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SE snow threat 1-15/16?


Cheeznado

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The NAM is too warm and it really doesn't look like the EURO anyway. It's also not in the same time frame as the EURO, which implied our little snow system at hour ~96. If the Euro is right and precip falls in the pre-dawn hours Thursday, then obviously that is better for snow, especially if we get a little wound up at 500MB.

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The problem is while we're cold enough at 850, we're above freezing below that level all the way to the surface. Significantly above freezing.

Yeah soundings is where it's at...a little too excitement for a minimal QPF event like this one, with one run support. I can't wait until we get a real storm to track.

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That's unlikely with surface temps starting in the 40s and only light precip.

It's called cold advection, and the 850s are cold enough to support snow, and I know here in my area srf temps do not have to be all that cold for it to snow here. If cold advection takes over and drops it to 36/37 it would be snow, I've seen it snow here many a time with a srf temp around say 37 as long as upper level temps support it.

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Even though this is just one model run... a step in the right direction stronger system and more expansive precip shield. Thermal profile soundings is questionable from 18z. Depending on the amount of dry air above should allow for evaporative cooling. 

 

Really it appears that the freezing level is only about 1500 feet with the 18z.

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RAH afternoon discussion keeps my interest up:

 

FOR WED THROUGH THU: AN INTERESTING FORECAST. MODELS AGREE OVERALL
ON THE NORTHERN STREAM ENERGY CULMINATING IN A NARROWING AND
STRONGLY AMPLIFYING TROUGH SHIFTING EASTWARD OVER THE EASTERN
STATES. THE NAM IS WEAKER AND FASTER THAN THE GFS/ECMWF... AND THE
LATTER TWO ARE COMING INTO BETTER AGREEMENT ON A STRENGTHENING
VORTICITY CENTER DROPPING INTO THE TROUGH BASE OVER SRN GA WED
EVENING. THE ECMWF CONTINUES TO BE A LITTLE SLOWER AND STRONGER WITH
ITS 12Z RUN... AND AS A RESULT IT GENERATES A SURFACE LOW EVEN
CLOSER TO THE NC COAST THAN ITS PREVIOUS RUN. THE ECMWF THEN BOMBS
THIS LOW JUST OFF THE OUTER BANKS THU MORNING AS THE STRONGEST
VORTICITY WITHIN THE TROUGH BASE SWINGS OFF THE CAROLINA COAST WITH
A NEGATIVE TILT. THE PREVIOUS ECMWF GENERATED A SURFACE LOW BUT WAS
MUCH FARTHER OFFSHORE... AND THE GFS (WHICH HAS A SIMILAR MID LEVEL
PATTERN BUT WITHOUT THE STRONG NEG TILT) BY THU MORNING HAS KICKED
THE BAROCLINIC ZONE WELL OFFSHORE WITH CLEARING SKIES FOR NC. THE
12Z ECMWF`S SOLUTION IS ENOUGH OF A DEPARTURE FROM ITS PREVIOUS RUN
TO LOWER OUR CONFIDENCE IN IT... BUT REGARDLESS... THIS MID LEVEL
PATTERN IN GENERAL CONTINUES TO BE AN ACTIVE AND ANOMALOUS ONE... SO
THIS SITUATION DOES BEAR WATCHING IN THE COMING DAYS. WILL STAY WITH
LOW CHANCE POPS... WITH ONLY MINOR CHANGES TO THE EXISTING
FORECAST... BRINGING LOW CHANCES INTO THE NW EARLY WED BEFORE
SHIFTING THESE CHANCES EAST THEN OUT IN THE AFTERNOON INTO EARLY
EVENING. THE GFS HAS LOW COVERAGE AND QPF... A REFLECTION OF HOW
MOISTURE-STARVED THIS SYSTEM SHOULD BE WITH WEAK MOISTURE INFLUX...
HOWEVER WE`VE SEEN MANY TIMES THAT A STRONGLY FORCED SYSTEM LIKE
THIS CAN PRODUCE MASS IMBALANCE AND VIGOROUS LIFT THAT COULD LEAD TO
RAPID SATURATION WHERE THERE OTHERWISE WOULD BE NONE. THE MOISTURE
SHOULD ALL BE BENEATH 700 MB WHERE LAPSE RATES WILL STEEPEN WITH THE
APPROACHING TROUGH ALOFT. PARTIAL THICKNESSES AND FORECAST SOUNDINGS
(INCLUDING WET BULB PROFILE) AREAWIDE SUPPORT THIS STARTING AS A
VERY LIGHT RAIN/SNOW MIX (WITH TYPE BEING DRIVEN BY LIFT AND PRECIP
RATES) BEFORE TRENDING TO MOSTLY VERY LIGHT SNOW AS THE COLDER AIR
ARRIVES AND NEAR-SURFACE WET BULB TEMP DROPS TO NEAR FREEZING. AT
THIS POINT IT APPEARS THIS WILL BE A VERY LIGHT PRECIP EVENT WITH
FEW TO NO CONSEQUENCES. EXPECT CLEARING SKIES WED NIGHT AND MOSTLY
SUNNY THU AS ANOTHER MILD SURFACE HIGH SHIFTS EASTWARD ACROSS THE
GULF COAST AND FL. BUT AGAIN... IF THE ECMWF IS ONTO SOMETHING...
THIS FORECAST COULD CHANGE.
WILL STAY WITH THE LOWER END OF GUIDANCE
FOR HIGHS WED WITH COOLER AIR MOVING IN AND PARTLY TO MOSTLY CLOUDY
SKIES FOR MUCH OF THE DAY. HIGHS FROM THE LOW 40S TO AROUND 50. LOWS
24-28. HIGHS 43-47 THU WITH A COOL AND STABLE COLUMN. WE MAY SEE
INCREASING MID CLOUDS LATE THU AHEAD OF THE NEXT TROUGH. -GIH

 

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I don't even know how to respond to this. The column is saturated with no way to cool off.

I guess he is referring to the latent heat absorption of melting snow as it falls through the lower layers. this would require higher precip rates than are currently being shown. A near freezing isothermal sounding can result from an above freezing saturated layer as snow falls through it provided that there is no warm air advection to negate the effect.

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still looks like the lee side screw job is still on, very light amounts (irregardless of temps). until i see a more southern storm, or a nice juicy gulf low these waves from the west or nw just dont do it for a lot of ne ga, the upstate and just east of the nc mtns

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This pattern the past few days has reminded me of the Inauguration storm from 6 years ago.  I don't have the maps but I remember it was not modeled until nearly 2 days prior to the event and even just before the storm models were only spitting out 0.1 or 0.2 of precip.  Needless to say in the Triangle it turned into a nice event.  Not saying it will happen this time, although if trends on todays Euro are right   it certainly has similarities with the trailing vorticity really strengthening on the coast.

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You mean to tell me the LR NAM made a drastic change? What?!

Man, I just saw the euro for Saturday. That really looks like something we could work with.

 

Shocked I'm sure. Maybe the God's will smile upon us and give us a surprise since the Panthers lost to the refs today. I just hope the Euro keeps that look and is sniffing something out instead of being on crack. 

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This pattern the past few days has reminded me of the Inauguration storm from 6 years ago.  I don't have the maps but I remember it was not modeled until nearly 2 days prior to the event and even just before the storm models were only spitting out 0.1 or 0.2 of precip.  Needless to say in the Triangle it turned into a nice event.  Not saying it will happen this time, although if trends on todays Euro are right   it certainly has similarities with the trailing vorticity really strengthening on the coast.

There was an Inauguration storm 6 years ago, in January 2008 ?

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