Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 231903
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
100 PM EST SUN NOV 23 2014

.SYNOPSIS...A WARM FRONT WILL SURGE NORTHWARD THROUGH THE CAROLINAS
AND MID-ATLANTIC LATE TODAY INTO TONIGHT AS A LOW PRESSURE SYSTEM
TRACKS NORTHEAST FROM THE LOWER MIDWEST TO THE GREAT LAKES. AN
ASSOCIATED COLD FRONT WILL SWEEP EASTWARD THROUGH THE CAROLINAS
MONDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM SUNDAY...

HIGH PRESSURE OFFSHORE STILL EXTENDS ACROSS CENTRAL NC THIS
MORNING...WITH STRENGTHENING SOUTHWESTERLY FLOW ALOFT AHEAD OF A
LONGWAVE TROUGH OVER THE WEST-CENTRAL US.  A VIGOROUS SHORTWAVE
CURRENTLY OVER THE ARKLATEX REGION WILL BECOME NEGATIVELY TILTED
THIS MORNING AND LIFT NORTHEAST TOWARD THE GREAT LAKES REGION.  OUT
OF AHEAD OF THIS WAVE...MOISTURE IS ON THE INCREAS OVER NC AND THE
FIRST ROUND OF RAIN IS CURRENTLY MOVING THROUGH THE SOUTHERN
PIEDMONT.  RAINFALL AMOUNTS HAVE BEEN VERY LIGHT THUS FAR...LESS
THAN A TENTH OF AN INCH...AS THE PRECIP ENCOUNTERS DEWPOINTS IN THE
UPPER 20S TO LOWER 30S. A SLIGHTLY HEAVIER BAND ASSOCIATED WITH A
REGION OF MID-LEVEL FGEN OVER SC WILL SPREAD IN THROUGH MIDDAY. AN
IN-SITU CAD AIRMASS WILL DEVELOP AS THIS RAIN SPREADS NORTH THIS
MORNING THROUGH EARLY AFTERNOON...WITH AREAS TO THE NORTHEAST LIKELY
TO SEE A LITTLE BETTER WARMING PRIOR TO THE ONSET OF PRECIP BY 18Z.
HAVE MADE SOME MINOR ADJUSTMENTS TO TEMPS TO REFLECT THE CURRENT
RADAR TRENDS AND EXPECTED EXPANSION OF PRECIP.  THERE MAY BE BIT OF
A LULL IN RAIN AFTER 18Z...BEFORE A BETTER SURGE OF 295-300K
ISENTROPIC LIFT ARRIVES ACROSS THE PIEDMONT AROUND 21Z. REGIONAL OBS
SHOW THE SFC AND 850MB WARM FRONT STILL WELL TO OUR SOUTH OVER
SOUTHERN AL/GA...SO INSTABILITY WILL BE ABSENT DURING THE DAY...WITH
THE SMALL SEVERE THREAT TO EVOLVE LATER THIS EVENING. -BLS

TONIGHT... THE 850 MB FRONT IS EXPECTED TO SURGE INTO AND ACROSS THE
AREA THIS EVENING... WITH 850 MB SOUTHERLY WINDS OF AROUND 50 TO 70
KTS. AS THE SFC-850 MB WARM FRONT MOVES THROUGH THE AREA EXPECT WE
COULD SEE A FEW ISOLATED EMBEDDED STORMS... WITH EVEN THE THREAT OF
AN ISOLATED TORNADO ACROSS OUR FAR SOUTHEAST (SAMPSON/WAYNE... MAYBE
CUMBERLAND AND WILSON AND EDGECOMBE) AS LOW LEVEL AND DEEP LAYER
SHEAR WILL BE STRONG... WITH LARGE CYCLONIC LOOPING HODOGRAPHS...
BUT INSTABILITY WILL BE MINIMAL TO NIL (BEST CHANCE OF SURFACE BASED
INSTABILITY ACROSS OUR FAR SE/E). SPC DAY ONE OUTLOOK CLIPS OUR FAR
EAST/SOUTHEAST WITH THE MARGINAL AREA... AND ONLY EXTREME SOUTHERN
SAMPSON WITH THE SLIGHT RISK AREA. THE SMALL WINDOW FOR AN ISOLATED
SEVERE STORM ACROSS OUR FAR EAST/SOUTHEAST WOULD BE FROM AROUND 00Z
TO 04/05Z... WITH THE MAIN THREATS OF AN ISOLATED TORNADO AND/OR
DAMAGING WIND GUST. MID LEVEL DRY AIR IS THEN FORECAST TO SURGE INTO
OUR AREA... AS WARM FRONT LIFTS NORTH AND NORTHWEST OF OUR AREA.
THUS... EXPECT TEMPS WILL RISE THIS EVENING INTO THE EARLY MORNING
HOURS... THEN BECOMING STEADY. THUS... LOW TEMPS FOR THE OVERNIGHT
PERIOD WILL ACROSS AT THE START OF THE OVERNIGHT. EXPECT TEMPS TO
WARM INTO THE 60S AREAWIDE ACROSS THE AREA BY 12Z MONDAY. -BSD

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 325 AM SUNDAY...

