-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 140707
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
305 AM EDT FRI MAR 14 2014

.SYNOPSIS... 
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HIGH PRESSURE CENTERED OVER THE REGION THIS MORNING
WILL SHIFT OFFSHORE THIS AFTERNOON. A WEAK COLD FRONT WILL APPROACH
THE AREA FROM THE WEST SATURDAY AND DISSIPATE. A STRONGER COLD FRONT
WILL PUSH SOUTH ACROSS THE MID ATLANTIC SUNDAY. A LOW PRESSURE
SYSTEM WILL DEVELOP OVER THE MISSISSIPPI VALLEY SUNDAY AND MOVE EAST
ACROSS THE SOUTHEAST AND MOVE OFF THE COAST NEAR CAPE HATTERAS ON
MONDAY.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 240 AM WEDNESDAY...

THE UPPER LEVEL TROUGH THAT MOVED ACROSS THE EASTERN U.S. THURSDAY
WILL MOVE FURTHER OFFSHORE AND AWAY FROM THS REGION TODAY AS WEAK
SHORT WAVE RIDGING MOVES INTO THE MID ATLANTIC AND CAROLINAS TODAY.
THE SOUTHERN EXTENT OF A PROGRESSIVE LOW AMPLITUDE NORTHERN-STREAM
SHORT WAVE TROUGH MOVES ACROSS THE APPALACHIANS TONIGHT WITH A
WESTERLY FLOW ALOFT SETTING UP FOR SATURDAY. SURFACE HIGH PRESSURE
OVER EASTERN NC EARLY THIS MORNING WILL SLIP OFFSHORE TODAY. A WEAK
COLD FRONT ASSOCIATED WITH THE NORTHERN STREAM SHORT WAVE WILL
APPROACH THE APPALACHIANS TODAY AND THEN DISSIPATE AS IT MOVES
FURTHER EAST.

FOR TODAY...SUNNY SKIES THIS MORNING WILL GIVE WAY TO AN INCREASE IN
HIGH CLOUDS FROM THE NORTHWEST LATE THIS AFTERNOON. WITH LOTS OF
SUNSHINE AND A STEADY SOUTHWEST WIND...TEMPERATURES WILL MODERATE
CONSIDERABLY TODAY COMPARED TO THURSDAY. HIGHS SHOULD RANGE FROM 59
ACROSS THE NORTHEAST NEAR ROANOKE RAPIDS TO 63 ACROSS THE SOUTHWEST
NEAR ROCKINGHAM.

MID AND HIGH CLOUDS WILL INCREASE TONIGHT RESULTING IN PARTLY TO
OCCASIONALLY MOSTLY CLOUDY SKIES AS MOISTURE ASSOCIATED WITH THE
WEAK MID AND UPPER LEVEL TROUGH MOVES ACROSS THE REGION. NO
PRECIPITATION IS EXPECTED AS THE MOISTURE IS LIMITED AND THERE IS NO
APPRECIABLE FORCING FOR ASCENT. WITH THE CLOUD COVER AND A LIGHT
SOUTHWEST WIND TONIGHT...LOWS WILL RANGE IN THE 40-45 DEGREE RANGE.

DRY WEATHER IS EXPECTED TO CONTINUE ON SATURDAY UNDER A MIX OF
CLOUDS AND SUNSHINE. CLOUDS WILL BE MORE CONSEQUENTIAL EARLY IN THE
DAY...ESPECIALLY ACROSS THE SANDHILLS AND THE SOUTHERN COASTAL PLAIN
WHERE A LOW OVERCAST IS POSSIBLE AROUND DAYBREAK SATURDAY. BUT A
DEVELOPING WESTERLY FLOW SHOULD PROMOTE DRYING AND MORE AFTERNOON
SUNSHINE. TEMPERATURES WILL MODERATE EVEN MORE WITH HIGHS IN THE
UPPER 60S TO LOWER 70S. -BLAES

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
AS OF 225 AM FRIDAY...

