DaculaWeather Posted January 23, 2013 Share Posted January 23, 2013 URGENT - WINTER WEATHER MESSAGENATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC307 PM EST WED JAN 23 2013...POTENTIAL ICE STORM FRIDAY....A FRONTAL SYSTEM WILL MOVE THROUGH THE REGION ON FRIDAY BRINGINGA PERIOD OF PRECIPITATION. WITH COLD AIR WEDGED AGAINST THESOUTHERN APPALACHIANS...A WINTRY MIX OF PRECIPITATION TYPES WILLRESULT ESPECIALLY IN THE MOUNTAINS.GAZ010-017-NCZ051-052-058-059-062>065-SCZ001>003-240400-/O.NEW.KGSP.WS.A.0003.130125T0600Z-130126T0400Z/RABUN-HABERSHAM-SWAIN-HAYWOOD-GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-OCONEE MOUNTAINS-PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-INCLUDING THE CITIES OF...CLAYTON...CLARKESVILLE...BRYSON CITY...WAYNESVILLE...SYLVA...FRANKLIN...BREVARD...HENDERSONVILLE307 PM EST WED JAN 23 2013 THE NATIONAL WEATHER SERVICE IN GREENVILLE-SPARTANBURG HAS ISSUEDA WINTER STORM WATCH...WHICH IS IN EFFECT FROM LATE THURSDAYNIGHT THROUGH FRIDAY EVENING.* LOCATIONS...THE MOUNTAINS OF SOUTHWEST NORTH CAROLINA...FAR NORTHWEST SOUTH CAROLINA...AND FAR NORTHEAST GEORGIA.* HAZARDS...WINTRY PRECIPITATION...MOSTLY IN THE FORM OF FREEZING RAIN...BUT ALSO MIXED WITH SLEET AT TIMES.* TIMING...EARLY FRIDAY MORNING THROUGH EARLY SATURDAY MORNING...WITH MOST OF THE PRECIPITATION FALLING AROUND MIDDAY FRIDAY.* ACCUMULATIONS...AROUND ONE QUARTER OF AN INCH OF ICE...ALONG WITH SNOW AND SLEET ACCUMULATION OF UP TO A HALF INCH.* IMPACTS...ICE AND SLEET WILL CAUSE ROADWAYS AND SIDEWALKS TO BECOME SLIPPERY...MAKING TRAVEL DANGEROUS...ESPECIALLY ON BRIDGES AND OVERPASSES. ICE MAY ALSO ACCUMULATE ON POWER LINES AND CAUSING THEM TO FALL...LEADING TO POWER OUTAGES.* TEMPERATURES...IN THE UPPER 20S TO LOWER 30S.* WINDS...SOUTH 5 TO 10 MPH WITH GUSTS UP TO 20 MPH. Link to comment Share on other sites More sharing options...
franklin NCwx Posted January 23, 2013 Share Posted January 23, 2013 Well, the ukie drops plenty of qpf. It's still amped Link to comment Share on other sites More sharing options...
