-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 020524
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
125 AM EDT SAT AUG 2 2014

.SYNOPSIS...
THE COMBINATION OF A UNSEASONABLY STRONG UPPER TROUGH AND A NEARLY
STATIONARY SURFACE FRONT WILL KEEP VERY MOIST CONDITIONS ACROSS THE
REGION THROUGH THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 937 PM FRIDAY...

A HISTORICAL (FOR MID SUMMER) HYBRID COLD AIR DAMMING DEVELOPED
TODAY OVER CENTRAL NC IN RESPONSE TO THE ALMOST WINTER-LIKE PATTERN
THAT IS RELATIVELY UNHEARD OF DURING THE LAST WEEK IN JULY AND THE
FIRST WEEK OF AUGUST OF ANY YEAR. A 1022 MB SURFACE HIGH PRESSURE
ACTUALLY STRENGTHENED TODAY AS IT WAS CENTERED OFF THE NJ COAST...
AND EXTENDED SW ACROSS THE PIEDMONT OF NC/SC INTO GA. A MID/UPPER
TROUGH OVER THE REGION... UNSEASONABLY STRONG UPPER JET... AND A
VORTICITY MAXIMUM TRACKING IN THE SW FLOW ALOFT FORCED STRONG LIFT TO
PRODUCE WIDESPREAD RAIN. IT WAS A GOOD SOAKING OF 1 TO 2 INCHES ACROSS
A GOOD PORTION OF THE PIEDMONT REGION... WITH LESS WIDESPREAD BUT STILL
LOCALLY HEAVY RAIN AMOUNTS IN THE SE ZONES.

IN ADDITION... A WEAK SURFACE LOW PRESSURE DEVELOPED ALONG THE
NEARLY STATIONARY FRONT OVER THE SANDHILLS AND COASTAL PLAIN THAT
PLACED A PORTION OF SOUTHEASTERN NC INTO THE WARM SECTOR... WHILE
THE VAST MAJORITY OF CENTRAL NC COOLED UNDER THE LOW CLOUDS...
RAIN... FOG... AND NE FLOW. GREENSBORO RECORDED THE COOLEST MAXIMUM
TEMPERATURE EVER FOR THE AUGUST 1 DATE... 68 DEGREES. THIS WAS 20
DEGREE BELOW THE 30 YEAR AVERAGE AND 4 DEGREES LOWER THAN THE
PREVIOUS RECORD DAILY COOLEST MAXIMUM RECORDED IN 2010 OF 72
DEGREES. EVEN THE HOTTEST PLACES ON AVERAGE IN NC HAD THEIR DAILY
HIGHS REMAIN IN THE 70S TODAY. FAYETTEVILLE RECORD 77 (14 DEGREES
BELOW NORMAL).

MID EVENING CONDITIONS CONTINUED TO BE DOMINATED BY THE HYBRID
DAMMING EVENT... WITH THE 1023 MB HIGH PRESSURE CENTERED OFF THE VA
COAST... BUT EXTENDING SW ACROSS THE PIEDMONT OF THE CAROLINAS INTO
GA. THE TEMPERATURES WERE IN THE 60S THROUGHOUT CENTRAL NC...
EXCEPT RIGHT ALONG AND ON THE WARM SIDE OF THE NEARLY STATIONARY
BOUNDARY EXTENDING FROM SW TO NE ACROSS THE COASTAL AREA (OUR
SOUTHERN SAMPSON COUNTY MARKED THE LOCATION OF THE BOUNDARY OVER
OUR REGION). EVERYONE TO THE WEST AND NORTH OF THE BOUNDARY REPORTED
A LOW OVERCAST WITH OCCASIONAL LIGHT RAIN... MIST... FOG... AND A
NORTHERLY WIND. THE BOUNDARY HAS SHIFTED ABOUT 25 MILES EAST THIS
EVENING IN RESPONSE TO THE PASSING OF A WEAK LOW PRESSURE... WITH
GOLDSBORO AND FAYETTEVILLE NOW SOLIDLY ON THE COOLER AND MORE
STABLE SIDE.

