Chill Storm Discussion and Obs

[aldie 22]

You might see ice or snow at onset but it should change to rain pretty quickly. I sure don't see any ice storm in mby with the models raising the surface temp to 50 or so.

Have a wonderful holiday Wes...Merry Christmas!!

[IWC]

Hi Folks, I want to wish you all a MERRY CHRISTMAS from IWC.

[aldie 22]

Nam just a bit cooler for this storm...cold rain coming

[mitchnick]

Nam just a bit cooler for this storm...cold rain coming

it looks like NAM is close to giving us come back end wet snow thanks to the u/l low that passes through central VA

bl the problem ahhhhhhgain

[WinterWxLuvr]

The GFS and NAM might suggest this is still an evolving situation.

[Ji]

Gfs says 3 inches for jyo before change over

[Ian]

Storm has trended south a bit out west. Colder rain for DC?

[usedtobe]

Storm has trended south a bit out west. Colder rain for DC?

yeah, that's about it.

[usedtobe]

can we ban those?

I look at the soundings for Ji from the NMA and thought where'd the 3 inches come from as it looks to run to rain or freezing rain pretty doggone quick as a warm layer come in above 850mb.

[Deck Pic]

I look at the soundings for Ji from the NMA and thought where'd the 3 inches come from as it looks to run to rain or freezing rain pretty doggone quick as a warm layer come in above 850mb.

GFS is borderline for west of IAD at 54 hours but probably snow....I imagine it will be close for those 1st few hours for some areas and I would expect we will see advisories and/or warnings for some areas....

[usedtobe]

GFS is borderline for west of IAD at 54 hours but probably snow....I imagine it will be close for those 1st few hours for some areas and I would expect we will see advisories and/or warnings for some areas....

here's 54 hr and 57 hrs Note how close it is to above freezing at 800mb at 54hrs and how that layer warms to 2.6C by 57 hrs. To me that suggests the changeover at IAd to sleet or rain would be pretty quick as the boundary layer is around 36 degrees at onset and the wet bulb is already at 33 degrees. Back west of Leesburg, I think they will have some warnings for the mountains and advisories for Leesburg but also suspect that the advisories will extend too far east.

