phil882 Posted February 9, 2011 Share Posted February 9, 2011 Delayed but not denied, I think the northwest trend is giving us one last tease. Just look at the 700mb relative humidity field and compare that with the RUC from three hours ago... much more moist and deeper omega than expected even just three hours ago. I think the jet streak is doing its trick... 150 knots and being on the right entrance region certainly has its benefits I would also like to mention that the NAM is completely in la la land again... like it was during our major precipitation event last week. Link to comment Share on other sites More sharing options...
Cheeznado Posted February 9, 2011 Share Posted February 9, 2011 Copped from the Central thread: Link to comment Share on other sites More sharing options...
bingcrosbyb Posted February 9, 2011 Share Posted February 9, 2011 According to the NAM, the northern edge should completely fall apart right at the MS/AL line. If it holds together, we are in business for points east. Link to comment Share on other sites More sharing options...
GaWx Posted February 9, 2011 Share Posted February 9, 2011 Here are the 12Z Wed. operational models' snowfall amounts I'm estimating for tonight/early tomorrow from the models I've seen for ATL-AHN and vicinity vs. the amounts suggested on runs from 24 hours ago (in parentheses): CMC: 3" (4") GFS: 2.5" (1") JMA: 2.5" (3.5") UKMET: 2" (2.5") Euro: 1" (2.5") NAM: 1" (2") Avg. 2" (vs. 2.6"/2.0"/1.75" from runs 24/48/72 hours ago). The much heavier than expected AR snowfall suggests the system will probably overperform. Due to this, I'm now going to go higher than the 2" model average. However, in deference to the 1" of the well-respected Euro, I won't go too much higher. Therefore, I've decided to up my best guess for the overall average for ATL-AHN to 2.5" from the 2" I predicted 24 hours ago. Link to comment Share on other sites More sharing options...
kanc2001 Posted February 9, 2011 Share Posted February 9, 2011 Interesting afternoon disco outta KILM 000 FXUS62 KILM 091932 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 232 PM EST WED FEB 9 2011 .SYNOPSIS... -- Changed Discussion --COLD AIR SETTLED OVER THE REGION AND A DEVELOPING LOW PRESSURE SYSTEM OFFSHORE...WILL BRING A CHANCE OF SNOW TO INLAND LOCATIONS OVERNIGHT INTO EARLY THURSDAY...WITH MAINLY COLD RAIN EXPECTED ALONG THE COAST. FAIR CONDITIONS WILL FOLLOW LATE THURSDAY THROUGH EARLY NEXT WEEK...AS HIGH PRESSURE HOLDS OVER THE GULF COAST STATES.-- End Changed Discussion -- && .NEAR TERM /THROUGH TONIGHT/... -- Changed Discussion --AS OF 3 PM WEDNESDAY...A POSITIVELY TILTED UPPER TROUGH OVER THE SOUTHERN PLAINS WILL RACE EAST TONIGHT...MOVING ACROSS THE CAROLINAS SHORTLY AFTER DAYBREAK THURSDAY. AT THE SURFACE A COASTAL TROUGH DEVELOPING ALONG THE GEORGIA AND SOUTH CAROLINA COAST WILL CLOSE OFF INTO A SYNOPTIC LOW THIS EVENING. THIS LOW HAS SPREAD STRATOCUMULUS IN FROM THE OCEAN ACROSS MOST OF EASTERN SOUTH CAROLINA AND THE ADJACENT PORTIONS OF NORTH CAROLINA THIS AFTERNOON. CLOUDS AND EVEN SOME LIGHT RAIN ARE POSSIBLE FROM THIS FEATURE BEFORE IT ZIPS OUT TO SEA AFTER MIDNIGHT. ALL EYES ARE ON THE POSITIVELY TILTED UPPER TROUGH AS IT APPROACHES