Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 261809 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 210 PM EDT TUE MAY 26 2015 .SYNOPSIS...THE WESTERN EXTENT OF BROAD SURFACE HIGH PRESSURE...AND A SEASONABLY MOIST AIR MASS...WILL PREVAIL OVER THE REGION FOR THE WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM TUESDAY... THE LATEST UPPER-AIR ANALYSIS SHOWED THE WEST PART OF RIDGING SURFACE AND ALOFT OVER THE CAROLINAS...AND THE LATEST SATELLITE WATER VAPOR IMAGES SHOWS AMPLE MID-LEVEL DRY AIR ALONG THE CAROLINA COAST. DURING THE MORNING...THE SPC MESOANALYSIS HAS SHOWN A GRADUAL INCREASE IN PRECIPITABLE WATER VALUES OVER AND EAST OF THE COASTAL PLAIN...IN CONCERT WITH THE RAP WHICH FORECASTS OVERALL PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES OVER CENTRAL NORTH CAROLINA BY 00Z. WHILE FORECAST SOUNDINGS ARE FAIRLY STABLE...THE RAP DOES FORECAST AFTERNOON MLCAPE IN THE LOWEST 3KM TO 500J/KG OR LESS. 850MB LIFT IS GREATEST TOWARD KFAY AND KCTZ EARLY THIS AFTERNOON... WHERE THE LATEST REGIONAL RADAR IMAGES SHOW ISOLATED TO SCATTERED SHOWERS NEAR AND JUST NORTH OF KILM. THE HRRR WRF GUIDANCE IS DOING WELL WITH THIS MODEST CONVECTION...AND DESPITE ONLY MODEST INSTABILITY...IN THE MOISTURE ADVECTION THE HRRR WRF DOES SHOW MOSTLY ISOLATED SHOWERS SLOWLY MOVING NORTH ACROSS THE KFAY AND KCTZ AREAS TO NEAR KRDU AND KRWI BY LATE IN THE DAY. FARTHER WEST...RAP SOUNDINGS SHOW DECENT CIN THROUGH MUCH OF THE DAY...AND ANY ISOLATED SHOWER OR STORM MAY HOLD OFF AS WELL UNTIL VERY LATE IN THE DAY GIVEN THE WEAK LIFT AND LIMITED FORCING. HIGH TEMPERATURES IN THE MID TO UPPER 80S WITH A FEW WIND GUSTS IN THE TEENS KNOTS WITH MIXING DURING THE DAY...925MB AND 850MB WINDS TO 15KT. CONVECTION SHOULD BE LARGELY DIURNALLY DRIVEN...BUT WILL KEEP A SLIGHT CHANCE ACROSS THE WESTERN PIEDMONT OVERNIGHT WHERE THE POTENTIAL FOR GLANCING SHOT DPVA ATTENDANT TO UPPER DISTURBANCES IS HIGHEST. LOWS IN THE MID TO UPPER 60S. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 300 AM TUESDAY... MODELS GENERALLY AGREE THAT THE MID/UPPER LEVEL RIDGE MAY WEAKEN A BIT WHILE DRIFTING EVER SO SLIGHTLY EASTWARD OVER THE WESTERN ATLANTIC. FACTORS CONTRIBUTING TO RAIN CHANCES TODAY(DAYTIME HEATING AND RESULTANT DESTABILIZATION...POTENTIAL FOR SHORTWAVE DISTURBANCES ALOFT...AND SEABREEZE BOUNDARY) WILL ESSENTIALLY GOVERN RAIN CHANCES AGAIN ON WEDNESDAY...BUT PERHAPS WITH MORE EQUITABLE RAIN CHANCES EASTWARD INTO CENTRAL PIEDMONT. HIGHER RAIN CHANCES AND CLOUD COVER MAY KNOCK A DEGREE OR TWO OFF OF DAYTIME HIGHS. HIGHS IN THE LOWER/80S NORTHWEST TO MID/UPPER 80S SOUTHEAST. LOWS IN THE MID/UPPER 60S. && .LONG TERM /THURSDAY THROUGH TUESDAY/...
