eurojosh Posted December 7, 2013 Share Posted December 7, 2013 I guess they are waiting for the GFS to make a decision on the remaining watch area. Yes... So is LWX: SUN NGT SLT WARMING IS XPCTD ALOFT...CHANGING PCPN TO LIQUID. BUT THE HIGH TO THE N WL KEEP COLD AIR FUNNELING INTO THE AREA...WHICH WL LKLY LEAD TO ACCUMULATING FRZG RA...WHICH IS THE BIGGEST CONCERN FM THIS STORM. IT IS PSBL THAT A WINT STORM WRNG MAY BE NEEDED FOR THE NWRN CORNER OF THE CWA...BUT AS THE ACCRETION WOULD BE HIGHEST SUN NGT THIS WOULD BE ISSUED BY A LATER SHIFT. TEMPS IN THE I-95/METRO AREAS WL BE BORDERLINE....AND AT CURRENT ROAD TEMPS THERE ARE IN THE MU40S...SO FRZG ACCUMS MAY NOT BE AS BAD THERE. BUT FURTHER W THE SUB FRZG COLD POCKET COULD LAST THRUT THE NGT...ESPECIALLY IN WRN MD/MINERAL+GRANT/FREDERICK VA. AT THIS TIME WE STILL HV A WTCH IN EFFECT. WE`LL NEED TO MAKE SOME DECISIONS THIS AFTN...ALTHO IF SIG ICING IS XPCTD IT PRBLY WON`T BE UNTIL SUN EVE...WHICH IS STILL OVR 30 HRS AWAY. FOR NOW WL BE HOLDING W/ THE WINT STORM WTCH...BUT MAY BE ISSUING SOME ADVISORIES W/ THE AFTN PCKG. CONFIDENCE OF REACHING WRNG LVL ICING/OR COMBO OF P-TYPES IS QUSTNBL ATTM. Link to comment Share on other sites More sharing options...
swva Posted December 7, 2013 Share Posted December 7, 2013 18z NAM finally admits LYH will be below freezing Monday, 7am The cold air always takes longer to erode in these CAD events than models show. I think they are catching on now. Could be a really nasty ice storm per the trends. But NAM seems a little warmer.. I think for this to have a huge impact the temperatures have to be below 30 degrees. Link to comment Share on other sites More sharing options...
PhineasC Posted December 7, 2013 Share Posted December 7, 2013 We won't get a warning around the cities. Link to comment Share on other sites More sharing options...
Huffwx Posted December 7, 2013 Share Posted December 7, 2013 The cold air always takes longer to erode in these CAD events than models show. I think they are catching on now. Could be a really nasty ice storm per the trends. But NAM seems a little warmer.. I think for this to have a huge impact the temperatures have to be below 30 degrees. Well, it's not a driving rain thought-- it's light to moderate stuff. That's a difference as well. Back in the day, using the 975 modeled number was a good guess of the actual surface temp on the nam--if we applied that we are looking at upper 20s Link to comment Share on other sites More sharing options...
wxdude64 Posted December 7, 2013 Share Posted December 7, 2013 The cold air always takes longer to erode in these CAD events than models show. I think they are catching on now. Could be a really nasty ice storm per the trends. But NAM seems a little warmer.. I think for this to have a huge impact the temperatures have to be below 30 degrees. I've got the generator set up and gas cans full. Link to comment Share on other sites More sharing options...
WVclimo Posted December 7, 2013 Share Posted December 7, 2013 My point and click updated, and says 1-3" of snow during the day and 0.1" of ice overnight. So WWA likely up here. I'm still in the green for total precip through 12Z Monday on the 18Z NAM. Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 18z RGEM continues to insist on snow... 8 to 10mm of it for DCA Link to comment Share on other sites More sharing options...
TSSN+ Posted December 7, 2013 Share Posted December 7, 2013 18z RGEM continues to insist on snow... 8 to 10mm of it for DCA Pretty solid run. Then ice death NW. 10-15mm ZR. Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 Just a small difference of heavy precip placement between the 18z NAM at 15 hrs (in C MS) and the 18z GFS at 15 hrs (in E TN/W NC) Link to comment Share on other sites More sharing options...
PhineasC Posted December 7, 2013 Share Posted December 7, 2013 The GFS looks like crap to me. Link to comment Share on other sites More sharing options...
ACFD FIREMAN Posted December 7, 2013 Share Posted December 7, 2013 The GFS looks like crap to me. .50-75+ areawide...frozen w/ front-end snow. Not sure what you're looking at..... Link to comment Share on other sites More sharing options...
snowdude Posted December 7, 2013 Share Posted December 7, 2013 The GFS looks like crap to me. Has that heavier band south of the city like the NAM Link to comment Share on other sites More sharing options...
