wncsnow Posted January 23, 2013 Share Posted January 23, 2013 Guys its the 18Z NAM at 40+hour so I dont think it will portray exactly what will happen.. Many times in these types of storms I have noticed the the depth of the cold air with the wedge is often deeper than modeled leading to a longer period of snow on the front end before chaning over to IP and ZR. Here is what GSP things in terms of snow, Link to comment Share on other sites More sharing options...
FallsLake Posted January 23, 2013 Share Posted January 23, 2013 Significant ice storm for the Triangle. >.25 liquid would meet Winter Storm criteria. **This seems to be close to the 12Z GFS >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 I-40 really straddles the 0C 850 mb line. I'm not really sure if areas from the Triad northward change over at all, upon reflection, especially if the precip is falling at a moderate rate. There may be a warm nose elsewhere in the atmosphere, though. I've just looked at 850s so far. Link to comment Share on other sites More sharing options...
deltadog03 Posted January 23, 2013 Share Posted January 23, 2013 After looking over everything, I just can't see the RPM verifying as it stands right now. Matter of fact, I think even ATL might have a hard time seeing frozen or freezing precip. Its not that its not cold enough, but models are delaying QPF just long enough to really only show rain. (ATL South) Now, I know models looooooooove to scour the wedge out too quickly, so we shall see about that, but I just don't see much for ATL south to MCN. *IF* the precip comes in the morning on Friday, then yes we will have some potential issues. Link to comment Share on other sites More sharing options...
eastkywx Posted January 23, 2013 Share Posted January 23, 2013 Here is what JKL is saying for Eastern KY. Their AFD is rather bland with just a mention of snow. They did mention a mix to rain at some point during the day on Friday, but from everything I've seen, I don't see where that's even remotely an issue for my neck of the woods? Here is their "huge" writeup on what to expect in their AFD.... EXPECT LIGHT SNOWPOSSIBLY MIXED WITH SLEET IN THE SWRN COUNTIES TO START THE FCST FRIMORNING. WITH THE COLD AIR IMPINGING ON THE AREA FROM THE NWHOWEVER...THE SLEET SHOULD CHANGE TO ALL SNOW BY EARLY MORNING. THENTHE SFC LOW WILL BRING SOME WARMER AIR AND CHANGE THE SRN PCPN TORAIN BY FRI AFTERNOON. THERE WILL BE A ZONE THRU THE MIDDLE OF THEAREA THAT WILL LIKELY SEE A MIX OF SLEET AND SNOW BEFORE ALL PCPNCHANGES BACK TO ALL SNOW BY SUNSET. BY MIDNIGHT FRI NIGHT THE SYSTEMWILL BE MOSTLY GONE WITH JUST SOME LINGERING LIGHT SNOW IN THE ERNMTN COUNTIES THRU EARLY SAT MORNING. Here is their map they put out... Link to comment Share on other sites More sharing options...
franklin NCwx Posted January 23, 2013 Share Posted January 23, 2013 I-40 really straddles the 0C 850 mb line. I'm not really sure if areas from the Triad northward change over at all, upon reflection, especially if the precip is falling at a moderate rate.warm nose is above 850 There may be a warm nose elsewhere in the atmosphere, though. I've just looked at 850s so far. Link to comment Share on other sites More sharing options...
franklin NCwx Posted January 23, 2013 Share Posted January 23, 2013 I-40 really straddles the 0C 850 mb line. I'm not really sure if areas from the Triad northward change over at all, upon reflection, especially if the precip is falling at a moderate rate. warm nose is above 850 There may be a warm nose elsewhere in the atmosphere, though. I've just looked at 850s so far. Link to comment Share on other sites More sharing options...
tnweathernut Posted January 23, 2013 Share Posted January 23, 2013 Over 0.50 on NAM for Knoxville and Tri-Cities I am in a meeting and don't have access to the text data Grit............I assume (with the talk about how much warmer this is) that quite a bit of that at KTYS is in the form of zr or cold rain, but wonder what KTRI's text data puts out as snow vs zr. Anyone have access? Link to comment Share on other sites More sharing options...
NCSNOW 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. Nice hit for sure. lock it up Link to comment Share on other sites More sharing options...
