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3/6 - 3/7 Event is it this seasons last gasp?

WXinCanton

By WXinCanton,
in Southeastern States

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packbacker

packbacker

Posted
Posted

The surface low off of Myrtle beach is definitely stronger.  More robust precip shield over NC.  Everything looks a little north of 12z.

 

The Euro has the ULL further south than the NAM, think the NAM will correct tonight/tomorrow, curious to see how that affects everything.

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packfan98

packfan98

Posted
Posted

YOU MUST READ!!!!

 

NWS Raleigh AFD: 

 

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...

...A WINTRY MIX IS LOOKING MORE LIKELY... MAINLY OVER THE NORTHWEST
PIEDMONT THURSDAY NIGHT INTO EARLY FRIDAY... THIS INCLUDES THE
PIEDMONT TRIAD AND ROXBORO...

... RAIN IS EXPECTED ELSEWHERE... BUT MAX MIX WITH A LITTLE SLEET
AND FREEZING RAIN THURSDAY EVENING FROM ALBEMARLE TO RALEIGH TO
ROCKY MOUNT...

THE MID/UPPER LOW CURRENTLY EXITING THE TEXAS PANHANDLE IS FORECAST
TO TAKE A SOUTHERLY TRACK ALONG THE GULF COAST THURSDAY NIGHT...
THEN SLOWLY TURN ENE ALONG THE SOUTH CAROLINA COAST FRIDAY...
EXITING THE NC FRIDAY EVENING. THIS SOLUTION IS A PREFERRED BLEND OF
THE 12Z/GFS/ECMWF/UKMET. THE LATEST MODEL GUIDANCE HAS BEEN TRENDING
COLDER WITH LESS OF A WARM NOSE IN THE MID-LEVELS BACK OVER THE
NORTHWEST PIEDMONT FOR THE MAIN PART OF THE EXPECTED PRECIPITATION
EVENT. FOR THE SURFACE LOW PRESSURE DEVELOPMENT/TRACK EXPECTED FROM
THE GULF OF MEXICO NORTHEAST JUST OFFSHORE THE SC/NC COAST THURSDAY
NIGHT AND FRIDAY... IT IS HARD TO ARGUE WITH WPC`S PREFERENCE OF A
BLEND OF THE 12Z/UKMET WITH THE 00Z/ECMWF AND ECMWF ENSEMBLE MEAN
FOR THE FORECAST SOLUTION. THERE HAS BEEN A SLOWING TREND WITH THE
GUIDANCE AND CONFIDENCE HAS ALSO INCREASED WITH BETTER CLUSTERING
FROM THE ENSEMBLE PLOTS.

ANOTHER CRITICAL FEATURE IS THE PRONOUNCED VERY COLD PARENT SURFACE
HIGH PRESSURE THAT IS FORECAST TO BUILD FROM NEW ENGLAND DOWN THE
EASTERN SEABOARD INTO NC/UPSTATE SC LATE WEDNESDAY NIGHT AND
THURSDAY... AND BE IN PLACE THURSDAY EVENING. THIS HIGH IS OF
SUFFICIENT STRENGTH (1040ISH+ MB) AND PREFERRED LOCATION NY/NEW
ENGLAND TO DELIVER COLD DRY AIR INTO OUR REGION AS THE STORM
ARRIVES. ONE QUESTION HAS BEEN HOW QUICKLY THE HIGH WILL RETREAT AND
THIS APPEARS TO BE THURSDAY NIGHT. HOWEVER... CLASSICAL DAMMING IS
EXPECTED TO UNFOLD THURSDAY EVENING AS THE MAIN PRECIPITATION
SATURATES THE COLUMN QUICKLY.

IN ADDITION... THE WARM NOSE ALOFT IS ALSO CRITICAL AS MODELS HAVE
BEEN TRENDING COOLER WITH TIME WITH LESS OF A WARM NOSE REACHING
WELL BACK INTO THE FOOTHILLS/BLUE RIDGE. WE WERE NOT BITING OFF
TOTALLY ON THESE SOLUTIONS AS THERE IS STILL A LOT OF UNCERTAINTY.

IF THESE TRENDS CONTINUE... A WINTER WEATHER ADVISORY OR EVEN A
WINTER STORM WATCH MAY BE NEEDED IN THE NW PIEDMONT FOR THURSDAY
NIGHT INTO EARLY FRIDAY FOR A WINTRY MIXTURE OF MOSTLY FREEZING RAIN
WITH EVEN SOME MEASURABLE SNOW AND SLEET. THE WARM NOSE ALOFT MAY
ACTUALLY EVEN VERIFY LESS INTENSE IF THE LIFT IS STRONG ENOUGH TO
OFFSET THE WAA ABOVE THE NEAR SURFACE COLD NOSE. THIS MAY LEAD TO A
CHANGE TO WET SNOW AT TIMES IN HEAVIER PRECIPITATION. THE TRACK OF
THE MID LEVEL LOW IS ALSO CRITICAL... AND THIS REMAINS WELL SOUTH
AND EAST OF OUR REGION THIS MODEL RUN... SUPPORTING COLDER AIR
ALOFT.

