Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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754
FXUS62 KRAH 081804
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
100 PM EST MON FEB 8 2016

.SYNOPSIS... AN UPPER LEVEL DISTURBANCE AND COLD FRONT WILL CROSS
THE REGION THIS EVENING AND OVERNIGHT...FOLLOWED BY AND EXTENDED
PERIOD OF COLD TEMPERATURES THROUGH THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM MONDAY...

SHORTWAVE RIDGING IN THE WAKE OF THE THE DEPARTING UPPER LOW OFF THE
MID-ATLANTIC COAST IS GIVING WAY TO  A DEEP TROUGH DIGGING THROUGH
THE MIDWEST. WITH 100-150M HEIGHT FALLS APPROACHING OUR REGION...THE
BIGGEST FORECAST INTEREST TODAY WILL BE THE POTENTIAL DEVELOPMENT OF
A BAND OF SHOWERS AS A LEAD FRONTAL ZONE CROSSES THE MOUNTAINS THIS
AFTERNOON.  CONVECTION ALLOWING MODELS SHOW SOME SHOWERS DEVELOPING
ALONG THE FRONT AND/OR A PREFRONTAL TROUGH SITTING IN THE LEE OF THE
MOUNTAINS SOMETIME AROUND 20Z...AND THEN PROGRESSING EAST ACROSS
CENTRAL NC BETWEEN 21Z AND 03Z.  WITH DEWPOINTS ONLY IN THE UPPER
20S AND LOWER 30S...MODELS BARELY SHOW ANY MLCAPE AT ALL.
HOWEVER...AN AXIS OF STEEP 7-7.5 C/KM MID-LEVEL LAPSE RATES CENTERED
JUST UPSTREAM OVER UPSTATE SC COMBINED WITH A WARMING SOUTHERLY FLOW
MAY ALLOW FOR SOME WEAK INSTABILITY TOP DEVELOP...ESPECIALLY JUST IN
ADVANCE OF THE FRONT.  THE HRRR SHOWS THE BAND OF SHOWERS
STRENGTHENING A BIT WITH TIME AND EASTWARD EXTENT LATE THIS
AFTERNOON...AND GIVEN A FAIRLY DRY SUB-CLOUD LAYER AND STEEPENING
LOW-LEVEL LAPSE RATES...WIND GUSTS OF 30-40MPH WITH THE SHOWERS
SEEMS ENTIRELY POSSIBLE.  A FEW LIGHTNING STRIKES ARE ALSO PLAUSIBLE
WITHIN THE LINE GIVEN THE THE STEEP MID-LEVEL LAPSE RATES...BUT
WITHOUT BETTER FORECASTS CAPE...PREFER TO MONITOR THE EVOLUTION OF
THE CONVECTIVE ELEMENTS BEFORE ADDING THUNDER TO THE FORECAST.
HIGHS WILL BE IN THE UPPER 40S AND LOWER 50S.  -22

TONIGHT...
AS THE LOW PRESSURE FORMS ALONG THE FRONT AND TRACKS OVER
VA THEN OFFSHORE THIS EVENING... THE COLD FRONT WILL PUSH THROUGH
TONIGHT. MUCH COLDER AND DRIER AIR WILL ARRIVE BEHIND THE FRONT.
THIS IS LARGELY A DOWNSLOPE FLOW. HOWEVER... SEVERAL MODELS
INCLUDING SOME OF THE LATEST HI-RES MODELS SHOW SOME LINGERING
MOISTURE MAY GET WRUNG OUT AS SNOW SHOWERS OR PATCHY FLURRIES LATE
TONIGHT MAINLY ALONG THE NC/VA BORDER AND NORTHEAST OF RALEIGH. AT
THE CURRENT TIME... IT APPEARS THAT A QUICK DUSTING OR TRACE AMOUNTS
WOULD BE THE WORST CASE SCENARIO FOR AREAS AROUND ROXBORO TO ROCKY
MOUNT TO THE VA BORDER. OTHERWISE... THE COLD DRY ADVECTION WILL
QUICKLY END THE SHOWER THREAT. WINDS WILL BECOME WESTERLY AT 10-15
MPH. LOWS WITH CAA SHOULD DIP INTO THE 25-30 RANGE NW... AND LOWER
TO MID 30S ELSEWHERE BY TUESDAY MORNING.

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 227 AM MONDAY...

BLUSTERY AND COLD CONDITIONS ARE EXPECTED TUESDAY AND TUESDAY NIGHT
AS THE VERY COLD MID/UPPER TROUGH DIVES FROM THE OHIO VALLEY ACROSS
THE CENTRAL APPALACHIANS THE MID-ATLANTIC STATES. THE TROUGH AXIS IS
FORECAST TO PIVOT THROUGH OUR REGION LATE TUESDAY. WEAK HEIGHT FALLS
ALOFT AND AFTERNOON STEEPENING LAPSE RATES WITH MOISTURE ALOFT WILL
LEAD TO VARIABLY CLOUDY SKIES. THERE MAY BE A FEW FLURRIES
ESPECIALLY OVER THE NORTHERN AND EASTERN ZONES DURING THE AFTERNOON.
HOWEVER... AS IS TYPICALLY THE CASE... THE AREAS DOWNWIND OF THE
APPALACHIANS WILL NOT SEE MEASURABLE OR SIGNIFICANT PRECIPITATION.
HIGHS ONLY IN THE LOWER TO MID 40S NW... TO NEAR 50 SE.

