The Return of the 12/5 Snowstorm

[H2O]

9 minutes ago, stormtracker said:

I think it’s about time to face the music for us.  Imma hang on till after 12z

Just gimme a dusting. Something small is ok. A snow that will make my leaves look like Xmas cookies with powdered sugar on them. 

[SomeguyfromTakomaPark]

I am liking the look of the 12z HRRR compared to the overnight runs based on the first 15 hours, perhaps an improvement incoming.

[TSSN+]

3 minutes ago, SomeguyfromTakomaPark said:

I am liking the look of the 12z HRRR compared to the overnight runs based on the first 15 hours, perhaps an improvement incoming.

Yup congrats southern folks 

 

 

[Terpeast]

7 minutes ago, SomeguyfromTakomaPark said:

I am liking the look of the 12z HRRR compared to the overnight runs based on the first 15 hours, perhaps an improvement incoming.

Yeah, its almost back to where 00z was, not quite as beefy but the northern extent is back up just north of the dc metro - and I'm looking at 1km radar not composite reflectivity. I wouldn't count us out yet.

Just to clarify, my expectations are coating to 1" tops north of 66/50 up to 70

[SnowenOutThere]

4 minutes ago, Terpeast said:

Yeah, its almost back to where 00z was, not quite as beefy but the northern extent is back up just north of the dc metro - and I'm looking at 1km radar not composite reflectivity. I wouldn't count us out yet.

Just to clarify, my expectations are coating to 1" tops north of 66/50 up to 70

What would you expect for Charlottesville? I'm thinking that at least an inch is a safe bet with a max of 3 (1.5-2 is my target). Only worry is down sloping or a further slip south (though with the H5 that would be quite a change to skunk me) but generally I think I'm pretty locked in for a pretty Friday morning on Grounds. 

[scope1]

Special Weather Statement

Special Weather Statement
National Weather Service Baltimore MD/Washington DC
750 AM EST Thu Dec 4 2025

DCZ001-MDZ004>006-008-011-013-014-016>018-503>508-VAZ053>055-501-
502-505-506-526-527-041900-
District of Columbia-Frederick MD-Carroll-Northern Baltimore-
Cecil-Southern Baltimore-Prince Georges-Anne Arundel-Charles-
St. Marys-Calvert-Northwest Montgomery-
Central and Southeast Montgomery-Northwest Howard-
Central and Southeast Howard-Northwest Harford-Southeast Harford-
Fairfax-Arlington/Falls Church/Alexandria-Stafford-
Northern Fauquier-Southern Fauquier-Western Loudoun-
Eastern Loudoun-Northwest Prince William-
Central and Southeast Prince William/Manassas/Manassas Park-
Including the cities of Washington, Frederick, Ballenger Creek,
Eldersburg, Westminster, Reisterstown, Cockeysville, Elkton,
Baltimore, Bowie, Suitland-Silver Hill, Clinton, College Park,
Greenbelt, Laurel, Camp Springs, Glen Burnie, Annapolis, Severn,
South Gate, Severna Park, Arnold, Odenton, St. Charles, Waldorf,
Lexington Park, California, Chesapeake Beach, Huntingtown,
Dunkirk, North Beach, Lusby, Prince Frederick, Germantown,
Damascus, Bethesda, Rockville, Gaithersburg, Silver Spring,
Lisbon, Columbia, Ellicott City, Jarrettsville, Aberdeen, Reston,
Herndon, Annandale, Centreville, Chantilly, McLean, Franconia,
Arlington, Alexandria, Falls Church, Falmouth, Warrenton,
Turnbull, Purcellville, Leesburg, Ashburn, Sterling, Haymarket,
Dale City, Manassas, Woodbridge, Lake Ridge, and Montclair
750 AM EST Thu Dec 4 2025

...POTENTIAL WINTER COMMUTING HAZARD FOR THE BALTIMORE/
WASHINGTON METRO AREAS FRIDAY MORNING...

There is a potential for hazardous commuting conditions for the
Friday morning commute. A period of light snow is POSSIBLE (a 30
to 50 percent chance) Friday morning across the
Baltimore/Washington DC metro areas with up to an inch of snow
possible accumulation on untreated roadways.

If this threat does materialize during the Friday morning rush
hour, many roads could quickly turn icy. This could lead to
dangerous traveling conditions, multiple accidents, and extensive
delays.

If commuting Friday morning, be aware of the POSSIBILITY of
significant travel disruptions. Plan ahead by allowing for extra
travel time, and consider using public transportation and telework
options.

In addition, light snow or freezing drizzle accumulations may
also impact the evening commute as the storm system is slow to
depart late Friday afternoon and evening.

Stay tuned for updates on this potential winter weather episode.

$$

EST/DHOF

[Terpeast]

4 minutes ago, SnowenOutThere said:

What would you expect for Charlottesville? I'm thinking that at least an inch is a safe bet with a max of 3 (1.5-2 is my target). Only worry is down sloping or a further slip south (though with the H5 that would be quite a change to skunk me) but generally I think I'm pretty locked in for a pretty Friday morning on Grounds. 

Not too familiar with cville microclimate but I'd worry about downsloping since the flow is basically east to west. Perhaps 1-1.5" is a safe bet for you. Just basing this on the HRRR and ignoring the NAM, which is about to get retired.