OVERNIGHT... MOST MODELS SUGGEST THE BOUNDARY WILL STALL... THEN
BEGIN TO SHIFT BACK WESTWARD INTO THE COASTAL PLAIN LATER TONIGHT
AND SATURDAY MORNING AS ANOTHER UPPER LEVEL DISTURBANCE APPROACHES
IN THE FLOW ALOFT. OCCASIONAL LIGHT RAIN OR DRIZZLE IS EXPECTED
OVERNIGHT... WITH A CHANCE OF SHOWERS WITH HEAVY RAIN AGAIN LATER
TONIGHT IN THE SE. THIS CHANCE WILL THEN SHIFT BACK NW ON SATURDAY.
OTHERWISE... OVERNIGHT... COOL AND CLOUDY WITH THE OCCASIONAL LIGHT
RAIN. LOWS 60-65 EXCEPT UPPER 60S SE. ADDITIONAL QPF SHOULD AVERAGE
FROM A FEW HUNDREDTHS TO AROUND 0.25 SE.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM FRIDAY...

THE UNSETTLED PATTERN WILL CONTINUE FOR SATURDAY AS THE UPPER LEVEL
TROUGH REMAINS CAMPED TO OUR WEST WITH AN INVERTED COASTAL TROUGH AT
THE SURFACE. THIS WILL HELP FOCUS PRECIPITATION EAST OF HIGHWAY 1 ON
SATURDAY WITH A RELATIVE MINIMUM IN THE TRIAD ALTHOUGH ALL AREAS
COULD EXPERIENCE RAIN BY THE END OF THE DAY. MODELS ARE STILL HIGHLY
VARIABLE ON HOW MUCH QPF EXACTLY WILL FALL WITH ANYTHING FROM 0 TO 3
INCHES POSSIBLE AT ANY GIVEN LOCATION. WILL GO WITH A FORECAST OF A
WIDESPREAD QUART TO A HALF OF AN INCH IN THE WEST AND RANGING
UPWARDS OF AN INCH TO AN INCH AND A HALF IN THE EAST WITH LOCALLY
HIGHER TOTALS. WHILE THERE SHOULD BE GOOD INSTABILITY IN THE
EAST...THE SHEAR WILL NOT BE AS GOOD AS IT WAS TODAY AND NOT MANY
STRONG SHORT WAVES MOVING THROUGH THE UPPER FLOW TO PROVIDE ANY
SUPPORT FOR THUNDERSTORMS. THEREFORE THERE SHOULD BE GOOD COVERAGE
OF RAINFALL ACROSS THE AREA TOMORROW WITH BETTER THUNDERSTORM
COVERAGE ACROSS THE EAST...BUT NOT TOO MUCH IN THE WAY OF SEVERE
WEATHER. VERY SHORT STRAIGHT HODOGRAPHS PRETTY MUCH RULE OUT ANY
ISOLATED TORNADO THREAT AS WELL. HIGH TEMPERATURES IN THE UPPER 70S
TO LOWER 80S ACROSS THE AREA. RAIN IS EXPECTED TO CONTINUE INTO
SATURDAY NIGHT WITH IFR CEILINGS AGAIN LIKELY. LOW TEMPS IN THE MID
60S TO LOWER 70S.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 200 PM FRIDAY...

LITTLE CHANGE IS SHOWN IN THE PATTERN ON SUNDAY WITH THE LONGWAVE
TROUGH AXIS STILL CENTERED OVER THE OH AND TN VALLEYS...AND MOIST
SOUTHERLY FLOW CONTINUING ACROSS THE CAROLINAS. SEVERAL EMBEDDED
SHORT WAVES WITHIN THIS FLOW ARE PROGGED TO MOVE NE AND ACROSS THE
CENTER AND EASTERN PORTIONS OF THE STATE SUNDAY AND SUNDAY NIGHT...
BRINGING THE CHANCE FOR SHOWERS AND TSTMS WITH EACH WAVE. GIVEN
LIMITED INSTABILITY BUT HIGH PWAT VALUES AROUND 2 INCHES...THE MAIN
IMPACT CONCERN DURING THIS TIME WILL BE THE ONGOING CHANCE FOR
LOCALIZED POOR DRAINAGE FLOODING. NOTED THAT THE PWAT DOES DECREASE
WESTWARD...THUS THE HIGHEST RISK FOR HEAVY RAIN AND SUBSEQUENT
FLOODING APPEARS TO BE ACROSS THE EASTERN HALF OF OUR CWA.