BullCityWx Posted January 23, 2013 Share Posted January 23, 2013 CLT looks like mostly, if not all sleet. Link to comment Share on other sites More sharing options...
beanskip Posted January 23, 2013 Share Posted January 23, 2013 I'm not sure why I keep seeing forecasts for CLT/Shelby/I-85/US 74 corridor to start as a period of snow. All the soundings I see show a brief period of sleet followed by ZR. 18z NAM definitely not snowy at 48 hours when precip breaks out. Link to comment Share on other sites More sharing options...
calm_days Posted January 23, 2013 Share Posted January 23, 2013 Whatever does happen it is going to be very interesting to watch from a distant point of view. Some of the large oceanic features will still be present while the smaller systems organize between their influences. It could be very mundane locally, but unique continentally/atmospherically. : ) (here is the same image from the 19th) Link to comment Share on other sites More sharing options...
GaWx Posted January 23, 2013 Share Posted January 23, 2013 After looking over everything, I just can't see the RPM verifying as it stands right now. Matter of fact, I think even ATL might have a hard time seeing frozen or freezing precip. Its not that its not cold enough, but models are delaying QPF just long enough to really only show rain. (ATL South) Now, I know models looooooooove to scour the wedge out too quickly, so we shall see about that, but I just don't see much for ATL south to MCN. *IF* the precip comes in the morning on Friday, then yes we will have some potential issues. Chris, Based on my viewing of recent models and considering trends since 0Z, I pretty much agree with you. It does seem possible that the ATL area actually gets no ZR. The trend is a reversal of the trend toward more and more ZR with yesterday's runs. Yeah, any delay in precip. is a killer in this case. There's still time for a double reversal in the trends, but it will need to start soon. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 23, 2013 Share Posted January 23, 2013 After looking over everything, I just can't see the RPM verifying as it stands right now. Matter of fact, I think even ATL might have a hard time seeing frozen or freezing precip. Its not that its not cold enough, but models are delaying QPF just long enough to really only show rain. (ATL South) Now, I know models looooooooove to scour the wedge out too quickly, so we shall see about that, but I just don't see much for ATL south to MCN. *IF* the precip comes in the morning on Friday, then yes we will have some potential issues. My biggest concern is that its an overrunning event and those can be tricky where you can all sorts of precip or drizzle breaking out well ahead of when you think it will Link to comment Share on other sites More sharing options...
Met1985 Posted January 23, 2013 Share Posted January 23, 2013 URGENT - WINTER WEATHER MESSAGE NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 307 PM EST WED JAN 23 2013 ...POTENTIAL ICE STORM FRIDAY... .A FRONTAL SYSTEM WILL MOVE THROUGH THE REGION ON FRIDAY BRINGING A PERIOD OF PRECIPITATION. WITH COLD AIR WEDGED AGAINST THE SOUTHERN APPALACHIANS...A WINTRY MIX OF PRECIPITATION TYPES WILL RESULT 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...HENDERSONVILLE 307 PM EST WED JAN 23 2013 THE NATIONAL WEATHER SERVICE IN GREENVILLE-SPARTANBURG HAS ISSUED A WINTER STORM WATCH...WHICH IS IN EFFECT FROM LATE THURSDAY NIGHT 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. Ya Steve this is what really worries me about this storm is the ice around here. We still have snow on the ground and the temps the past two days have not reached freezing up here. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 I am in a meeting and don't have access to the text data Grit............I assume (with the talk about how much warmer this is) that quite a bit of that at KTYS is in the form of zr or cold rain, but wonder what KTRI's text data puts out as snow vs zr. Anyone have access? Just looking at the 18z NAM soundings.. 15z Friday supports all snow. 18z Friday the 800mb level warms to 1.1 which could turn it over to sleet possibly. Other soundings not out yet.... Link to comment Share on other sites More sharing options...
deltadog03 Posted January 23, 2013 Share Posted January 23, 2013 My biggest concern is that its an overrunning event and those can be tricky where you can all sorts of precip or drizzle breaking out well ahead of when you think it will Great point!! That is my concern as well. I just noticed that the RPM shows the qpf coming through GA from late morning into the afternoon, and its frozen or freezing from MCN north. Clearly it keeps the wedge held in longer. Problem is, FZDZ can cause some hella concerns as well. I guess we shall see. This has VERY high bust potential written all over it. Link to comment Share on other sites More sharing options...
SnowNiner Posted January 23, 2013 Share Posted January 23, 2013 Check out my updated forecast for CLT from NWS: Friday Rain, snow, freezing rain, and sleet, becoming all freezing rain after 3pm. High near 33. Southeast wind 3 to 6 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible. Friday Night A chance of freezing rain before 7pm. Mostly cloudy, with a low around 27. Light and variable wind. Chance of precipitation is 30%. Where'd they get those numbers from? That came out of the blue. Huge difference between .10 to .25 and .25 to .50. Link to comment Share on other sites More sharing options...
