-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 091506
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1100 AM EDT WED JUL 9 2014

.SYNOPSIS...A SURFACE TROUGH WILL PERSIST OVER CENTRAL NORTH
CAROLINA TODAY. A WEAKENING COLD FRONT WILL MOVE INTO OUR REGION
THURSDAY...THEN DRIFT TOWARD THE COAST FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 1100 AM WEDNESDAY...

12Z UPPER AIR ANALYSIS SHOWS OUR AREA ON THE SE PERIPHERY OF A BROAD
UPPER TROUGH CENTERED OVER THE NORTHERN GREAT LAKES.  A COUPLE WEAK
WAVES WITHIN THE WSW FLOW ON THE PERIPHERY OF THIS TROUGH WERE
NOTED...INCLUDING ONE OVER NORTHERN MS/AL. AT H7...A NARROW SWATH OF
ENHANCED MOISTURE EXTENDS FROM THE MID ATLANTIC COAST SW ACROSS THE
WESTERN NC PIEDMONT AND DOWN ACROSS NRN GA...MS...AND AL. IT IS
WITHIN THIS NARROW BAND OF MOISTURE THAT WE ARE CURRENTLY SEEING A
FAIR AMOUNT OF MID-LEVEL CLOUDS AND EVEN A FEW SPRINKLES MOVING TO
THE NE ACROSS OUR TRIAD ZONES. DRIER AIR FROM H7-H9 WAS NOTED ACROSS
THE NC/SC COASTAL PLAIN...AND VIS SAT CURRENTLY SHOWS MOSTLY CLEAR
SKIES IN THIS REGION. AT THE SFC WE ARE SEEING THE IMPACTS FROM THE
CLOUDS...AS TEMPS ACROSS THE TRIAD ARE CURRENTLY IN THE UPPER
70S...WHILE MID 80S ARE FOUND FROM RALEIGH TO WADESBORO EASTWARD
UNDER CLEAR SKIES.

AS WE HEAD INTO THE AFTERNOON...SCATTERED SHOWERS/TSTMS ARE EXPECTED
TO DEVELOP ACROSS PARTS OF OUR CWA...WITH THE BEST CHANCES INVOF OF
THE PIEDMONT TROUGH...BUT ALSO NEAR THE DIFFERENTIAL HEATING
BOUNDARY THAT APPEARS TO BE TAKING SHAPE ATTM ACROSS THE CENTER OF
OUR CWA. WHILE THE WEAK UPPER WAVE OVER NORTHERN MS/AL MAY PROVIDE
SOME MODEST SUPPORT FOR SHOWERS/TSTMS OVER OUR AREA LATER TODAY AS
THE WAVE MOVES TO THE NE...FLOW IN THE MID-UPR LEVELS IS STILL
EXPECTED TO REMAIN WEAK. IN TERMS OF SEVERE POTENTIAL...AN ISOLATED
STRONG TO DAMAGING WIND GUST OR TWO CAN`T BE RULED OUT...HOWEVER
DEEP LAYER SHEAR CURRENTLY IS AND IS PROJECTED TO REMAIN LESS THAN
25 KT THE REST OF TODAY...THUS CELLS ARE LIKELY TO BE MORE PULSE IN
NATURE OR PERHAPS A FEW MULTICELL CLUSTERS.

SCATTERS SHOWERS/TSTMS EXPECTED TO WIND DOWN DURING THE EVENING
HOURS AFTER SUNSET...AND SHOULD BE DRY ACROSS MOST OF THE CWA BY
MIDNIGHT...ASIDE FROM PERHAPS A FEW WEAK LEFTOVER SHOWERS OR
SPRINKLES.

AS FOR TEMPS...MORNING TRENDS AND CLOUDS SUPPORT THE CURRENT HIGH
TEMP FORECAST THAT SHOWS A RANGE FROM COOLEST NW TO WARMEST SE.
WHILE THE CURRENT READINGS IN THE TRIAD SUGGEST IT MAY BE TOUGH TO
REACH 90...ONLY A BRIEF BREAK IN THE CLOUDS WOULD ALLOW A QUICK
UPWARD JUMP IN THE TEMPS...SO 88-90 IN THE TRIAD STILL LOOKS
POSSIBLE. OTHERWISE...MID 90S SHOULD BE FELT ACROSS MUCH OF THE REST
OF OUR CWA. LOWS TONIGHT UPPER 60S NW TO LOWER 70S SE.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 320 AM WEDNESDAY...

