Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 030150 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 950 PM EDT MON MAY 2 2016 .SYNOPSIS... WARM SOUTHWEST FLOW WILL PREVAIL AHEAD OF A SLOW-MOVING COLD FRONT...AND ASSOCIATED WAVES OF LOW PRESSURE...THAT WILL APPROACH FROM THE NORTHWEST AND CROSS THE MIDDLE ATLANTIC STATES LATE TUE THROUGH EARLY WED. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 950 PM MONDAY... WEAK IMPULSES WILL CONTINUE TO EJECT EASTWARD THROUGH THE REGION... IN ADVANCE OF A POSITIVELY TILTED TROUGH OVER THE CENTRAL US/MID MS VALLEY. ASSOCIATED SFC COLD FRONT WILL MAKES IT WAY INTO THE NC MTNS BY AROUND DAYBREAK. WITH A UNSEASONABLY MOIST AIRMASS IN PLACE (PWATS 1.5-1.7" ~200% OF NORMAL)...40 TO 50MB H5 SYNOPTIC HEIGHT FALLS...DPVA...AND INCREASING UPPER DIVERGENCE WITHIN A RIGHT ENTRANCE REGION OF A JET STREAK WILL SUPPORT SHOWERS AND STORMS OVERNIGHT...WITH HIGHEST POPS EXPECTED ACROSS THE WEST IN CLOSER PROXIMITY TO BETTER FORCING. WITH MOST OF THE AREA HAVING ALREADY SEEN RAINFALL FROM EARLIER CONVECTION/STORMS...AIRMASS HAS BEEN WORKED OVER QUITE A BIT WITH ONLY WEAK ~500 J/KG OF SBCAPE REMAINING. ADDITIONALLY...WEAK MID- LEVEL LAPSE RATES OF 5.5-6.0 C/KM PROVE OF LITTLE CONCERN FOR SEVERE WEATHER OVERNIGHT. INSTEAD...MAIN THREAT WILL BE FROM LOCALLY HEAVY/EXCESSIVE RAINFALL IN URBANIZED AREAS...RESULTING IN STREET FLOODING ALONG WITH CREEKS/STREAMS TEMPORARILY LEAVING THEIR BANKS. WARM AND MUGGY WITH OVERNIGHT TEMPS IN THE MID-UPPER 60S.
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&& .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 345 PM MONDAY... APPEARS HIGHLY LIKELY THAT ANOTHER ROUND OF CONVECTION WILL AFFECT CENTRAL NC TUESDAY AFTERNOON AND TUESDAY NIGHT WITH POTENTIAL FOR A FEW SEVERE STORMS. MAIN FOCUS FOR CONVECTIVE DEVELOPMENT WILL LIKELY BE ALONG AND EAST OF HIGHWAY 1 WHERE REMNANT OUTFLOWS FROM TONIGHT`S CONVECTION SHOULD RESIDE. ALSO...CONVECTION MAY NOT DEVELOP UNTIL VERY LATE IN THE DAY OR DURING THE EVENING HOURS AS BETTER SUPPORT ALOFT CROSSES OUR REGION AT THAT TIME. BULK SHEAR COULD BE AS HIGH AS 45-50KTS TUESDAY AFTERNOON WITH MLCAPE AROUND 1000 J/KG. THIS SUGGEST POTENTIAL FOR BROKEN BANDS OF STRONG STORMS WITH BOWING SEGMENTS. THOSE CELLS WITH STRONG/SUSTAINED UPDRAFTS COULD PRODUCE LARGE HAIL. CAVEAT TO THIS IS THAT THERE IS A POSSIBILITY THAT LINGERING/DIMINISHING SHOWERS FROM CONVECTION TONIGHT MAY PERSIST OVER THE EASTERN COUNTIES TUESDAY MORNING. THIS WILL INITIALLY INHIBIT THE ATMOSPHERE FROM DESTABILIZING UNTIL LATE N THE DAY. SIMILAR TO CONCERNS FOR TODAY...SHOWERS/STORMS WILL BE EFFICIENT RAIN PRODUCERS...LEADING TO LOCALLY HEAVY/EXCESSIVE RAINFALL. FOR TUESDAY/TUESDAY...WILL HAVE HIGHEST POPS ALONG AND EAST OF HIGHWAY 1 THOUGH A DECENT CHANCE FOR CONVECTION WILL STILL EXIST IN THE WEST. SIMILAR TO TONIGHT... EXPECT CONVECTION TO PERSIST WELL INTO TUESDAY NIGHT AS A SLOW MOVING COLD FRONT APPROACHES AND EVENTUALLY ENTERS THE AREA. MAX TEMPS TUESDAY DEPENDENT UPON THE EXTENT OF CLOUDS/REMNANT SHOWERS IN THE MORNING. BELIEVE THAT THERE WILL BE SOME EXTENSIVE CLOUDINESS THROUGH 9 AM...THEN LOW CLOUDS SHOULD LIFT/DISSIPATE THEREAFTER. MAX TEMPS TUESDAY MID 70S NW TO AROUND 80 EAST. MIN TEMPS TUESDAY NIGHT MID-UPPER 50S. