-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 080605
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
105 PM EST FRI MAR 7 2014

.SYNOPSIS...
STRONG LOW PRESSURE OFF OF THE CAROLINA COAST WILL MOVE
AWAY FROM OUR REGION OVERNIGHT. A DRY COLD FRONT WILL APPROACH FROM
THE NORTHWEST SATURDAY AND CROSS OUR REGION SUNDAY MORNING.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1012 PM FRIDAY...

MID-UPPER LEVEL LOW FINALLY PULLING AWAY FROM COASTAL NORTH CAROLINA
WITH BACKEDGE OF CLOUDINESS EXITING OUR COASTAL PLAIN COUNTIES. DUE
TO PRESSURE GRADIENT...EXPECT SFC WINDS EAST OF HIGHWAY 1 TO REMAIN
4-8KTS THROUGH 1-3 AM THEN DECOUPLE.

MAIN FORECAST CHALLENGE IS THE EXPANSION/SEVERITY OF FOG IN THE
PIEDMONT. SFC WINDS HAVE DECOUPLED AND SKIES HAVE CLEARED. WITH
SATURATED TOP SOIL...THIS USUALLY SUGGEST DECENT POTENTIAL FOR FOG
FORMATION. UNCERTAIN IF DENSE FOG WILL DEVELOP. IF VISIBILITIES DO
GO DOWN BELOW A HALF MILE AND TEMPS ARE BELOW FREEZING...A FREEZING
FOG ADVISORY WILL BE NEEDED. FOR NOW WILL HANDLE SITUATION WITH A
SPS AND MAINTAIN ADVISORY FOR BLACK ICE.

TEMP TREND VERIFYING WELL THIS EVENING SO PLAN LITTLE IF ANY
ADJUSTMENT TO MIN TEMPS OVERNIGHT.

NICE (AND APPRECIATED) WARM UP STILL APPEARS ON TARGET FOR SATURDAY
AFTERNOON.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 240 PM FRIDAY...

TO START THIS PERIOD OF THE FORECAST...A MUCH DIFFERENT SATURDAY IS
EXPECTED COMPARED TO TODAY...WITH DRY CONDITIONS AND A MUCH WARMER
BOUNDARY LAYER DEVELOPING AS WINDS ALOFT ON GFS BUFR SOUNDINGS
QUICKLY BACK FROM NORTH TO NORTHWEST VERY EARLY SATURDAY...TO DEEP
WESTERLY BY SATURDAY AFTERNOON. GUIDANCE TEMPERATURES SUPPORT HIGHS
REBOUNDING NICELY TO THE LOWER TO MID 60S SATURDAY AFTERNOON...AND
THE 1000-850MB THICKNESSES...WHICH GRADUALLY RISE OVERNIGHT AND
CONTINUE TO RISE SATURDAY...CORRESPOND TO SUCH HIGHS AS WELL.
OVERNIGHT LOWS SATURDAY NIGHT QUITE POSSIBLY WILL BE HIGHER THAN
DAYTIME HIGHS TODAY...IN ADVANCE OF AN APPROACHING COLD FRONT ONLY
FALLING TO THE LOWER TO MID 40S.

CURRENTLY ANTICIPATE A COLD FRONT MOVING THROUGH SUNDAY TO MOVE
THROUGH DRY...WITH BOTH THE GFS AND ECMWF PRODUCING NO QPF FOR
CENTRAL NORTH CAROLINA WITH THE FRONTAL PASSAGE. THE GFS BUFR
SOUNDINGS FOR THE AREA SUGGEST POSSIBLY ENOUGH MID-LEVEL MOISTURE
FOR A FEW SPRINKLES OR PATCH OF LIGHT RAIN...MOST LIKELY NORTH OF
U.S. 64 EARLY SUNDAY WHERE THE NAM FORECASTS MINIMAL QPF AND ITS
GUIDANCE POPS ARE HIGHER. LATER FORECASTS MAY NEED TO INTRODUCE SOME
SPRINKLES OR A SMALL CHANCE FOR LIGHT RAIN THEN. BY SUNDAY NIGHT
GOOD DRYING TAKES PLACE BEHIND THE FRONT THOUGH WITH GFS BUFR
SOUNDINGS TOWARD KFAY SHOWING SOME SHALLOW MOISTURE REMAINING NEAR
THE INVERSION AT 850MB TO KEEP PARTLY CLOUDY CONDITIONS IN THAT PART
OF CENTRAL NORTH CAROLINA FOR THE OVERNIGHT HOURS. WILL FORECAST
HIGHS NEAR THE COOLER MAV GUIDANCE FOR SUNDAY DUE TO THE FRONTAL
PASSAGE AND ANTICIPATED CLOUDS...BUT STILL THIS SHOULD RESULT IN
HIGHS IN THE MID TO UPPER 60S WITH SKIES BECOMING AT LEAST PARTLY
SUNNY. LOWS SUNDAY NIGHT IN THE MID 30S TO AROUND 40.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 240 PM FRIDAY...