I85Greenville Posted January 23, 2013 Share Posted January 23, 2013 GSP disco is up, and Winter Storm Watch has been issues for some counties in the Upstate and WNC SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/ AS OF MIDDAY WED...NOT MUCH GOING ON IN THE UPPER ATMOSPHERE TO START THE PERIOD AT 00Z FRI...WITH A PRONOUNCED TROUGH SLIDING OFF INTO THE ATLANTIC LEAVING QUASI-ZONAL FLOW IN PLACE ACROSS THE EAST BEFORE NEXT TROUGH MOVES FROM THE NORTHERN PLAINS OVER THE MID-ATLANTIC REGION LATE IN THE SHORT TERM PERIOD. MOST OF THE ACTION WILL COME FROM LOW LEVEL FORCING ASSOCIATED WITH SPRAWLING SFC HIGH SHIFTING FROM THE OHIO VALLEY ONTO THE EASTERN SEABOARD THU NIGHT SETTING UP IN-SITU CAD ACROSS THE CAROLINAS. SFC LOW DEVELOPS IN ITS WAKE OVER THE NRN PLAINS AT THAT TIME...MAGNIFYING SOUTHERLY FLOW ACROSS THE LOWER MISS VALLEY AND LEADING TO DEVELOPMENT OF PRECIP IN THE BAROCLINIC ZONE THERE. THE LOW SHIFTS INTO THE GREAT LAKES REGION OVERNIGHT THU NIGHT PULLING THE BEST ISENTROPIC LIFT AND MOISTURE ADVECTION INTO THE TENN VALLEY BY EARLY FRI MORNING. AS NOTED YESTERDAY...NAM IS FIRST TO BRING PRECIP INTO OUR SW MTNS WITH ACCUMULATIONS ALREADY BY DAYBREAK FRI. HOWEVER THE ISENTROPIC LIFT WITH LOW CONDENSATION PRESSURE DEFICITS IS SEEN ON THE GFS/EC PRIOR TO THAT TIME SO I FAVOR THE EARLY START. THE RELATIVELY RAPID MOVEMENT OF THE LOW MEANS THE PRECIP SHOULD SPREAD EAST QUICKLY AND NOT BE AN ESPECIALLY LONG DURATION EVENT. QPF VALUES ARE HIGHEST FROM THE NAM...WHICH IS A LITTLE SURPRISING GIVEN THE SLIGHTLY HIGHER PWATS SEEN ON THE GFS. FOR THE MOST PART...FAVORED A BLEND OF HPC AND GFS GUIDANCE WHICH WERE FAIRLY CLOSELY MATCHED. THE TRACK OF THE LOW IS SUCH THAT IT COULD ERODE THE CAD WEDGE...AND THE MODELS SHOW THIS. HOWEVER GIVEN THE PRE-EXISTING COLD AIR MASS PRESENTLY IN PLACE AND PAST EXPERIENCE WITH HIGH PRESSURE CENTERS FOLLOWING THIS TRACK...THE WEDGE COULD HOLD STRONG. THE NAM HOLDS ON TO THE WEDGE THE LONGEST OF THE OPNL MODELS AND ALSO HAS THE COOLEST RAW TEMPS. THAT SEEMS LIKE THE MOST PLAUSIBLE SOLUTION SO I FAVORED A BLEND OF RAW NAM AND NAM MOS TEMPS FRIDAY...ALONG WITH NAM THERMAL PROFILES THROUGH THE EVENT. WITH THE STRONG WARM ADVECTION OVERRIDING THE COLD WEDGE...MOST OF THE CWFA LOOKS TO GET MOSTLY FREEZING RAIN. SOME SLEET WILL OCCUR FURTHER NORTH WHERE THE WARM NOSE WILL NOT BE QUITE AS STRONG PER BOURGOUIN PTYPE TECHNIQUE...WITH MOSTLY TO ALL SNOW ACROSS OUR NORTHERN TIER OF COUNTIES. AS THE SFC LOW MOVES INTO THE MID-ATLANTIC AND TURNS FLOW WESTERLY ACROSS THE REGION...MOISTURE AND WARMER AIR ARE PUSHED OUT OF THE PIEDMONT BY FRI EVENING. UPSLOPE WILL ALLOW CONTINUING PRECIP IN THE MTNS. THE SHALLOW MOIST LAYER IS TOO WARM FOR ICE NUCLEATION SO FREEZING RAIN SHOULD RESULT...THOUGH WITH ONLY VERY SMALL ADDITIONAL ACCUMULATION. SAID PCPN IS EXPECTED TO BE CONFINED TO PRIME UPSLOPE AREAS IN THE NRN NC MTNS AND DIMINISH BY MID MORNING SAT. HIGHS WILL REBOUND A BIT OVER THE PIEDMONT GIVEN THE SUNSHINE...BUT STILL SEVERAL DEGREES BELOW NORMAL. Link to comment Share on other sites More sharing options...
deltadog03 Posted January 23, 2013 Share Posted January 23, 2013 Of course, 48-72 hours prior to our last event, the RPM didn't even have a drop of rain in the western Carolinas..... nevermind that 2+" soaking before any wintry precip. I remember because it was totally unusable on air for me at that point.... I agree Matt, I remember that as well. It did a really good job once we got in about 36hr... We shall see. I just can't buy that it won't put anymore qpf than its showing. Link to comment Share on other sites More sharing options...