WilkesboroDude Posted January 23, 2013 Share Posted January 23, 2013 NAM is even better this run for the northern foothills... (3-4 inches) Link to comment Share on other sites More sharing options...
dsaur Posted January 23, 2013 Share Posted January 23, 2013 After looking over everything, I just can't see the RPM verifying as it stands right now. Matter of fact, I think even ATL might have a hard time seeing frozen or freezing precip. Its not that its not cold enough, but models are delaying QPF just long enough to really only show rain. (ATL South) Now, I know models looooooooove to scour the wedge out too quickly, so we shall see about that, but I just don't see much for ATL south to MCN. *IF* the precip comes in the morning on Friday, then yes we will have some potential issues. If there is cad, I always come in colder, but the GFS has been steadily giving me less and less, of very little precip. Guess it'll come down to watching middle Ala. and then wondering if the Ala/Ga line makes any moisture there is go poof, lol. I can't get excited much unless there is a Gom low knocking at the door, like Goofy has shown a few times lately for later on. Tony Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 23, 2013 Share Posted January 23, 2013 Great point!! That is my concern as well. I just noticed that the RPM shows the qpf coming through GA from late morning into the afternoon, and its frozen or freezing from MCN north. Clearly it keeps the wedge held in longer. Problem is, FZDZ can cause some hella concerns as well. I guess we shall see. This has VERY high bust potential written all over it. I'm thinking the temps won't be a big issue in ATL if it precipitates say before 14-15Z, the NAM MOS trended notably colder and its entirely possible that early cloud decks tomorrow might prevent much of a warmup which could give the wedge a head start on low temps THU NIGHT/FRI AM...it comes down big time to if anything can fall in time. Link to comment Share on other sites More sharing options...
Poimen Posted January 23, 2013 Share Posted January 23, 2013 The 18Z NAM snow maps from Allan's site is still spitting out a wide swath of 3-4" amounts over a sizable portion of NC. I'm not sure how this is happening... Link to comment Share on other sites More sharing options...
WilkesboroDude Posted January 23, 2013 Share Posted January 23, 2013 The 18Z NAM snow maps from Allan's site is still spitting out a wide swath of 3-4" amounts over a sizable portion of NC. I'm not sure how this is happening... Not all snow. Wxrisk.com Link to comment Share on other sites More sharing options...
nwupstatewx Posted January 23, 2013 Share Posted January 23, 2013 NAM simulated radar looks promising for N. GA, Upstate SC during the heart of the event. Link to comment Share on other sites More sharing options...
GaWx Posted January 23, 2013 Share Posted January 23, 2013 I'm thinking the temps won't be a big issue in ATL if it precipitates say before 14-15Z, the NAM MOS trended notably colder and its entirely possible that early cloud decks tomorrow might prevent much of a warmup which could give the wedge a head start on low temps THU NIGHT/FRI AM...it comes down big time to if anything can fall in time. Snowgoose, There has been a marked reduction in the last three GFS runs regarding verbatim ZR for the Atlanta area in case you haven't seen it. For example, Marietta was getting 0.25" on yesterday's 12z and 18z runs. That dropped to 0.20" on today's 0z, 0.15" on the 6z, and only 0.03" on today's 12z. Other models give little or none. This trend needs to reverse back to make it much of a threat. Link to comment Share on other sites More sharing options...
Hammer Posted January 23, 2013 Share Posted January 23, 2013 Looks ok for moisture, more worried that the cold won't make it time and I will have nothing but rain. Link to comment Share on other sites More sharing options...