... THE NORTHWEST PIEDMONT TO ROXBORO AND OXFORD...

RIGHT NOW... THE FORECAST 1000/850 AND 850/700 PARTIALS INDICATE
1295-1305M/1545-1555M DURING MUCH OF THE OVERNIGHT PERIOD THURSDAY.
NOMOGRAMS SUGGEST A WINTRY MIXTURE WITH MORE SNOW/SLEET THE LESS THE
WARM NOSE... AND MORE IN THE WAY OF FREEZING RAIN/RAIN IF THE WARMER
NOSE VERIFIES. WE WILL LOOK TO SURFACE WET BULB FORECASTS FOR
PLACEMENT OF THE MOST CRITICAL REGION THAT WOULD LIKELY SEE THE
HIGHEST PROBABILITIES OF THE WINTRY MIXTURE/ICING. CURRENT FORECASTS
INDICATE WET BULBS OF 30-32 FROM NEAR LEXINGTON TO GREENSBORO TO
ROXBORO THURSDAY NIGHT... AND SUB 30 POSSIBLE FROM WINSTON-SALEM AND
THE PTI AIRPORT NORTH AND WEST. THESE WILL BE THE MOST CRITICAL
LOCATIONS FOR POTENTIAL WINTER WEATHER. HERE... WE WILL FORECAST A
MIXTURE OF FREEZING RAIN AND SLEET... POSSIBLY WET SNOW AT TIMES.
GLAZING OF ICE OF 0.1 TO 0.2 POSSIBLE... WITH SNOW AND SLEET OF LESS
THAN AN INCH. THESE ARE PRELIMINARY NUMBERS AND WILL LIKELY CHANGE
AS THE STORM EVOLVES. TEMPERATURES SHOULD FALL TO NEAR THE WET
BULBS... UPPER 20S TO AROUND 30. COLD AIR DAMMING SHOULD BE LOCKED
IN FOR A WHILE. HOWEVER... TEMPS SHOULD SLOWLY RISE TO NEAR OR ABOVE
32 MOST AREAS... INTO THE MID TO UPPER 30S. UNLESS PRECIPITATION
RATES CONTINUE HEAVY... PRECIPIATION SHOULD CHANGE TO RAIN. WET SNOW
CAN NOT BE RULED OUT IN HEAVIER BANDS.

...TO THE SOUTH AND EAST INCLUDING ALBEMARLE TO RALEIGH TO ROCKY
MOUNT... RAIN IS EXPECTED THAT MAY MIX WITH A LITTLE SLEET OR
FREEZING RAIN THROUGH MIDNIGHT... THEN CHANGE TO RAIN AS TEMPS RISE
SLOWLY OVERNIGHT. WET BULBS NEAR 32 DO SUPPORT SOME GLAZING... BUT
ONLY ON ELEVATED SURFACES. RAINFALL RATES SHOULD LIMIT ICING. LOWS
31-32... RISING TO 34-35 OVERNIGHT. RAIN IS EXPECTED FRIDAY. MAY BE
SOME WET SNOW (NON ACCUMULATING) DUE TO THE WET GROUNDS DURING HEAVY
PRECIP BANDS/RATES FRIDAY. HIGHS 37-44.

ALL RAIN IS EXPECTED FROM ROCKINGHAM TO LILLINGTON TO WILSON
SOUTHWARD DURING THE EVENT WITH WET BULBS LIKELY REMAINING ABOVE 33
AND RISING TOWARD 40 OVERNIGHT. RAIN FRIDAY... HIGHS IN THE 40S.

THE BOTTOM LINE AT THIS POINT IS THAT WE ARE CONFIDENT THAT THE
NORTHWEST PIEDMONT HAS THE BEST CHANCE OF A WINTRY MIX... WITH
LESSER CHANCES CLOSER TO THE TRIANGLE AND NIL POINTS SOUTH AND EAST
OF THE ROCKINGHAM TO RALEIGH TO WILSON AREAS.

MODELS HAVE TRENDED TOWARD MORE OF A WINTRY MIX... WITH MORE
FREEZING RAIN AND EVEN SNOW/SLEET OVER THE NW PIEDMONT

CONFIDENCE IN THE PREDOMINATE PRECIP TYPE AND POSSIBLE ACCUMULATIONS
IS STILL LOW GIVEN SOME OF THE DIFFERENCES IN THE EXTEND OF THE
DAMMING... THE SURFACE/850MB LOW TRACK... AND WESTERN
EXTENT/STRENGTH OF THE WARM NOSE.

PRECIPTATION SHOULD END LATE FRIDAY BUT TEMPERATURES SHOULD REMAIN
ABOVE FREEZING FRIDAY AFTERNOON AND NIGHT KEEPING ADDITIONAL
PROBLEMS WITH FREEZING VERY LOW.

