December 16/17 threat

[EasternUSWX]

SNOW IS EXPECTED ACROSS OTHER PORTIONS OF THE OUTLOOK AREA DURINGTHE DAY THURSDAY. A WINTER WEATHER ADVISORY MAY BE NEEDED FORPORTIONS OF THE WASHINGTON AND BALTIMORE COMMUTING AREAS.

http://forecast.weather.gov/showsigwx.php?warnzone=MDZ003&warncounty=MDC043&firewxzone=MDZ003&local_place1=Fairplay+MD&product1=Hazardous+Weather+Outlook

[yoda]

Yay

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC

825 PM EST WED DEC 15 2010

DCZ001-MDZ009-010-013-014-VAZ042-053-054-160930-

/O.EXB.KLWX.WW.Y.0025.101216T1500Z-101217T0200Z/

DISTRICT OF COLUMBIA-MONTGOMERY-HOWARD-PRINCE GEORGES-

ANNE ARUNDEL-LOUDOUN-FAIRFAX-ARLINGTON/FALLS CHURCH/ALEXANDRIA-

INCLUDING THE CITIES OF...WASHINGTON...GAITHERSBURG...COLUMBIA...

ANNAPOLIS...LEESBURG...FAIRFAX...ALEXANDRIA...FALLS CHURCH

825 PM EST WED DEC 15 2010

...WINTER WEATHER ADVISORY IN EFFECT FROM 10 AM TO 9 PM EST

THURSDAY...

THE NATIONAL WEATHER SERVICE IN BALTIMORE MD/WASHINGTON HAS

ISSUED A WINTER WEATHER ADVISORY FOR SNOW...IN EFFECT FROM 10 AM

TO 9 PM EST THURSDAY.

* PRECIPITATION TYPE...SNOW.

* ACCUMULATIONS...1 TO 2 INCHES.

* TIMING...SNOW WILL BEGIN BETWEEN 9 TO 11 AM THURSDAY MORNING AND WILL

CONTINUE THROUGH THURSDAY AFTERNOON.

* TEMPERATURES...LOWS IN THE TEENS TONIGHT. HIGHS IN THE MID TO UPPER

20S THURSDAY.

* WINDS...LIGHT AND VARIABLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE

TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY ROADS AND LIMITED

VISIBILITIES...AND USE CAUTION WHILE DRIVING.

&&

[weathercoins]

Prediction: they extend WWA to Baltimore by morning with the "possibility of 1" during commute" rule.

[yoda]

21z SREFs are in. Pretty much locked in to where 15z was. Very little, if any movement as far as I can tell. 0.25 line probably just north of EZF. 0.1 line straddles Mason-Dixon Line

[yoda]

Prediction: they extend WWA to Baltimore by morning with the "possibility of 1" during commute" rule.

Unlikely. The snow will start after morning rush is done. 10 AM is after rush hour in the morning

[wxmeddler]

Unlikely. The snow will start after morning rush is done. 10 AM is after rush hour in the morning

If I read the AFD right, I think they were considering it for the afternoon commute.

[yoda]

If I read the AFD right, I think they were considering it for the afternoon commute.

Yes, but this WAA is issued for the day tomorrow. So it means WAA criteria were reached instead of the Afternoon Commute WAA rule

[wxmeddler]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
254 PM EST WED DEC 15 2010

.SHORT TERM /THURSDAY/...

-- Changed Discussion --THE LOW WL TRACK NEAR THE VA/NC BRDR ON THU...SPREADING MOISTURE
INTO THE CWA. THERE MAY BE A SHARP SNOW CUTOFF IN THE CWA...W/
CLOSE TO THE MASON-DIXON LN RCVG LTL TO NONE. HIGHLAND TO
NELSON/ALBE LOOKS TO RCV THE MOST SNOW...UP TO 4". GREENE TO ST.
MARYS SHOULD RCV 2-3". DC METRO UP TO 1". BECAUSE OF THIS WE`VE
ISSUED A WINTER WX ADVSRY FOR THU WELL S OF DC. IT MAY BE THAT A
"1" FOR THE AFTN COMMUTE" ADVSRY MAY BE REQUIRED FOR THE GREATER
DC AREA...BUT THAT WL BE A LATER ISSUANCE - EITHER ON MIDNIGHT
SHIFT...OR PSBLY EVEN ON THU MRNG. SNOW FM THIS SYSTEM WL END
QUICKLY - LATE AFTN/ERLY EVE IN THE HIGHLANDS TO MID EVE IN LOWER
SRN MD.-- End Changed Discussion --

[WinterWxLuvr]

Just checked the NWS. Frederick and Clarke, only counties in Va. not under WW advisories. I swear to god, these guys do this sh*t just to tick me off, I think. Joking. But this is just like last Jan 30 in that regard. Anyway, good to see the latest trends.