TEMPERATURES SHOULD BE ABOVE NORMAL EARLY IN THIS PERIOD AS DRY
CONDITIONS CONTINUE. TEMPERATURES COULD REACH HIGHS IN THE LOWER TO
MID 70S TUESDAY AHEAD OF A LOW PRESSURE SYSTEM THAT WILL MOVE OVER
OR NEAR CENTRAL NORTH CAROLINA WEDNESDAY. THIS SHOULD PROVIDE A GOOD
CHANCE OF SHOWERS TO THE AREA THEN...AND MODEL SOUNDINGS AND
THICKNESSES ARE WELL WARM FOR ANYTHING BUT LIQUID. SOME OF THE
LATEST MODEL SOUNDINGS SUGGEST THE POTENTIAL FOR ELEVATED
INSTABILITY...AND SUCH INSTABILITY APPEARS LIMITED CURRENTLY...BUT
GIVEN THE STRENGTH OF THE LOW AND ITS ASSOCIATED MID-LEVEL SHORTWAVE
WILL INTRODUCE FOR NOW AT LEAST A SLIGHT CHANCE OF THUNDER IN THE
FORECAST FOR THE DAY WEDNESDAY IN THE GRIDDED DATA. TEMPERATURES ARE
DIFFICULT WEDNESDAY DUE TO THE TIMING OF PRECIPITATION AND THE TRACK
OF THE LOW...BUT WILL ANTICIPATE THE POTENTIAL FOR A GOOD GRADIENT
IN TEMPERATURE NORTH TO SOUTH THEN...WITH HIGHS POSSIBLY ONLY NEAR
60 TOWARD THE VIRGINIA BORDER TO AROUND 70 IN THE FAR SOUTH.
TEMPERATURES WILL RETURN COOLER WITH DRIER CONDITIONS EXPECTED FOR
THE END OF THE WEEK AS GFS BUFR SOUNDINGS ARE QUITE DRY FROM
THURSDAY THROUGH THE DAY ON FRIDAY. OF THESE TWO DAYS...THURSDAY
SHOULD BE BREEZIER IN A TIGHTER GRADIENT BEHIND LOW PRESSURE
FOLLOWED BY HIGH PRESSURE AND LIGHTER WINDS ON FRIDAY.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
AS OF 1245 AM SATURDAY...

MAIN ISSUE FOR TONIGHT WILL BE THE POTENTIAL FOR FOG/FREEZING FOG.
THE HIGHEST PROBABILITIES FOR FOG TO DEVELOP TONIGHT WILL BE ACROSS
AREAS WEST OF THE TRIANGLE...MAINLY KINT AND KGSO (POSSIBLY KRDU
ALSO). THE GROUND IS VERY WET FROM RECENT RAINFALL...WINDS HAVE
BECOME VIRTUALLY CALM AND SKIES HAVE CLEARED OUT ACROSS THE WESTERN
HALF OF THE FORECAST AREA. ALL OF THIS ADDS TO THE POTENTIAL FOR
FOG. FURTHER EAST...CURRENT CLOUD COVER WILL GRADUALLY SHIFT OFF TO
THE EAST WITH THE DEPARTING LOW. HOWEVER...THE PRESSURE GRADIENT
SHOULD NOT BE AS WEAK DUE TO PROXIMITY OF THE DEPARTING COASTAL LOW
AND THIS WILL RESULT IN WINDS STAYING UP SLIGHTLY...WHICH SHOULD
INHIBIT WIDESPREAD FOG DEVELOPMENT. ANY FOG THAT DOES DEVELOP SHOULD
LIFT/DISSIPATE BY 14-15Z ON SATURDAY...WITH VFR CONDITIONS AND
MOSTLY CLEAR SKIES EXPECTED FOR THE REMAINDER OF THE TAF PERIOD.

OUTLOOK...A COLD FRONT WILL MOVE THROUGH EARLY SUNDAY MORNING...BUT
AT THIS TIME IS NOT EXPECTED TO BRING MUCH MORE THAN A BRIEF PERIOD
OF INCREASED CLOUDINESS...POSSIBLY HIGH END MVFR. THEN THE NEXT
CHANCE OF ADVERSE AVIATION CONDITIONS WILL OCCUR LATE TUESDAY NIGHT
INTO WEDNESDAY...AS A LOW PRESSURE SYSTEM SPREADS PRECIP INTO THE
AREA...WITH EVEN A THUNDERSTORM POSSIBLE ON WEDNESDAY.
-- End Changed Discussion --

&&

.RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY THROUGH
9 AM EST SATURDAY FOR NCZ007>009-021>025-038>040.

&&

$$

SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...DJF
LONG TERM...DJF
AVIATION...KRD