FOR SAT NIGHT: UNSETTLED PATTERN KICKS INTO FULL GEAR... FEATURING A
MID LEVEL TROUGH DIGGING OVER THE FAR SRN PLAINS/NRN MEXICO WITH
INJECTION OF NRN STREAM ENERGY... AND A DEEP VORTEX OVER HUDSON BAY/
ONTARIO AND CORRESPONDING TROUGH COVERING THE NRN LAKES/ST LAWRENCE
VALLEY/NORTHEAST STATES. THIS NRN STREAM TROUGH PUSHES AN INITIALLY
DRY BACKDOOR FRONT SOUTHWARD TOWARD NC... WITH A LIKELY FRONTAL
PASSAGE (BASED ON CONSENSUS OF MODEL GUIDANCE) SAT NIGHT. THE CORE
OF THE POST-FRONTAL POLAR HIGH WILL BE SITUATED NEAR THE MN
ARROWHEAD... STILL QUITE FAR TO OUR NW... SO DON`T EXPECT TO SEE THE
FULL BRUNT OF THE COLDER AIR SAT NIGHT. CLOUDS WILL THICKEN WITH
LOWERING BASES AS SOUTHWESTERLY OVERRUNNING FLOW INCREASES ATOP THE
STRENGTHENING SURFACE FRONTAL ZONE... AHEAD OF THE APPROACHING 850
MB LOW TRACKING INTO THE LOWER MISS VALLEY... AND WITH INCREASING
DPVA AS MID LEVEL FLOW BACKS TO SOUTHWESTERLY. THE NAM/GFS/ECMWF
HOLD THE STRONGEST FORCING FOR ASCENT SW OF THE FORECAST AREA UNTIL
AFTER DAYBREAK SUN... AND NAM FORECAST SOUNDINGS RETAIN RATHER DRY
AIR BELOW 850 MB... SO WILL KEEP JUST A SMALL CHANCE OF RAIN OVER
THE SW CWA ONLY LATE SAT NIGHT. LOWS FROM 41 NEAR THE VA BORDER TO
NEAR 47 SOUTH.

FOR SUNDAY: LIFT INCREASES QUICKLY OVER NC AS THE PLAINS TROUGH
DEEPENS FURTHER TO THE SSW OVER TX/NE MEXICO SUNDAY... SENDING
POCKETS OF DPVA NORTHEASTWARD TOWARD NC... WHILE STRONG UPPER
DIVERGENCE IN THE RIGHT ENTRANCE REGION OF A JETLET OVER THE
NORTHEAST STATES CROSSES THE REGION. AT THE SURFACE... THE POLAR
HIGH CENTER DRIFTS ACROSS FAR SRN ONTARIO... AS LOW PRESSURE DEEPENS
NEAR MEMPHIS AND HEADS EAST OVER TN/NRN AL... WITH THE 850 MB LOW
CLOSE BY. THE APPROACH OF THE 850 MB LOW WILL LEAD TO FURTHER
STRENGTHENING OF THE OVERRUNNING FLOW OVER NC ATOP THE SLOPED
FRONTAL ZONE (MODELS INDICATE 30-40 KTS OF SOUTHERLY FLOW). GIVEN
THIS INCREASING AND DEEPENING FORCING FOR ASCENT AND INCOMING 1+
INCH PW AIR... HAVE LITTLE DOUBT THAT WE`LL SEE A WET SUNDAY WITH
RAIN OVERSPREADING CENTRAL NC... AND THE DEEP LAYER LIFT MAY SUPPORT
LOCALLY HEAVY RAINFALL. WILL STICK WITH CATEGORICAL POPS SUNDAY.
TEMPS ARE TOUGH AS WE SHOULD SEE READINGS LEVELING OFF AS THE RAIN
MOVES IN. THE LATEST MODEL RUNS HAVE TENDED TO PULL THE FRONTAL ZONE
NORTHWARD INTO THE SRN/SE CWA... ESSENTIALLY BECOMING A WEDGE FRONT
AS THE PRIMARY LOW NEARS WRN NC (WITH DIFFERENCES IN SPEED/TRACK
AMONG THE MODELS)... LEADING TO A MUCH GREATER THERMAL RANGE FROM NW
TO SE ACROSS THE CWA WITH WARM THICKNESSES IN THE SE AND COOLER NW.
WHILE IT`S UNCLEAR IF THIS FRONT WILL REALLY WORK FAR INTO THE SE
CWA... HAVE LEANED IN THIS DIRECTION AND EXPANDED THE RANGE OF HIGHS
TO 51 NW TO 61 SOUTH. RAINFALL THROUGH SUNSET SUNDAY COULD APPROACH
ONE INCH. -GIH

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
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AS OF 300 AM FRIDAY...