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AS OF 210 PM TUESDAY... THE REMNANT MOISTURE AND SHEAR AXIS FROM THE SYSTEM CURRENTLY OVER THE MISS RIVER VALLEY WILL MOVE EAST AND BECOME CENTERED OVER CENTRAL NC BY THURSDAY. WHILE THE BEST MID/UPR ENERGY WILL HAVE LIFTED WELL TO OUR NORTH...THERE SHOULD BE ENOUGH MOISTURE AND FORCING FOR AT LEAST SCATTERED AFTERNOON/EVENING SHOWERS/TSTMS. INSTABILITY AND SHEAR VALUES SUGGEST SUB-SEVERE ACTIVITY. THE UPPER RIDGE OFF THE EAST COAST WILL THEN REBUILD OVER THE SOUTHEAST COASTAL REGION FRIDAY THROUGH THE WEEKEND...AND SHOULD HELP LIMIT THE COVERAGE OF SHOWER/TSTM ACTIVITY OVER OUR AREA FRIDAY AND SATURDAY. A COLD FRONT CROSSING THE MIDWEST ON FRIDAY IS PROGGED BY THE LATEST GFS TO DROP SOUTH ACROSS OUR AREA BY SUNDAY AND DISSIPATE OVER US BY MONDAY. DESPITE THE LIFT PROVIDED BY THIS FRONT...MODELS SUGGEST THE AFOREMENTIONED RIDGE OVER THE SOUTHEAST WILL KEEP THE BULK OF THE MOISTURE JUST TO OUR NORTH. NEVERTHELESS...THERE`S ENOUGH FORCING AND MOISTURE TO WARRANT A DECENT CHANCE POP ACROSS OUR AREA LATE IN THE WEEKEND INTO EARLY NEXT WEEK. AS FOR TEMPS...PERSISTENCE IS THE BEST FORECAST AT THIS POINT WITH LITTLE CHANGE IN THE AIRMASS. HIGHS IN THE MID TO UPPER 80S AND LOWS IN THE MID 60S EACH DAY DURING THE PERIOD.
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&& .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 200 PM TUESDAY... FOR THE 18Z VALID TAF PERIOD...VFR CONDITIONS OUTSIDE OF ANY MOSTLY ISOLATED...DEEP CONVECTION SHOULD PERSIST THROUGH MUCH OF TONIGHT. AS OF THIS WRITING...ISOLATED TO SCATTERED SHOWERS WERE NOTED TOWARD KCTZ...AND DURING THIS EVENING WITH A WEAK SHORTWAVE MOVING NORTH OVER THE WESTERN CAROLINAS...ISOLATED TO SCATTERED SHOWERS MAY OCCUR MORE TOWARD THE TRIAD. THERE EXISTS A MODEST PROBABILITY OF IFR CONDITIONS IN LOW CLOUDS OVERNIGHT. SREF MODEL PROBABILITIES OF SUCH ARE HIGH ESPECIALLY WEST OF INTERSTATE 95...HOWEVER...THE STATISTICAL GUIDANCE IS NOT AS BULLISH AND MODEL SOUNDINGS FROM THE GFS AND NAM DIFFER AS TO THE POTENTIAL OF LOW CLOUDS LATE. SINCE LOW CLOUDS OCCURRED MAINLY TOWARD THE YADKIN RIVER AND THE TRIAD EARLY THIS MORNING...THE OVERALL AIR MASS HAS MOISTENED...AND 925MB WINDS SHOULD BE FAVORABLE OVERNIGHT...HAVE FORECAST IFR CONDITIONS BY 10Z IN THE TRIAD AND AT KRDU...WITH TEMPORARY CONDITIONS OF SUCH AT KFAY AND KRWI WHERE CONFIDENCE CURRENTLY IS NOT AS HIGH WITH LIGHTER 925MB WINDS AND LESSER PROBABILITIES EVEN ON THE AGGRESSIVE SREF. DURING WEDNESDAY MORNING...ANY IFR CONDITIONS SHOULD LIFT AT LEAST INTO MVFR...WITH SCATTERED SHOWERS BEGINNING TO DEVELOP TOWARD THE END OF THE TAF PERIOD. ANY SOUTHWEST WIND GUSTS SHOULD BE LIMITED TO THE LOWER TO MID TEENS KNOTS WITH MIXING WEDNESDAY AND BE BRIEF. BEYOND THE 18Z VALID TAF PERIOD...THE LATEST MODEL SOUNDINGS SUGGEST THAT LOW CLOUDS ARE POSSIBLE AGAIN THURSDAY MORNING...THOUGH WITH A BETTER PROBABILITY TOWARD KFAY AND KRWI RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA. ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS ARE ALSO POSSIBLE. LOWEST CHANCES OF THOSE APPEAR TO BE SATURDAY WHEN THE AIR MASS IS RELATIVELY MORE STABLE COMPARED TO OTHER DAYS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF/CBL SHORT TERM...CBL LONG TERM...RAH AVIATION...DJF

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