ncwinterwxman Posted January 24, 2013 Share Posted January 24, 2013 RAH Discussion: .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...AS OF 258 PM WEDNESDAY...A WINTER WEATHER ADVISORY WILL BE ISSUED FOR FRIDAY AFTERNOON ANDFRIDAY EVENING FOR ALL OF CENTRAL NC WITH THE EXCEPTION OF THE FARSOUTHEASTERN COUNTIES (SAMPSON/CUMBERLAND/HOKE/SCOTLAND).OVERVIEW:A WEAK SURFACE LOW ALONG THE WESTERN END OF A COLD FRONT IS FORECASTTO DEVELOP NEAR THE LOWER MISSISSIPPI VALLEY BY FRIDAY MORNING...ANDTHEN QUICKLY TRACK EAST-NORTHEASTWARD THROUGH THE CAROLINAS ONFRIDAY...WHERE A CENTRALIZED LOW WILL EMERGE OFF THE MID-ATLANTICCOAST FRIDAY NIGHT.MODEL TRENDS:AS PREVIOUS DISCUSSIONS HAVE NOTED...MODELS CONTINUES WITH THEDEPICTION OF A WEAK SFC WAVE/FRONTAL PASSAGE...WITH FORCINGPRIMARILY DRIVEN BY LOW-LEVEL WARM ADVECTION VIA A H8 40 TO 50KTSWLY LLJ.THE HIGHER LIQUID EQUIVALENT TOTALS OF A 0.25 TO 0.50" A DAY OR TWOAGO ACROSS CENTRAL NC HAVE TRENDED LOWER WITH TIME. EVEN THE MOREAMPLIFIED/WETTER NAM SOLUTION HAS SHOWN A DRASTIC CUT-BACK IN LIQUIDQPF AMOUNTS WITH THE LATEST 12Z/24 RUN...TRIMMING QPF AMOUNTS TOAROUND A TENTH OF AN INCH IN THE WEST...APPROACHING TWO-TENTHS INTHE EAST...WITH EXPECTATIONS THAT THE A LIGHT PRECIP BAND WILLSPREAD INTO WESTERN PIEDMONT AT AROUND NOON...ATTEMPTING TO FILL INDURING THE AFTERNOON AND EARLY EVENING ACROSS CENTRAL AND EASTERN NCAS SURFACE LOW EMERGES OFF THE DELMARVA COAST.THE 12Z MODEL GUIDANCE ALSO REVEALS A MORE PROMINENT WARM NOSE (2TO 4C)WHILE STILL SHOWING LIMITED/BRIEF PERIOD OF SUFFICIENT MOISTUREWITHIN THE DENDRITIC SNOW GROWTH ZONE. THESE OBSERVATIONS STRONGLYSUGGEST LESS IN THE WAY OF SNOW ACCUMULATIONS...WITH SLEET ANDAND FREEZING RAIN/DRIZZLE THE MAIN PRECIP TYPE(AFTER A BRIEFONSET OF SNOW).TEMPERATURES AND PRECIP TYPES:ONSET OF PRECIP REMAINS IN QUESTION...WITH A PREFERENCE TOWARDS THESLOWER TIMING OF THE EC AND GFS AS IT WILL TAKE SOME TIME TOOVERCOME THE ANTECEDENT DRY ARCTIC BOUNDARY LAYER CONDITIONS(SFCDEWPOINTS IN THE SINGLE DIGITS TO TEENS). WHILE EARLIER ARRIVAL OFPRECIP WILL KEEP THE FAVOR WESTERN PIEDMONT DAMMING REGION BELOWFREEZING...THE SLOWER TIMING COULD POSSIBLY ALLOW TEMPERATURES TORISE ABOVE FREEZING INTO THE 34 TO 39 BY NOON TIME ALONG AND EAST OFTHE TRIANGLE...BEFORE TEMPERATURES WETBULBING BACK DOWN INTO THELOWER TO MID 30S(32 TO 35)AS PRECIPITATION BEGINS TO REACH THESURFACE. MODELS ARE IN GOOD AGREEMENT WITH RETREATING THE FREEZINGSFC WET-BULB ALONG A LINE EXTENDING FROM ROCKINGHAM TO FAYETTEVILLETO GOLDSBORO. IT IS TO THE NORTH OF THIS LINE...WHERE WE EXPECTTHE MOST IMPACTS WITH A LIGHT COATING OF A SNOW/SLEET MIXTURE...WITHA THIN LAYER OF ICE ACCRUAL ON TOP. SOUTH OF THE LINE...WHILE PRECIPCOULD START OUT AS WET SNOW/SLEET...IT WILL QUICKLY CHANGE-OVER TOA COLD RAIN.SNOW AND ICE AMOUNTS:HAVE DECREASED SNOW AMOUNTS ACROSS THE AREA...WITH LESS THAN AN INCHEXPECTED ACROSS THE NORTHERN AND CENTRAL PIEDMONT AND COASTAL PLAINSCOUNTIES...HIGHEST ALONG THE ADJACENT VIRGINIA BORDERING COUNTIESWHERE DEPTH OF COLD AIR IS GREATEST. THEN THE TRICKY IS PART ISWHERE EXACTLY THE CORRIDOR OF ICE WILL LIE...POSSIBLY JUSTOVERLAPPING AND SOUTH OF THE BETTER SNOW ACCUMULATION LINE...WITH AA TENTH OF AN INCH OF ICE POSSIBLE.FACTORS TO CONSIDER THAT MAY ALTER ACCUMULATIONS ARE...1)TIME OF DAYIS UNFAVORABLE WITH THE MAIN BAND PUSHING