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AS OF 220 PM MONDAY... THE MAIN WEATHER STORY IN THIS PERIOD WILL BE A CLOSED LOW PROGGED TO DROP SOUTH ACROSS THE GREAT LAKES ON WEDNESDAY AND MOVE ACROSS THE CAROLINAS ON THURSDAY INTO EARLY FRIDAY. THE MAIN IMPACT OF THIS PATTERN WILL BE BELOW NORMAL TEMPS THURSDAY THROUGH FRIDAY MORNING...BEFORE THE AIRMASS REBOUNDS AS THE TROUGH DEPARTS TO OUR EAST ON FRIDAY. IN TERMS OF PRECIP CHANCES...LOOK FOR THE BEST CHANCE FOR RAIN WEDNESDAY NIGHT WITH THE PASSAGE OF THE SFC COLD FRONT (AS THE UPPER TROUGH IS DIVING SOUTHWARD ACROSS THE OHIO VALLEY)...AND THURSDAY AFTERNOON INTO EARLY FRIDAY AS THE UPPER TROUGH MOVES ACROSS OUR AREA. FOR THIS WEEKEND INTO MONDAY...RIGHT NOW FAIR WEATHER STILL APPEARS TO BE ON TRACK FOR THIS WEEKEND...ALTHOUGH WE`LL HAVE TO KEEP OUR EYES ON A COUPLE WEAK SHORT WAVES EMBEDDED IN THE NW FLOW ON THE BACK SIDE OF THE AFOREMENTIONED TROUGH...AS THESE FEATURES COULD BRIEFLY INCREASE THE CLOUDS ACROSS OUR AREA...AND PERHAPS BRING A FAST-MOVING AND BRIEF SHOWER OR TWO. TEMPS NEAR TO SLIGHTLY ABOVE NORMAL. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... AS OF 800 PM MONDAY... 24 HOUR TAF PERIOD: SCATTERED THUNDERSTORMS AROUND THE AREA CONTINUE THIS EVENING WITH STORMS SUB-SEVERE AT THIS TIME...HOWEVER SHORT TERM MODELS INDICATE SOME MORE ORGANIZED STORMS MOVING THROUGH THE TRIANGLE AREA AROUND 3Z. THERE COULD BE SOME SCATTERED STORMS AROUND THE TRIAD AS WELL AS THERE IS A LINEAR FEATURE NORTHWEST OF THE AREA BUT IT IS UNCLEAR AT THIS TIME IF THE LINE WILL GO TO THE NORTH OF KGSO AND KINT. WILL CONTINUE TO MONITOR. WIND GUSTS IN THE OBSERVED STORMS HAVE BEEN IN THE 30-40 KT RANGE. OVERNIGHT EXPECT VISIBILITIES TO POSSIBLY DROP TO THE 4-6SM RANGE BUT CEILINGS WILL BE THE BIGGER PROBLEM AS FAR AS FLIGHT RESTRICTIONS GO WITH MVFR AND POSSIBLY IFR CEILINGS IN PLACE AT MOST TAF SITES THROUGH AT LEAST 12Z. GETTING INTO TUESDAY AFTERNOON...EXPECT THUNDERSTORM ACTIVITY TO DEVELOP AGAIN...THIS TIME MAINLY FROM THE TRIANGLE TO THE SOUTH AND EAST. SOME OF THESE STORMS COULD BECOME SEVERE. OUTSIDE OF THUNDERSTORMS...CONDITIONS SHOULD REMAIN VFR THROUGH THE END OF THE TAF PERIOD. LONG TERM: A FRONTAL SYSTEM WILL HANG OVER THE AREA THROUGH WEDNESDAY BEFORE AN UPPER LEVEL LOW DROPS INTO THE CAROLINAS...PROVIDING RAIN CHANCES THROUGH FRIDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...26 NEAR TERM...CBL SHORT TERM...WSS LONG TERM...RAH AVIATION...ELLIS

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