MID LEVEL SHEAR AXIS AND ASSORTED PERTURBATIONS WILL DRIFT OVER THE
REGION THURSDAY. ATTENDANT SFC FRONT WILL AID TO FOCUS LOW LEVEL
MOISTURE AND CONVERGENCE...LEADING TO A LIKELIHOOD OF
SCATTERED/NUMEROUS SHOWERS AND THUNDERSTORMS. SEVERE WEATHER THREAT
APPEARS LESS THAN TODAY...THOUGH STORMS WITH SUSTAINED UPDRAFTS MAY
CAUSE STRONG/LOCALLY DAMAGING WINDS DUE TO PRECIP LOADING. THIS
ASPECT APPEARS MORE LIKELY ACROSS THE SANDHILLS AND COASTAL PLAIN.
DEEP UNIDIRECTIONAL FLOW SUGGEST THAT SHOWERS AND STORMS MAY TRAIN
REPEATEDLY OVER THE SAME LOCATION FOR A COUPLE OF HOURS. WITH THE
MOISTURE RICH AIR MASS IN PLACE (PW VALUES 1.7-2 INCHES
PROJECTED)...THIS MAY LEAD TO LOCALIZED FLOODING...ESPECIALLY IN
URBANIZED AREAS. PLAN TO MAINTAIN LIKELY POPS OVER BULK OF THE
FORECAST AREA.

MAX TEMPS WILL BE HELD DOWN DUE TO EXTENSIVE CLOUD COVERAGE AND
COVERAGE OF SHOWERS AND STORMS. HIGH TEMPS MID 80S NW TO LOWER 90S
FAR SOUTH. MIN TEMPS UPPER 60S-LOWER 70S.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 310 AM WEDNESDAY...

FRIDAY THROUGH SUNDAY NIGHT: THE WEAK MID LEVEL TROUGH IS EXPECTED
TO PUSH TO THE EAST OF CENTRAL NC LATE FRIDAY AFTERNOON/EVENING...
WITH THE WEAK SURFACE TROUGH STALLING ACROSS THE COASTAL PLAIN LATE
FRIDAY AFTERNOON/EVENING. BEHIND THE MID LEVEL TROUGH... WE SHOULD
SEE DRIER MID/UPPER LEVEL AIR. THUS... WILL LOWER POPS IN THE
WEST/NORTHWESTERN PIEDMONT TO SLIGHT CHANCE FRIDAY. EXPECT THE BEST
CHANCE OF SHOWERS AND STORMS WILL BE ACROSS THE COASTAL PLAIN AND
SANDHILLS (WHERE THE BEST INSTABILITY AND WEAK SURFACE CONVERGENCE
WILL BE DURING THE AFTERNOON... AND BETTER MOISTURE AS MENTIONED
ABOVE). DEEP LAYER SHEAR LOOKS TO BE LESS THAN 20 KTS WHERE THE BEST
INSTABILITY IS EXPECTED (ACROSS COASTAL PLAIN/SANDHILLS) FRIDAY
AFTERNOON/EVENING. THUS... EXPECT ANY SEVERE THREAT WILL BE QUITE
MARGINAL AT BEST. HOWEVER... EXPECT WE COULD SEE SOME ISOLATED
STRONG TO SEVERE STORMS... WITH THE MAIN THREAT FROM DAMAGING
DOWNBURST WINDS. GIVEN THE LINGERING HIGH PW`S ACROSS OUR EASTERN
COUNTIES... A LOCALIZED FLASH FLOODING THREAT CANNOT BE RULED OUT...
ESPECIALLY WITH A FAIRLY WEAK STEERING FLOW. EXPECT HIGH TEMPS WILL
GENERALLY BE IN THE UPPER 80S... WITH PERHAPS EVEN A FEW MID 80S
ACROSS OUR FAR EAST WHERE CLOUDS/SCATTERED CONVECTION WILL HELP
LIMIT INCOMING SOLAR RADIATION. ANY LINGERING CONVECTION LATE FRIDAY
EVENING SHOULD GENERALLY PUSH TO THE EAST/SOUTHEAST OF THE AREA
AND/OR DISSIPATE WITH THE LOSS OF HEATING. LOWS SATURDAY MORNING ARE
EXPECTED TO BE IN THE UPPER 60S TO LOWER 70S.

MID LEVEL FLOW WILL BECOME MORE NORTHWESTERLY TO WEST-NORTHWESTERLY
OVER THE WEEKEND... WITH THE POTENTIAL OF UPSTREAM CONVECTION/MCV`S
TO TRACK ACROSS CENTRAL NC. THE LATEST GUIDANCES HAS SHIFTED THE
MORE ACTIVE DAY TO SUNDAY NOW... AS THE MID/UPPER LEVEL TROUGH
BEGINS TO AMPLIFY ACROSS THE UPPER MIDWEST/NORTHERN PLAINS AND GREAT
LAKES REGION. GIVEN SUCH DISTURBANCES IN NORTHWEST FLOW ARE HARD TO
TRACK WILL LIMIT POPS TO LOW END CHANCE FOR THE WEEKEND... HIGHEST
ON SUNDAY. LOW LEVEL THICKNESS VALUES ARE EXPECTED TO SLOWLY
INCREASE THIS WEEKEND. THIS WILL RESULT IN HIGH TEMPS IN THE UPPER
80S TO LOWER 90S SATURDAY TO THE LOWER 90S SUNDAY (TO PERHAPS EVEN
SOME MID 90S ACROSS THE SOUTH). LOW TEMPS ARE EXPECTED TO GENERALLY
BE AROUND 70/LOWER 70S.