FROM THE WEST TONIGHT. WEAK SURFACE LOW PRESSURE ALONG THE GULF COAST WILL MOVE EAST TOWARD FLORIDA LATE...BUT ALL THE ACTION WILL BE NORTH OF THE LOW WHERE A BROAD ZONE OF ISENTROPIC LIFT WILL GENERATE RAIN ACROSS THE ENTIRE SOUTHEAST. RAIN WITH THIS SYSTEM MAY HOLD OFF UNTIL NEARLY MIDNIGHT...BUT POPS AFTER MIDNIGHT QUICKLY RAMP UP TO 90 PERCENT. COLD ADVECTION WILL BEGIN IN EARNEST AFTER MIDNIGHT MAINLY AT AND BELOW THE 800 MB LEVEL. TRADITIONAL THICKNESS-BASED FORECASTING TECHNIQUES AND MODEL FORECAST SOUNDINGS INDICATE RAIN SHOULD MIX WITH AND EVENTUALLY CHANGE TO SNOW IN THE 3-6 AM TIME FRAME FROM DARLINGTON AND BENNETTSVILLE TO DILLON... LUMBERTON AND ELIZABETHTOWN. THIS IS THE AREA WE HAVE HIGHLIGHTED FOR A WINTER WEATHER ADVISORY BEGINNING AT MIDNIGHT. MODELS ARE NOT UNANIMOUS IN THEIR SUPPORT OF THIS IDEA HOWEVER: THE 12Z GFS MAINTAINS SLIGHTLY WARMER LOW-LEVEL TEMPERATURES THAT COULD DELAY THE ONSET OF SNOW FOR A FEW CRITICAL HOURS WITH DELETERIOUS EFFECTS ON ACCUMULATIONS. OUR FORECAST IS SUPPORTED BY THE 12Z NAM...09Z SREF...AND NATIONAL GUIDANCE FROM THE NWS`S HYDRO- METEOROLOGICAL PREDICTION CENTER. IN TERMS OF ACCUMULATIONS...OUR FORECAST IS FOR AROUND ONE INCH ACROSS THE AFOREMENTIONED AREAS... WITH VERY LITTLE EXPECTED TO THE SOUTH DUE TO AIR AND GROUND TEMPERATURES REMAINING ABOVE FREEZING. SO WHAT COULD GO WRONG? THERE ARE CLUES IN THE PAST SEVERAL RUNS OF THE MODELS THAT THERE MAY BE ENHANCED AREAS OF MESOSCALE LIFT WITHIN THE LARGER PRECIPITATION SHIELD LATE TONIGHT. THESE ARE KEYED TO BULLSEYES OF FRONTOGENETIC FORCING IN THE 700-850 MB LAYER AND ARE ALSO DISCERNIBLE IN ISENTROPIC ANALYSIS ON THE 290 K THETA SURFACE. WHETHER OR NOT THESE AREAS OF MESOSCALE ASCENT (AND INFERRED HEAVIER PRECIPITATION RATES) ARE ABLE TO COOL THE LOW-LEVELS SUFFICIENTLY TO INCREASE SNOWFALL AMOUNTS IS AN UNANSWERED QUESTION. RIGHT UP UNTIL 12Z THURSDAY FORECAST SOUNDINGS (ESPECIALLY FROM THE GFS) SHOW WE WILL BE BATTLING AS MUCH AS A 2000 FOOT-DEEP LAYER OF ABOVE-FREEZING AIR EVEN BACK IN FLORENCE AND LUMBERTON. IF THE WARMER GFS THERMAL PROFILES VERIFY WE MAY DEPEND SOLELY ON MESOSCALE EFFECTS TO SEE ANY SNOW HERE AT THE GROUND.-- End Changed Discussion -- && SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3 PM WEDNESDAY...DAYBREAK THURSDAY AN ELONGATED SURFACE LOW PRESSURE COMPLEX ORIENTED SW TO NE WILL BE POSITIONED OFFSHORE OF THE SC/NC COASTLINE...LOCATED BEYOND THE 20NM COASTAL WATERS. A PCPN MIX SHOULD PREVAIL ACROSS THE EASTERN CAROLINAS AT DAYBREAK THURSDAY. FROZEN PCPN WILL REMAIN FAVORED ACROSS FAR N AND W ZONES WHERE DEWPOINT RECOVERY FROM ONSHORE FLOW TONIGHT SHOULD BE FELT LEAST...AND WHERE BEST WET-BULB/EVAP COOLING SHOULD SET-UP EARLY THURSDAY. GFS IS WETTEST WITH SYSTEM AND FOR QPF FIELDS WE HAVE BLENDED GFS/NAM WITH WEIGHT ON GFS. CONSENSUS IS GOOD AMONG ALL SHORT RANGE MODELS THAT PCPN WILL BE WINDING DOWN/SHUTTING OFF ACROSS THE ILM FORECAST AREA BY THU AFTN. SHARP DRYING THU AFTN ESPECIALLY ALOFT...SHOULD BRING PARTLY SUNNY SKIES INTO THE REGION SOMETIME THU AFTN...MOST PROBABLE OVER THE FAR INTERIOR LOCATIONS AWAY FROM THE LINGERING COOL/WET MARITIME AIR MASS NEAR THE ATLANTIC. Link to comment Share on other sites More sharing options...
