December 15-16 Mixed Bag of Precip

[nj2va]

Threat of winter event for the area with precip arriving in parts of the subforum within 78 hours.  Potential exists for an impactful event, especially in the western zones.

[nj2va]

Re-posting here.  00Z GFS made a decent shift to a colder solution for the area.

[mappy]

Thanks for starting a thread! 

Let’s try to limit banter, especially during model runs. 

[IronTy]

Seems like a good chance for a cold rain down here. Awesome.  

[NorthArlington101]

Unsurprisingly, the GEFS are going to follow the OP. Some nice looking (snowier) members in the mix, can share once it runs through.

[NorthArlington101]

Unsurprisingly, the GEFS are going to follow the OP. Some nice looking (snowier) members in the mix, can share once it runs through.

Might’ve oversold this but we are substantially more in the game than a few runs ago. Pretty much every ensemble member at least starts as something wintry, which is a big step up from just a few runs ago.

[TSSN+]

1 minute ago, NorthArlington101 said:

Might’ve oversold this but we are substantially more in the game than a few runs ago. Pretty much every ensemble member at least starts as something wintry, which is a big step up from just a few runs ago.

P13 looks good to me. Bring it. 

[nj2va]

9 minutes ago, NorthArlington101 said:

Might’ve oversold this but we are substantially more in the game than a few runs ago. Pretty much every ensemble member at least starts as something wintry, which is a big step up from just a few runs ago.


 

All about expectations.  It’s been an uphill battle for the coastal plain but there’s a shot at seeing some frozen at the start of it.  N&W in the game for a mixed bag. 

[NorthArlington101]

Canadian ENS say it’ll be quite slick. Few flip to snow but the highlight is this panel.

[Ji]

Euro warm /north but more ice in Loudoun than 12z run

[Weather Will]

WB 6Z GFS

[mappy]

from LWX's 4am discussion - mix bag for most before the flip to a cold rain. places out west are probably in for a much longer icy event.

Warm advection precipitation starts to reach areas along I-64
and back toward Augusta and Highland counties by the afternoon
hours. Strong ascent atop the seasonably cold air mass will make
for a messy winter precipitation scenario by the evening into
overnight hours. A bulk of the initial activity falls on
Wednesday night with 925-850 mb temperatures rising above
freezing. Given sub-freezing air likely holding on at the
ground, a number of spots will see a freezing rain/sleet
mixture, particularly off to the west of I-95. It remains to be
seen if conditions are cold enough within the urban sprawl.
Significant icing is possible across the Shenandoah Valley,
Alleghenies, Blue Ridge, and their mountain valleys. However, a
great deal of uncertainty plagues the forecast which will help
dictate the timing and precipitation types/overall intensity.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
There remains subtle spread and inherent fluctuations between
different global guidance on a run to run basis. Expect fluctuations
in model guidance to continue, with guidance continuing to narrow
down the potential outcomes of storm track, intensity, and wintry
precip duration as the ULL trough/energy associated with this storm
becomes better sampled over the Pacific NW. Ensemble guidance
continues to support an ULL moving through the northern Ohio Valley
early Thursday and eventually stalling into the Great Lakes Friday
into Saturday before eventually shearing out by Sunday. How far
south the ULL tracks in the Ohio Valley in turn will influence
where/when a coastal low develops in the vicinity of the Mid
Atlantic in this Miller B setup.

Confidence continues to increase in a prolonged wintry event ongoing
to start the long term at 12Z Thursday. Given the anomalous high
pressure north of the region and surface ridge extending down the
spine of the Appalachians, wintry precipitation (all types) is
likely across the entire area Thursday morning. Given the forecast
850/925 mb temps, snow, sleet, freezing rain, and rain area all a
possible. Areas east of the Blue Ridge will change to all rain
quicker. Those locations west of the Blue Ridge, especially
sheltered valleys prone to hold onto the cold air longer, will see a
mixture of wintry precip through the day on Thursday into Thursday
night and possible Friday. Travel impacts are becoming increasingly
likely during this timeframe.

As the ULL moves offshore, there is the potential for a period of
upslope snow as several vorticity maxes move over the Appalachians,
starting Friday into Saturday/Saturday night. This will be highly
dependent on the aforementioned system and ULL pattern.

Strong winds are possible areawide on the backside of the low. Temps
will be below normal behind the system with high presure building in
late Sunday.

[Weather Will]

WB 6Z EURO…overnight Wed.  and Th. am look icy in the N&W suburbs.  Thursday is a good day to telecommute.

[Imgoinhungry]

WB 6Z EURO…overnight Wed.  and Th. am look icy in the N&W suburbs.  Thursday is a good day to telecommute.

Have loudon county schools closed yet?


.

[WxUSAF]

15 minutes ago, Imgoinhungry said:

Have loudon county schools closed yet?


.

Yo @mattie g, be on the lookout for emails from Fairfax Co schools today!

 

[CAPE]

Outside of possible freezing/frozen at onset for NW areas, this looks like a potentially heavy rain event with 1-2", and the wind- especially for eastern areas- could gust to 40 mph.

[SnowenOutThere]

16 minutes ago, WxUSAF said:

Yo @mattie g, be on the lookout for emails from Fairfax Co schools today!

 

Really pulling for FCPS to have at least a two hour delay Thursday with the freezing rain, I have a bunch of tests this week and need a break before my swim meets Friday and Sunday. 

[mattie g]

If I start out with a little slop, that'll get me on the board with a first Trace (that I'm aware of). I guess that'll have to do!

[Weather Will]

WB 12Z NAM.  Temps go above freezing NW between 10 am and 1pm.

[Buddy1987]

@Weather Will 12Z Nam not joking around with ZR totals... guidance has really been trending back toward what they were showing last Friday with this system.

[WhiteoutMD]

WB 12Z NAM.  Temps go above freezing NW between 10 am and 1pm.

What time do we think precip starts Wednesday night?


.

[SnowenOutThere]

RDPS also went colder with the storm on the 12z run 

[mappy]

I hate sleet, but something wintry would be nice. 

[WesternFringe]

8 minutes ago, WhiteoutMD said:

What time do we think precip starts Wednesday night?


.

NAM says 5 or 6 am for you in Annapolis 

[TSSN+]

Lookin sleety and icy before cold

rain. Least it will be something frozen to start off the winter season. 

[Weather Will]

10 minutes ago, WhiteoutMD said:

What time do we think precip starts Wednesday night?


.

East of the mountains after midnight, but before the morning rush to the MD/PA border on the latest NAM run.

[Stormfly]

If nothinburgers are high in cholesterol, I, along with many others are seriously fubar'd.

[Buddy1987]

12Z GFS basically a north of 64 threat and especially as you get into Northern VA along 81. We will see what happens as we get closer to the event and the NAM comes more into range for its sniffing out of CAD. So far this morning it's Canadian's/NAM vs GFS with how far the cold air is entrenched.

[Paleocene]

Take it and run! (most/all of this will be washed away by rain, but potential for an icy/slushy/snowy start is clear)

 

[TSSN+]

Thursday morning going to be a mess. Sleet covered roads excellent