow. No thank, I'm going out now, gonna shovel, then lay some salt down.
Really hope that weather.com is right, they're saying temps will get up to 35 tonight for both Dundalk and AA county.

TQ said...

At 4 PM...secondary development can be observed over eastern NC.

http://weather.unisys.com/surface/sfc_con_3pres.html

Eta takes this nascient LOW to the Delmarva by 06z.

terpguy said...

Mr. F-

done!

TG

manda said...

do you think there could be a HEREFORD ZONE closed day tomorrow? because that would be amazing!

Chris said...

Things here in Hereford are winding down we have switched over to freezing rain but it is very light ceasing at times. I think we'd be lucky to get a delay this storm just came to early.

Mr. Foot said...

It is getting icy in Dundalk. Temp about 31. I just salted the heck out of everything, and 2 hours later it is a slippery glaze. What say ye in the north of BCPS?

kristine said...

Northern BCPS...freezing rain here...side roads are plowed and salted...cars seem to be driving ok...I am thinking at least a delay because it will most definitely ice over...well at least I will keep my fingers crossed for at least a delay...

chip said...

Hi Mr. Foot and all! I teach in the Hereford Zone, but live in the Towson area, so I am interested in any input from folks on the ground up in the Zone. At 6:30 here in Towson, it seems to be a light freezing drizzle. Ice forming slowly on cars, but I am not sure if it is icing up on roads or the ground. I think it is below freezing here now. Are temps going up tonight, Mr. Foot, so as to melt stuff, and prevent ice? Or are we looking at icing up/re-freezing? We await wise words...

runner said...

Very icy in southern PA (Shrewsbury) with freezing drizzle falling. Temps are predicted tonight to be in
the high 20's, and you know much more about the off-shore low (or lack thereof) than I do. I'd say the morning could be tricky all the way around. Probably a delay. My interims are an hour from completion. I'm not taking any chances, but my whole 'hood is icy.

Chris said...

I am a Hereford High School Student and I live about 5-10 minutes north from the school. We have freezing rain on and off. The roads are still a little slushy and everything seems to be getting a nice iced glaze to it. I think a delay would be a safe bet if the freezing rain keeps up.

Mr. Foot said...

Here's a good graphic of regional temps. Don't get scared by the slug of warm air, it's been there a while and hasn't moved.

http://nws-sc.met.psu.edu/wxobs/curtemp/region_temp.gif

In a normal storm, skies clear and everything is plowed and dried up. This time, lots of leftover moisture and dewpoints still high... no no drying up, and refreezing likely.

Julee said...

Okay Mr S ... you made me think about the whole snow-ice/ice-snow thing so I cleaned off the car.

Scraped those windows CLEAN as a whistle, and when I was finished, they were were all iced up again. Grrrrrrr.
Scraped them again ... same thing.
So I quit THAT exercise in futility.
Then I cleaned off the front steps and THEY iced up immediately.

Je suis FINIS!!!!!!

runner said...

I'd bet on at least a one-hour delay all around. Considering last week's HZ delays, I noticed that the one-hour delay, while seemingly insignificant, allows for students and busses to be on the road in the light. If we were to face these icy conditions in December or January, we'd probably have two-hour delays for the shorter hours of daylight. It makes sense; the light allows drivers and walkers to distinguish between black ice, salt, and bare road. If transportation officials decide to wait for some melting, I'd predict a two-hour delay. Otherwise, a one-hour delay. This reminds me of bitter cold stormy mornings in West Virginia thirty years ago when my brother and I would study forecast models and make predictions about school. How did we ever do it without the internet? We'd listen in the dark to WKAZ Charleston. Guess the name of one of our young meteorologists just starting out. That would be Tom Tasselmyer, Operation Snowflake, Charleston, WV!

Anonymous said...

I am sure hoping for a delay since the snow plow just socked me in... :::grumbling::: gonna need extra time just to dig myself out!

Mrs. Burke said...

Hmm . . . Light freezing rain at my inlaws in Kingsville.

2 hour delay .... in Harford County? It would be nice to sleep in tomorrow! I can make myself a lovely breakfast!

Of course, we certainly won't know anything until 6:30 when all of us teachers are already awake, showered, dressed ... etc. But that's cool :)

Anonymous said...

Mr. Foot,

The heavey snow has now turned to light sleet here in Philly. Any predictions that the Philly area may still get up to ten inches? I hope so!

Your site is the best! Thank you so much for keeping all of us informed!

wvmommyof4 said...

Berkeley Co. is closed tomorrow as well as Loudoun Co. Virginia!!!

Russ said...

I think everyone has forgotten that the grounds crews may have not touched anything tonight. I know for a fact that each crew has between 8-11 schools to clear and that does not include all the trailers that need to be cleared, and they are done by hand. If this freezing rain continues tonight it could be an interesting call. By the way--Maryland--89 NC--87

elevation said...

Road is pretty clear up here in N. HarCo where I live. But I do live on the same road as a school, so I don't know about everywhere else.

Ed-ETHS said...

Perry Hall High School parking lot is a mess. No BCPS trucks are in sight. As for delays, I suppose it depends on how the temps hold overnight.

It's been 30.4°F in P.H. for the last four hours.

chip said...

Hi everyone, I just saw on WBALTV's Closings page that Boys Latin is delayed 2 hours tomorrow, as is Gilman school, which means that Bryn Mawr and Roland Park are delayed 2 hours also (they coordinate schedules). If schools in the city are going with a delay, I would hope the Hereford Zone, at least would be considered for a delay. There is about 1/8" of ice on the cars outside here in the Towson area. The roads seem to be in fair shape. Will we get much re-freeze tonight? What do you think, Mr. Foot?

terpguy said...

Steady rain, 31.6F here in Fallston. 2046 local.

chip said...

I agree that taking care of school lots and sidewalks is going to be a pretty big factor. Any other observations of school properties being cleaned or not?

Ed-ETHS said...

Well, just checked the radar - all ugly green. I guess that means our thin layer of subfreezing air is eroding away. Maybe those of us south of the Hereford zone should plan for a normal day(?)

Mr. Foot said...

I'll be signing off early tonight, hoping to catch up on lost sleep of late. Here's my final thoughts for the night, as in likelihood of the event as it pertains to schools in Maryland:

Closed:
Frederick, Carroll, MontCo, SE PA (York Co)

2-HR delay most likely:
Cecil, Harford, Anne Arundel

1-HR delay most likely
Balto County, Balto City

Open on time:
Most colleges and universities, including JHU

Open 3 hours early to compensate for Valentine's Storm:
Howard County

Overall I like and agree with runner's statements earlier. For the larger county systems like BCPS, a 1-hr delay makes sense if temps do not fall to much overnight and roads are just wet.

If you all wake up to a Krispy Kreme Glazed Supreme, then 2-hr delay. If the daytime highs are knocked down considerably to mid 30's and limited sun, and that glaze is still there, slight chance of being closed,or put it this way:

50% chance of 1-hr delay
30% chance of 2-hr delay
20% chance of closed

That's how I see it, I think Politics and Science win this one.

See you all in the AM for an interesting run down of reports. You know I realized just the other day that Maryland area school have generally not had 1 full 5 day uninterrupted week of school since Mon Jan 8. That's 6 weeks of shortened weeks in some manner, and the trend will probably continue tomorrow morning.

G'nite!

Mr.B said...

Nite. Anyone that wants to come over to my chat on Mr. B's page. Fill free to do so. I am on all the time. LOL

Anonymous said...

Mr. B's chat is same as Foot's! Fun and informative!