THROUGH THE AREA BETWEEN20 TO 24Z...LIKELY LIMITING THE MAIN IMPACT TO HOW MUCH FREEZINGRAIN/DRIZZLE FALLS BEHIND THE MAIN BAND...2)FRESH DELIVERY OF ARCTICAIR TODAY AND TONIGHT(LOWS TONIGHT IN THE LOWER 20S) WILL MAKE SOILTEMPERATURES SUFFICIENTLY COLD (MID TO UPPER 30S) TO READILYACCUMULATION OF SNOW/SLEET.FINALLY...STRONG CAA AND LATE CLEARING WITH ALLOW LOWS FRIDAYNIGHT/SATURDAY MORNING TO FALL INTO THE LOWER TO MID 20S...ALLOW ANYMOISTURE TO FREEZE WHILE KEEP SNOW/ICE ACCUMULATIONS ADHERED TOSURFACES...ESPECIALLY BRIDGES AND OVERPASSES. Link to comment Share on other sites More sharing options...
Poimen Posted January 24, 2013 Share Posted January 24, 2013 lol 18Z NAM is back to higher qpf across NC...it even has a qpf max of .47 just east of RDU. Link to comment Share on other sites More sharing options...
nchighcountrywx Posted January 24, 2013 Share Posted January 24, 2013 KGSP Forecast Discussion: AT OR ABOVE 4500 TO 5000 FEET WILL SEE MORE SNOW AND SLEET. IN FACT THESE LOCATIONS MAY HITWARNING CRITERIA...BUT WE DO NOT ISSUE WARNINGS FOR THE RIDGE TOPS. (High Country Folks are on our own!) Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 24, 2013 Share Posted January 24, 2013 Nice max showing in northern TN. With all the technology and complex mathmatical formulas in place it makes you wonder how models can be so different with showing a qpf max from a day away? One model shows it in northern AL/GA, the other modeling in northern TN. Impressively frustrating. More like irritating. Back in the day when I was at UNCA (early 90s) the NGM was the primary model but this new model was coming out called the ETA which had more resolution and was going to replace the NGM. But it never happened and the old AVN model became the GFS and the primary model of choice while the ETA turned into the NAM and is still considered the lesser model of choice. Go figure... Link to comment Share on other sites More sharing options...
Bozart Posted January 24, 2013 Share Posted January 24, 2013 > Matthew east on twitter. Rah will issue waa for Raleigh area.> even before RAH lays out the WAA.> Gsp discussion is out. Waa for most of the area. Do y'all really mean WWA (Winter Weather Advisory), or am I seriously confused? Link to comment Share on other sites More sharing options...
tnweathernut Posted January 24, 2013 Share Posted January 24, 2013 If he cared about his credibility back here in TN (which I am sure he doesn't) he'd take the 2-4 and 3-5 out. I'll eat my car (and invite everyone in the southeast forum to watch) if ktri gets 3-5 and ktys gets 2-4. uh oh, the new NAM says I need to get my car eating shoes on. (ok, well the clown map says I do). I am sure there will be a warm nose,(could be severe icing), but what is most interesting (for our area) is the trend north was abruptly ended and the heaviest qpf field has settled back south a little. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 24, 2013 Share Posted January 24, 2013 18z NAM says TRI is all snow at 10am but changes over to freezing rain before 1pm and stays below freezing for the duration of the whole event. TYS sounding don't support snow unfortunately. Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 24, 2013 Share Posted January 24, 2013 New map Link to comment Share on other sites More sharing options...
