Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 280331
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1031 PM EST THU NOV 27 2014

.SYNOPSIS...BENEATH HEIGHT RISES IN NORTHWESTERLY FLOW ALOFT...HIGH
PRESSURE WILL BUILD OVER THE REGION FROM THE WEST THROUGH EARLY
SATURDAY...BEFORE MOVING OFFSHORE LATE SATURDAY THROUGH SUNDAY.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1030 PM THURSDAY...

TONIGHT: A LARGE AREA OF HEIGHT RISES ALOFT FROM THE SOUTHERN
APPALACHIANS TO THE NORTHERN PLAINS...BEHIND A TROUGH LIFTING AWAY
FROM THE MIDDLE ATLANTIC STATES...WILL CONTINUE TO SPREAD EAST AND
ACROSS CENTRAL NC TONIGHT. BENEATH THESE HEIGHT RISES ALOFT AND
ASSOCIATED SUBSIDENCE...1033 MB CONTINENTAL POLAR HIGH PRESSURE WILL
LIKEWISE BUILD EAST FROM THE MID-MS VALLEY...RESULTING IN CAA AND A
LIGHT NW WIND FOR MOST OF THE NIGHT - SUPPORTIVE OF LOWS MOSTLY IN
THE MIDDLE TO UPPER 20S...THOUGH SOME LOWER 20S ARE PROBABLE BY
DAYBREAK WHERE SUSTAINED CALM DEVELOPS (MOST LIKELY OVER THE
SOUTHERN AND WESTERN PIEDMONT). WHILE A FEW STREAMERS OF
STRATOCUMULUS MAY SQUEEZE BETWEEN THE RIDGES INTO THE PIEDMONT...
LIKE ONE SUCH PATCH FROM NEAR KTDF TO KRDU AT 03Z...SKIES WILL
OTHERWISE BE CLEAR.

FOR FRI/FRI NIGHT: A QUIET DAY AND NIGHT WITH HIGH PRESSURE BUILDING
OVERHEAD AND STRONGLY SUBSIDING MID LEVELS. EXPECT LOTS OF SUNSHINE
DURING THE DAY. THE THERMAL TROUGH LIFTS OUT DURING THE LATTER HALF
OF THE DAY... AND THICKNESSES ACCORDINGLY REBOUND CONSIDERABLY
(ALTHOUGH THIS 1000-850 MB LAYER GRABS SOME OF THE WARMER AIR ABOVE
THE SUBSIDENCE INVERSION). USING A LOW LEVEL DRY ADIABATIC PROFILE
TO 925 MB INDICATES HIGHS OF 42-46... A SLIGHT LEAN TO THE COOL SIDE
OF GUIDANCE AND IN LINE WITH EARLIER FORECAST HIGHS. THE SURFACE
RIDGE SHOULD BE OVERHEAD EARLY FRI NIGHT BUT SHIFTING EASTWARD
LATE... SO WINDS SHOULD BE FAIRLY LIGHT WITH GENERALLY CLEAR
SKIES... ALTHOUGH WE`LL SEE INCREASING HIGH CLOUDS LATE AS MINOR
WAVES TRACK ESE INTO NC WITHIN THE FAST STEERING FLOW ALOFT. STILL
EXPECT LOWS IN THE MID-UPPER 20S. -GIH

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 PM THURSDAY...

HIGH PRESSURE WILL SHIFT OFFSHORE DURING THE DAY ON SATURDAY...
ALLOWING RETURN FLOW TO FIRMLY SET UP OVER THE REGION FOR THE
WEEKEND. IN ADDITION...MID LEVEL RIDGING WILL BUILD NORTH AND EAST
ACROSS THE AREA. ALL OF THIS WILL LEAD TO FAIR WEATHER AND A WARMING
TREND...WITH HIGHS EXPECTED TO BE IN THE LOW TO MID 50S ON SATURDAY
AND THEN LOW TO MID 60S BY SUNDAY. OVERNIGHT LOWS WILL ALSO MODERATE
THROUGH THE PERIOD...WITH MOSTLY MID/UPPER 30S SATURDAY NIGHT AND
THEN MID/UPPER 40S SUNDAY NIGHT.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 245 PM THURSDAY...

