Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 271608
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1105 AM EST THU NOV 27 2014

.SYNOPSIS...AN UPPER LEVEL DISTURBANCE AND ASSOCIATED LOW PRESSURE
SYSTEM WILL TRACK EAST ACROSS THE REGION THROUGH EARLY THIS
AFTERNOON. HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE WEST
LATE TODAY THROUGH TONIGHT... THEN SETTLE OVER THE CAROLINAS ON
FRIDAY AND SATURDAY... BEFORE PUSHING EAST OFF THE COAST SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1105 AM THURSDAY...

HAPPY THANKSGIVING!

FORECAST REQUIRED LITTLE CHANGE THIS MORNING. THE LEADING SHORTWAVE
TROUGH EVIDENT ON WATER VAPOR IMAGERY IS NOW WOBBLING ACROSS NORTH
CENTRAL NC... GENERATING NUMEROUS SHOWERS ACROSS THE NRN CWA. FAST
ON ITS HEELS IS THE SECOND WEAKER WAVE GENERATING SNOW SHOWERS ON
THE WEST SLOPES OF THE SOUTHERN APPALACHIANS... HOWEVER MUCH OF THIS
APPEARS TO BE DRYING UP AS THE PRECIP HEADS JUST EAST OF THE
MOUNTAINS WHERE THE LOW LEVEL FLOW HAS A NOTABLE DOWNSLOPE
COMPONENT. NEVERTHELESS... BOTH ON THE TAIL END OF THE LEADING WAVE
AND WITH THE SECOND WAVE AS IT SHIFTS EAST ACROSS THE STATE... WILL
NEED TO MONITOR FOR A FEW POCKETS OF MIXED RAIN AND WET SNOW OVER
THE EXTREME NNW CWA. IN FACT... KRAX DUAL POL PRODUCTS INDICATE THE
MELTING LEVEL AT AROUND 2200 FT... A BIT LOWER THAN RAP FORECAST
SOUNDINGS SUGGEST... SO WE COULD DEFINITELY SEE SOME WET FLAKES
WHERE PRECIP RATES ARE HIGHER. TEMPS RANGE FROM THE UPPER 30S TO
LOWER 40S NORTH TO THE UPPER 40S/NEAR 50 SOUTH... AND THE NORTHERN
HALF IS UNLIKELY TO SEE MUCH MORE THAN A ONE TO PERHAPS TWO CATEGORY
CLIMB FOR THE REST OF THE DAY... AND EVEN THEN ONLY IF WE CAN GET
ENOUGH SUNSHINE. THESE CHANCES DON`T LOOK TOO GOOD GIVEN THE
PERSISTENT MOISTURE IN THE LOW LEVELS NOTED ON UPPER AIR ANALYSES.
WILL ADJUST NORTHERN HIGHS DOWN JUST A TAD... TO RANGE FROM MID 40S
NORTH (AND AGAIN THIS MAY BE OPTIMISTIC) UNDER MOSTLY CLOUDY SKIES
TO MID 50S SOUTH (WHICH COULD BE PESSIMISTIC GIVEN THE FAIR SKIES
THERE). -GIH

TONIGHT...SKIES WILL CLEAR OFF FAIRLY QUICKLY WEST-TO EAST LATE THIS
AFTERNOON EARLY EVENING AS DRIER AIR OVERSPREADS THE REGION. COLD
AIR ADVECTION WILL KEEP THE NEAR SURFACE ATMOSPHERE WELL MIXED UNTIL
JUST PRIOR TO DAYBREAK. THE CAA WILL SEND TEMPS INTO THE MID-UPPER
20S BY EARLY FRIDAY.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 305 AM THURSDAY...

FRIDAY...CHILLY HIGH PRESSURE WILL BUILD INTO AND SETTLES OVERHEAD.
LOW LEVEL THICKNESSES AVERAGE 45M BELOW NORMAL...SUGGESTIVE OF MAX
TEMPS 10-14 DEGREES BELOW NORMAL. THIS YIELDS MAX TEMPS IN THE LOW-
MID 40S. SKIES WILL REMAIN MOSTLY CLEAR ASIDE FROM A FEW PASSING
CIRRUS IN THE AFTERNOON. -WSS

FRIDAY NIGHT: SURFACE HIGH PRESSURE WILL SETTLE OVER THE REGION ON
FRIDAY NIGHT. MEANWHILE... MID LEVEL FLOW WILL REMAIN OUT OF THE WNW
WITH THE POTENTIAL FOR A FEW WEAK DISTURBANCES TO MOVE ACROSS THE
MID ATLANTIC REGION. HOWEVER... WE WILL REMAIN DRY WITH ONLY AN
INCREASE IN SOME HIGH CLOUDS ON SATURDAY MORNING. STILL THINK THE
CLOUDS WILL BE THIN ENOUGH NOT TO HAVE A SIGNIFICANT IMPACT ON LOW
TEMPS. GIVEN THIS... THINK WE SHOULD SEE TEMPS PLUMMET INTO THE 20S
ACROSS THE ENTIRE AREA... WITH LOWS IN THE MID TO UPPER 20S (MAYBE
EVEN A FEW LOWER 20S IN THE USUAL RURAL COLD SPOTS DEPENDING ON THE
CLOUD COVER). -BSD

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 310 AM THURSDAY...

