Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 311725 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 125 PM EDT MON AUG 31 2015 .SYNOPSIS...
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AN UPPER LEVEL LOW WILL MOVE NORTHEASTWARD AWAY FROM THE AREA THROUGH THE REST OF TODAY. OTHERWISE... A WEAK SURFACE TROUGH WILL HOLD OVER EASTERN NORTH CAROLINA... WHILE HIGH PRESSURE CENTERED OVER KENTUCKY EXTENDS OVER WESTERN NORTH CAROLINA.
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&& .NEAR TERM /THROUGH TONIGHT/... AS OF 935 AM MONDAY... EARLIER UPDATE TARGETED THE CENTRAL/ERN CWA WITH HIGHEST POPS (LIKELY TO CATEGORICAL) FOR THE ONGOING TROPICAL RAINFALL. THESE HIGH POPS WILL SHIFT SLOWLY EASTWARD OVER THE NEXT SEVERAL HOURS AS THE UPPER LEVEL LOW THAT CROSSED THE STATE EARLIER THIS MORNING HEADS NNE INTO VA. RAIN RATES OF 1-2 INCHES PER HOUR HAVE BEEN COMMON... ENOUGH TO PRODUCE SOME MINOR URBAN AND STREET FLOODING AND RISING CREEKS BUT UNDER FLOODING THRESHOLDS... AND THIS RAIN SHOULD ACTUALLY BE BENEFICIAL FOR MOST. WATER VAPOR IMAGERY SHOWS DRYING OVER THE WRN CWA... SO WHILE A FEW WRAPAROUND SHOWERS ARE POSSIBLE IN AREAS NW OF THE TRIANGLE... THESE SHOULD GENERATE LITTLE ADDITIONAL RAINFALL. EASTERN SECTIONS ESPECIALLY ALONG AND EAST OF I- 95 MAY SEE A SLOWER TAPERING OF THE WIDESPREAD MODERATE RAIN... GIVEN THAT ANOTHER WAVE NOW APPROACHING SAVANNAH GA WILL BE TRACKING TO THE N OR NNE... SLOWING THE ARRIVAL OF DRIER AIR... AND THIS TREND IS NOTED WELL IN THE RECENT RAP RUNS. POPS WILL START OUT RANGING FROM ISOLATED AT MOST WEST TO CATEGORICAL EAST... TRENDING DOWNWARD WEST TO EAST THROUGH THE REST OF THE DAY. ANY INSTABILITY SHOULD BE MARGINAL... WITH MUCAPE MOSTLY HOLDING AT OR BELOW 1000 J/KG... SO WILL KEEP ANY THUNDER MENTION AT ISOLATED TO SCATTERED AT MOST. TEMPS ARE A TOUGH CALL GIVEN THE GREATLY LIMITED INSOLATION IN THE EAST... SO EXPECT HIGHS IN THE LOW-MID 80S WEST AND NEAR 80 TO LOWER 80S EAST... WITH THESE EASTERN HIGHS NOT BEING REACHED UNTIL VERY LATE IN THE DAY. -GIH LOWS TONIGHT IN THE UPPER 60S TO LOWER 70S. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 345 AM MONDAY... A WEAK/NONDESCRIPT SFC PATTERN WILL EXTEND ACROSS THE AREA ON TUESDAY WITH HEIGHTS ALOFT BUILDING OVER THE SOUTHEAST AS THE SUBTROPICAL RIDGE OVER THE SOUTHWEST ATLANTIC RETROGRADES WESTWARD. OTHER THAN DAYTIME HEATING ATOP A SEASONABLY MOIST AIRMASS... FORCING MECHANISM IS LACKING WITH ISOLATED DIURNAL CONVECTION AT BEST. HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS IN THE UPPER 60S TO LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 310 AM MONDAY... MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT IN SHOWING A WEAK DISTURBANCE ALOFT TRACKING FROM THE OHIO VALLEY MIDWEEK TO ACROSS CENTRAL NC THURSDAY OR THURSDAY NIGHT. HOWEVER... THE LATEST GFS AND ECMWF CONTINUE TO DISAGREE WRT WHAT HAPPENS TO IT. THE LATEST ECMWF CONTINUES TO SHOW THE S/W SHIFTING TO THE EAST/SOUTHEAST AND OFFSHORE BY THURSDAY AFTERNOON... WITH BRIEF S/W RIDGING BUILDING OVER THE AREA BEFORE A WEAK MID LEVEL