...WARM AND WINDY CONDITIONS ON MONDAY...

MONDAY AND MONDAY NIGHT: DRYING AND SUBSIDENCE ALOFT IN THE WAKE OF
THE EARLY MORNING MID/UPPER TROUGH PASSAGE TO THE NORTH WILL HELP TO
MIX OUT LINGERING LOW CLOUDS AND FOG MONDAY MORNING. AS SFC TEMPS
WARM MONDAY AFTERNOON AND LOW-LEVEL CONVERGENCE INCREASES WITH THE
APPROACH OF THE FRONT...THERE IS A CHANCE FOR SOME CONVECTIVE RE-
DEVELOPMENT OVER THE COASTAL PLAIN-EASTERN PIEDMONT MONDAY AFTERNOON
IN AN AXIS OF LOWER TO MIDDLE 60S SURFACE DEWPOINTS. OTHERWISE...THE
HEADLINES MONDAY WILL BE THE WARM TEMPERATURES AND STRONG WINDS LATE
MORNING AND THROUGH THE AFTERNOON. SOUNDINGS OVER THE PAST COUPLE OF
DAYS HAVE STEADILY TRENDED TOWARDS A DEEPER MIXED LAYER...TAPPING
INTO THE STRONG WINDS ALOFT...WITH LATEST SOUNDINGS INDICATING 35-
40KTS RIGHT OFF THE DECK AND 45 TO 50KTS AT THE TOP OF THE MIXED
LAYER. A WIND ADVISORY FOR MONDAY AFTERNOON MAY BE NEEDED IN LATER
FORECASTS FOR SUSTAINED WINDS OF 20 TO 25 MPH...WITH GUSTS BETWEEN
35 AND 45 MPH. ADDITIONALLY...DOWNWARD MOMENTUM TRANSFER OF THESE
STRONG WINDS WITH ANY CONVECTION THAT DEVELOPS MONDAY AFTERNOON
COULD RESULT IN THUNDERSTORM WIND DAMAGE.  HIGHS IN THE LOWER 70S NW
TO MID/UPPER 70S SE. COLD AND DRY ADVECTION BEHIND THE COLD FRONTAL
PASSAGE MONDAY EVENING/NIGHT WILL SUPPORT LOWS IN THE LOWER 40S NW
TO LOWER 50S EAST.


&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 325 AM SUNDAY...

TUESDAY THROUGH WEDNESDAY: A VIGOROUS SOUTHERN STREAM TROUGH
EMBEDDED AT THE BASE OF THE POSITIVELY LONG WAVE TROUGH WILL
TRAVERSE THE GULF COAST REGION ON TUESDAY AND THEN ACROSS THE
SOUTHEAST AND MID-ATLANTIC WEDNESDAY-WEDNESDAY NIGHT. APPROACH OF
THE SOUTHERN STREAM TROUGH WILL SPAWN SFC CYCLOGENESIS ALONG THE
STALLED BAROCLINIC FRONTAL ZONE OFF THE SOUTHEAST COAST LATE TUESDAY-
TUESDAY NIGHT AND WILL TRACK NORTH ALONG THE NC COAST ON WEDNESDAY
AND UP THE MID-ATLANTIC AND INTO SOUTHERN NEW ENGLAND WEDNESDAY
NIGHT. DURING THE MEANTIME...A TRANSITORY 1027 MB SURFACE HIGH
PRESSURE WILL BUILD EASTWARD INTO THE MIDDLE ATLANTIC STATES TUE
NIGHT.

