-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 250651
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
255 AM EDT FRI JUL 25 2014

.SYNOPSIS...A COLD FRONT PUSHING SOUTHEAST THROUGH THE REGION EARLY
THIS MORNING WILL WEAKEN AND STALL NEAR THE SOUTH CAROLINA BORDER
LATER TODAY...AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTH. THIS
FRONT WILL DISSIPATE OVER THE WEEKEND AS SOUTHWEST FLOW RETURNS. A
STRONGER COLD FRONT WILL MOVE THROUGH THE REGION EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 255 AM FRIDAY...

WITH THE COLD FRONT HAVING PUSHED SOUTHWARD THROUGH MUCH OF NC...
ASIDE FROM VARIABLY CLOUDY SKIES TODAY... MUCH OF CENTRAL NC WILL
SEE IMPROVED WEATHER CONDITIONS... WITH THE EXCEPTION OF THE SE AND
FAR SRN CWA. LAST NIGHT`S WIDESPREAD CONVECTION HAS SHIFTED OFF THE
COAST... ALONG WITH A LEADING PROMINENT SHORTWAVE TROUGH SWINGING
THROUGH THE BASE OF A WEAKENING TROUGH COVERING THE ERN THIRD OF
NOAM. THE LOCATION OF THE COLD FRONT IS NOT EASY TO SPECIFY ON THE
LATEST SURFACE MAP AS IT APPEARS TO HAVE MERGED WITH THE PREFRONTAL
TROUGH... BUT IT LOOKS TO STRETCH FROM THE NC COASTAL AREA BACK
ACROSS SRN NC AND NRN GA/AL. SURFACE WINDS HAVE SHIFTED AROUND TO
LIGHT N OR NE AREAWIDE... AND THESE LIGHT SPEEDS COMBINED WITH
STABILIZING LOW LEVELS POST-FRONT AND PLENTY OF RESIDUAL LOW LEVEL
MOISTURE HAVE KEPT AREAS OF LOW CLOUDS OVER CENTRAL NC... CLOUDS
THAT WILL BE SLOW TO DISLODGE/DISPERSE DESPITE LIMITED CLOUDINESS
ABOVE. AS SUCH... EXPECT VARIABLY CLOUDY SKIES TODAY... WITH A BIT
LOWER HUMIDITY LEVELS ESPECIALLY NORTH OF 64. THE FRONT IS EXPECTED
TO REMAIN ACROSS SRN NC TODAY AS WEAK HIGH PRESSURE NOW CENTERED
OVER NRN OH BUILDS IN... AND WHILE PW WILL SLIP TO NEAR/BELOW NORMAL
VALUES OVER MOST OF CENTRAL NC... SOUTHERN SECTIONS SHOULD HOLD NEAR
2.0 INCHES. WITH ELEVATED DEW POINTS PERSISTING THERE ALONG WITH
WEAK DPVA AND LINGERING WEAK UPPER DIVERGENCE... THE RISK OF
SHOWERS/STORMS WILL CONTINUE ON OUR SOUTH... FOCUSED THROUGH THE
AFTERNOON AND EARLY EVENING. A STORM OR TWO COULD BECOME STRONG
GIVEN THAT DEEP LAYER SHEAR SHOULD STILL BE 25-30 KTS WITH MODELS
SHOWING MUCAPE OF 1000-2000 J/KG... ALTHOUGH THIS RISK WITH BE LOWER
IF THE THICKER LOW CLOUDS HANG ON LONGER AND INHIBIT INSOLATION.
ISOLATED SHOWERS ARE A GOOD BET OVER THE REST OF THE FORECAST AREA
THIS MORNING WITH A LOBE OF VORTICITY SWINGING THROUGH THE AREA...
BUT LATE MORNING THROUGH THE AFTERNOON SHOULD BE DRY OUTSIDE OF THE
AFOREMENTIONED SOUTHERN SECTIONS WITH 20-30 M HEIGHT RISES. HIGHS 84-
89... IN LINE WITH THICKNESSES THAT ARE PROJECTED TO BE 15-20 M
BELOW NORMAL. MOISTURE PERSISTING BENEATH THE SUBSIDENCE INVERSION
ALOFT SHOULD TRANSLATE TO PARTLY CLOUDY SKIES TONIGHT. HAVE HELD
ONTO LOWS IN THE 66-71 RANGE. -GIH
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
-- Changed Discussion --
AS OF 305 PM THURSDAY...

SATURDAY AND SATURDAY NIGHT...A WEAK UPPER DISTURBANCE...POSSIBLY
EMANATING FROM CONVECTION NORTH OF THE SOUTHERN PLAINS RIDGE...WILL
SWING ACROSS THE AREA ON SATURDAY.  CURRENTLY...MODELS SHOW THE WAVE
DEAMPLIFYING AS IT CROSSES THE MOUNTAINS...AND THE EARLY DAY TIMING
WOULD ALSO BE UNFAVORABLE FOR CONVECTIVE INITIATION.  MOST OF
CENTRAL NC WILL REMAIN DRY...WITH THE EXCEPTION BEING THE FAR
SOUTHEAST CWA WHERE THE SEABREEZE MAY MAKE A RUN DURING THE
AFTERNOON.  WEST-SOUTHWESTERLY LOW-LEVEL FLOW WILL PROMOTE DEEPER
MIXING AND A WARMER DAY WITH HIGHS LIKELY IN THE LOWER 90S.  LOWS
SAT NIGHT WILL BE WARMER AS WELL IN THE LOWER 70S.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 305 PM THURSDAY...

