Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 281130 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 730 AM EDT SUN JUL 28 2014 .SYNOPSIS...A STRONG COLD FRONT WILL CROSS THE AREA THIS AFTERNOON... BRINGING NOTICEABLY COOLER AND LESS HUMID AIR INTO THE AREA. HIGH PRESSURE BUILDS OVER MUCH OF THE REGION FOR TUESDAY INTO WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 240 AM MONDAY... AMPLIFYING UPPER-LEVEL TROUGH WILL DIG SEWD INTO THE REGION TODAY WITH ATTENDANT STRONG COLD FRONT CROSSING EWD ACROSS THE CAROLINAS THIS AFTERNOON AND THEN OFF THE COAST DURING THEN EVENING. EVOLVING LINEAR BAND OF CONVECTION CURRENTLY MOVING INTO THE WESTERN PIEDMONT... ALONG THE LEADING EDGE OF THE IMPRESSIVE UPPER TROUGH DYNAMICS... WILL CONTINUE TO PROGRESS EASTWARD THROUGH THE PREDAWN HOURS...THAT IS IF IT HOLDS TOGETHER AS IT ENCOUNTERS INCREASING BOUNDARY LAYER CIN AND STRENGTHENING DOWN COMPONENT EAST OF THE MOUNTAINS. ONCE THIS CONVECTIVE BAND PUSHES EAST OF THE AREA...IT WILL SPELL THE END OF RAIN CHANCES ACROSS THE WESTERN TWO-THIRDS OF THE FORECAST AREA...WHICH IS PRETTY MUCH THE ENTIRE NC PIEDMONT COUNTIES AND NORTHERN PORTIONS OF THE COASTAL PLAIN...AS EASTWARD PUSH OF DRIER LOW-LEVEL AIR BEHIND THE FRONT WILL STABILIZE THE AIRMASS. IT WILL BE A LITTLE DIFFERENT STORY ACROSS THE SANDHILLS/SOUTHERN COASTAL PLAIN...BUT EVEN MORE SO ACROSS THE IMMEDIATE COASTAL COUNTIES WHERE CONVECTION WILL BE APT TO RE-DEVELOP THIS AFTERNOON INVOF THE MODEST LOW-LEVEL CONVERGENCE ALONG THE FRONT AND WITHIN THE CONTINUED LOW-LEVEL HIGH THETA-E AXIS. WILL CONTINUE TO ADVERTISE SCATTERED THUNDERSTORMS THIS AFTERNOON FOR THE FAR SOUTHEASTERN ZONES(SAMPSON-WAYNE-CUMBERLAND-SCOTLAND-HOKE). ANY STORMS ROOTED IN THE 40-50KT DEEP LAYER SHEAR COUPLED WITH MODERATE INSTABILITY OF 1000-2000 J/KG WILL BE SUPPORTIVE OF SEVERE STORMS CAPABLE OF PRODUCING LARGE HAIL...DAMAGING THUNDER WIND GUSTS AND EVEN A TORNADO OR TWO ACROSS SOUTHEASTERN NC. THE GOOD NEWS IS THAT THE SEVERE THREAT SHOULD WIND DOWN RATHER QUICKLY BY OR BEFORE SUNSET...OWING TO THE TIMING OF THE FRONT AND EASTERN PUSH OF LOW- LEVEL DRY AIR FEED. HIGH TEMPERATURES TODAY RANGING FROM UPPER 80S NORTHWEST TO MID 90S SE. NOTICEABLY COOLER LESS HUMID AIR BEGINS TO BUILD IN TONIGHT...WITH LOWS RANGING FROM LOWER 60W NW TO MID-UPPER 60 SE. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AS OF 240 AM MONDAY... UPPER LEVEL TROUGHING WILL STAY IN PLACE OVER THE EAST COAST THROUGHOUT THE SHORT TERM PERIOD...WHILE AT THE SURFACE COOL...CANADIAN HIGH PRESSURE WILL GRADUALLY SETTLE EAST OVER THE EAST COAST...KEEPING THE FRONT OFFSHORE. ALL OF THIS WILL LEAD TO BELOW NORMAL TEMPS...WITH HIGHS GENERALLY IN THE LOW/MID 80S AND OVERNIGHT LOWS IN THE LOW/MID 60S...POSSIBLY EVEN SOME UPPER 50S IN THE NORMAL COOLER SPOTS. IN ADDITION...MOSTLY DRY CONDITIONS ARE EXPECTED THROUGH AT LEAST THURSDAY AS NORTHWESTERLY FLOW ALOFT MAINTAINS A DRY COLUMN...WITH PWAT VALUES PROGGED TO HOVER JUST ABOVE 1 INCH. && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 240 AM MONDAY... BY LATE IN THE WEEK AND ESPECIALLY INTO THE WEEKEND...THE HIGHLY AMPLIFIED RIDGE OVER THE ATLANTIC WILL SHIFT WESTWARD...NUDGING THE UPPER LEVEL TROUGH BACK TOWARDS THE MS RIVER VALLEY. AS A RESULT...THE LINGERING FRONT/INVERTED TROUGH WILL WILL ALSO MOVE CLOSER TO THE COAST...AND LIKELY INLAND BY THE LATTER HALF OF THE WEEKEND. IN ADDITION...MOISTURE WILL GRADUALLY INCREASE (PWATS RISING BACK OVER 1.5 INCHES BY SATURDAY...THEN APPROACHING 2 INCHES BY SUNDAY) AS FLOW ALOFT BECOMES MORE SOUTHWESTERLY. AS A RESULT OF ALL OF THIS...WILL SHOW PRECIP CHANCES GRADUALLY INCREASING INTO THE 30-40 PERCENT RANGE BY SUNDAY. HIGH TEMPS WILL STILL BE IN THE LOW/MID 80S...WITH OVERNIGHT LOWS IN THE LOW/MID 60S. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 730 AM MONDAY... DRIER AIR WILL ALOFT AND AT THE SURFACE WILL CONTINUE TO SPREAD WEST TO EAST INTO CENTRAL NORTH CAROLINA THROUGH THE DAY ON MONDAY AS A STRONG COLD FRONT CROSSES THE AREA. THIS SHOULD SHIFT THE FOCUS FOR CONVECTIVE INITIATION ACROSS SOUTHEASTERN NC. LATEST HI-RES CONVECTIVE ALLOWING MODELS HAVE ALL RE-DEVELOPMENT WELL EAST OF KFAY AND KRWI AND THUS DO NOT PLAN ON CARRYING ANY MENTION OF THUNDER WITH THE 12Z ISSUANCE. AS SUCH...EXPECT VFR CONDITIONS WITH DAYTIME MIXING RESULTING IN WESTERLY WIND GUSTS TO AROUND 20KTS. BEYOND THE 24 HOUR TAF PERIOD...VFR CONDITIONS SHOULD PREVAIL FOR MUCH OF THE REST OF THE WORK WEEK...WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS FROM FRIDAY INTO THE WEEKEND. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MWS/DJF NEAR TERM...CBL SHORT TERM...KRR LONG TERM...KRR AVIATION...CBL

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