FOR SUNDAY NIGHT-TUE: FORECAST DETAILS REMAIN A BIT MURKY IN THIS
TIME FRAME... HOWEVER THE LATEST GFS/ECMWF/NAM HAVE COME IN WARMER
THROUGH THE COLUMN THAN YESTERDAY`S RUNS AT LEAST THROUGH EARLY
MON... SUPPORTIVE OF LESS OF A WINTRY WEATHER THREAT THROUGH SUN
NIGHT. THE MID LEVEL TROUGH IS EXPECTED TO TRACK FROM ERN TX ACROSS
THE GULF COAST/NRN GULF AND SOUTHEAST STATES THROUGH EARLY TUE. THE
PRIMARY SURFACE LOW IS LIKELY TO WEAKEN OVER FAR SW NC AS SECONDARY
LOW CENTERS FORM JUST OFF THE GA/SRN SC COAST SUNDAY NIGHT THROUGH
MONDAY. MEANWHILE THE 850 MB LOW SHIFTS ENE TOWARD SW VA... PUSHING
THE BETTER MOISTURE FLUX TO OUR EAST (ALTHOUGH THE GFS FORMS A
SECOND SURFACE-850 MB OVER THE CENTRAL GULF COAST). WHILE PRECIP
RATES SHOULD BE RAMPING DOWN DURING THIS PERIOD WITH PARTIAL DRYING
AT AND ABOVE 700 MB... THERE WILL REMAIN PLENTY OF LOW LEVEL
MOISTURE IN PLACE... WITH PERSISTENT LIFT ASSOCIATED WITH THE
APPROACHING MID LEVEL TROUGH AND LINGERING STRONG UPPER DIVERGENCE.
WILL MAINTAIN HIGH CHANCE POPS SUN NIGHT/MON... WITH LOWER CHANCES
LINGERING THROUGH MON NIGHT/TUE AS THE MID LEVEL TROUGH CROSSES THE
REGION. REGARDING PTYPE... DESPITE THE ABOVE-NOTED WARMER COLUMN
HEADING INTO MONDAY... AS THE COASTAL LOWS DEVELOP AND HELP TO
REINFORCE THE NNE LOW LEVEL FLOW INTO NC... THE APPROACHING MID
LEVEL TROUGH WILL LEAD TO GRADUAL COOLING ALOFT. BUT THE GFS/ECMWF
SHOW THE HEART OF THE POLAR HIGH HOLDING NORTH OF THE ST LAWRENCE
SEAWAY AND RETREATING FURTHER NORTH MONDAY... WHICH BRINGS INTO
QUESTION THE AVAILABILITY OF COLD AIR THAT WOULD SUPPORT A NON-
LIQUID PTYPE. STRICT INTERPRETATION OF GFS FORECAST SOUNDINGS AND
ECMWF PARTIAL THICKNESSES SUPPORTS A PERIOD OF PRECIP TAPERING DOWN
AS MOSTLY SNOW OR PERHAPS SNOW/SLEET OVER NRN PARTS OF CENTRAL NC
MON NIGHT AS THE TROUGH AXIS MOVES OVERHEAD. THIS MORE BRIEF WINDOW
OF A POSSIBLE WINTRY MIX AS COMPARED TO YESTERDAY`S MODELS IS MORE
CLIMATOLOGICALLY REASONABLE... AND IT`S STILL LIKELY THAT THIS WILL
AMOUNT TO LITTLE TO NO IMPACT GIVEN THE TIME OF YEAR. LOWS MON 34-43
AND HIGHS 42-51 WITH A GOOD CHANCE OF RAIN BUT FAIRLY LOW QPF. WILL
INCLUDE A CHANCE OF RAIN/SNOW MIX IN THE NORTH HALF AND JUST RAIN
ELSEWHERE MON NIGHT. EXPECT DECREASING POPS EARLY TUE WEST TO EAST
AS THE MID LEVEL TROUGH SHIFTS OFF THE COAST FOLLOWED BY INCOMING
SHORTWAVE RIDGING... HOWEVER THE OFFSHORE LOW WILL CONTINUE TO PUMP
LOW LEVEL ATLANTIC MOISTURE INTO CENTRAL NC... AND EXPECT MORE
CLOUDS THAN SUN ON TUE... KEEPING HIGHS WELL BELOW NORMAL.

