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T-day eve possible SE winter storm (11/26/14)


GaWx

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GFS is cooler. I dont trust the NAM to tell me the sky is blue, personally.

Remember how the NAM did with thermals on today's storm? It was the first to show low to mid 40s during the event while other models like GFS and Euro were showing mid and upper 30s. I'll go with the model that does best on thermals even if it's not what I like. GFS may be cooler but it is warm from 925mb down as well, too warm for snow especially at the surface. I think later in December and January we will all finally see some snow, but tomorrow the clipper doesn't have the thermal profile to support any white stuff making it to the ground.

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East of the apps in NC just use the actual first and last day of winter, Dec 21 through March 21 as a refernce point. It works out way better than using met winter as your metric. Really does well for summer to, doesn't consistently start getting uncomfortable until June 20 and want let off the gas pedal humidity wise till around Sept 21stish for good.

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but winter begins in just a little over 4 days. Surely the wavelengths can't be that much longer on December 1st than they are on November 26th.

it's not that simple, like cold rain said it's gradual. And the jet slowly sags south over the course of winter too. Not reaching it's average south position until Feb.
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Remember how the NAM did with thermals on today's storm? It was the first to show low to mid 40s during the event while other models like GFS and Euro were showing mid and upper 30s. I'll go with the model that does best on thermals even if it's not what I like. GFS may be cooler but it is warm from 925mb down as well, too warm for snow especially at the surface. I think later in December and January we will all finally see some snow, but tomorrow the clipper doesn't have the thermal profile to support any white stuff making it to the ground.

What's your location? My point and click forecast from the NWS says 40% chance of rain and snow tonight with a low of 34. I think that they are using their forecasting skills and gut feelings. Models are just tools..... sometimes the models are right and sometimes not.

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That clipper tomorrow looks like a dud too. No snow outside the mountains. Yes the upper levels are cold enough but not the surface extending up to and just beyond 925mb.  By the time it does turn cold enough winds will be nw over the mountains and d/s kills all. But atm the greatest moisture seems to be assoicated with the waa taking place just above the surface. A hand full of people may see sleet flurries, rain. But not many with this setup.

 

post-7245-0-17548300-1417051211_thumb.gi

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The 00z NAM has a really nice heavy shower passing through this area in the wee hours of the morning, but like you said the BL is pretty terrible.  Upper 30s.  Even if the model missed the mark and was too warm by a couple degrees, it likely wouldn't be enough.  We seem to usually run into BL issues with clippers, though, and this is no exception.

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My temp is rising. lol was down to 37.3 now setting at 40 So my guess since it's not cold enough to snow the moisture will make it over the mountains! Now if it was in low-mid 30s I would bet on the skip over the foothills deal.... Maybe by late December we MIGHT have a pattern that will produce a chance of snow here, until then I say (enjoy the weather it's the only weather you got)!  lol

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It probably won't matter because the cooling is only near the surface from radiational cooling. Once the precip starts, the cool air will probably mix out.

I wouldn't doubt it. That blob will probably move too far north before it gets to us in Durham anyways.

EDIT: RAH says no snow:

.NEAR TERM /THROUGH THURSDAY/...

AS OF 1040 PM WEDNESDAY...

REMARKABLE CHANGES OF THE THERMODYNAMIC PROFILE OBSERVED AT KGSO

DURING THE PAST 12 HOURS...SUCH THAT THE DEEP NEAR FREEZING

ISOTHERMAL LAYER FROM THE SURFACE TO 550 MB THIS MORNING HAS BEEN

REPLACED BY MUCH STEEPER LAPSE RATES IN THE SAME LAYER THIS

EVENING...INCLUDING A 12 HR 500 MB CHANGE OF 15 DEGREES. LAPSE RATES

WILL CONTINUE TO STEEPEN OVERNIGHT...MOST NOTABLY ACROSS THE

NORTHERN PIEDMONT...AS A SERIES OF MID-UPPER LEVEL VORTICITY MAXIMA

AND ASSOCIATED COLDER TEMPERATURES ALOFT - INCLUDING MINUS 30 C AT

KBNA AT 00Z - ROUND THE BASE OF A MEAN TROUGH AND CROSS NC. THE

STEEPENING OF THE LAPSE RATES...AND RE-MOISTENING/RE-SATURATION OF

THE LOWEST 3-4 KM OWING TO THE APPROACH AND PASSAGE OF STRONG QG-

FORCING ACCOMPANYING BOTH THE VORTICITY MAXIMA ALOFT AND A BRIEF LOW

LEVEL WAA REGIME IN ASSOCIATION WITH ELONGATED 850 MB LOW PRESSURE

FROM THE MID-MS VALLEY TO THE SOUTHERN APPALACHIANS...WILL CAUSE AN

AREA OF MIXED CHARACTER RAIN/SHOWERS TO FURTHER BLOSSOM IN THE LEE

OFF THE APPALACHIANS...AND ACROSS THE NORTHERN NC PIEDMONT...

TONIGHT.

ALTHOUGH TEMPERATURES HAVE RADIATIONALLY COOLED BRIEFLY TO

NEAR FREEZING OVER PORTIONS OF THE PIEDMONT...THE INCREASING

CLOUDINESS ACCOMPANYING THE INCOMING PRECIPITATION WILL CAUSE

SURFACE TEMPERATURES TO CREEP UP (FROM DOWNWARD L/W RADIATION) INTO

THE MIDDLE TO UPPER 30S - SIMILAR TO WHAT WAS OBSERVED AT KBUY AND

K5W8 FROM 02-03Z - SUCH THAT ALL RAIN IS EXPECTED. IN FACT...RECENT

AMDAR DATA FROM RDU INDICATES A WARM LAYER WITH A MAXIMUM

TEMPERATURE OF AROUND 5 DEGREES IS PRESENT BETWEEN A 3-5 THOUSAND FT

FREEZING LEVEL...AND THE AFOREMENTIONED NEAR FREEZING TEMPERATURE

RIGHT AT THE SURFACE - MUCH TOO DEEP AND WARM FOR SNOW. WHILE IT IS

POSSIBLE FOR A FEW LIGHTNING STRIKES TO OCCUR WITH THE PRECIPITATION

TONIGHT...OVER THE NW PIEDMONT WHERE LAPSE RATES WILL BE STEEPEST

AND TOTAL TOTALS AND K-INDICES ARE FORECAST TO PEAK AROUND 55 AND

NEAR 30 C...RESPECTIVELY...THE RELATIVE BETTER (BUT STILL LOW

PROBABILITY) WILL BE WITH DIURNAL HEATING/BENEATH THE COLD POOL

ALOFT ON THU.

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