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GaWx

GaWx

Posted
Posted

As has just been noted by others, 18Z NAM is colder. At 850/925 it si colder. It has 925 near to below 0C for much of the time ATL-AHN with heavy (1"+ )precip. And now we have a colder trend perhaps? Be wary! This is a very rare setup for early March.

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jburns

jburns

Posted
Posted

Is Canadian showing wintry precip at GSO? If so, howuch? If more than .25, then I believe nam, gfs, and can would all give GSO warning criteria between about midnight toe row night and mid/late morning Friday.

TW

 

I'll look forward to frolicking in the snow with my herd of unicorns.  The snow slows down the hydra so it's a lot safer.

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MillerA

MillerA

Posted
Posted

Gsp

Short term /6 am Thursday morning through Friday night/... as of early Wednesday afternoon...high pressure over the northestern US will continue to build tonight under confluent upper flow...with surface ridge extending down the East Coast and at least briefly configuring cold air damming by tomorrow. Parent high weakens and slips off the New England shore tomorrow night. Associated cold wedge lingering into Friday will focus low level upglide over the forecast area ahead of southern stream shortwave developing a surface low over the eastern Gulf of Mexico...likely producing precipitation across the region late tmrw into early Friday. Wedge will slowly erode beginning Friday...with all precipitation ending Friday evening. Spread between the NAM/GFS/ec/CMC has narrowed...but minor differences are still noted which are of particular consequence due to temperatures at the surface and in the lower troposphere supportive of a winter weather threat. Differing placement of highest quantitative precipitation forecast and strength of the warm nose over The Wedge lead to vastly different ice/snow accums. Ec seems to waffle from run to run between the NAM/GFS extremes with respect to low track...but consensus at this point is for the low to ride near the Carolina coast and depart just east of the Outer Banks. All models now develop notable quantitative precipitation forecast response to deformation zone crossing the area with short wave early Friday but by this time the ridge appears to be weakening and surface temperatures warm enough for a changeover to rain that persists until precipitation ends. In terms of timing...trends seem to be for the event to be pushed later into Friday. Ec/NAM soundings feature a more significant warm nose which could be attributed to the more onshore track and lower pressure of the surface low. These scenarios would result in mainly freezing rain in the presence of surface temperatures below 0c. GFS is colder in llvls and has a weak warm nose...giving more sleet or even snow. Blended thermal profiles were used with the top-down technique to arrive at precipitation type. Surface temperatures are expected to remain near raw model values for the duration of The Wedge...and bottom out very close to freezing Thursday and Friday mrngs over much of the forecast area...allowing for modest wet bulb effects in the moist environment. Rain is expected to begin spreading north across the area during the day tmrw...changing along/east of the Blue Ridge and north of I-40 to sleet and then freezing rain as the warm nose strengthens toward Friday morning. Assuming The Wedge is able to weaken Friday as currently expected...temperatures should warm enough to end the wintry precipitation. Being moderately conservative with quantitative precipitation forecast...and following the evolution outlined above...both snow and ice totals remain under Winter Storm Watch criteria for now. && Long term /Saturday through

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FallsLake

FallsLake

Posted
Posted

ie...get ready triad and NW NC up to ROA, if the Euro is off by 1-2 degrees this could get ugly by early Friday morning.  

 

Can you imagine if that HP was 50 miles west and didn't scoot out as fast.

I still think we have a small chance of getting something significant here in the RDU area. As RAH has stated we'll be right on the line for wintery precip. Really hoping the cold influx from up north is colder than modeled (..from snow pack). That 1-2 degrees would put us right in the middle of the game.  

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Marion_NC_WX

Marion_NC_WX

Posted
Posted

I think given the very borderline temps GSP is doing a good thing keeping this conservative and not posting any products in the afternoon package...because I can tell you if they went broad-brush and issued Winter Storm Watches for most of their NC Counties, a lot of people and groups of people would over-react and then blame them if it didn't verified.

 

This gives them 2 more model runs and then they can pull the trigger tomorrow AM.

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GaWx

GaWx

Posted
Posted

Well the NAM is the furthest north with the ULL so would think that is playing some factor in it?

 

 I mean that on 3/6 they look too warm. Example: how does it warm 12 degrees at CLT tomorrow between 7 AM and 1 PM under cloudy skies and great CAD??

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deltadog03

deltadog03

Posted
Posted

As has just been noted by others, 18Z NAM is colder. At 850/925 it si colder. It has 925 near to below 0C for much of the time ATL-AHN with heavy (1"+ )precip. And now we have a colder trend perhaps? Be wary! This is a very rare setup for early March.

It def. is colder.. I truly think we have to watch out for that ULL when that heavy band comes through N and CGA

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mackerel_sky

mackerel_sky

Posted
Posted

I mean that on 3/6 they look too warm. Example: how does it warm 12 degrees at CLT tomorrow between 7 AM and 1 PM under cloudy skies and great CAD??

Really, it's the high March sun angle/ radiation getting through! With no rain till late tomorrow , I would not be surprised to get to 45-50 imby, then drop to upper 30s after precip starts.
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