FoothillsNC Posted February 9, 2011 Share Posted February 9, 2011 the 18z Nam is down to nothing once again for Raleigh West in NC. The trends are going both ways today. Most everything has been trending wetter but its strange to see the Nam bone dry here where other models show .2 or so the way I look at this, even though all models have gotten wetter, as many suspected they would esp. in Ala, GA and the eastern Carolinas, the basic same premise holds in the lee areas and the central Piedmont region of NC and northwest SC area because of a bad transfer of energy that is forecast to happen. Our only hope here for any significant, or even just .10" of precip in that big hole is for the precip to be strong and with good forcing coming out of GA, and to be honest, thats asking a lot in any year with a marginal situation, and in this particular special setup, its even going to be harder to overcome all the negative factors. The writing on the wall, all ensembles and individual members, operations show this same general gap, some have a little precip and others have a brief window of snow, but usually this doesn't give much surprises here. Unlike times when we're watching an overrunning event, where moisture can drift a little more north and west than initially shown, this one looks like much less of a chance of that happening. However, its not totally out of the question, I just wouldn't bank on anything more than 1" in that general area, and some areas may get only 5 minutes of flakes. Link to comment Share on other sites More sharing options...
HWY316wx Posted February 9, 2011 Share Posted February 9, 2011 Latest from the FFC .WINTER WEATHER EVENT OVERVIEW AND UNCERTAINTIES... OVERALL FORECAST REMAINS UNCHANGED FOR THE UPCOMING PACKAGE WITH GFS/ECMWF AND NAM12 BEGINNING TO HONE IN ON A SOLUTION WHICH IS CLOSE TO CURRENT FORECAST. LOW PRESSURE WILL CONTINUE TO DEVELOP OVER THE NORTHERN GULF BUT HAVE A TOUGH TIME SPREADING THE DEEPEST MOISTURE NORTHWARD. WILL INSTEAD HAVE TO RELY ON A TOP DOWN MOISTENING OF THE COLUMN IN RESPONSE TO APPROACHING SHORTWAVE. GIVEN CURRENT LOW LEVEL PROFILES INITIAL WAVE OF PRECIP WILL BE UTILIZED IN SATURATING THE LOW LEVELS...FURTHER LIMITING TOTALS. IN ADDITION...A BRIEF PERIOD OF RAIN MIXED WITH SNOW INITIALLY ALONG WITH ABOVE FREEZING GROUND TEMPS WILL KEEP ACCUMULATIONS IN CHECK THROUGH MIDNIGHT. WHILE THESE WOULD BE NEGATIVE FACTORS FOR ACCUMULATING SNOWFALL...SUBTLE CHANGES IN THE MODELS...NAMELY FORCING FROM BOUNDARY LAYER FRONTOGENESIS AND EQUIVALENT POTENTIAL VORTICITY ALOFT...SUGGEST POTENTIAL FOR SOME BANDING FEATURES ACROSS NORTHERN SECTIONS AND A SEPARATE AREA ACROSS EASTERN ZONES THU MORNING. THIS WOULD ALLOW ISOLATED LOCATIONS TO SEE A QUICK BURST OF MODERATE SNOWFALL BUT REMAINS TOO DIFFICULT AT THIS TIME TO PIN DOWN DEFINITIVE AREAS OF CONCERN. WILL HIGHLIGHT ISOLATED HIGHER AMOUNTS IN WEBINAR AND UPCOMING UPDATED WINTER WEATHER ADVISORY FOR THE AREA. HAVE ALSO ADJUSTED SNOW TOTALS SLIGHTLY UPWARD TO SHOW CLOSER TO 1.5 TO 2 INCH AVERAGE ACROSS THE NORTH AND AROUND AN INCH FOR ATLANTA METRO AND SURROUNDING AREAS. FINAL TWEAK WAS TO EXTEND WINTER WEATHER ADVISORY SOUTHWARD BY A TIER OF COUNTIES...MAINLY FOR COORDINATION PURPOSES. Link to comment Share on other sites More sharing options...