ACFD FIREMAN Posted December 7, 2013 Share Posted December 7, 2013 In fact it's wetter than 12z. Link to comment Share on other sites More sharing options...
aldie 22 Posted December 7, 2013 Share Posted December 7, 2013 Were you living here in 2007 or 1999? The Valentine's sleet storm in 2007 we had out in the western suburbs was a major ice storm in SE MD-- more than 100,000 power outages. 1/14-15/99 was the area's largest power outage until Isabel. Yeah, high impact like that is rare, but it does occasionally happen. This looks more like the ones we get once every other winter. Sorry I meant freezing rain Link to comment Share on other sites More sharing options...
eurojosh Posted December 7, 2013 Share Posted December 7, 2013 LWX experimental winter page just removed their snow graphics, which had previously been showing 1-2" for DC metro, and now have a line that says "we do not expect measurable snow within the next 36 hours".... http://www.erh.noaa.gov/lwx/winter/index.php#table Edit: Never mind, I must have hit refresh between updates, it's back. Sorry for any heartburn... Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted December 7, 2013 Share Posted December 7, 2013 Looks like a snow sounding at 24, and a sleet or freezing rain sounding at 27 for DCA, so 0.1+ before the changeover to sleet/frz rain. Link to comment Share on other sites More sharing options...
Bob Chill Posted December 7, 2013 Share Posted December 7, 2013 Gfs right within the envelope of guidance. And stays below freezing through 2am 95 and West. The precip maxima with the front wave seems anchored just south of dc but hard to say where it verifies. You can pick any solution today and have equal odds at being right. I'll stick with the euro. Link to comment Share on other sites More sharing options...
TSSN+ Posted December 7, 2013 Share Posted December 7, 2013 Still think this ice map is horrible. Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 Gfs right within the envelope of guidance. And stays below freezing through 2am 95 and West. The precip maxima with the front wave seems anchored just south of dc but hard to say where it verifies. You can pick any solution today and have equal odds at being right. I'll stick with the euro. 12z EURO/18z GFS/18z RGEM allow for some snow... 18z NAM does not Link to comment Share on other sites More sharing options...
Bob Chill Posted December 7, 2013 Share Posted December 7, 2013 12z EURO/18z GFS/18z RGEM allow for some snow... 18z NAM does not 18z nam could be right but it's an outlier for now. Guidance has been really steady for days and days overall. It just feels like big swings because we are walking such a tight line with temps overhead. Also, the initial precip max is pretty narrow. 20 miles shifts are really small but they feel really huge. I'm looking forward to nowcast tomorrow. I'm kinds burnt on models for a bit. Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 Interesting ...LOWER MS VLY TO OH/TN VALLEYS AND MID-ATL REGION...THE UPPER SHORT WAVE DEPARTING THE WEST WILL IGNITE THE NEXT ROUNDOF LARGE SCALE MOISTURE RETURN FROM THE GULF OF MEXICO/SUBTROPICSAND OVERRUN INTO THE SETTLED ARCTIC AIR MASS SPRAWLING FROM THEMIDWEST TO EAST. THIS WILL RESULT IN A WIDESPREAD ARRAY OF PRECIPTYPES AND A COUPLE OF WAVES OF PRECIP. THE INITIAL ONSET OFMOISTURE WILL BE ICING/FREEZING RAIN TMRW MORNING FROM NRN LA/MSAND PARTS OF AR INTO THE TN VALLEY BEFORE THEN CHANGING OVER TO ASTEADY MDT RAIN IN THE AFTN WITH A SECOND WAVE. MEANWHILE ACROSSOH VALLEY TMRW MORNING MOST OF THE QPF WILL BE FREEZINGRAIN/PERHAPS SOME SLEET BUT THIS SHIELD OF PRECIP WILL ADVECTDOWNSTREAM INTO THE MID-ATL STATES FOR LATE MORNING/MIDDAY THROUGHTHE REST OF THE FCST PERIOD. THE LARGE SCALE CONFLUENT UPPER FLOWWILL PRODUCE AN IMPRESSIVE DAMMING SITUATION OF HIGH PRESSURE EASTOF THE APPALACHIANS FOR WIDESPREAD HEAVY AND POSSIBLY PARALYZINGICING FROM WRN NC INTO SWRN/SOUTH CENTRAL VA. THEN ACROSS THEDC/BAL METRO AREA NORTH INTO SRN PA... EXPECT THE PRECIP TO STARTOFF AS ALL SNOW AND THEN POSSIBLY TRANSITION TO FREEZING RAIN...THE FIRST TRUE TASTE OF WINTER FOR SOME HERE. OVERALL... WPCSTAYED VERY CLOSE TO THE OPERATIONAL VERSIONS OF THE GFS/ECMWFWITH THE INTERNAL PSEUDO BIAS CORRECTED GUIDANCE FOR QPF AMOUNTS. http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=qpfpfd Link to comment Share on other sites More sharing options...
CoastalWx Posted December 7, 2013 Share Posted December 7, 2013 Those areas SW of DCA might have a serious icing event since the warm air aloft floods that area very quickly, but they will obviously be wedged. Link to comment Share on other sites More sharing options...
wxdude64 Posted December 7, 2013 Share Posted December 7, 2013 NWS Blacksburg just increased my point and click forecast from 1-2 inches snow/sleet and 0.50 of ice to 2-4 inches snow/sleet and 0.30-0.50 inches of ice? Link to comment Share on other sites More sharing options...