SUNDAY THROUGH MONDAY NIGHT... A STRONG SHORTWAVE MOVING SOUTHEAST
OUT OF THE CANADIAN ROCKIES ON SUNDAY WILL BEGIN THE AMPLIFICATION
OF THE LONGWAVE PATTERN HEADING INTO NEXT WEEK.  CONVECTION PASSING
TO OUR NORTH ACROSS VA MAY BLEED SOUTH INTO MAINLY THE NORTHERN
PORTIONS OF THE AREA...PARTICULARLY SUNDAY EVENING BASED ON CURRENT
PROGS.  HOWEVER THE MAIN FORCING TO IMPACT CENTRAL NC WILL COME
MONDAY WHEN MODELS SHOW ADDITIONAL ENERGY...ACCOMPANIED BY STRONG
HEIGHT FALLS AND A BELT OF ENHANCED WESTERLIES...SWINGING ACROSS THE
AREA.  GIVEN THAT TEMPS ARE EXPECTED TO BE WELL INTO THE MID 90S ON
SUNDAY AND AT LEAST THE LOWER 90S ON MONDAY...INSTABILITY SHOULD BE
FAVORABLE AHEAD OF THE FRONT.  WHILE THERE IS STILL SOME UNCERTAINTY
AS TO HOW MUCH OVERLAP THERE WILL BE BETWEEN THE BEST INSTABILITY
AND STRONGEST SHEAR...THE SETUP LOOKS PRETTY GOOD FOR SEVERE WEATHER
AT DAY 5 IN LATE JULY.

TUESDAY THROUGH THURSDAY... MEDIUM RANGE ENSEMBLES SHOW AN
UNSEASONABLY DEEP UPPER TROUGH DEVELOPING OVER THE EASTERN US BY MID
WEEK WITH AN UPPER LOW CENTERED JUST SOUTH OF THE HUDSON BAY.  GIVEN
THAT BOTH THE GFS AND ECMWF SHOW THE SYNOPTIC FRONT REACHING THE
GULF OF MEXICO... CONFIDENCE IS HIGH THAT TEMPS WILL BE BELOW NORMAL
MUCH OF NEXT WEEK.  LOW-LEVEL THICKNESSES ARE PROGGED TO DIP BELOW
1390M...WHICH SUGGESTS HIGHS IN THE LOW/MID 90S AND LOWS IN THE
LOW/MID60S... POSSIBLY TOUCHING THE UPPER 50S IN THE COOLEST SPOTS.
THE AIRMASS CHANGE WILL ALSO BRING LOWER HUMIDITY...AND WITH
DEWPOINTS DROPPING INTO THE 50S THE CHANCES OF SHOWERS OR STORMS
WILL BE RELATIVELY LOW UNTIL RETURN FLOW DEVELOPS LATER IN THE WEEK.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 125 AM FRIDAY...

PROBLEMATIC AVIATION CONDITIONS EARLY THIS MORNING... AS SCATTERED
TO BROKEN CLOUDS BASED BETWEEN 600 AND 1400 FT AGL MEANDER ABOUT
CENTRAL NC. WITH THESE LOW CIGS EXPECTED TO COME AND GO THROUGH
DAYBREAK... THE TIMING OF MVFR/IFR CIGS IS MADE DIFFICULT. EXPECT
CIGS TO VARY BETWEEN VFR AND MVFR/IFR THROUGH DAYBREAK AT ALL SITES
AS THESE CLOUDS DRIFT OVER THE REGION... WITH MVFR/IFR DOMINATING.
MVFR CIGS ARE EXPECTED THROUGH THE MORNING AS THESE CLOUDS LIFT
SLOWLY... WITH CIGS NOT REACHING VFR UNTIL CLOSE TO 18Z... AND EVEN
AFTER THIS TIME AT FAY... CLOSE TO WHERE THE COLD FRONT IS EXPECTED
TO HAVE PUSHED BY AFTERNOON. A FEW SHOWERS AND ISOLD STORMS WILL BE
RESTRICTED TO NEAR FAY THIS AFTERNOON. VFR CIGS ARE EXPECTED TO
PERSIST THEN FROM MID AFTERNOON THROUGH THE END OF THE TAF PERIOD.
AS THE FRONT SETTLES SOUTH OF ALL TAF SITES THIS MORNING... EXPECT A
LIGHT BREEZE FROM THE NORTH TO DOMINATE THROUGH THE DAY.

LOOKING BEYOND 06Z EARLY SAT MORNING... EXPECT CONTINUED VFR CIGS
THROUGH DAYBREAK SAT... ALTHOUGH POCKETS OF IFR FOG ARE POSSIBLE 09Z-
13Z SAT MORNING... ESPECIALLY AT RWI/FAY. OTHERWISE... VFR
CONDITIONS ARE LIKELY TO DOMINATE THROUGH THE WEEKEND WITH HIGH
PRESSURE BUILDING IN... FOLLOWED BY A RESUMPTION OF SOUTHWEST FLOW
AND PIEDMONT TROUGH LATE IN THE WEEKEND. A COLD FRONT WILL APPROACH
FROM THE NW EARLY NEXT WORK WEEK... BRINGING THE POTENTIAL FOR SUB-
VFR SHOWERS/STORMS... PARTICULARLY MONDAY. -GIH

&&

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

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...BLS
LONG TERM...BLS
AVIATION...HARTFIELD