MN Transplant Posted January 20, 2012 Share Posted January 20, 2012 Have to see the text, but that might be 0.2" to 0.25" of ice for nw burbs just over 3 hours in the morning. Link to comment Share on other sites More sharing options...
Deck Pic Posted January 20, 2012 Share Posted January 20, 2012 forget what I said about QPF...Nam is still a cold juicy beast :lol Link to comment Share on other sites More sharing options...
MN Transplant Posted January 20, 2012 Share Posted January 20, 2012 to snow at the end GFS hinted at it 850s are +5 at 10am, unless I'm getting what you mean mixed up. Link to comment Share on other sites More sharing options...
yoda Posted January 20, 2012 Share Posted January 20, 2012 I'd probably take off 0.05 to at most 0.1 for rain (21-24 hrs)... but good QPF still Link to comment Share on other sites More sharing options...
TUweathermanDD Posted January 20, 2012 Share Posted January 20, 2012 forget what I said about QPF...Nam is still a cold juicy beast :lol Yes indeed, hey its trying to win us over. Link to comment Share on other sites More sharing options...
stormtracker Posted January 20, 2012 Share Posted January 20, 2012 Not out of the question DC could see up to 2" before changeover IF the Nam is correct. Not sure where this "crippling" meme is coming from as it never looked that way around the city anyway. Near the Mason Dixon line could be another story...but it's survivable. Link to comment Share on other sites More sharing options...
TUweathermanDD Posted January 20, 2012 Share Posted January 20, 2012 Not out of the question DC could see up to 2" before changeover IF the Nam is correct. Not sure where this "crippling" meme is coming from as it never looked that way around the city anyway. Near the Mason Dixon line could be another story...but it's survivable. Nothing historic obviously, nam was pretty wintry this run regardless. Link to comment Share on other sites More sharing options...
mappy Posted January 20, 2012 Share Posted January 20, 2012 Not out of the question DC could see up to 2" before changeover IF the Nam is correct. Not sure where this "crippling" meme is coming from as it never looked that way around the city anyway. Near the Mason Dixon line could be another story...but it's survivable. I'm not expecting to survive this. Link to comment Share on other sites More sharing options...
Deck Pic Posted January 20, 2012 Share Posted January 20, 2012 maybe it scores a coup...go NAM! Link to comment Share on other sites More sharing options...
stormtracker Posted January 20, 2012 Share Posted January 20, 2012 Damn..NAM still has DC sfc at freezing around 15z Link to comment Share on other sites More sharing options...
stormtracker Posted January 20, 2012 Share Posted January 20, 2012 I'm not expecting to survive this. I will be praying for you. Link to comment Share on other sites More sharing options...
usedtobe Posted January 20, 2012 Share Posted January 20, 2012 850s are +5 at 10am, unless I'm getting what you mean mixed up. It's interesting, the temps in the warm layer drop between 10 am and 1 PM. Here's the sounding for IAD off the plymouth site. It's still below freezing at the surface and the max temp in the warm layer is below plus 3 which on average is a sleet sounding. The other interesting thing is the temp on the sounding below does not jive with 2m temp on the plane view on the NCEP site Date: 24 hour Eta valid 18Z SAT 21 JAN 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 1003 100 -0.1 -0.9 94 0.9 -0.4 321 7 272.9 273.5 272.6 282.5 3.55 1 1000 121 -0.1 327 7 273.1 2 950 530 -1.5 -1.8 98 0.2 -1.6 336 9 275.6 276.2 274.2 285.3 3.53 3 900 962 2.1 2.0 99 0.2 2.1 313 17 283.7 284.6 280.2 297.4 4.90 4 850 1425 2.8 2.4 97 0.4 2.6 304 14 289.0 290.0 283.1 304.3 5.35 5 800 1916 2.2 1.9 98 0.4 2.1 265 28 293.5 294.5 285.1 309.5 5.48 6 750 2435 -0.1 -0.2 100 0.0 -0.2 262 33 296.4 297.4 285.8 311.3 5.04 7 700 2985 -2.6 -2.9 98 0.3 -2.7 258 32 299.6 300.4 286.4 312.9 4.42 8 650 3571 -5.4 -6.0 96 0.5 -5.7 259 41 302.8 303.5 286.9 314.3 3.77 9 600 4194 -9.1 -10.0 93 0.9 -9.4 254 49 305.6 306.2 287.1 314.9 2.98 10 550 4863 -13.2 -14.4 91 1.2 -13.6 247 51 308.4 308.8 287.3 315.6 2.27 11 500 5582 -18.0 -19.5 88 1.5 -18.4 242 51 311.1 311.4 287.6 316.5 1.64 12 450 6360 -23.8 -25.7 84 1.9 -24.2 239 50 313.3 313.5 287.7 316.9 1.05 13 400 7207 -31.4 -33.9 79 2.5 -31.7 240 52 314.2 314.3 287.5 316.1 0.55 14 350 8135 -39.5 -42.7 71 3.2 -39.7 240 59 315.5 315.6 287.6 316.4 0.25 15 300 9171 -47.6 -51.6 63 4.0 -47.7 241 75 318.3 318.3 288.3 318.7 0.11 16 250 10352 -56.6 238 84 321.9 17 200 11739 -61.3 248 70 335.8 18 150 13534 -59.2 262 67 368.0 19 100 16067 -60.8 257 51 410.3 Link to comment Share on other sites More sharing options...