MONDAY AND TUESDAY: A DEEP TROUGH IS EXPECTED TO DEVELOP ACROSS THE
EASTERN HALF OF THE COUNTRY EARLY NEXT WEEK. THIS SHOULD RESULT IN
THE INCREASING LIKELIHOOD OF SHOWERS AND STORMS EARLY NEXT WEEK AS A
SURFACE COLD FRONT APPROACHES THE REGION FROM THE NORTHWEST...
POSSIBLY MOVING INTO THE AREA ON TUESDAY. GIVEN WE ARE TALKING ABOUT
DAY 6 AND 7 OF THE FORECAST WILL LIMIT POPS TO THE 30-40 PERCENT
RANGE FOR NOW. AFTERNOON LOW LEVEL THICKNESS VALUES ARE PROGGED TO
INCREASE TO AROUND 1430 METERS DURING THIS TIME. THIS WOULD SUPPORT
AT LEAST HIGH TEMPS IN THE LOWER TO MID 90S... WITH PERHAPS SOME
UPPER 90S. FOR NOW WILL LIMIT HIGH TEMPS TO THE LOWER 90S... TO A
FEW MID 90S ACROSS THE SOUTH.... GIVEN THE INCREASED CHANCES FOR
SHOWERS AND STORMS. LOWS DURING THE PERIOD ARE EXPECTED TO BE IN THE
LOWER 70S... WITH EVEN SOME MID 70S POSSIBLE.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 645 AM WEDNESDAY...

VFR CONDITIONS WILL GENERALLY PERSIST THROUGH 18Z. A FEW SHOWERS MAY
OCCUR NEAR THE KINT AND KGSO VICINITIES THROUGH 18Z. AFTER 18Z...A
SERIES OF UPPER LEVEL DISTURBANCES COUPLED WITH A SLOWLY WEAKENING
SURFACE COLD FRONT WILL INCREASE THE THREAT FOR SCATTERED CONVECTION
ACROSS CENTRAL NC. BETWEEN 20Z AND 01Z...THE THREAT FOR SCATTERED
CONVECTION AND ASSOCIATED MVFR/IFR CEILINGS AND VISIBILITIES WILL BE
GREATEST ON VICINITY OF THE TRIAD TERMINALS AS WELL AS KRDU. IN
VICINITY OF THE STRONGER CONVECTION...WIND GUSTS UP TO 40KTS
PROBABLE.

THE ATMOSPHERE WILL REMAIN UNSETTLED TONIGHT THROUGH THURSDAY NIGHT
AS THE SURFACE COLD FRONT GRADUALLY DRIFTS SEWD ACROSS THE REGION
AND THE SERIES OF DISTURBANCES LIFT ACROSS THE REGION. WHILE
CONVECTIVE COVERAGE AND INTENSITY WILL DWINDLE OVERNIGHT...ISOLATED
TO SCATTERED SHOWERS AND T-STORMS WILL STILL OCCUR WELL PAST
MIDNIGHT. THE CONVECTIVE ACTIVITY IS EXPECTED TO REACH ITS PEAK
COVERAGE THURSDAY AFTERNOON AND EVENING WHEN SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO BE NUMEROUS.

BETTER AVIATION CONDITIONS ANTICIPATED FRIDAY THROUGH SATURDAY AS A
SLIGHTLY DRIER MORE STABLE AIR MASS ENCOMPASSES MOST OF THE REGION.
SCATTERED AFTERNOON-EARLY EVENING CONVECTION WILL STILL BE PROBABLE
IN VICINITY OF KFAY AND KRWI WHERE AVAILABLE MOISTURE AND LOW LEVEL
INSTABILITY WILL BE BEST. BY SUNDAY...REMNANTS OF DECAYING
THUNDERSTORM COMPLEXES ORIGINATING IN THE MIDWEST MAY BEGIN TO
AFFECT CENTRAL NC...LEADING TO A BETTER CHANCE FOR SCATTERED
CONVECTION AND ASSOCIATED MVFR CONDITIONS.

&&

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

&&

$$

SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...WSS