Mr Bob Posted January 24, 2013 Share Posted January 24, 2013 If he cared about his credibility back here in TN (which I am sure he doesn't) he'd take the 2-4 and 3-5 out. I'll eat my car (and invite everyone in the southeast forum to watch) if ktri gets 3-5 and ktys gets 2-4. Yup...why not have a map that just includes the specific area you are forecasting for...it would not take much effort...very sloppy... Link to comment Share on other sites More sharing options...
SnowDeac Posted January 24, 2013 Share Posted January 24, 2013 Wonder if GSP is issuing nothing, or just taking their time. Seems like they would issue before RAH, simply since the precip will be here sooner, and amounts should be similar. Link to comment Share on other sites More sharing options...
MillerA Posted January 24, 2013 Share Posted January 24, 2013 > Matthew east on twitter. Rah will issue waa for Raleigh area. > even before RAH lays out the WAA Yea. Sorry > Gsp discussion is out. Waa for most of the area. Do y'all really mean WWA (Winter Weather Advisory), or am I seriously confused? Link to comment Share on other sites More sharing options...
calculus1 Posted January 24, 2013 Share Posted January 24, 2013 18Z NAM with the precipitation hole in the lee of the Apps...................once again. It is to be expected. Link to comment Share on other sites More sharing options...
burgertime Posted January 24, 2013 Share Posted January 24, 2013 Hi-Res NAM puts RDU around .40 and south CLT around .25 we'll have to see if the short range models start upping QPF...if so this could be trouble. Link to comment Share on other sites More sharing options...
Mr Bob Posted January 24, 2013 Share Posted January 24, 2013 More like irritating. Back in the day when I was at UNCA (early 90s) the NGM was the primary model but this new model was coming out called the ETA which had more resolution and was going to replace the NGM. But it never happened and the old AVN model became the GFS and the primary model of choice while the ETA turned into the NAM and is still considered the lesser model of choice. Go figure... The NGM was good because we knew where it would fail...ETA was all over the place and extremely biased on QPF (Wet-A) so it was not altogether popular at first. Today's NAM is way better than those day but it will never get precise enough to satisfy the current generation. Link to comment Share on other sites More sharing options...
burgertime Posted January 24, 2013 Share Posted January 24, 2013 Also per the Hi-RES NAM...RDU starts as snow...goes over to sleet then looks to end as snow. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 24, 2013 Share Posted January 24, 2013 Hi-Res NAM puts RDU around .40 and south CLT around .25 we'll have to see if the short range models start upping QPF...if so this could be trouble. You use Storvista for that? Link to comment Share on other sites More sharing options...
Poimen Posted January 24, 2013 Share Posted January 24, 2013 Hi-Res NAM puts RDU around .40 and south CLT around .25 we'll have to see if the short range models start upping QPF...if so this could be trouble. agreed. .40 of mostly ice with the already established cold would spell much trouble. But then again it's the NAM... Link to comment Share on other sites More sharing options...
jburns Posted January 24, 2013 Share Posted January 24, 2013 > even before RAH lays out the WAA. Do y'all really mean WWA (Winter Weather Advisory), or am I seriously confused? Typo. WAA is what Brick does. Link to comment Share on other sites More sharing options...
burgertime Posted January 24, 2013 Share Posted January 24, 2013 You use Storvista for that? Yea using SV looking at the SE quadrant. Link to comment Share on other sites More sharing options...