LOW LIFTS NORTHEASTWARD OUT OF THE NORTHWEST GULF OF MEXICO AND INTO THE CAROLINAS BY FRIDAY NIGHT AND LINGERING THROUGH THE END OF THE FORECAST PERIOD. MEANWHILE... THE LATEST GFS IS SLOWER MOVING THE INITIAL S/W DISTURBANCE THROUGH THE AREA ON THURSDAY... LINGERING INTO FRIDAY MORNING. THE S/W IS THEN EXPECTED TO CLOSE OFF INTO A MID LEVEL LOW AND CONTINUE TO SLOWLY SINK SOUTHWARD AS A STRONG 595 DECAMETER HIGH BEGINS TO BUILD SOUTHWARD TOWARDS CENTRAL NC. GIVEN THIS PATTERN... THE LOW IN THE NORTHWESTERN GULF OF MEXICO ACTUALLY SINKS FURTHER SOUTH AND NOT IN THE DIRECTION OF CENTRAL. AT THE SURFACE... WE SHOULD SEE SOME TYPE OF WEAK SURFACE TROUGH TRACK ACROSS THE AREA WITH THE INITIAL S/W DISTURBANCE... WITH SURFACE HIGH PRESSURE BUILDING/EXTENDING INTO CENTRAL NC FROM THE NORTH/NORTHEAST DURING THE WEEKEND. THUS... AT THIS TIME... WILL KEEP POPS GENERALLY LOW... SLIGHT CHANCE TO LOW END CHANCE DURING THE MEDIUM RANGE... GIVEN THE UNCERTAINTY IN WHAT WILL GENERALLY BE MEAN RIDING OVER THE EASTERN HALF OF THE COUNTRY DURING THIS TIME (WITH THE EMBEDDED DISTURBANCES/WEAK CLOSED LOWS). HIGH TEMPS WILL GENERALLY BE NEAR TO SLIGHTLY ABOVE NORMAL FOR THE MID TO LATE WEEK TIME FRAME... THEN NEAR NORMAL TO POSSIBLY SLIGHT BELOW NORMAL FOR THE WEEKEND. LOW TEMPS ARE EXPECTED TO BE NEAR TO SLIGHTLY ABOVE NORMAL DURING THE PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/...
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AS OF 125 PM MONDAY... MVFR CONDITIONS ARE LIKELY TO DOMINATE AT INT/GSO/FAY INTO TONIGHT... WHILE IFR/LIFR CONDITIONS ARE EXPECTED TO DOMINATE AT RDU/RWI. A STREAM OF TROPICAL MOISTURE WHICH BROUGHT THIS MORNING`S RAIN IS BEING PUSHED SLOWLY EASTWARD INTO COASTAL NC... BUT LOWER CIGS REMAIN WELL BACK INTO CENTRAL NC WITH WEAK SURFACE WINDS AND PLENTY OF LINGERING LOW LEVEL MOISTURE. THESE TWO FACTORS WILL KEEP A HIGH CHANCE OF SUB-VFR CIGS THROUGH THIS EVENING AT CENTRAL NC TERMINALS... ALTHOUGH INT/GSO/FAY MAY BRIEFLY BREAK OUT TO VFR THIS AFTERNOON. CIGS SHOULD REMAIN IFR AT RDU/RWI... ALTHOUGH THESE SITES TOO MAY BRIEFLY JUMP UP A CATEGORY TO MVFR TODAY. CLOUDS ARE EXPECTED TO BECOME SCT AT INT/GSO OVERNIGHT... BUT WITH A THREAT OF MVFR TO IFR VSBYS IN FOG. AT FAY AND ESPECIALLY AT RDU/RWI... CIGS ARE EXPECTED TO HOLD AT IFR OR EVEN LIFR OVERNIGHT INTO TUE MORNING... WITH A RISK OF MVFR TO IFR FOG. LOW CLOUDS SHOULD SLOWLY LIFT AND MIX OUT TO MVFR THEN VFR TUE MORNING IN THE 14-18Z TIME FRAME... WITH CIGS AT RWI LAST TO LIFT TO VFR. LOOKING BEYOND 18Z TUE: VFR CONDITIONS ARE EXPECTED TUE AFTERNOON INTO TUE NIGHT... BUT MVFR TO IFR FOG IS POSSIBLE LATE TUE NIGHT INTO WED MORNING. VFR CONDITIONS SHOULD THEN PREVAIL THROUGH SAT. SCATTERED SUB-VFR SHOWERS/STORMS ARE POSSIBLE EACH AFTERNOON/EVENING WED THROUGH SAT... ALTHOUGH FORECAST CONFIDENCE IS QUITE LOW WITH DETAILS OF POSSIBLE TIMING OR COVERAGE. -GIH
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...KS NEAR TERM...HARTFIELD/CBL SHORT TERM...CBL LONG TERM...77 AVIATION...HARTFIELD

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