AFTER A DRY START TO THE DAY ON TUESDAY...RAIN CHANCES WILL RETURN
TUESDAY EVENING/NIGHT AND INTO THE DAY ON WEDNESDAY AS WESTERN EDGE
OF DEEPER MOISTURE AXIS ATTENDANT TO OFFSHORE FRONTAL ZONE RETREATS
INLAND WITH DEEP LAYER FORCING OWING TO STRONG DPVA AND UPPER LEVEL
DIVERGENCE WITHIN THE RIGHT ENTRANCE REGION OF A 140-150KT
JETSTREAK. THE CANADIAN HAS STARTED TO CONVERGE TOWARDS THE WETTER
GFS AND EC SOLUTIONS..WHILE THE NAM IS AN OUTLIER...KEEPING IT DRY
WITH THE FRONTAL ZONE AND LOW PRESSURE WAVE FARTHER OFFSHORE. IT
LOOKS TO BE A COLD RAIN FOR MOST OF CENTRAL NC WITH TEMPERATURES IN
THE UPPER 30S AND LOWER 40S...WITH PARTIAL THICKNESSES SUGGESTING
THE POTENTIAL FOR A LITTLE WET SNOW MIXING IN WITH THE RAIN OVER THE
NW PIEDMONT. GIVEN THE MARGINALLY COLD THERMODYNAMIC PROFILES OWING
TO THE TRANSITORY AND WEAK PARENT HIGH AND AND FREEZING LEVELS
AROUND 1000 FT OVER THE PIEDMONT...NO ACCUMULATIONS ARE EXPECTED.
FOR NOW WILL KEEP IT ALL RAIN ACROSS THE AREA.

THURSDAY THROUGH SATURDAY: MEDIUM RANGE GUIDANCE HAS TRENDED
SIGNIFICANTLY LESS AMPLIFIED WITH THE UPPER AIR PATTERN OVER THE
CONUS. A MILDER/MORE MODIFIED HIGH PRESSURE OVER THE SOUTHEAST
STATES AND POSSIBLY MORE IN THE WAY OF ZONAL FLOW ALOFT COULD KEEP
CENTRAL NC ON THE SOUTHERN PERIPHERY OF THE ARCTIC AIRMASS TO THE
NORTH. EXPECT DRY CONDITIONS WITH BELOW NORMAL TEMPERATURES...BUT
JUST HOW FAR BELOW NORMAL WILL NEED TO BE RE-EVALUATED OVER THE NEXT
COUPLE OF DAYS.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 100 PM SUNDAY...

AREAS OF LIGHT RAIN CONTINUE TO MOVE EAST-NORTHEAST ACROSS THE AREA
THIS AFTERNOON.  LOW-LEVEL DRY AIR HAS KEPT LOW CEILINGS FROM
DEVELOPING AT MOST TERMINALS...BUT THE TREND CONTINUES TO BE DOWN
AND MVFR/IFR CEILINGS ARE ESSENTIALLY ON THE DOORSTEP OF
KGSO/KINT/KRDU/KFAY.  EXPECT ALL SITES TO DROP TO IFR BY 21Z AND
STAY THERE FOR MUCH OF THE EVENING.  WINDS WILL STAY OUT OF THE EAST-
NORTHEAST.  LATE THIS EVENING...A WARM FRONT WILL MOVE INTO THE AREA
FROM THE SOUTH...WHICH SHOULD CASE SOME LIFTING OF CEILINGS AT KFAY
AND KRWI BETWEEN 00Z AND 06Z.  THE FRONT WILL ATTEMPT TO PUSH ALL
THE WAY PAST KRDU TO KGSO/KINT...THOUGH ITS STILL UNCERTAIN WHETHER
OR NOT THE TRIAD TERMINALS.  AT THE SAME TIME A STRONG 50-60KT LOW
LEVEL JET WILL MOVE OVER THE AREA...WHICH MAY CREATE LOW-LEVEL WIND
SHEAR FROM KRDU WEST. A FEW STRONG STORMS WILL ALSO BE
POSSIBLE...MAINLY FROM KFAY TO KRWI AND EAST.

AFTER 06Z...AN EFFECTIVE FRONT WILL SWEEP ACROSS THE AREA AND WINDS
WILL TURN TO MORE SOUTH-SOUTHWESTERLY.  WIND GUSTS TO 20-25KT WILL
BE POSSIBLE...INCREASEING TO AS HIGH AS 30-35KT DURING THE DAY ON
MONDAY.   THERE WILL BE SOME IMPROVEMENT IN CEILINGS DURING THE DAY
MONDAY...THOUGH LOW-LEVEL MOISTURE WON COMPLETELY SCOUR UNTIL THE
ACTUAL COLD FRONT CROSSES THE AREA MONDAY NIGHT.

OUTLOOK...ANOTHER SYSTEM WILL IMPACT THE REGION BY MIDWEEK...THOUGH
THERE IS SOME UNCERTAINTY AS TO HOW MUCH OF THE AREA WILL BE
IMPACTED BY PRECIPITATION AND ADVERSE AVIATION CONDITIONS AS A
SURFACE LOW MOVES ALONG THE EAST COAST.

&&

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

&&

$$

SYNOPSIS...BSD/VINCENT
NEAR TERM...BSD/BLS
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...BLS/BSD


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