HIGH PRESSURE WILL SHIFT TO THE SOUTH AND EAST OF CENTRAL NC THIS
WEEKEND ALLOWING FOR A WARMING TREND. HIGH TEMPS ARE EXPECTED TO BE
IN THE LOWER TO MID 50S FOR SATURDAY AND LOWER TO MID 60S FOR
SUNDAY. MID LEVEL RIDGING IS FORECAST TO BUILD NORTHWARD DURING THIS
TIME FRAME AND NUDGE INTO OUR AREA. HOWEVER... AS A NORTHERN STEAM
TROUGH IS FORECAST TO TRACK NEAR THE U.S./CANADIAN (EAST COAST THAT
IS) BORDER DURING THIS TIME FRAME A TRAILING COLD FRONT WILL DROP
SOUTHWARD AND INTO CENTRAL NC EARLY NEXT WEEK. MODEL GUIDANCE HAS
TRENDED TOWARDS THE SURFACE FRONT MOVING INTO THE AREA ON MONDAY
NIGHT INTO EARLY TUESDAY MORNING... PUSHED BY A 1035-1040 MB SURFACE
HIGH TO THE NORTH/NORTHWEST. THIS SHOULD ALLOW FOR ONE LAST WARM DAY
ON MONDAY... WITH HIGHS IN THE 60S TO LOWER 70S SOUTH.

GIVEN THE LAST SEVERAL DAYS MEDIUM RANGE MODELS HAVE TRENDED WETTER
WITH THE AFOREMENTIONED FRONT AND THE POTENTIAL FOR AT LEAST SOME
HYBRID COLD AIR DAMMING FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...
WPC STILL PREFERS TO KEEP POPS LOW WITH THE ARRIVAL OF THE FRONT
GIVEN THE APPARENT SPREAD IN GUIDANCE/ENSEMBLES GUIDANCE OVER THE PAST
FEW DAYS AND DIFFERENCES WITH THE OPERATIONAL MODELS VS THEIR
ENSEMBLES. THUS... FOR NOW PREFER TO KEEP POPS AT SLIGHT CHANCE FOR
MONDAY NIGHT INTO TUESDAY AND TREND TEMPS DOWNWARD. FOR WEDNESDAY...
WE MAY HAVE SOME FORM OF LINGERING CAD ACROSS THE AREA. HOWEVER...
THE PARENT SURFACE HIGH SHOULD BE WELL OFF THE NORTHEAST U.S. COAST
BY THIS TIME. THE NEXT SYSTEM WILL QUICKLY APPROACH FROM THE
NORTHWEST. HOWEVER... THERE IS A LARGE SPREAD AMONG THE GUIDANCE IN
TIMING OF THE FRONT. WPC HOLDS THE FRONT TO OUR NORTH DURING THIS
TIME FRAME... GOING WITH A LESS AMPLIFIED PATTERN. GIVEN THE LOWER
CONFIDENCE WILL KEEP TEMPS WITHIN A COUPLE CATEGORIES OF NORMAL AT
WORST... GIVEN THE LARGE POSSIBLE SPREAD IN TEMPS. THIS YIELDS HIGHS
ON TUESDAY IN THE UPPER 40S TO 50S... WITH HIGHS ON WEDNESDAY IN THE
50S TO SOME 60S... AND LOWS IN THE 30S AND 40S.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 635 AM THURSDAY...

A STRONG UPPER LEVEL DISTURBANCE CROSSING CENTRAL NC EARLY THIS
MORNING WILL EXIT OUR REGION BY EARLY THIS AFTERNOON. THIS SYSTEM IS
TRIGGERING PATCHES OF LIGHT RAIN ACROSS THE NORTHERN PIEDMONT AND
NORTHERN COASTAL PLAIN ALONG WITH VARYING CEILINGS...RESULTING IN
POCKETS OF LIFR CONDITIONS.  CEILINGS ARE EXPECTED TO LIFT AND
DISSIPATE FROM THE SW LATER THIS MORNING...LEADING TO IMPROVING
AVIATION CONDITIONS.

AFTER 14Z...WEST TO NW SFC WINDS WILL BE BLUSTERY WITH GUSTS 18-23
KTS LIKELY. THE GUSTS WILL BECOME LESS LIKELY AFTER 22Z...THOUGH A
STEADY NW WIND AROUND 10KTS EXPECTED WELL INTO TONIGHT.

HIGH PRESSURE WILL BUILD INTO CENTRAL NC TONIGHT AND SETTLE OVERHEAD
FRIDAY THROUGH SATURDAY...PROVIDING A PERIOD OF VFR CONDITIONS WITH
SFC WINDS LESS THAN 10KTS.

THE HIGH WILL SHIFT OFFSHORE SUNDAY. THE RESULTING SOUTH-SOUTHWEST
LOW LEVEL FLOW WILL ADVECT MOISTURE INTO OUR REGION BY LATE SUNDAY-
SUNDAY NIGHT LEADING TO THE POTENTIAL FOR AREAS OF MVFR FOG OR IFR
CEILINGS IN STRATUS BY EARLY MONDAY.

&&

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

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/WSS
SHORT TERM...WSS/BSD
LONG TERM...BSD
AVIATION...WSS



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