yoda Posted January 20, 2012 Share Posted January 20, 2012 Damn..NAM still has DC sfc at freezing around 15z Yes... its prob in the middle of transitioning to rain... just north and west of DC proper still FZRA Link to comment Share on other sites More sharing options...
WxUSAF Posted January 20, 2012 Share Posted January 20, 2012 maybe it scores a coup...go NAM! Ahem...if there is ~3" of snow in central MD tomorrow morning, it will be the RGEM that scored the coup Link to comment Share on other sites More sharing options...
mappy Posted January 20, 2012 Share Posted January 20, 2012 I will be praying for you. Thank you for the kind words Link to comment Share on other sites More sharing options...
Deck Pic Posted January 20, 2012 Share Posted January 20, 2012 Not out of the question DC could see up to 2" before changeover IF the Nam is correct. Not sure where this "crippling" meme is coming from as it never looked that way around the city anyway. Near the Mason Dixon line could be another story...but it's survivable. my benchmark for significant is from a weenie perspective and in the context of DC climo in general and this winter...I don't need to have widespread week long power outages, felled trees on roofs and wires and roads, thousands of minor/major auto accidents and loss of life to enjoy a weather event or judge its impact Link to comment Share on other sites More sharing options...
Ian Posted January 20, 2012 Author Share Posted January 20, 2012 And with that Ian, NAM a bit wetter thru 9 and slightly colder with the 850's. Also, precip shield a few miles south. SREF QPF > NAM QPF at this range probably. Tho I really have not looked at much today as I'm crushed at work. Link to comment Share on other sites More sharing options...
TUweathermanDD Posted January 20, 2012 Share Posted January 20, 2012 Ahem...if there is ~3" of snow in central MD tomorrow morning, it will be the RGEM that scored the coup True true, well there is certainly a chance. Link to comment Share on other sites More sharing options...
yoda Posted January 20, 2012 Share Posted January 20, 2012 FWIW AREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 302 PM EST FRI JAN 20 2012 .SYNOPSIS... -- Changed Discussion -- LOW PRESSURE WILL BRING A WINTRY MIX OF PRECIPITATION TO MID ATLANTIC REGION OVERNIGHT AND SATURDAY...FOLLOWED BY A COLD FRONT SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN FROM THE NORTH SUNDAY INTO EARLY MONDAY...WITH LOW PRESSURE PASSING TO THE SOUTH. A SECOND COLD FRONT WILL MOVE ACROSS THE REGION MONDAY NIGHT INTO TUESDAY. -- End Changed Discussion -- && .NEAR TERM /THROUGH SATURDAY/... -- Changed Discussion -- COLD FRONT NOW SITUATED ACROSS THE CAROLINAS...WITH HIGH PRESSURE BUILDING IN FROM THE NORTH. OVER THE LAST SEVERAL HOURS...HAVE NOTICED DEWPOINTS ARE SEVERAL DEGREES LOWER THAN MODEL GUIDANCE AND TEMPS HAVE ALSO BEEN SLOWER TO RISE TODAY. RIDGE AXIS WILL SHIFT OFFSHORE EARLY THIS EVENING AS LOW PRESSURE MOVES INTO THE MID ATLANTIC FROM THE TN VALLEY. THE LOW CENTER IS EXPECTED TO PASS OVER THE EXTREME SOUTHERN CWFA OR JUST TO THE SOUTH. MOISTURE WILL BEGIN TO OVERSPREAD THE COLD AND DRY AIRMASS IN PLACE FOR THE REMAINDER OF THE AFTERNOON AND EARLY EVENING HOURS. PRECIP IS EXPECTED TO BREAK OUT IN THE WEST FIRST AND SPREAD TO THE EAST BY THE LATE EVENING. BUFKIT SOUNDINGS DO SHOW A WINTRY MIX OF SNOW...SLEET AND FREEZING RAIN FOR OVERNIGHT AND EARLY SATURDAY ACROSS MUCH OF THE CWFA. SOME RAIN MAY MIX WITH SLEET ACROSS LOWER