Date: 54 hour Eta valid 18Z WED 26 DEC 12

Station: KIAD

Latitude: 38.95

Longitude: -77.45

-------------------------------------------------------------------------------

LEV PRES HGHT TEMP DEWP RH DD WETB DIR SPD THETA THE-V THE-W THE-E W

mb m C C % C C deg knt K K K K g/kg

-------------------------------------------------------------------------------

SFC 1006 101 2.3 -1.5 76 3.8 0.8 71 9 275.0 275.5 273.6 284.3 3.40

1 1000 152 1.5 -1.1 83 2.6 0.4 72 11 274.6 275.2 273.6 284.3 3.53

2 950 562 -1.7 -3.4 88 1.7 -2.3 84 22 275.5 276.0 273.5 284.1 3.13

3 900 993 -2.4 -4.4 87 1.9 -3.2 110 28 279.0 279.5 275.4 287.6 3.06

4 850 1447 -1.6 -2.0 97 0.4 -1.7 128 23 284.5 285.1 279.3 295.5 3.89

5 800 1931 -0.6 -0.7 99 0.1 -0.6 157 28 290.5 291.3 282.8 303.6 4.54

6 750 2447 -1.0 -1.1 99 0.1 -1.0 175 29 295.5 296.4 285.1 309.4 4.72

7 700 2996 -3.0 -3.3 98 0.3 -3.1 193 36 299.2 299.9 286.1 312.0 4.30

8 650 3579 -5.9 -6.4 96 0.5 -6.1 203 43 302.3 303.0 286.5 313.4 3.64

9 600 4204 -8.7 -9.4 94 0.7 -9.0 210 48 306.1 306.6 287.3 315.8 3.12

10 550 4873 -12.6 -13.7 92 1.1 -13.0 215 50 309.1 309.6 287.7 316.8 2.41

11 500 5594 -17.6 -19.2 87 1.6 -18.0 221 49 311.6 311.9 287.8 317.1 1.68

12 450 6374 -23.3 -25.4 83 2.1 -23.8 226 47 313.9 314.1 287.9 317.5 1.08

13 400 7224 -29.8 -32.3 79 2.5 -30.2 223 46 316.3 316.4 288.2 318.5 0.63

14 350 8160 -37.4 -40.5 73 3.1 -37.7 228 49 318.3 318.3 288.5 319.4 0.32

15 300 9204 -46.6 -49.8 70 3.2 -46.7 235 57 319.7 319.8 288.8 320.2 0.13

16 250 10384 -57.6 -61.5 61 3.9 -57.7 238 59 320.4 320.4 288.9 320.6 0.04

17 200 11753 -66.6 -71.0 53 4.4 -66.7 240 72 327.3 327.3 291.0 327.3 0.01

18 150 13524 -60.1 -76.9 9 16.8 -60.3 252 52 366.5 366.5 299.9 366.6 0.01

19 100 16053 -60.4 -81.9 4 21.5 -60.6 256 42 411.1 411.1 306.6 411.1 0.00

Date: 57 hour Eta valid 21Z WED 26 DEC 12

Station: KIAD

Latitude: 38.95

Longitude: -77.45

-------------------------------------------------------------------------------

LEV PRES HGHT TEMP DEWP RH DD WETB DIR SPD THETA THE-V THE-W THE-E W

mb m C C % C C deg knt K K K K g/kg

-------------------------------------------------------------------------------

0 1000 101

SFC 1000 102 2.1 0.8 91 1.3 1.6 74 15 275.3 276.0 274.8 286.3 4.06

2 950 512 -0.9 -0.9 100 0.0 -0.9 83 36 276.3 276.9 274.9 286.6 3.77

3 900 945 0.5 0.3 99 0.2 0.4 113 48 282.0 282.7 278.6 294.1 4.33

4 850 1403 1.1 1.0 99 0.1 1.0 135 46 287.3 288.2 281.8 301.0 4.83

5 800 1894 2.6 2.6 100 0.0 2.6 161 55 293.9 294.9 285.5 310.6 5.75

6 750 2415 0.9 0.9 100 0.0 0.9 183 59 297.5 298.5 286.6 313.6 5.44

7 700 2968 -1.6 -1.6 100 0.0 -1.6 198 64 300.7 301.6 287.2 315.3 4.85

8 650 3555 -5.2 -5.6 97 0.4 -5.4 205 64 303.0 303.8 287.1 314.9 3.88

9 600 4179 -8.7 -9.4 95 0.7 -9.0 210 60 306.0 306.6 287.3 315.8 3.13

10 550 4851 -11.6 -12.8 91 1.2 -12.1 217 54 310.3 310.8 288.3 318.6 2.60

11 500 5574 -16.1 -18.3 83 2.2 -16.7 214 51 313.4 313.8 288.5 319.4 1.81

12 450 6359 -21.8 -28.3 55 6.5 -23.1 219 50 315.9 316.0 288.3 318.7 0.82

13 400 7214 -28.5 -39.9 33 11.4 -29.8 218 48 317.9 318.0 288.4 319.0 0.30

14 350 8153 -37.0 -45.0 43 8.0 -37.6 214 44 318.9 318.9 288.6 319.6 0.20

15 300 9199 -46.1 -50.6 60 4.5 -46.3 213 36 320.4 320.4 289.0 320.9 0.12

16 250 10382 -57.1 218 33 321.1

17 200 11755 -66.0 226 64 328.3

18 150 13521 -59.7 244 58 367.3

19 100 16054 -60.0 256 36 411.7

[Deck Pic]

here's 54 hr and 57 hrs Note how close it is to above freezing at 800mb at 54hrs and how that layer warms to 2.6C by 57 hrs. To me that suggests the changeover at IAd to sleet or rain would be pretty quick as the boundary layer is around 36 degrees at onset and the wet bulb is already at 33 degrees. Back west of Leesburg, I think they will have some warnings for the mountains and advisories for Leesburg but also suspect that the advisories will extend too far east.