TUESDAY NIGHT WILL BE PARTLY CLOUDY AND COLD WITH DIMINISHING NW
WINDS. LOWS GENERALLY 20-25 NW TO 25-28 SE.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 335 AM MONDAY...

...A SECONDARY COLDER INTRUSION OF ARCTIC AIR WILL DESCEND SOUTH
INTO THE REGION THIS WEEKEND...

WEDNESDAY THROUGH THURSDAY NIGHT:

CORE OF COLD AIR ASSOCIATED WITH ANOMALOUSLY DEEP UPPER
TROUGH(H5ANOMALIES 2 TO 4 SD BELOW NORMAL)IN PLACE ACROSS THE
EASTERN US WILL BE CENTERED OVER THE REGION LATE WEDNESDAY AND INTO
THURSDAY. H8 TEMPS ARE EXPECTED TO BOTTOM OUT ~15C WITH LOW-LEVEL
THICKNESSES 1240-1245M WEDNESDAY NIGHT...60 TO 70 METERS BELOW
NORMAL. HIGHS WEDNESDAY AND THURSDAY IN THE LOWER TO MID 30S NORTH
TO UPPER 30S/NEAR 40 SOUTH. LOWS IN THE TEENS AND 20S. FRIDAY
THROUGH SUNDAY:

HEIGHTS ALOFT WILL RISE BRIEFLY THURSDAY NIGHT AND INTO THE FRIDAY
BEFORE THE NEXT SUCCESSION OF SHORTWAVE ENERGY DIVING OUT OF
CANADA...ANCHORED BY A STRONG VORTEX DROPPING SOUTH THROUGH SOUTHERN
CANADA AND THE NORTHEAST/NORTHERN MID-ATLANTIC REGION...LEADS TO
RENEWED AMPLIFICATION OF THE COLD EASTERN US TROUGH WITH EVEN COLDER
ARCTIC AIR DESCENDING INTO THE SOUTHEAST OVER THE WEEKEND.

AS WE GET CLOSER IN TIME...ONE FEATURE WE WILL NEED TO BE MONITOR
OVER THE NEXT COUPLE OF DAYS WILL BE EVENTUAL TRACK OF A SHORTWAVE
DIVING DOWN THE BACK-SIDE OF THE TROUGH THAT COULD POTENTIALLY
SUPPORT LIGHT RAIN OR SNOW FRIDAY/FRIDAY NIGHT. HIGHS FRIDAY IN THE
UPPER 30S TO LOWER 40S.

BOTH THE EC AND GFS INDICATE THAT THE EARLIER MID-WEEK ARCTIC
INTRUSION WILL PALE IN COMPARISON TO THE WEEKEND INTRUSION WITH H8
PROGGED TO BE IN THE -20TO -25C WITH LOW-LEVEL THICKNESSES TANKING
TO 1210-1215M. IF THESE INCREDIBLY COLD THICKNESSES VERIFY...HIGHS
OVER THE WEEKEND WILL STRUGGLE TO CLIMB ABOVE FREEZING WITH
OVERNIGHT LOWS IN THE SINGLE DIGITS.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 100 PM MONDAY...

SOUTHERLY WINDS WILL SLOWLY INCREASE THIS AFTERNOON AHEAD OF A COLD
FRONT AND BAND OF SHOWERS EXPECTED TO CROSS CENTRAL NC BETWEEN 20Z
AND 02Z...THEN TURN TO WESTERLY BEHIND THE FRONT.  A BRIEF PERIOD OF
MVFR CONDITIONS AND A WIND GUST TO 30-35MPH IS POSSIBLE WITH THE
SHOWERS...THOUGH THE STRONGER GUSTS WOULD BE VERY ISOLATED AND ARE
NOT INCLUDED IN THE TAF. AS THE SHOWERS EXIT THE COASTAL PLAIN LATE
THIS EVENING...A SURFACE LOW IS FORECAST TO FORM ALONG THE FRONT
OVER SOUTHERN VA..WHICH MAY DRAW SOME ADDITIONAL MOISTURE SOUTH
ACROSS THE NORTHERN COASTAL PLAIN AND CAUSE A FEW EXTRA SHOWERS OR
SNOW SHOWERS...MAINLY NORTH OF KRDU AND KRWI AFTER 09Z.

WESTERLY WINDS WILL INCREASE TO 9-12KT AND GUST TO AROUND 20KT ON
TUESDAY

OUTLOOK...WEDNESDAY AND THURSDAY WILL FEATURE VFR CONDITIONS WITH
GUSTY NORTHWEST WINDS OF 20-25.  THE NEXT CHANCE OF SUB-VFR
CONDITIONS WILL COME FRIDAY AS A WEAK LOW PRESSURE SYSTEM CROSSES
THE AREA.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.


&&

$$

SYNOPSIS...BADGETT
NEAR TERM...BADGETT/SMITH
SHORT TERM...BADGETT
LONG TERM...CBL
AVIATION...SMITH



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