phil882 Posted February 9, 2011 Share Posted February 9, 2011 Considering how badly its busting in West Tennessee... I think its safe to say its out to lunch. Link to comment Share on other sites More sharing options...
Srain Posted February 9, 2011 Share Posted February 9, 2011 Greetings for icy Houston. I've got about a 1/8 inch of ice coating everything here. Nice little surprise over this way. Stay safe folks and good luck! Link to comment Share on other sites More sharing options...
strongwxnc Posted February 9, 2011 Share Posted February 9, 2011 Jason, If I was ever stuck in the middle of now where with nothing. You would need to be around. Your optimism is great man... I do not know folks...maybe it's the inner weenie in me, but it appears that the moisture transport is holding up quite well. Cloud deck is thickening around here. Has a good snow look to it . Also, it looks like moisture is streaming in more from the gulf than what was forecasted? http://www.intellica...px?animate=true Thanks for the obs.. Good luck Greetings for icy Houston. I've got about a 1/8 inch of ice coating everything here. Nice little surprise over this way. Stay safe folks and good luck! Link to comment Share on other sites More sharing options...
FoothillsNC Posted February 9, 2011 Share Posted February 9, 2011 Considering how badly its busting in West Tennessee... I think its safe to say its out to lunch. busting there though but for good reasons. However, all models have been pegging the lee zone as basically dry with less that .10". Do you think its going to be much more than that in here? Link to comment Share on other sites More sharing options...
Lookout Posted February 9, 2011 Share Posted February 9, 2011 hmm Ruc is actually intensifying the precip as it moves east Link to comment Share on other sites More sharing options...
buckeyefan1 Posted February 9, 2011 Share Posted February 9, 2011 Greetings for icy Houston. I've got about a 1/8 inch of ice coating everything here. Nice little surprise over this way. Stay safe folks and good luck! Nothing better than a sweet suprise Link to comment Share on other sites More sharing options...
Northern Foothills Snowman Posted February 9, 2011 Share Posted February 9, 2011 How are the models trending for NW North Carolina ? Link to comment Share on other sites More sharing options...
kanc2001 Posted February 9, 2011 Share Posted February 9, 2011 a buddy's webcam stream in Fayetteville, AR storm pretty much over, but look all that snow http://www.ustream.t...el/honest-tunes Link to comment Share on other sites More sharing options...
strongwxnc Posted February 9, 2011 Share Posted February 9, 2011 It also works to bring it into WNC and kill the hole.... hmm Ruc is actually intensifying the precip as it moves east Link to comment Share on other sites More sharing options...
kanc2001 Posted February 9, 2011 Share Posted February 9, 2011 How are the models trending for NW North Carolina ? go take a peek yourself http://raleighwx.americanwx.com/models.html Link to comment Share on other sites More sharing options...
mst87 Posted February 9, 2011 Share Posted February 9, 2011 hmm Ruc is actually intensifying the precip as it moves east Since we're getting pretty close to the event now (and some are already underway), would the RUC be the model of choice to watch at this point in time? (other than watching the radar itself) Link to comment Share on other sites More sharing options...
DaculaWeather Posted February 9, 2011 Share Posted February 9, 2011 Yes Link to comment Share on other sites More sharing options...
