December 15-16 Mixed Bag of Precip

[a.salt]

It was 17 degrees and frosty IMBY this morning...still cloudy and near freezing.

[mappy]

8 minutes ago, a.salt said:

It was 17 degrees and frosty IMBY this morning...still cloudy and near freezing.

I'm about 11 miles, as the crow flies, to your east and only 34. Def seems colder than I thought it would be. 

[DarkSharkWX]

Got to a low of 18 here in Gaitherburg, colder than I had expected. Right now 37/17

[Terpeast]

39/18 Ashburn

[WEATHER53]

Looks like when we get to 85%+ rh temp will evap to 30 so that’s dicey.  The high is not in a good location but it is quite strong and not moving. As I said yesterday it’s an In situ and to me it appeared snow and sleet would dominate.  Real big freezing rain  storms are rare around here, about every 15 years yet there are modeled 1-3 times every winter.  

 

[NorthArlington101]

Looks like when we get to 85%+ rh temp will evap to 30 so that’s dicey.  The high is not in a good location but it is quite strong and not moving. As I said yesterday it’s an In situ and to me it appeared snow and sleet would dominate.  Real big freezing rain  storms are rare around here, about every 15 years yet there are modeled 1-3 times every winter.  
 

Just to get it on the record - what do you actually think happens? Always curious what you’re thinking

[Solution Man]

41/18 in Haymarket

[MDSnowyWxTracker]

Started the morning at 17 degrees here in the Walkersville area.  A bit colder than I thought it would be this morning. Current 36/23

[Paleocene]

41/20 inside the beltway near downtown silver spring.

[WesternFringe]

34/31 here NW of Staunton

[Interstate]

36.5/23.1  in 21057

[lpaschall]

Running about 5 degrees cooler than forecasted here in Westminster.  35/23

Not sure that will make much difference in the end. 

[WVclimo]

35/19 and cloudy.  Calm wind.  Baro 30.18 and falling.

[Jeff B]

36.7/18.3

[mattie g]

Hope everyone gets as much cold rain as they can handle!

[WEATHER53]

4 hours ago, MillvilleWx said:

Currently have a bit of a separation of camps setting up between the globals and the hi-res due to the obvious resolution concerns that crop up in the short range. In the short range, it's important to follow the trends in dew point obs and temps, as well as cloud cover advancement and increasing SE flow as the low begins to develop early tomorrow morning. 

The current setup is indicative for a period of icing for all areas, including east of the fall line, but I have my doubts the impact will be too substantial for the DC/Balt urban areas as temps will be borderline, at best for prime ice accretion. To the west of the fall line, there will be an extended period of icing that starts early AM and last until close to Noon for locations above 600' elevation and even longer for places out by I-81 where the warm nose will take more time to protrude deep in the boundary layer and warm up enough to switch from ZR to rain. 

Here are two pieces of guidance I like for the current indications of potential. Note, NBM is blended guidance and will not handle CAD as well compared to higher res solutions, thus the numbers a bit degraded compared to where they may end up. One of the trends I noticed on looking at models this AM is a period where the temps will warm slightly before falling due to evaporative cooling processes as the precip becomes "heavier". This is a solution that has merit, but I wonder if this will limit any ice potential for areas along I-95 and east. Highest impact will be the valleys west of Frederick up to South Mountain and the Catoctins. Also, the I-81 corridor from Winchester down to Luray will be a mess as the warm air will struggle to mix to the surface and temps hold between 30-32F for an extended period. 

Current thinking is the WWA/WSW are in the right places given the recent guidance and trends in the short term. KOKX around 0.25" of ice is certainly in the cards. 0.25-0.5" out by Hancock and along the ridges in Western MD. T-0.05" along I-95 and inside the beltways. 0.05-0.15" for areas along and west of the fall line. Catoctins will likely be WSW criteria, but because it falls in Frederick Co, they will remain a WWA due to the population center away from the mountains. 

Millville and any others-

when West of I-95 is referenced can you clarify that metric further? I am 5 miles west, is that too close or does it mean literally west if 95 period or 10-15 miles or more?

thanks 

 

also-just hit  40 with dp 20. 

[Kmlwx]

1 minute ago, WEATHER53 said:

Millville and any others-

when West of I-95 is referenced can you clarify that metric further? I am 5 miles west, is that too close or does it mean literally west if 95 period or 10-15 miles or more?

thanks 

Distance will matter as usual. The father NW, the more icy. We will be right on the line in the Colesville/Wheaton/Cloverly areas. Probably minor icing for us 

[IUsedToHateCold]

40 degrees. I get maybe a flake and some sleet pellets before my cold rain. I’ll take it.

[Baltimorewx]

19 minutes ago, WEATHER53 said:

Millville and any others-

when West of I-95 is referenced can you clarify that metric further? I am 5 miles west, is that too close or does it mean literally west if 95 period or 10-15 miles or more?

thanks 

 

also-just hit  40 with dp 20. 

I think the point is that north and west of 95 with continuing elevation will have worse conditions generally speaking. So if you're 5 miles west and the elevation is relatively low still, probably similar impacts to I95 and S/E

[mappy]

Looks like 35 for my high today. Expected to be closer to 40. 

35/23 currently

[Paleocene]

35 minutes ago, WEATHER53 said:

Millville and any others-

when West of I-95 is referenced can you clarify that metric further? I am 5 miles west, is that too close or does it mean literally west if 95 period or 10-15 miles or more?

thanks 

 

also-just hit  40 with dp 20. 

For illustrative purposes, check out this site. It lets you paint areas below a given elevation above mean sea level as blue. https://www.floodmap.net/?ct=US.  it's not perfect but close enough for a zoomed out view.

Here's our (inner) region if sea levels were 100 meters higher. Note how 95 in Maryland between DC and Baltimore basically traces that 100m contour.

If you're below 100m, you're gonna have a soggy time tomorrow

 

 

[Interstate]

36.5/24.3  DP is coming up... but the temp has not moved over the last couple of hours... 21057

[wawarriors4]

41/21 just NW of FXBG, looking forward to my driving cold rain storm

[Mrs.J]

6 hours ago, catoctin wx said:

 

Great minds think alike @MrsJ 

 

I went out on a limb with my 11th grader and say a 60-70% chance of at least a delay. 30-40% closing. Her teachers today were calling a 80% chance of closing. 

[aldie 22]

41/20 personally not expecting much of an impact here but if my decorations get a little glaze on them that could be cool to see

[kristia]

4 minutes ago, Mrs.J said:

 

I went out on a limb with my 11th grader and say a 60-70% chance of at least a delay. 30-40% closing. Her teachers today were calling a 80% chance of closing. 

I’m in Frederick County also. Delay would be nice. Closed would be even better

[Mrs.J]

Just now, kristia said:

I’m in Frederick County also. Delay would be nice. Closed would be even better

Yeah. I can handle snow. Grew up in NW OH. But I give ice respect. FredCo is so big and anything above and W of 70 usually dictates the decision. 

[Weather Will]

WB 18Z 3K NAM.  Temps above freezing most areas east of the mountains by 10am.

[mappy]

Pivotal's version of the FRAM map, for 18z NAM. Not as bad as Will's WB map above. 

[RIC_WX]

39/23 Leesburg

30/16 DCL Swanton

Hoping they keep power at the lake but not super optimstic.  I turn the water off when I am not there but wasn't really prepared to have pipes freeze if the outage is extended.