Date: 54 hour Eta valid 18Z WED 26 DEC 12

Station: KIAD

Latitude: 38.95

Longitude: -77.45

-------------------------------------------------------------------------------

LEV PRES HGHT TEMP DEWP RH DD WETB DIR SPD THETA THE-V THE-W THE-E W

mb m C C % C C deg knt K K K K g/kg

-------------------------------------------------------------------------------

SFC 1006 101 2.3 -1.5 76 3.8 0.8 71 9 275.0 275.5 273.6 284.3 3.40

1 1000 152 1.5 -1.1 83 2.6 0.4 72 11 274.6 275.2 273.6 284.3 3.53

2 950 562 -1.7 -3.4 88 1.7 -2.3 84 22 275.5 276.0 273.5 284.1 3.13

3 900 993 -2.4 -4.4 87 1.9 -3.2 110 28 279.0 279.5 275.4 287.6 3.06

4 850 1447 -1.6 -2.0 97 0.4 -1.7 128 23 284.5 285.1 279.3 295.5 3.89

5 800 1931 -0.6 -0.7 99 0.1 -0.6 157 28 290.5 291.3 282.8 303.6 4.54

6 750 2447 -1.0 -1.1 99 0.1 -1.0 175 29 295.5 296.4 285.1 309.4 4.72

7 700 2996 -3.0 -3.3 98 0.3 -3.1 193 36 299.2 299.9 286.1 312.0 4.30

8 650 3579 -5.9 -6.4 96 0.5 -6.1 203 43 302.3 303.0 286.5 313.4 3.64

9 600 4204 -8.7 -9.4 94 0.7 -9.0 210 48 306.1 306.6 287.3 315.8 3.12

10 550 4873 -12.6 -13.7 92 1.1 -13.0 215 50 309.1 309.6 287.7 316.8 2.41

11 500 5594 -17.6 -19.2 87 1.6 -18.0 221 49 311.6 311.9 287.8 317.1 1.68

12 450 6374 -23.3 -25.4 83 2.1 -23.8 226 47 313.9 314.1 287.9 317.5 1.08

13 400 7224 -29.8 -32.3 79 2.5 -30.2 223 46 316.3 316.4 288.2 318.5 0.63

14 350 8160 -37.4 -40.5 73 3.1 -37.7 228 49 318.3 318.3 288.5 319.4 0.32

15 300 9204 -46.6 -49.8 70 3.2 -46.7 235 57 319.7 319.8 288.8 320.2 0.13

16 250 10384 -57.6 -61.5 61 3.9 -57.7 238 59 320.4 320.4 288.9 320.6 0.04

17 200 11753 -66.6 -71.0 53 4.4 -66.7 240 72 327.3 327.3 291.0 327.3 0.01

18 150 13524 -60.1 -76.9 9 16.8 -60.3 252 52 366.5 366.5 299.9 366.6 0.01

19 100 16053 -60.4 -81.9 4 21.5 -60.6 256 42 411.1 411.1 306.6 411.1 0.00

Date: 57 hour Eta valid 21Z WED 26 DEC 12

Station: KIAD

Latitude: 38.95

Longitude: -77.45

-------------------------------------------------------------------------------

LEV PRES HGHT TEMP DEWP RH DD WETB DIR SPD THETA THE-V THE-W THE-E W

mb m C C % C C deg knt K K K K g/kg

-------------------------------------------------------------------------------

0 1000 101

SFC 1000 102 2.1 0.8 91 1.3 1.6 74 15 275.3 276.0 274.8 286.3 4.06

2 950 512 -0.9 -0.9 100 0.0 -0.9 83 36 276.3 276.9 274.9 286.6 3.77

3 900 945 0.5 0.3 99 0.2 0.4 113 48 282.0 282.7 278.6 294.1 4.33

4 850 1403 1.1 1.0 99 0.1 1.0 135 46 287.3 288.2 281.8 301.0 4.83

5 800 1894 2.6 2.6 100 0.0 2.6 161 55 293.9 294.9 285.5 310.6 5.75

6 750 2415 0.9 0.9 100 0.0 0.9 183 59 297.5 298.5 286.6 313.6 5.44

7 700 2968 -1.6 -1.6 100 0.0 -1.6 198 64 300.7 301.6 287.2 315.3 4.85

8 650 3555 -5.2 -5.6 97 0.4 -5.4 205 64 303.0 303.8 287.1 314.9 3.88

9 600 4179 -8.7 -9.4 95 0.7 -9.0 210 60 306.0 306.6 287.3 315.8 3.13

10 550 4851 -11.6 -12.8 91 1.2 -12.1 217 54 310.3 310.8 288.3 318.6 2.60

11 500 5574 -16.1 -18.3 83 2.2 -16.7 214 51 313.4 313.8 288.5 319.4 1.81

12 450 6359 -21.8 -28.3 55 6.5 -23.1 219 50 315.9 316.0 288.3 318.7 0.82

13 400 7214 -28.5 -39.9 33 11.4 -29.8 218 48 317.9 318.0 288.4 319.0 0.30

14 350 8153 -37.0 -45.0 43 8.0 -37.6 214 44 318.9 318.9 288.6 319.6 0.20

15 300 9199 -46.1 -50.6 60 4.5 -46.3 213 36 320.4 320.4 289.0 320.9 0.12

16 250 10382 -57.1 218 33 321.1

17 200 11755 -66.0 226 64 328.3

18 150 13521 -59.7 244 58 367.3

19 100 16054 -60.0 256 36 411.7

makes sense...I was looking at GFS which is a bit colder...I think the period between 48 and 54 is the one to watch based on that model