Lookout Posted February 9, 2011 Share Posted February 9, 2011 It also works to bring it into WNC and kill the hole.... Question is, is it right? It sure looks good on it's simulated radar. Link to comment Share on other sites More sharing options...
bingcrosbyb Posted February 9, 2011 Share Posted February 9, 2011 According to John Oldshue in Birmingham, light snowing now in Starkville, MS. Link to comment Share on other sites More sharing options...
FoothillsNC Posted February 9, 2011 Share Posted February 9, 2011 It also works to bring it into WNC and kill the hole.... I've been following it, and the last couple of runs did drop precip all over w. NC but sometimes the run has nothing here, others it does, and to varying degrees, obviously some chaos factor going on, at one point it had a huge dry slot coming in almost to here by 5 am , coming across n. Ala, and GA and reaching us, but the last run changed that. It will be interesting to see how it ends up, we're only 8 or 9 hours from start time, if it makes it to us. I'm still thinking midnight to 5 am is our chance. Actually the RUC has several bands that sweep across us, and theres the outside chance at some enhanced banding thanks to the mtn. chain effects here in the lee, but thats very hard to forecast, but the RUC did show that last run. Link to comment Share on other sites More sharing options...
valkhorn Posted February 9, 2011 Share Posted February 9, 2011 Why don't you go do your own research your own way and please leave GaWx alone? He re-crunched the numbers and indeed they were different. For those of us who actually average about a foot or more each winter, we know that snowfall totals for a season are best calculated for that season and not the year. Link to comment Share on other sites More sharing options...
strongwxnc Posted February 9, 2011 Share Posted February 9, 2011 Not a fan of the sim.. But it is cool to see what the it might do. I agree with robert that at least for WNC. The LEE side will not see much if any.. Question is, is it right? It sure looks good on it's simulated radar. Link to comment Share on other sites More sharing options...
Shawn Posted February 9, 2011 Share Posted February 9, 2011 AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 255 PM EST WED FEB 9 2011 NEAR TERM /TONIGHT THROUGH THURSDAY/ THE MAIN FORECAST PROBLEM IS THE WINTER WEATHER THREAT TONIGHT AND EARLY THURSDAY. THE SURFACE TROUGH EXTENDING THROUGH THE LOWER MISSISSIPPI RIVER VALLEY THIS AFTERNOON WILL SHIFT EASTWARD AND DEVELOP OFF THE SOUTHEAST COAST LATE TONIGHT AND THURSDAY. THE MODELS SHOW LITTLE IN THE WAY OF ISENTROPIC LIFT...BUT DO SHOW SIGNIFICANT UPPER-LEVEL LIFT MAINLY ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF THE H25 JET. THE NAM AND GFS PLUS SREF DATA SHOW QPF OF MAINLY 0.2 TO 0.4 OF AN INCH WITH THE HIGHER AMOUNTS IN THE SOUTHEAST PART. THE MODELS SHOW CONSIDERABLE LIFT IN THE SNOW GROWTH REGION. BOTH THE NAM AND GFS SHOW H85 TEMPERATURES BELOW FREEZING AND SURFACE DEW POINT TEMPERATURES BELOW FREEZING. HOWEVER...THE MOS HOURLY TEMPERATURE GUIDANCE APPEARS RELATIVELY WARM WITH READINGS IN THE MIDDLE TO UPPER 30S. THESE TEMPERATURES MAY BE CORRECT BECAUSE OF THE CLOUD COVER WITH JUST LIGHT PRECIPITATION. HOWEVER...CONTINUED EVAPORATIVE COOLING SHOULD LEAD TO A CHANGE FROM RAIN INTO SNOW OVER MOST OR ALL OF THE FORECAST AREA. FORECAST CONFIDENCE IS LOW BECAUSE OF MARGINAL SURFACE TEMPERATURES AND UNCERTAINTY WITH THE TIMING OF THE CHANGE FROM RAIN INTO SNOW. WE BELIEVE THE MOST LIKELY SNOW AMOUNT WILL BE AROUND ONE INCH WHICH IS SUPPORTED BY THE SREF MEAN. THE SREF RANGE WAS FROM ZERO TO AROUND 3 INCHES. THE HIGHER AMOUNTS MAY OCCUR IF IT TURNS OUT TO BE SLIGHTLY COLDER. IF THE HIGHER AMOUNTS DO VERIFY THEN THE PLACEMENT MAY BE IN A BAND EXTENDING THROUGH THE CENTRAL MIDLANDS WHERE A FAVORABLE COMBINATION OF QPF AMOUNTS AND TEMPERATURES MAY OCCUR. STILL...WITH THE MOST LIKELY AMOUNT AROUND ONE INCH WE HAVE ISSUED A WINTER WEATHER ADVISORY...AND HAVE HELD OFF ISSUING A WINTER STORM WARNING. THE MOST FAVORABLE TIME FOR SNOW WILL BE IN THE 400 AM TO 800 AM PERIOD. DRYING SHOULD OCCUR THURSDAY AFTERNOON AS THE SYSTEM SHIFTS EASTWARD. Link to comment Share on other sites More sharing options...