SOUTHERN MARYLAND. MODELS HAVE COME IN COLDER THE PAST FEW RUNS...SO MORE SLEET/SNOW MAY MIX WITH THE FREEZING RAIN...ESPECIALLY ACROSS THE NW AND ALONG THE MASON DIXON LINE. ONE TO THREE INCHES OF SNOW/SLEET IS POSSIBLE ESPECIALLY ALONG THE MASON DIXON LINE. SNOW/SLEET WILL TRANSITION OVER TO FREEZING RAIN LATE EARLY SATURDAY MORNING. ICE ACCUMULATIONS BETWEEN ONE AND TWO TENTHS OF AN INCH ARE EXPECTED ACROSS THE NORTHERN TWO THIRDS OF THE CWFA...WHILE LESS THAN A TENTH OF AN INCH IS EXPECTED ACROSS THE SOUTHERN THIRD OF THE CWFA. LOCALLY HIGHER AMOUNTS OF ICING ARE POSSIBLE ACROSS NORTHEAST MD...NEAR THE MASON DIXON LINE...AND ACROSS THE FAR WESTERN SUBURBS OF DC. THIS AXIS OF LOCALLY HIGHER ICING (MESOSCALE BANDING) MAY SHIFT WITH LATER MODEL RUNS...SO NOT CONFIDENT ENOUGH TO ISSUE A WARNING AT THIS TIME. FREEZING RAIN EARLY SATURDAY MORNING WILL HANG ON THE LONGEST ACROSS THE NORTHERN QUARTER OF THE CWFA...WHERE COLD AIR IS HARD TO SCOUR OUT. ELSEWHERE...FREEZING RAIN WILL TRANSITION TO ALL RAIN DURING THE MID TO LATE MORNING. PRECIP IS EXPECTED TO HANG ON NEAR THE FRONT THROUGH THE AFTERNOON. -- End Changed Discussion -- Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted January 20, 2012 Share Posted January 20, 2012 SREF QPF > NAM QPF at this range probably. Tho I really have not looked at much today as I'm crushed at work. It's wetter than it was at 9z. Temps at a quick glance seem comparable. Link to comment Share on other sites More sharing options...
mappy Posted January 20, 2012 Share Posted January 20, 2012 High res NAM on e wall has snow starting in DC around 1am Link to comment Share on other sites More sharing options...
Ian Posted January 20, 2012 Author Share Posted January 20, 2012 my benchmark for significant is from a weenie perspective and in the context of DC climo in general and this winter...I don't need to have widespread week long power outages, felled trees on roofs and wires and roads, thousands of minor/major auto accidents and loss of life to enjoy a weather event or judge its impact no one needs the above to make it a decent event. plenty of folks have been taking forecast precip and calling it all ice. this is like a mod event as forecast, maybe mod+ if the "worst case" happens. yeah in this winter its like feb 5-6. Link to comment Share on other sites More sharing options...
Deck Pic Posted January 20, 2012 Share Posted January 20, 2012 no one needs the above to make it a decent event. plenty of folks have been taking forecast precip and calling it all ice. this is like a mod event as forecast, maybe mod+ if the "worst case" happens. yeah in this winter its like feb 5-6. I think it is a 1 in 3/4 year event potentially when you talk about ice/sleet....I'll do an assessment after and maybe compare to other events since I don't think many are as familiar with ice events...It is sometimes hard to compare....2/12/08 happened right before the evening rush so its impact was widespread and if not crippling, very high impact...thousands of accidents...shut down i-95 for a few hours.....-ra and 30 degrees onto a lot of untreated surfaces....but it changed to moderate/heavy rain and mid 30s everywhere by like midnight and was washed away quickly...80-90% of the QPF was rain...it was all timing....I'm not sure how you compare that to an event happening overnight and into a Saturday morning that is less QPF overall but probably higher percent frozen.... Link to comment Share on other sites More sharing options...
