December 22-23, 2022: Warm Rain to Arctic Chill

[Jeff B]

29.3/24° in 4 miles west of Oregon Ridge Park

[nukeing]

29/23 northern mt airy

[poolz1]

Quote

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Moisture will increase gradually through early Thursday
morning. Wintry precipitation is expected to move from southwest
to northeast early Thursday morning. Cold air is expected to be
abundant across the area via cold air damming. Still expecting
the Potomac Highlands and western MD mountains to start as snow.
There remains uncertainty with when the transition to a wintry
mix of sleet, freezing rain, and snow occurs. There is
frontogenetical forcing increasing in the low to mid levels in
most numerical guidance. Current thinking is dynamic cooling
from heavy precip (QPF of 0.1-0.2" an hour) will allow for snow
to be the predominant precipitation type in this area through
the morning. The typical climo factors will be in play with an
easterly flow favoring more of a sleet/freezing rain forecast
for western Garrett County, MD given the subtle downsloping and
warming while snow/sleet is favored to the east.

 

[Ji]

30/23 now

5 degreed colder than pending ice storm last week

[Warm Nose]

7 minutes ago, poolz1 said:

 

Here's the rest of the relevant discussion ...

 

The eastern slopes will be those with higher snow amounts through
this event. Uncertainty also exists regarding long the Shenandoah
Valley holds near or below freezing temperatures, and therefore
snow and freezing rain accumulations. The higher ridges along
and west of the Blue Ridge will hold the freezing rain the
longest. Do think all areas eventually change to freezing rain
before ending as rain sometime late Thursday afternoon or
evening. Regardless of the wintry precipitation type, it will be
impactful especially across far western MD and the counties in
the WV under a Winter Storm Warning due to liquid equivalent
frozen QPF amounts of 0.50-0.75". For anyone looking at snow
maps from model output, 10:1 is overdone and positive snow depth
is the better output from guidance (more on the 7-8:1 ratio).

Those along the Allegheny Front and Potomac Highlands should be
prepared for a period of wintry precipitation that can result in
travel disruptions Thursday morning into the afternoon. Impacts
could be possible across I-68, I-70, and I-81 given forecast
rates Thursday morning.

For areas in the warning that are east of the Allegheny Front,
this will be for 4- 7 inches of accumulating snow, while for
those west of the Allegheny front (western Garrett and western
Grant counties) a quarter inch or more of freezing rain is
possible. Winter Weather Advisories have been hoisted elsewhere
along and west of the Blue Ridge as well as a tier of counties
to the east. Largely for the threat of a tenth to two tenths of
an inch of freezing rain along and west of the Blue Ridge, and a
trace to a tenth in the counties in an advisory east of the Blue
Ridge. It is possible to see some lighter accumulations of
freezing rain just east of the current advisory as well, but
held off on advisories for now as certainty is lower. Will let
future shifts evaluate.

[87storms]

1 minute ago, Ji said:

10 minutes ago, Terpeast said:

30/23 now

5 degreed colder than pending ice storm last week

Yea, even if the mid-levels warm quicker than we hope for, there could be more icing than anticipated a day ago.

[DarkSharkWX]

28/25 gaithersburg

[Lucketts Life]

27/25 

[Blue Dream]

13 minutes ago, wxtrix said:

why are there PHL obs in this thread?

Isn’t PHL part of the Mid-Atlantic?

[Warm Nose]

1 minute ago, Blue Dream said:

Isn’t PHL part of the Mid-Atlantic?

Not on this site. They have their own subforum.

[southmdwatcher]

28/25

Much colder than the last busted event.

[dailylurker]

26.5 and falling. Hopefully I can take pictures of our Christmas tree with snow falling outside the window tomorrow morning. 

[AtlanticWx]

snowing near VA/NC line rn, was snow even expected for them? regardless, good signs for snow prospects fs

[Imgoinhungry]

Starting to think morning commute is not going to be fun.


.

[Chris78]

Gfs not backing down for NW areas

[jayyy]

Gfs not backing down for NW areas

Show us young Jedi


.

[Chris78]

Moved a little East compared to 18z.

[Deck Pic]

36/27

waiting for my storm

[hstorm]

29/25 in Great Falls. Feels like snow (which means it will rain). 

[poolz1]

Latest HRRR with plenty of 1"/hr+ rates tomorrow morning as NWS noted in their latest AFD.

[pazzo83]

34 minutes ago, Deck Pic said:

36/27

waiting for my storm

34/27 near DC's highest point.

[WEATHER53]

I’m going to pull out my old weather diary.  Started it as a 13 year old during Blizzard of 66 in Salisbury. And stoped in 2012.  Gotta be done good details on a few others. 
This one may actually be beyond Mega Front.

[Swiscaster]

No matter who gets any snow, isn’t it going to rain for hours on end after it?

[BristowWx]

53 minutes ago, Swiscaster said:

No matter who gets any snow, isn’t it going to rain for hours on end after it?

Yes yes it is 

[SnowenOutThere]

It’s 34 degrees out and no precip has fallen, however, the roads are salted for some unknown reason. 

[weatherCCB]

33/30

[nw baltimore wx]

Frederick county MD has a 2 hour delay this AM.

[Imgoinhungry]

Frederick county MD has a 2 hour delay this AM.

Argh. I’m mcps and my kid is fcps. Pain in the rear end


.

[Ruin]

7 hours ago, Blue Dream said:

Isn’t PHL part of the Mid-Atlantic?

I never understood this either on here. grew up in southern PA and MD we always counted PA DE MD VA for the mid atlantic 

[weatherCCB]

Little sleet mixed with light rain.

up to 34, so shouldn’t last long.