[usedtobe]

makes sense...I was looking at GFS which is a bit colder...I think the period between 48 and 54 is the one to watch based on that model

It is cooler though it's boundary layer temp is still above freezing by 54 hrs. I guess much depends on how quickly the precip moves into the area. The faster it gets here, the better.

[Deck Pic]

euro is cold

[Huffwx]

euro is cold

Very- Major ice even into ROA. Matches the shift in the GFS and NAM, Parkesburg WV-- i track for my Dad is much colder as well.

[aldie 22]

LOL...I just noticed that the 12z NAM has some of the Wednesday storm as snow...a few inches....so does the GFS...come on now...really

[Deck Pic]

LOL...I just noticed that the 12z NAM has some of the Wednesday storm as snow...a few inches....so does the GFS...come on now...really

To me Euro looks like a Warning event for far burbs....borderline for you

[aldie 22]

To me Euro looks like a Warning event for far burbs....borderline for you

It's reasonable to say that the trend is for these things to get a bit colder as they get closer...still a couple of days away...interesting

[clueless]

Nice coasting out here. Best part no shoveling for today.

[WVclimo]

To me Euro looks like a Warning event for far burbs....borderline for you

Euro is a fairly major winter storm for here on Wednesday. Snow hrs 48-60. Sleet/freezing rain hrs 63-69.

[Ji]

MRB which is 35 miles from Leesburg is all frozen. Would love one more big east ship

[WinterWxLuvr]

Never give in. Still 36 hours out, can still get better. I can't see the Euro, but Matt's comments tell me a lot.

[Yeoman]

It's reasonable to say that the trend is for these things to get a bit colder as they get closer...still a couple of days away...interesting

As well as the snow has held on today given that just 24 hours ago we thought this would be largely an areawide rain/ZR event I think portends well to perhaps this storm looking better as we get closer and over performing.

[Bob Chill]

The 35dbz returns in moco is all snow. solid mod with big flakes. Regardless of accums, today is going down in the great holiday memory file and only old age can take that away from me.

[Dalfy]

Snowing nicely with a coating on the ground. This i all I could ever ask for on christmass eve . It's jebwalk time.

[mitchnick]

The 35dbz returns in moco is all snow. solid mod with big flakes. Regardless of accums, today is going down in the great holiday memory file and only old age can take that away from me.

coming down nicely here and just starting to get hints of accumulation on roofs and grass....but only a weenie like me would be looking close enough to see it!

[mitchnick]

the NAM was the first to pick up on the u/l low passing due west through VA yesterday, now the other models seem to have joined that party

keep an eye on each future runs of the NAM as it may continue to sniff out the colder solutions

[aldie 22]

As well as the snow has held on today given that just 24 hours ago we thought this would be largely an areawide rain/ZR event I think portends well to perhaps this storm looking better as we get closer and over performing.

I'm gonna take a weenie guess and say that the type of precip you are seeing today may match what you see on Wednesday...at least to start.

[mitchnick]

18Z NAM opens up the 5H low at only 21 hrs and that ridge in SE Canada looks a bit more impressive too

may not get colder, but I don't think it's going to be warmer (famous last words)

[Deck Pic]

NAM says next