SnowNiner Posted January 23, 2013 Share Posted January 23, 2013 Brad Panovich's Blog http://wxbrad.com/winter-storm-chances-increasing-friday/ I still think this thing dries out and it's a non-event for east of the mountains/foothills. Link to comment Share on other sites More sharing options...
WeatherNC Posted January 23, 2013 Share Posted January 23, 2013 RAH called QPF in for questioning, guess it's suspect. DO NOT PLAN ANY TO GO WITH ANY WINTER STORM ADVISORIES AT THISTIME...WITH PREFERENCE TO WAIT AND SEE ANOTHER MODEL ITERATION TOINTERROGATE CRITICAL LIQUID PRECIP AMOUNTS. Link to comment Share on other sites More sharing options...
Poimen Posted January 23, 2013 Share Posted January 23, 2013 NCDOT is putting down brine up here this afternoon...that's the surest sign yet that this event will be a non-event. Link to comment Share on other sites More sharing options...
WilkesboroDude Posted January 23, 2013 Share Posted January 23, 2013 There is so much salt already on the roads from the last storm to handle any possible snow in Wilkes. Roads are very white in places. Link to comment Share on other sites More sharing options...
superjames1992 Posted January 23, 2013 Share Posted January 23, 2013 18z NAM looks pretty identical to 12z so far to me; just maybe a tick north. Link to comment Share on other sites More sharing options...
GaWx Posted January 23, 2013 Share Posted January 23, 2013 I'm down for a good .1-.25" ice storm. So if the current temperatures hold, will all precipitation fall in the form of ZR in the northern Atlanta burbs? Or will it warm up above freezing after a few hours? Jason, Right now, the trend is not your friend. Yesterday's 12Z and 18Z GFS runs were giving Marietta 0.25" of ZR verbatim. Today's 0Z dropped it some to 0.20". Today's 6Z dropped down to ~0.15". Today's 12Z GFS dropped way down to only .03". Other credible models are showing very little and in some cases, none. There's still time for a trend reversal but until then consider me much less impressed than I was earlier for the northern burbs of ATL. There could even be no ZR as it looks now if the precip. is delayed from reaching the ground. Link to comment Share on other sites More sharing options...
FallsLake Posted January 23, 2013 Share Posted January 23, 2013 18z NAM looks pretty identical to 12z so far to me; just maybe a tick north. RAH really agressive with 20:1 ratios. If the precip amounts shown on the NAM (from 12z) could verify we would be looking at a nice event (..maybe 5 inches) Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2013 Share Posted January 23, 2013 NAM is slightly north @45 compared to 12z. Link to comment Share on other sites More sharing options...
Poimen Posted January 23, 2013 Share Posted January 23, 2013 RAH really agressive with 20:1 ratios. If the precip amounts shown on the NAM (from 12z) could verify we would be looking at a nice event (..maybe 5 inches) except, per their discussion, the window of opportunity for snow is a small one due to shallow moisture. Of course, this is subject to change, but for now ZR is probably the bigger concern. Link to comment Share on other sites More sharing options...
beanskip Posted January 23, 2013 Share Posted January 23, 2013 Yes, applying Brad's reasoning from the 12z Euro, I would say the NAM is coming north (which virtually guarantees it will go south). NAM is slightly north @45 compared to 12z. Link to comment Share on other sites More sharing options...
superjames1992 Posted January 23, 2013 Share Posted January 23, 2013 RAH really agressive with 20:1 ratios. If the precip amounts shown on the NAM (from 12z) could verify we would be looking at a nice event (..maybe 5 inches) I wouldn't count on that, haha. It seems like we've had some decent overrunning events here in the past, though I can't really think of any any good analogs off the top of my head. Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2013 Share Posted January 23, 2013 NAM looks further north with the precip and warmer @48 to me...we'll see where it goes. Link to comment Share on other sites More sharing options...