Blue Ridge Posted January 23, 2013 Share Posted January 23, 2013 MRX issued a WSA for the entire CWA with their afternoon package. AFD has not been released yet. ...WINTER STORM EXPECTED TO IMPACT THE SOUTHERN APPALACHIANS LATETHURSDAY NIGHT THROUGH FRIDAY NIGHT...WITH SIGNIFICANT ICINGPOSSIBLE ACROSS MUCH OF THE EAST TENNESSEE VALLEY....A STRONG STORM SYSTEM WILL IMPACT THE EAST TENNESSEE VALLEY ANDSOUTHERN APPALACHIANS LATE THURSDAY NIGHT INTO FRIDAY. THECOMBINATION OF SUBFREEZING SURFACE TEMPERATURES AND ABUNDANT GULFMOISTURE WILL RESULT IN A LONG DURATION SNOW AND ICE EVENT FOR THEENTIRE FORECAST AREA. PRECIPITATION WILL MOVE INTO THE CUMBERLANDPLATEAU AND SOUTHEAST TENNESSEE LATE THURSDAY NIGHT...AND BECOMEHEAVIER AT TIMES AFTER SUNRISE ON FRIDAY AS IT OVERSPREADS THEENTIRE REGION FROM WEST TO EAST. WITH TEMPERATURES ALOFT REMAININGABOVE FREEZING FOR MOST OF THE EVENT ACROSS THE EAST TENNESSEEVALLEY...A LONG DURATION FREEZING RAIN AND SLEET EVENT ISANTICIPATED...WITH WIDESPREAD ACCUMULATIONS BETWEEN ONE TENTH TOONE QUARTER OF AN INCH OF ICE POSSIBLE. FURTHER TO THE NORTH ACROSSNORTHEAST TENNESSEE AND SOUTHWEST VIRGINIA ...COLDER AIR WILL BE INPLACE WHICH WILL ALLOW FOR AN ALL SNOW EVENT...WITH THE POSSIBILITYOF SOME SLEET MIXING IN AS WELL IN AREAS THAT APPROACH THE FREEZINGMARK LATER IN THE AFTERNOON. PRECIPITATION WILL GRADUALLY BEGIN TOTAPER OFF LATE FRIDAY AFTERNOON AND EVENING....WINTER STORM WATCH IN EFFECT FROM LATE THURSDAY NIGHT THROUGHFRIDAY EVENING...THE NATIONAL WEATHER SERVICE IN MORRISTOWN HAS ISSUED A WINTERSTORM WATCH...WHICH IS IN EFFECT FROM LATE THURSDAY NIGHT THROUGHFRIDAY EVENING.* EVENT...LATE THURSDAY NIGHT THROUGH FRIDAY EVENING A WINTRY MIX OF PRECIPITATION WILL OVERSPREAD THE ENTIRE REGION. MOST OF THE TENNESSEE VALLEY TO THE SOUTH AND WEST OF MORRISTOWN WILL EXPERIENCE A MIX OF FREEZING RAIN AND SLEET...WITH LOCATIONS ACROSS NORTHEAST TENNESSEE AND SOUTHWEST VIRGINIA REMAINING ALL SNOW OR A MIXTURE OF SNOW AND SLEET.* TIMING...PRECIPITATION WILL MOVE INTO THE CUMBERLAND PLATEAU AND SOUTHEAST TENNESSEE LATE THURSDAY NIGHT AND OVERSPREAD THE ENTIRE REGION FRIDAY MORNING AND AFTERNOON...BEFORE TAPERING OFF BY FRIDAY EVENING.* IMPACTS...SIGNIFICANT ICING AND HEAVY SNOWFALL WILL CREATE EXTREMELY HAZARDOUS DRIVING CONDITIONS EARLY FRIDAY MORNING THROUGH FRIDAY NIGHT. ACCUMULATING ICE AND SNOW MAY PULL DOWN TREES AND POWER LINES IN SOME AREAS. LOCALIZED TO WIDESPREAD POWER OUTAGES ARE POSSIBLE. Link to comment Share on other sites More sharing options...
calm_days Posted January 23, 2013 Share Posted January 23, 2013 Check out my updated forecast for CLT from NWS: Friday Rain, snow, freezing rain, and sleet, becoming all freezing rain after 3pm. High near 33. Southeast wind 3 to 6 mph. Chance of precipitation is 80%. New precipitation amounts between a quarter and half of an inch possible. Friday Night A chance of freezing rain before 7pm. Mostly cloudy, with a low around 27. Light and variable wind. Chance of precipitation is 30%. Where'd they get those numbers from? That came out of the blue. Huge difference between .10 to .25 and .25 to .50. The Nasa-goddard climate simulation seems to show a lot of precipitation. I don't know that NWS uses it officially forecastwise but I'm sure they look at it! Later, other models may reflect this trend. Link to comment Share on other sites More sharing options...
tnweathernut Posted January 23, 2013 Share Posted January 23, 2013 Just looking at the 18z NAM soundings.. 15z Friday supports all snow. 18z Friday the 800mb level warms to 1.1 which could turn it over to sleet possibly. Other soundings not out yet.... Just looking at the 18z NAM soundings.. 15z Friday supports all snow. 18z Friday the 800mb level warms to 1.1 which could turn it over to sleet possibly. Other soundings not out yet.... Thanks for the info Moto, trends (which are most important at this point). It appears as if modeling all day has come in a bit warmer each run. I really want to see the hi-resolution NAM and look at all the sounding data as I get more time. Link to comment Share on other sites More sharing options...
MotoWeatherman Posted January 23, 2013 Share Posted January 23, 2013 FFC has all areas north of ATL under WSW now. Link to comment Share on other sites More sharing options...
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