Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 260727 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 327 AM EDT TUE MAY 26 2015 .SYNOPSIS...AN UPPER LEVEL RIDGE OVER THE REGION WILL SLOWLY SHIFT OFFSHORE THROUGH MID-WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 AM TUESDAY... A STRONG 592-593 DECAMETER MID-UPPER LEVEL RIDGE WILL REMAIN ANCHORED ALONG THE EASTERN SEABOARD. MORE SUMMER-LIKE CONDITIONS RETURN TODAY OWING TO THE RETURN OF LOW-LEVEL MOISTURE/HUMIDITY...AND SUBSEQUENT WEAK INSTABILITY ON THE BACK SIDE OF THE OFFSHORE SFC HIGH. THE BETTER RAIN CHANCES SHOULD REMAIN CLOSELY ROOTED TO THE NC MTNS AND FTHLS...FUELED BY AN UPSLOPE FLOW REGIME. HOWEVER THE THE POTENTIAL FOR WEAK SUPPORT ALOFT IN THE FORM OF WEAK DPVA ATTENDANT TO SMALL AMPLITUDE SHORTWAVE DISTURBANCES LIFTING NORTHWARD THROUGH THE SOUTHERN APPALACHIANS IN ADVANCE OF THE PRIMARY SHORTWAVE BACK OVER THE MS VALLEY JUSTIFIES SLIGHT CHANCE POPS INTO THE WESTERN PIEDMONT. ADDITIONALLY...SOME OF THE CAMS SUGGEST A FEW SHOWERS/STORMS OVER THE SANDHILLS AND SOUTHERN COASTAL PLAINS LATER THIS AFTERNOON AS THE SEABREEZE WORKS INLAND. HAVE ADDED SLIGHT CHANCE POPS TO ACCOUNT FOR THIS SCENARIO. ALONG WITH RISING HUMIDITY LEVELS...LOW-LEVEL THICKNESSES ARE PROGGED TO BE INCREASE ANOTHER ~10 METERS TODAY...WHICH SHOULD YIELD MOST AREAS A GOOD CATEGORY WARMER THAN YESTERDAY. HIGHS IN THE MID 80S WEST TO UPPER 80S SOUTHEAST. 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 MONDAY/... AS OF 320 AM TUESDAY... STRONG UPPER LEVEL RIDGING ALONG THE SOUTHEAST COAST SHOWS SOME SIGNS OF WEAKENING BY THURSDAY BUT IS STILL STRONG ENOUGH TO DEFLECT THE SHORTWAVE CURRENTLY OVER THE CENTRAL PLAINS NORTH TOWARD THE GREAT LAKES AND KEEP THE ASSOCIATED FRONTAL ZONE TO OUR NORTHWEST. THOUGH FORCING OVER CENTRAL NC WILL BE WEAK ON THURSDAY...A WEAK REMNANT SHEAR AXIS AMIDST PW OVER 1.5 INCHES AND 600 TO 1200 J/KG OF MLCAPE...HIGHEST OVER THE WESTERN PIEDMONT...SHOULD LEAD TO INCREASED...THOUGH STILL SCATTERED COVERAGE OF AFTERNOON SHOWERS/STORMS. SHEAR WILL BE WEAK WITH THE UPPER TROUGH AND STRONGEST WESTERLIES WELL WEST OF THE MOUNTAINS...SO SEVERE STORMS WILL BE LIMITED. THE UPPER RIDGE THEN LOOKS TO BUILD BACK SLIGHTLY FRIDAY INTO THE WEEKEND WITH A LITTLE DRIER AIR ACTUALLY FORECAST TO FILTER IN FROM THE EAST ON FRIDAY. THUS EXPECT MAINLY ISOLATED SHOWERS AND STORMS FRIDAY AND SATURDAY AS THE AIRMASS SLOWLY RE-MOISTENS THROUGH THE WEEKEND. ANOTHER SHORTWAVE AND COLD FRONT ARE FORECAST TO MOVE INTO THE MIDWEST STATES EARLY NEXT WEEK...AND WHILE IT IS UNCERTAIN WHETHER THAT FRONT WILL MAKE IT ALL THE WAY INTO NC AS WELL...THE CHANCES OF CONVECTION WILL INCREASE FROM NORTH TO SOUTH SUNDAY THROUGH TUESDAY. THICKNESSES ARE PROJECTED TO BE NEARLY UNCHANGED THROUGH THE PERIOD...WITH HIGHS MOSTLY IN THE MID TO UPPER 80S NEARLY EVERYDAY...WITH SOME AREAS IN THE SOUTH REACHING 90 ON SATURDAY. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 120 AM TUESDAY... LOW-LEVEL MOISTURE RETURN ON THE WESTERN PERIPHERY OF THE DEEP LAYER RIDGE CENTERED JUST OFF THE EASTERN SEABOARD WILL SUPPORT AREAS OF STRATUS...ESPECIALLY ACROSS WESTERN PORTIONS OF THE STATE. CEILINGS IN THE IFR OR LOW END MVFR IS EXPECTED AT KINT AND KGSO WITH POCKETS OF LIFR CEILINGS POSSIBLE. THE LOW CEILINGS WILL PERSIST THROUGH THE MID MORNING HOURS...LIFTING INTO THE LOW END OF THE VFR CATEGORY AROUND EARLY AFTERNOON. PROBABILITIES OF SUB-VFR CEILINGS DEVELOPING THROUGH THIS MORNING SHOULD DECREASE WEST TO EAST...WITH A PERIOD OF SCATTERED TO BROKEN STRATUS BETWEEN 700-1200FT POSSIBLE AT KRDU. AT KRWI AND KFAY...THE STRATUS IS EXPECTED TO REMAIN FEW TO SCATTERED. A SHOWER OR THUNDERSTORM MAY THREATEN THE TRIAD TERMINALS LATE TUESDAY AFTERNOON THROUGH TUESDAY EVENING BUT THIS PROBABILITY APPEARS TOO LOW TO MENTION IN THE TERMINAL FORECAST AT THIS TIME. WIDESPREAD MVFR/IFR CEILINGS EXPECTED EACH MORNING THROUGH THE REMAINDER OF THE WORK WEEK AS SLY FLOW CONTINUES TO INCREASE OR MAINTAIN LOW LEVEL MOISTURE OVER CENTRAL NC. THERE WILL BE A BETTER CHANCE FOR AFTERNOON CONVECTION BOTH WEDNESDAY AND THURSDAY WITH THE GREATEST CHANCES ON WEDNESDAY OVER THE PIEDMONT...AND AREAWIDE THURSDAY. THE HIGH PRESSURE SYSTEM WILL BEGIN TO BUILD BACK INTO THE CAROLINAS FRIDAY INTO SATURDAY. THIS WILL BEGIN TO LIMIT THE CHANCES FOR AFTERNOON CONVECTION ON FRIDAY AND MORE SO SATURDAY. THERE WILL CONTINUE TO BE DECENT THREAT FOR EARLY MORNING MVFR/IFR CEILING AND FOG FRIDAY AND SATURDAY MORNINGS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...CBL SHORT TERM...CBL LONG TERM...BLS AVIATION...CBL/WSS

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