THE UPPER TROUGH AXIS WILL MAKE SLOW EASTWARD PROGRESSION MONDAY AND
TUESDAY...WITH ITS PASSAGE AND THE PASSAGE OF THE ASSOC SFC COLD
FRONT ACROSS CENTRAL NC SOMETIME DURING THE MIDDLE OF THE WEEK. THE
RESULT WILL BE THE CONTINUED CHANCE FOR SCATTERED SHOWERS AND TSTMS
DURING THIS TIME...WITH PERHAPS A BRIEF DECREASE IN THE RAIN CHANCE
TOWARD THE MIDDLE OF THE WEEK AFTER THE FRONT MOVES ACROSS. WILL
HAVE TO KEEP A SMALL CHANCE FOR RAIN DURING THE LATTER HALF OF THE
WEEK...SINCE THE SFC BOUNDARY LOOKS LIKE IT MAY STALL ACROSS OR JUST
SOUTH OF OUR AREA.

TEMPS DURING THE LONG TERM PERIOD WILL BE LARGELY DEPENDENT ON
CLOUD COVER AND PRECIP.  FOR NOW WILL STAY CLOSE TO NORMAL TEMPS
DURING THIS TIME...WITH THE UNDERSTANDING THAT DAYTIME TEMPS MAY BE
SOMEWHAT COOLER DEPENDING ON THE TIMING AND COVERAGE OF THE CLOUDS
AND RAIN.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
AS OF 125 AM SATURDAY...

HIGH CONFIDENCE THAT WIDESPREAD LIFR/IFR CONDITIONS WILL PERSIST
THROUGH MID-LATE MORNING. AFTERWHICH...CEILINGS WILL SLOWLY LIFT
INTO THE MVFR/LOW END VFR RANGE BY THIS AFTERNOON. ISOLATED TO
SCATTERED SHOWERS WILL OCCUR THROUGH LATE MORNING ALONG A STATIONARY
FRONT POSITIONED OVER THE COASTAL PLAIN. THESE SHOWERS WILL BE IN
THE VICINITY OF KFAY AND KRWI. AFTER 16Z...HEATING OF THE MOISTURE
RICH AIR MASS WILL TRIGGER SCATTERED TO NUMEROUS SHOWERS AND A FEW
THUNDERSTORMS. GREATEST LIKELIHOOD OF SHOWERS OR STORMS AFFECTING A
TERMINAL WILL BE KFAY AND KRWI.

SIMILAR CONDITIONS ANTICIPATED FOR SUNDAY EXCEPT THAT THE TRIAD
TERMINALS WILL HAVE A BETTER CHANCE OF VFR CONDITIONS BY SUNDAY
AFTERNOON.

AVIATION CONDITIONS ARE EXPECTED TO SLOWLY IMPROVE MONDAY AS THE AIR
MASS SLOWLY DRIES OUT AND THE BETTER LIFT FOR SHOWERS AND
THUNDERSTORMS DRIFTS EAST TOWARD THE IMMEDIATE COASTLINE.
STILL...THERE WILL BE PERIODS OF MVFR/IFR CEILINGS DUE TO RESIDUAL
MOISTURE...MAINLY IN THE LATE NIGHT-EARLY MORNINGS HOURS. FOR
TUESDAY AND WEDNESDAY...A RETURN OF MORE TYPICAL SUMMER-LIKE
CONDITIONS ANTICIPATED WITH EARLY MORNING MVFR/IFR PARAMETERS DUE TO
FOG/LOW CLOUDS GIVING WAY TO VFR CONDITIONS WITH SCATTERED
CONVECTION AND ASSOCIATED MVFR CONDITIONS DURING THE HOTTEST PART OF
THE DAY.
-- End Changed Discussion --

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY EVENING FOR NCZ028-043-078-088-089.

&&

$$

SYNOPSIS...32
NEAR TERM...32
SHORT TERM...ELLIS
LONG TERM...NP
AVIATION...WSS