phil882 Posted February 9, 2011 Share Posted February 9, 2011 busting there though but for good reasons. However, all models have been pegging the lee zone as basically dry with less that .10". Do you think its going to be much more than that in here? Well we are going to have good mid and upper level forcing over our area thanks to a pretty potent jet streak according to the RUC. This is not something that is forecast to occur... its happening right now. Thats why you are seeing the finger of higher precipitation streaming northward into Tennessee and Kentucky... this feature is providing the forcing to allow the band to setup despite the lack of a strong 850mb or 700mb low. This jetstreak is forecast to move to the NE at a rather rapid pace, so we should continue to see the precipitation expand as it moves westward, not fall apart like the NAM is suggesting. The RUC has a much better handle on whats going on in my opinion and even it might be underdone. I think this is why the NWS in Greenville has been pretty bullish on accumulating snowfall... since it looks like the upper features are in place. My opinion is that if we already have precipitation upstream, and our system will be moving into an area of increased upper level divergence, thats not going to weaken the precipitation all that much, and the surface low should actually intensify. Link to comment Share on other sites More sharing options...
DaculaWeather Posted February 9, 2011 Share Posted February 9, 2011 Question is, is it right? It sure looks good on it's simulated radar. Looks right to me... Link to comment Share on other sites More sharing options...
Lookout Posted February 9, 2011 Share Posted February 9, 2011 I've been following it, and the last couple of runs did drop precip all over w. NC but sometimes the run has nothing here, others it does, and to varying degrees, obviously some chaos factor going on, at one point it had a huge dry slot coming in almost to here by 5 am , coming across n. Ala, and GA and reaching us, but the last run changed that. It will be interesting to see how it ends up, we're only 8 or 9 hours from start time, if it makes it to us. I'm still thinking midnight to 5 am is our chance. Actually the RUC has several bands that sweep across us, and theres the outside chance at some enhanced banding thanks to the mtn. chain effects here in the lee, but thats very hard to forecast, but the RUC did show that last run. I'd be a bit surprised if your area didn't get something, which I have been thinking most of the way. Still don't think an inch is not out of the question because the column is so cold ratios should be high so you won't actually need much liquid. Ruc is still awful on surface temps/dewpoints. This morning it was showing dewpoints around 32 or 33 by now, and of course dewpoints remain in the upper teens/near 20. It continues to be about 10 degrees higher on dewpoints vs the nam/gfs and off around 15 degrees vs reality. I wonder though if this is part of the reason for it's impressive precip? Link to comment Share on other sites More sharing options...
WXinCanton Posted February 9, 2011 Share Posted February 9, 2011 RUC looks like 4 to 5 hours of snow for North GA. Link to comment Share on other sites More sharing options...
phil882 Posted February 9, 2011 Share Posted February 9, 2011 hmm Ruc is actually intensifying the precip as it moves east Question is, is it right? It sure looks good on it's simulated radar. Based of its handling of the upper level features... I'm inclined to believe it much more than the most recent NAM. Link to comment Share on other sites More sharing options...
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