-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 250526
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
125 PM EDT FRI JUL 25 2014

.SYNOPSIS...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM THURSDAY...

A S/W CROSSING THE CENTRAL APPALACHIANS WILL CONTINUE TO LIFT E-NE
INTO THE NORTHERN MID ATLANTIC OVERNIGHT. THE SURFACE FRONT
ASSOCIATED WITH THE S/W WAS DRIFTING SOUTHWARD ACROSS VA AT 01Z. A
PRE-FRONTAL TROUGH AHEAD OF THE SURFACE FRONT AIDED TO TRIGGER
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON
ACROSS CENTRAL NC. BY MID-EVENING..THE LINE OF CONVECTION HAD
DRIFTED SOUTHWARD INTO THE SOUTHERN COASTAL PLAIN AND SANDHILLS.
SHOWERS WITH A FEW ISOLATED THUNDERSTORMS WILL PERSIST WELL INTO THE
NIGHT ACROSS ROUGHLY THE SE HALF OF CENTRAL NC AS THE PRE-FRONTAL
TROUGH STALLS AND WAITS FOR THE APPROACHING SFC FRONT. AN ISOLATED
SHOWER OR THUNDERSTORM WILL BE POSSIBLE OVERNIGHT ACROSS THE NORTH
AS THE SFC FRONT CROSSES THE REGION. BY FRIDAY MORNING...SFC FRONT
SHOULD BLEND WITH THE SFC TROUGH THEN CONTINUE TO PUSH SOUTH AND
EAST AS SFC HIGH PRESSURE BUILDS INTO THE PIEDMONT.

MIN TEMPS OVERNIGHT SHOULD RANGE FROM THE LOWER 70S SOUTH TO THE MID-
UPPER 60S NORTH.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 305 PM THURSDAY...

FRIDAY AND FRIDAY NIGHT....THE MAIN UPPER TROUGH AXIS WILL MOVE EAST
OF THE AREA BY FRIDAY MORNING...WHILE THE ASSOCIATED RELATIVELY WEAK
COLD FRONT SLIPS SOUTH AND STALLS NEAR THE NC/SC BORDER.  HIGH
PRESSURE WILL BUILD QUICKLY ACROSS VA DURING THE DAY...WITH DRIER
MID-LEVEL AIR OVER MOST OF CENTRAL NC. THE AIRMASS DOESNT CHANGE
MUCH BEHIND THE FRONT...WITH DEWPOINTS ONLY DROPPING INTO THE MID
60S TO THE NORTHWEST AND HOVERING NEAR 70S IN THE SOUTH.  WEAK
INSTABILITY AND LEVEL CONVERGENCE IN THE VICINITY OF WHAT IS LEFT OF
THE FRONT MAY PRODUCE SOME VERY ISOLATED CONVECTION NEAR THE SC
BORDER.  HIGHS WILL BE IN THE MID 80S.  WEAK HIGH PRESSURE WILL BE
OFF THE VA COAST BY FRIDAY NIGHT...AND A LIGHT SOUTHEASTERLY RETURN
FLOW MAY PRODUCE SOME FOG AND LOW CLOUDS SATURDAY MORNING...SHOWN
MOST AGGRESSIVELY BY THE NAM.  LOWS IN THE MID/UPPER 60S.

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.

&&

.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/...
-- Changed Discussion --
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
-- End Changed Discussion --

&&

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

&&

$$

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