Jebman Posted December 7, 2013 Share Posted December 7, 2013 It would be useful to know what the road temps are in northern Virginia for eastern Prince William. I've been hoping that the couple days of mild weather would enable the roads to stay wet and not ice up tomorrow. Link to comment Share on other sites More sharing options...
snowdude Posted December 7, 2013 Share Posted December 7, 2013 It would be useful to know what the road temps are in northern Virginia for eastern Prince William. I've been hoping that the couple days of mild weather would enable the roads to stay wet and not ice up tomorrow. I think they said mid 40s and colder than that west of town Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 LWX went WWA for east of I95 including DC and Balt... 1 to 2 inch of snow and up to two tenths of an inch of ice... begins at 8am URGENT - WINTER WEATHER MESSAGENATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC555 PM EST SAT DEC 7 2013MDZ017-018-080700-/O.NEW.KLWX.WW.Y.0034.131208T1300Z-131209T0100Z/ST. MARYS-CALVERT-INCLUDING THE CITY OF...ST MARYS CITY555 PM EST SAT DEC 7 2013...WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM TO 8 PM ESTSUNDAY...THE NATIONAL WEATHER SERVICE IN BALTIMORE MD/WASHINGTON HASISSUED A WINTER WEATHER ADVISORY FOR SNOW...SLEET AND FREEZINGRAIN...WHICH IS IN EFFECT FROM 8 AM TO 8 PM EST SUNDAY.* PRECIPITATION TYPE...SNOW AND SLEET WILL CHANGE OVER TO FREEZING RAIN AND THEN RAIN.* ACCUMULATIONS...UP TO 1 INCH OF SNOW AND SLEET FOLLOWED BY UP TO A TENTH OF AN INCH OF ICE.* TIMING...SNOW AND SLEET WILL DEVELOP SUNDAY MORNING...THEN WILL CHANGE TO FREEZING RAIN SUNDAY AFTERNOON. FREEZING RAIN WILL THEN LIKELY CHANGE TO RAIN SUNDAY EVENING. URGENT - WINTER WEATHER MESSAGENATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC555 PM EST SAT DEC 7 2013DCZ001-MDZ007-011-013-014-016-VAZ054-057-080700-/O.UPG.KLWX.WS.A.0008.131208T1400Z-131209T1200Z//O.NEW.KLWX.WW.Y.0034.131208T1300Z-131209T1200Z/DISTRICT OF COLUMBIA-HARFORD-SOUTHERN BALTIMORE-PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ARLINGTON/FALLS CHURCH/ALEXANDRIA-KING GEORGE-INCLUDING THE CITIES OF...WASHINGTON...BALTIMORE...ANNAPOLIS...WALDORF...ALEXANDRIA...FALLS CHURCH555 PM EST SAT DEC 7 2013...WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM SUNDAY TO 7 AM ESTMONDAY...THE NATIONAL WEATHER SERVICE IN BALTIMORE MD/WASHINGTON HASISSUED A WINTER WEATHER ADVISORY FOR SNOW...SLEET AND FREEZINGRAIN...WHICH IS IN EFFECT FROM 8 AM SUNDAY TO 7 AM EST MONDAY.THE WINTER STORM WATCH IS NO LONGER IN EFFECT.* PRECIPITATION TYPE...SNOW AND SLEET WILL CHANGE OVER TO FREEZING RAIN AND THEN TO RAIN.* ACCUMULATIONS...1 TO 2 INCHES OF SNOW AND SLEET FOLLOWED BY UP TO TWO TENTHS OF AN INCH OF ICE.* TIMING...SNOW AND SLEET WILL DEVELOP SUNDAY MORNING...THEN IS EXPECTED TO CHANGE TO FREEZING RAIN SUNDAY AFTERNOON. FREEZING RAIN WILL CONTINUE SUNDAY NIGHT BEFORE CHANGING OVER TO RAIN BY EARLY MONDAY MORNING. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted December 7, 2013 Share Posted December 7, 2013 Don't know if this is what you guys call a southern stream, but this stuff definitely has a southern and tropical connection. Link to comment Share on other sites More sharing options...
snowdude Posted December 7, 2013 Share Posted December 7, 2013 LWX went WWA for east of I95 including DC and Balt They're running out of timmmeeeeee!! haha jk Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 And they keep the watch for now for everyone else? Link to comment Share on other sites More sharing options...
Jebman Posted December 7, 2013 Share Posted December 7, 2013 I think they said mid 40s and colder than that west of town I am very happy that I live well east of those mountains. They can enjoy all that ice on the roads. With a 45 degree road we should only have wet roads, and an inch of snow on a warm road is no prob. I for one do NOT want to get ''Dallas'ed''. Link to comment Share on other sites More sharing options...
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