BTRWx Posted January 20, 2012 Share Posted January 20, 2012 Tighter snow gradient but higher amounts north of the city from LWX's latest snow accumulation map. http://www.erh.noaa.gov/lwx/winterstorm/ Link to comment Share on other sites More sharing options...
mappy Posted January 20, 2012 Share Posted January 20, 2012 still no mention of rain in my forecast - 100% freezing rain tomorrow. Tonight: A chance of snow and sleet between 10pm and 1am, then snow, freezing rain, and sleet. Low around 27. East wind between 5 and 11 mph. Chance of precipitation is 100%. Total nighttime ice accumulation of 0.1 to 0.2 of an inch possible. Total nighttime snow and sleet accumulation of 1 to 3 inches possible. Saturday: Freezing rain before 1pm. High near 35. East wind 11 to 13 mph becoming north. Chance of precipitation is 100%. New ice accumulation of around a 0.1 of an inch possible. Link to comment Share on other sites More sharing options...
mitchnick Posted January 20, 2012 Share Posted January 20, 2012 Tighter snow gradient but higher amounts north of the city from LWX's latest snow accumulation map. http://www.erh.noaa....wx/winterstorm/ LWX forecast..................................................................................................................................................................................curve Link to comment Share on other sites More sharing options...
Ian Posted January 20, 2012 Author Share Posted January 20, 2012 I think it is a 1 in 3/4 year event potentially when you talk about ice/sleet....I'll do an assessment after and maybe compare to other events since I don't think many are as familiar with ice events...It is sometimes hard to compare....2/12/08 happened right before the evening rush so its impact was widespread and if not crippling, very high impact...thousands of accidents...shut down i-95 for a few hours.....-ra and 30 degrees onto a lot of untreated surfaces....but it changed to moderate/heavy rain and mid 30s everywhere by like midnight and was washed away quickly...80-90% of the QPF was rain...it was all timing....I'm not sure how you compare that to an event happening overnight and into a Saturday morning that is less QPF overall but probably higher percent frozen.... fair enough.. ice makes roads and sidewalks slippery--even a little if there is poor treatment. me and you are very close in our thoughts at this pt if not our choice of words.. there is no meme or whatever. there are certainly people who have commented in this thread that dont seem to get that .4" liquid falling at 28 degrees does not equal .4" of ice. if nws verifies isnt it pretty close to last years ice if also moer snow on the front end? Link to comment Share on other sites More sharing options...
Stormpc Posted January 20, 2012 Share Posted January 20, 2012 Weenie statement (rule #48 or 49)..... Compare the NAM simulated to the real time radar and it looks like the NAM is lagging about 2-3 hrs behind. Maybe a mid to late evening 9-11 start for many south of B'more. Ok, that's it for me. I will post obs because I'm likely to change over the quickest as I am Prince William Cty. Link to comment Share on other sites More sharing options...
gymengineer Posted January 20, 2012 Share Posted January 20, 2012 I think it is a 1 in 3/4 year event potentially when you talk about ice/sleet....I'll do an assessment after and maybe compare to other events since I don't think many are as familiar with ice events...It is sometimes hard to compare....2/12/08 happened right before the evening rush so its impact was widespread and if not crippling, very high impact...thousands of accidents...shut down i-95 for a few hours.....-ra and 30 degrees onto a lot of untreated surfaces....but it changed to moderate/heavy rain and mid 30s everywhere by like midnight and was washed away quickly...80-90% of the QPF was rain...it was all timing....I'm not sure how you compare that to an event happening overnight and into a Saturday morning that is less QPF overall but probably higher percent frozen.... ..well in the city, yes. It stayed freezing rain overnight for the western suburbs, even ones just outside the beltway (IAD didn't go above freezing until 10 am on the 13th). We had an Ice Storm Warning issued later in the evening on the 12th to replace the WWA. Most places in MoCo wast of the beltway got between 0.25 and 0.5" of ice. Link to comment Share on other sites More sharing options...
TL97 Posted January 20, 2012 Share Posted January 20, 2012 New Snow Map Gives Everyone DC and North 1+ Link to comment Share on other sites More sharing options...
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