[bncho]

the HRRR isn't the 6z debacle

[SnowenOutThere]

4 minutes ago, Terpeast said:

Not too familiar with cville microclimate but I'd worry about downsloping since the flow is basically east to west. Perhaps 1-1.5" is a safe bet for you. Just basing this on the HRRR and ignoring the NAM, which is about to get retired.

Do you know any resources I could use to see and possibly anticipate how much down sloping to expect (besides annoying my resident professor on microclimates which I plan to do)? 

[NorthArlington101]

4 minutes ago, SnowenOutThere said:

Do you know any resources I could use to see and possibly anticipate how much down sloping to expect (besides annoying my resident professor on microclimates which I plan to do)? 

Anecdotally I didn’t notice any vast disparity between Cville modeled totals and reality. All I learned is that they really need a new radar there and that it’s a mini-supercell alley just to the north. Go get a snowy Rotunda pic and hike the O Hill trails. Godspeed - think ur good for 1-2”

[SnowenOutThere]

3 minutes ago, NorthArlington101 said:

Anecdotally I didn’t notice any vast disparity between Cville modeled totals and reality. All I learned is that they really need a new radar there and that it’s a mini-supercell alley just to the north. Go get a snowy Rotunda pic and hike the O Hill trails. Godspeed - think ur good for 1-2”

Wonder if that mini supercell alley is a direct result of the gap in the mountains I-64 takes impacting the flow. As for pictures I already have my d850 charging and ready to go. I think I plan to get the class Rotunda Pic, Dell pictures, and various Garden pictures. If you have any other pretty snow picture spots on Grounds please let me know!

[Imgoinhungry]

the HRRR isn't the 6z debacle

But still south of DC.


.

[LP08]

To my eyes, I don't think the 12z NAM will be a rug pull.

[bncho]

2 minutes ago, LP08 said:

To my eyes, I don't think the 12z NAM will be a rug pull.

looks just about as good

[LP08]

3k looks better as well. 

[LP08]

6 minutes ago, bncho said:

looks just about as good

Gets kind of stretched out as it reaches us and loses a little bit of its punch.  Meh.

[WesternFringe]

34 minutes ago, SnowenOutThere said:

What would you expect for Charlottesville? I'm thinking that at least an inch is a safe bet with a max of 3 (1.5-2 is my target). Only worry is down sloping or a further slip south (though with the H5 that would be quite a change to skunk me) but generally I think I'm pretty locked in for a pretty Friday morning on Grounds. 

I'm not a met, but your expectations seem to be in line with the latest guidance.  I graduated from UVa twice, so I am familiar with how beautiful the grounds get with a nice coat of white powder.  Enjoy!

[LP08]

Probably the best run of the 3k (not saying much). Gets the 2" line to EZF, about 1 to DC.

[bncho]

1 minute ago, LP08 said:

Probably the best run of the 3k (not saying much). Gets the 2" line to EZF, about 1 to DC.

[Imgoinhungry]

Probably the best run of the 3k (not saying much). Gets the 2" line to EZF, about 1 to DC.

What time does it start in dc? 8am or so?


.

[bncho]

most modeling seems to be thinking that DC is the dividing line for an inch.

[LP08]

1 minute ago, Imgoinhungry said:

What time does it start in dc? 8am or so?


.

Earlier.  Like 4-5 am.

[Imgoinhungry]

Earlier.  Like 4-5 am.

Thanks. Will be interesting to see if it impacts morning rush and schools.


.

[NorthArlington101]

I think there is a pretty solid consensus right now that DC is about the northern extent of an inch. Further south - and you don't have to go too much further south - 1-3" seems right down to RIC. 

A casual 50mi shift north would help many of us, but some minor accumulations would be sweet.

[Interstate]

I also hate the mountains.

[87storms]

27 minutes ago, LP08 said:

3k looks better as well. 

12k is noticeably drier this run for dc.  This storm is fizzling on approach.

[87storms]

13 minutes ago, Interstate said:

I also hate the mountains.

They’re fun to bike and hike, though.

[87storms]

At minimum, should at least be first flakes of the season for dc/annapolis. It would be pretty lame to go much longer not getting a trace in this pattern. We’re still at goose eggs at each airport. In Frederick, we already had a couple of coatings by mid-December…confirmed via camera roll.

[wxdude64]

47 minutes ago, SnowenOutThere said:

Wonder if that mini supercell alley is a direct result of the gap in the mountains I-64 takes impacting the flow. As for pictures I already have my d850 charging and ready to go. I think I plan to get the class Rotunda Pic, Dell pictures, and various Garden pictures. If you have any other pretty snow picture spots on Grounds please let me know!

There are two micro climates on either side of the mountains from spring thru early fall there for about a 30-50 mile stretch S to N. When the wind direction is S to SW and storms form a tornado/hail alley is common from Greenville up to Grottoes on Rt 340 corridor and east side likes to form severe T-storms from C'ville up to Culpeper on Rt 29. I'm 99% sure the ridge there enhances stuff. 

[grhqofb5]

6 minutes ago, 87storms said:

They’re fun to bike and hike, though.

That John Denver guy is full of s***.