FallsLake Posted January 23, 2013 Share Posted January 23, 2013 except, per their discussion, the window of opportunity for snow is a small one due to shallow moisture. Of course, this is subject to change, but for now ZR is probably the bigger concern. But the NAM was colder at 850. ....this is going to come down to the wire. Link to comment Share on other sites More sharing options...
oconeexman Posted January 23, 2013 Share Posted January 23, 2013 Well maybe some of these little old counties that got left out last event will get a taste this time! GSP has shown it for here about all week which has me on the positive side. I know it's not gonna be much but it is the first Winter Storm Watch in a LONG time for here. Link to comment Share on other sites More sharing options...
burgertime Posted January 23, 2013 Share Posted January 23, 2013 Def. warmer on this run. 12z had the 850 line running just barely south of I-40...this has it running near the NC/VA border...ZR for most on this run. QPF simply appears to be shifted north. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 Well the 18z NAM stinks for N GA ice chances. Max QPF shifts into TN versus NGA like 12z run. 12Z... 18z Link to comment Share on other sites More sharing options...
beanskip Posted January 23, 2013 Share Posted January 23, 2013 LOL 18z NAM at 45 on NCEP shows four vorts strung out -- I'm sure it will key on them perfectly and this run will be precise. Link to comment Share on other sites More sharing options...
eyewall Posted January 23, 2013 Share Posted January 23, 2013 My first call for NC: Link to comment Share on other sites More sharing options...
WNCwx Posted January 23, 2013 Share Posted January 23, 2013 Here is the map from GSP of the Ice Storm they're projecting. If this holds true, it'll be devastating: Link to comment Share on other sites More sharing options...
FallsLake Posted January 23, 2013 Share Posted January 23, 2013 Def. warmer on this run. 12z had the 850 line running just barely south of I-40...this has it running near the NC/VA border...ZR for most on this run. QPF simply appears to be shifted north. Well there goes my hope of 5 inches of snow. But this would still be a big ice event for many. .25 is right on the edge of winter Storm criteria or Ice Storm Warning. Link to comment Share on other sites More sharing options...
Poimen Posted January 23, 2013 Share Posted January 23, 2013 NAM is wetter and warmer (for my area)....ice ice, baby. Link to comment Share on other sites More sharing options...
griteater Posted January 23, 2013 Share Posted January 23, 2013 Over 0.50 on NAM for Knoxville and Tri-Cities Link to comment Share on other sites More sharing options...
franklin NCwx Posted January 23, 2013 Share Posted January 23, 2013 What a horrible ice storm for sw nc. Link to comment Share on other sites More sharing options...
WeatherNC Posted January 23, 2013 Share Posted January 23, 2013 NAM looks further north with the precip and warmer @48 to me...we'll see where it goes. >0.25" of ZR is when we start running into problems Link to comment Share on other sites More sharing options...
superjames1992 Posted January 23, 2013 Share Posted January 23, 2013 NAM looks like maybe 2-4" of snow in the northern Piedmont before changing over to IP or ZR to me. In excess of 0.25" of QPF for I-40 northward as you can see here and it looks like all snow until it changes over later. Link to comment Share on other sites More sharing options...
packbacker Posted January 23, 2013 Share Posted January 23, 2013 Well there goes my hope of 5 inches of snow. But this would still be a big ice event for many. .25 is right on the edge of winter Storm criteria or Ice Storm Warning. Well we are still 48 hours away, it looks like this would be a mix of snow/IP for RDU, would love for this to verify, but NAM is all alone with these precip amounts. Link to comment Share on other sites More sharing options...
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