packfan98 Posted January 24, 2013 Share Posted January 24, 2013 18Z NAM with the precipitation hole in the lee of the Apps...................once again. It is to be expected. That's the first model I have seen in a while with .25 qpf for the Triad. I wouldn't be surprised if that area was extended a little more to the south on the next run. Can there be a mini-trend back up with the precip? Another .1 for many areas would cause many more problems. Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 24, 2013 Share Posted January 24, 2013 Atlanta NWS is in a quandary: WITH THAT ALL BEING SAID THERE ARE A COUPLE OF THINGS THAT STILL CONCERN ME ABOUT THIS FORECAST. 1. WE HAVE VERY LOW DEWPOINT TEMPERATURES ACROSS NORTHERN GEORGIA. MODEL SOUNDINGS DEPICT A SHALLOW DRY LAYER AT THE SURFACE. AS PRECIPITATION FALLS INTO THIS LAYER...THIS LAYER COULD COOL FASTER THAN FORECAST. THIS PRECIPITATION MAY ALSO LEAD TO A STRENGTHEN OF THE OVERALL CAD. IF THIS IS THE CASE...MORE ICE COULD ACCUMULATE THAN FORECAST...ESPECIALLY ACROSS NW GA AND METRO AREA. 2. OVERALL MOISTURE WITH THIS SYSTEM IS NOT TOO IMPRESSIVE. QPF VALUES SUGGESTS AN AREA OF SIGNIFICANT ICE ACROSS THE NE GA MOUNTAINS. HOWEVER...MOST OF THE MOISTURE THAT IS ADVECTING INTO THE AREA AT THE 295K ISENTROPIC SURFACE HAS A RATHER LONG FETCH ACROSS THE COASTAL SOUTHERN UNITED STATES. WHILE ITS SOURCE IS FROM THE GULF...THE FLOW COMES FROM THE EAST IN TEXAS. THIS MAY...LEAD TO LESS MOISTURE MAKING IT INTO THE AREA THAN FORECAST. IF THIS IS THE CASE THEN THE CURRENT ICE ACCUMULATION VALUES AND TOTAL QPF WOULD BE OVERDONE. Link to comment Share on other sites More sharing options...
BRAD74 Posted January 24, 2013 Share Posted January 24, 2013 wwa for Charlotte area Link to comment Share on other sites More sharing options...
franklin NCwx Posted January 24, 2013 Share Posted January 24, 2013 18Z NAM with the precipitation hole in the lee of the Apps...................once again. It is to be expected. not a good run for the sw mtns. Over .50 qpf and mostly ice maybe an inch of snow to start. Link to comment Share on other sites More sharing options...
RevDodd Posted January 24, 2013 Share Posted January 24, 2013 Per NWS Chat: GSP is writing up its WWA as we speak. Should include most, if not all, counties in the WSPA viewing area. Stand by your computers! Link to comment Share on other sites More sharing options...
NGaWxNerd Posted January 24, 2013 Share Posted January 24, 2013 Atlanta NWS is in a quandary: WITH THAT ALL BEING SAID THERE ARE A COUPLE OF THINGS THAT STILL CONCERN ME ABOUT THIS FORECAST. 1. WE HAVE VERY LOW DEWPOINT TEMPERATURES ACROSS NORTHERN GEORGIA. MODEL SOUNDINGS DEPICT A SHALLOW DRY LAYER AT THE SURFACE. AS PRECIPITATION FALLS INTO THIS LAYER...THIS LAYER COULD COOL FASTER THAN FORECAST. THIS PRECIPITATION MAY ALSO LEAD TO A STRENGTHEN OF THE OVERALL CAD. IF THIS IS THE CASE...MORE ICE COULD ACCUMULATE THAN FORECAST...ESPECIALLY ACROSS NW GA AND METRO AREA. 2. OVERALL MOISTURE WITH THIS SYSTEM IS NOT TOO IMPRESSIVE. QPF VALUES SUGGESTS AN AREA OF SIGNIFICANT ICE ACROSS THE NE GA MOUNTAINS. HOWEVER...MOST OF THE MOISTURE THAT IS ADVECTING INTO THE AREA AT THE 295K ISENTROPIC SURFACE HAS A RATHER LONG FETCH ACROSS THE COASTAL SOUTHERN UNITED STATES. WHILE ITS SOURCE IS FROM THE GULF...THE FLOW COMES FROM THE EAST IN TEXAS. THIS MAY...LEAD TO LESS MOISTURE MAKING IT INTO THE AREA THAN FORECAST. IF THIS IS THE CASE THEN THE CURRENT ICE ACCUMULATION VALUES AND TOTAL QPF WOULD BE OVERDONE. What kind of fence riding is this? Link to comment Share on other sites More sharing options...