[notvirga!]

@winterwxluvr: I hear u! They did this to Fred co two or three times last year. Seems to me we ended up with adv crit or warning criteria each time.

[WinterWxLuvr]

Just a couple of observations. Satellite looks like the NE vortex is sliding out of the way nicely, no precip yet falling east of about the IND-ILL state line. This thing seems to be packing some warm air at some level. 9 PM surface obs reveal rain or freezing rain pretty far north, such as St. Louis, with snow falling once you get up to about the lat of INDY.

[Dr No]

The ground tempatures may be too warm for good accumulating snow since it falls during the day.

[Riptide]

yeah, and look at TN

what's with the zr and mixed precip there?

I thought they were all snow on the models

http://www.weather.g...prodtype=hourly

It could be evidence that the Northward trend isn't done yet. I think CAD will help out many locations east of the apps. I'd be surprised if places north of a line near Richmond experience any mixed precip.

[EasternUSWX]

The ground tempatures may be too warm for good accumulating snow since it falls during the day.

As DT would say, you are inept. The ground is solidly frozen and it's only going to be in the 20's.

[Dr No]

As DT would say, you are inept. The ground is solidly frozen and it's only going to be in the 20's.

[mitchnick]

I posted this in model thread

NAM qpf:

IAD-.15"

DCA-.17"

BWI-.14"

a bit surprised how similar they are

2-3" with decent ratios possible?...2" yes, 3" I doubt

[Dr No]

Dendrites!

7 700 2856 -9.0 -10.0 92 1.0 -9.3 239 30 292.6 293.0 281.4 300.2 2.56

8 650 3428 -10.8 -12.0 91 1.2 -11.2 252 37 296.8 297.2 283.0 303.9 2.34

9 600 4041 -12.1 -13.5 90 1.4 -12.5 265 56 302.1 302.5 285.0 309.1 2.25

10 550 4704 -14.8 -16.3 89 1.4 -15.3 264 75 306.5 306.9 286.3 312.8 1.95

[yoda]

http://www.weatherof...SIC@012_024.jpg -- 0z RGEM at 24 hrs

Looks like 5mm just south of DC... thats around .20" QPF... clearly suggests 2"-3"

[Ian]

that damn sun angle is going to kill us

[yoda]

that damn sun angle is going to kill us

You've got it all wrong. Its the angle of the cold air fool

[aldie 22]

that damn sun angle is going to kill us

If it's too windy the snow will only stick to the side of hills

[PhineasC]

You've got it all wrong. Its the angle of the cold air fool

Ian just get b**ch slapped by yoda.

[Guest someguy]

You've got it all wrong. Its the angle of the cold air fool

its the angle of the dangle

[wxmeddler]

Just for kicks I ran the 0z NAM BWI Bufkit and see how the ratios are, that far north.

The Turquise Line and the scale on the far left corresponds to the Snow Ratios

The Red + Green lines are Temperature and Dewpoint and correspond to the far right scale (and the horizontal lines)

The Blue Bars are hourly snow totals and correspond to the gray scale (.01 etc.) on the right.

The Time scale is on the bottom in the brown area.

Snow Ratios are calculated by maximum temperature in the profile. BWI gets 1.7" according to this.

[Dr No]

PW County schools are still on. 19/12 right now....snow very close.

See the dark green bands up to the PA border from the Pittsburgh radar? This is going to be ugly today.

[mitchnick]

glad its too early to be drinking because looking at this sat pic I would have thought I was

look at the movement of everything in Canada starting in the Atlantic

its going the wrong way! (thanks to the block)

http://www.ssec.wisc.edu/data/us_comp/us_comp.html

[BTRWx]

I probably should have asked these questions first on here before Accuweather...Does anyone else use the WunderMap on the weatherunderground site? Can anyone explain those mesocyclone symbols in southwest VA? Could it be a glitch and is it even possible for a mesocyclone during a snowstorm? Radar looks pleasing and snow has been falling for about an hour now in Alexandria.