FOR TUE NIGHT THROUGH THU: THE MID LEVEL RIDGING BEHIND THE
DEPARTING TROUGH AND THE COOL (BUT SLOWLY MODIFYING) SURFACE RIDGE
NOSING INTO FROM THE NORTH SHOULD YIELD QUIET/DRY/WARMING WEATHER
TUE NIGHT/WED. YET ANOTHER BROAD BUT DEEPENING TROUGH PUSHES THROUGH
THE CENTRAL CONUS/GREAT LAKES REGION WED/THU... AND THE APPROACH OF
THE ASSOCIATED COLD FRONT SHOULD BRING IN A CHANCE OF RAIN LATE WED
INTO THU. -GIH
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&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 200 AM FRIDAY...

24-HR TAF PERIOD...HIGH CONFIDENCE OF VFR CONDITIONS THROUGH THE TAF
PERIOD ALTHOUGH CLOUDINESS WILL BE INCREASING TONIGHT AND
THERE IS THE POTENTIAL FOR MVFR/IFR CEILINGS JUST AFTER THE TAF
PERIOD TOWARD DAYBREAK SATURDAY AT KFAY/KRWI. HIGH PRESSURE CENTERED
OVER EASTERN NC EARLY THIS MORNING WILL SHIFT OFFSHORE TODAY AND
TONIGHT RESULTING IN AN INCREASE IN MID AND HIGH LEVEL CLOUDS THIS
AFTERNOON AND ESPECIALLY TONIGHT. VERY LIGHT/CALM WINDS ARE EXPECTED
THROUGH DAYBREAK WITH WINDS BECOMING SOUTHWESTERLY THIS MORNING AND
INCREASING TO 10-14KTS WITH OCCASIONAL GUSTS UP TO 20 KTS. SOUTHWEST
WINDS AROUND 8-10KTS WILL CONTINUE OVERNIGHT BUT BECOME LESS GUSTY.

BEYOND THE TAF PERIOD...A PERIOD OF MVFR/IFR STRATUS IS POSSIBLE
AT KFAY AND PERHAPS KRWI AROUND 12Z SATURDAY WITH CONDITIONS
QUICKLY BECOMING VFR BY MID MORNING. GENERALLY FAIR WEATHER
IS EXPECTED THE REST OF SATURDAY AND SATURDAY NIGHT. A
POTENTIALLY PROLONGED PERIOD OF ADVERSE AVIATION CONDITIONS
IS EXPECTED SUNDAY THROUGH AT LEAST LATE MONDAY AND PERHAPS INTO
TUESDAY AS MULTIPLE STORMS SYSTEMS MOVE ACROSS THE SOUTHEAST.
-BLAES

&&

.FIRE WEATHER...
AS OF 215 AM FRIDAY...

LOW SURFACE DEW POINTS AND FAIRLY DEEP MIXING TODAY WILL PROMOTE
RELATIVE HUMIDITY VALUES TO FALL TO OR BELOW 20 PERCENT AT TIMES
THIS AFTERNOON. AS HIGH PRESSURE MOVES OFFSHORE...THE LOW LEVEL FLOW
WILL BE SOUTHWESTERLY WITH SUSTAINED WINDS REACHING THE 10-16 MPH
RANGE AND WIND GUSTS RANGING FROM 20-28 MPH...BOTH BELOW RED FLAG
CRITERIA. COORDINATION WITH THE NCFS LATE THURSDAY NOTED THAT IF
CRITERIA WAS NOT MET...AN SPS WOULD BE FINE. AFTER COORDINATING WITH
ADJACENT OFFICES...WE WILL ISSUE AN SPS FOR INCREASED
FIRE DANGE FROM NOON TO 6PM TODAY. -BLAES

&&

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

&&

$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...BLAES
FIRE WEATHER...BLAES