Moonhowl Posted January 24, 2013 Share Posted January 24, 2013 KGSP Forecast Discussion: AT OR ABOVE 4500 TO 5000 FEET WILL SEE MORE SNOW AND SLEET. IN FACT THESE LOCATIONS MAY HIT WARNING CRITERIA...BUT WE DO NOT ISSUE WARNINGS FOR THE RIDGE TOPS. (High Country Folks are on our own!) LOL, No warning for you!! in my best Soup Nazi voice. It seems with GFS very low on QPF, dry air, and timing; I don't see this being much of an event for Asheville. Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 24, 2013 Share Posted January 24, 2013 New updates Link to comment Share on other sites More sharing options...
Mr Bob Posted January 24, 2013 Share Posted January 24, 2013 Gotta love these Tds down in the single digits into Nashville and Knoxville...unless you hate ice. KMRX AFD slightly downplaying accretions...more than a nuisance but not a major ice storm. Link to comment Share on other sites More sharing options...
DaculaWeather Posted January 24, 2013 Share Posted January 24, 2013 URGENT - WINTER WEATHER MESSAGENATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC333 PM EST THU JAN 24 2013...WINTRY PRECIPITATION LIKELY FRIDAY AFTERNOON AND FRIDAY NIGHT....A FAST MOVING FRONTAL SYSTEM WILL MOVE THROUGH EASTERN NORTHCAROLINA FRIDAY EVENING. THE ARCTIC AIRMASS IN PLACE COUPLED WITHINCREASING MOISTURE WILL LEAD TO A WINTRY MIX ACROSS PORTIONS OFEASTERN NORTH CAROLINA. PRECIPITATION WILL LIKELY BEGIN FRIDAYAFTERNOON AS MIX OF RAIN...SNOW...AND SLEET THEN TRANSITION TORAIN...SLEET...AND FREEZING RAIN. PRECIPITATION WILL TAPER OFFFRIDAY NIGHT.NCZ029-044-045-079-080-250900-/O.NEW.KMHX.WW.Y.0002.130125T2100Z-130126T0600Z/MARTIN-PITT-WASHINGTON-GREENE-BEAUFORT-INCLUDING THE CITIES OF...WILLIAMSTON...ROBERSONVILLE...GREENVILLE...PLYMOUTH...SNOW HILL...HOOKERTON...WASHINGTON...RIVER ROAD333 PM EST THU JAN 24 2013...WINTER WEATHER ADVISORY IN EFFECT FROM 4 PM FRIDAY TO 1 AM ESTSATURDAY...THE NATIONAL WEATHER SERVICE IN NEWPORT/MOREHEAD CITY HAS ISSUEDA WINTER WEATHER ADVISORY...WHICH IS IN EFFECT FROM 4 PM FRIDAYTO 1 AM EST SATURDAY.* HAZARD TYPES...SNOW...SLEET...FREEZING RAIN...AND FREEZING DRIZZLE.* ACCUMULATIONS...SNOW ACCUMULATION OF UP TO 1 INCH...ALONG WITH A LIGHT GLAZE OF ICE.* TIMING...FRIDAY AFTERNOON THROUGH FRIDAY NIGHT.* IMPACTS...SNOW AND ICE ACCUMULATIONS WILL LEAD TO SLICK ROADWAYS...ESPECIALLY ON BRIDGES AND OVERPASSES...CREATING HAZARDOUS DRIVING CONDITIONS. THIS WILL HAVE AN IMPACT ON THE EVENING RUSH HOUR.* TEMPERATURES...IN THE LOWER TO MIDDLE 30S.PRECAUTIONARY/PREPAREDNESS ACTIONS...A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW...SLEET...ORFREEZING RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FORSLIPPERY ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILEDRIVING. Link to comment Share on other sites More sharing options...
Dunkman Posted January 24, 2013 Share Posted January 24, 2013 The schools here in the Triad (and other similar) areas have a tough decision for tomorrow. They could probably squeeze in a half-day, and maybe get by with a 2-hour early release, but it would be cutting it very close. Many schools have gone to using a system with one set of buses to service the 3 schools in a district and using staggered start times. If the precip is even an hour or 2 earlier than forecast they may literally not be able to get the kids home. I know they hate to cancel school in situations like this (no guarantee of substantial winter weather) because the parents will be irate if it doesn't snow/ice. However, given what Raleigh had happen several years ago I'm not sure they can afford to take any chances. People literally had to leave their cars on the roads and start walking. Link to comment Share on other sites More sharing options...
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