A NORTHERN STREAM SHORT WAVE MOVING ALONG THE US/CANADIAN BORDER
WILL SUPPRESS THE MID LEVEL RIDGE TO THE SOUTH AS IT PROPELS A
SURFACE FRONT TOWARDS THE REGION EARLY NEXT WEEK. THIS TRAILING COLD
FRONT IS STILL PROGGED TO CROSS THE AREA MONDAY NIGHT INTO TUESDAY.
FORCING IS NOT THAT IMPRESSIVE WITH THIS SYSTEM GIVEN THE PARENT LOW
IS SO FAR NORTH OF THE AREA. HOWEVER...GIVEN SOME CONVERGENCE AND
MOISTURE POOLING ALONG THE BOUNDARY...WILL MAINTAIN SLIGHT CHANCE
POPS IN THE FORECAST. HIGHS WILL WARM UP NICELY WITHIN THE DEEP
SOUTHWESTERLY FLOW AHEAD OF THE FRONT...WITH MID TO UPPER 60S (NEAR
70 DEGREES ACROSS THE SOUTHEAST) EXPECTED. TEMPS WILL BE COOLER
BEHIND THE FRONT ON TUESDAY...WITH HIGHS GENERALLY IN THE UPPER 40S
TO MID/UPPER 50S (COOLEST IN THE NORTHWEST WHERE SOME CAD MAY
DEVELOP).

QUITE A BIT OF UNCERTAINTY THEN PERSISTS FOR THE REMAINDER OF THE
FORECAST PERIOD AS ANOTHER SYSTEM (POSSIBLY) APPROACHES FROM THE
NORTHWEST. THE ECMWF IS MUCH MORE AMPLIFIED/PROGRESSIVE WITH ANOTHER
SHORT WAVE SWINGING THROUGH THE AREA WEDNESDAY INTO THURSDAY...WILL
THE GFS IS MUCH LESS AMPLIFIED (WITH ZONAL FLOW ACTUALLY OVER THE
MID ATLANTIC REGION). GIVEN THE DIFFERENCES...WILL KEEP ANY POPS
LOW...WITH SEASONAL HIGHS/LOWS.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 719 PM THURSDAY...

SCATTERED SHOWER ACTIVITY FROM THIS AFTERNOON HAS STEADILY
DIMINISHED AFTER SUNSET. DRY WEATHER WITH VFR CONDITIONS WILL
PREVAIL OVER THE NEXT 24 HOURS. WINDS WILL CONTINUE TO BE LIGHT AND
FROM THE NORTHWEST AT 5-10 KTS AS HIGH PRESSURE BUILDS INTO THE
SOUTHEAST STATES.

LOOKING BEYOND 18Z FRI... VFR CONDITIONS ARE EXPECTED TO DOMINATE
THROUGH MON... ALTHOUGH AREAS OF MVFR OR IFR FOG ARE POSSIBLE EARLY
SUN MORNING AND EARLY MON MORNING. HIGH PRESSURE WILL SHIFT EASTWARD
OVER THE REGION THROUGH SAT... THEN MOVE EAST AND OFFSHORE SAT
NIGHT/SUN. A COLD FRONT WILL MOVE IN FROM THE NORTH LATE MON OR MON
NIGHT... BRINGING A GOOD CHANCE OF MVFR/IFR CONDITIONS MON NIGHT/TUE
AND PATCHY LIGHT RAIN. -GIH

&&

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

&&

$$

SYNOPSIS...MWS
NEAR TERM...MWS/HARTFIELD
SHORT TERM...KRD
LONG TERM...KRD
AVIATION...SEC/HARTFIELD


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