Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 010532 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1230 AM EST SUN FEB 1 2015 .SYNOPSIS...ARCTIC HIGH PRESSURE OVER THE CAROLINAS WILL SHIFT WILL SHIFT OFFSHORE THROUGH EARLY SUNDAY. A COLD FRONT WILL TRACK EAST ACROSS THE REGION SUNDAY NIGHT AND EARLY MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 957 PM SATURDAY... MID LEVEL CLOUDINESS CONTINUED TO OVERSPREAD WESTERN NORTH CAROLINA THIS EVENING. THE TEMPERATURES WERE ALREADY IN THE 20S IN THE NORTHEAST BUT RANGED INTO THE 40S IN THE SW... WHERE THE MID LEVEL CLOUDS HAD REACHED. BASED ON SATELLITE AND OBSERVATIONS IT APPEARS THAT THE MID LEVEL CLOUDS WILL REACH INTO THE TRIAD BY AROUND MIDNIGHT... THEN REACH EASTERN SECTIONS BEFORE 300 AM. THIS INCREASE IN THE MID LEVEL CLOUD DECK WILL HAVE A SIGNIFICANT IMPACT ON TEMPERATURES. THE TEMPERATURES IN THE WESTERN PIEDMONT SHOULD BOTTOM OUT AROUND OR BEFORE MIDNIGHT (UPPER 20S TO MID 30S). TEMPERATURES IN THE NE ZONES (THE LAST TO SEE THE THICKER MID LEVEL CLOUD DECK) WILL BOTTOM OUT AROUND 100 AM TO 300 AM (MID TO UPPER 20S)... THE RISE A BIT BY 12Z. WINDS WILL BE LIGHT AND MAINLY FROM THE SW OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH MONDAY/... AS OF 330 PM SATURDAY... WITH HIGH PRESSURE OFFSHORE SUNDAY MORNING...SOUTHERLY FLOW WILL ALLOW ADDITIONAL MODERATION AS THICKNESSES CLIMB BACK TOWARD 1320M WHICH IS 5-10 ABOVE NORMAL. MID AND HIGH CLOUDS WILL CONTINUE TO BLANKET THE REGION...BUT EXPECT THE SOUTHERLY WIND TO OVERCOME SOME OF THE LOSS OF HEATING...SO WILL KEEP TEMPS IN LINE WITH STATISTICAL GUIDANCE IN THE MID TO UPPER 50S AND MAYBE TOUCHING 60 IN THE SOUTH. MEANWHILE...A SURFACE LOW WILL DEVELOP IN RESPONSE TO THE UPPER TROUGH DIGGING THROUGH THE CENTRAL PLAINS AND MID-MISSISSIPPI VALLEY...MOVING ACROSS THE CENTRAL APPALACHIANS SUNDAY NIGHT. MODELS ARE IN PRETTY GOOD AGREEMENT ON PRECIP ARRIVING IN THE WESTERN PIEDMONT AFTER 00Z...WITH THE BULK OF THE PRECIP AFTER MIDNIGHT AS A 50KT LOW LEVEL JET SHIFTS ACROSS THE AREA. PW VALUES STAY BELOW 1.25"...BUT WITH ADDITIONAL SUPPORT FROM UPPER DIVERGENCE IN THE LEFT EXIT REGION OF A SPEED MAX STRENGTHENING OVER THE DEEP SOUTH...WOULD LEAN A LITTLE MORE TOWARD THE NAM/GFS QPF TOTALS WHICH ARE HIGHER AND GIVE BETWEEN A QUARTER TO HALF INCH IN TOTAL. WEAK LAPSE RATES AND POOR DIURNAL TIMING WILL LIMIT INSTABILITY...THOUGH THE GFS PRODUCES 200-300 J/KG MLCAPE AT KFAY AS IT STEEPENS MID- LEVEL LAPSE RATES TO AROUND 6 C/KM. THIS SEEMS OVERDONE GIVEN UPSTREAM SOUNDINGS...BUT IF THERE IS A CHANCE OF THUNDER IT SHOULD BE IN THE SOUTHERN COASTAL PLAIN MONDAY MORNING. STRONG 150+ METER HEIGHT FALLS AND A COLD FRONT WILL SWEEP ACROSS THE AREA BY EARLY MONDAY AFTERNOON. FORECAST SOUNDINGS SHOW 25-35KT IN THE DEEPENING POST-FRONTAL MIXED LATER MONDAY AFTERNOON...BUT MODELS CAN OFTEN OVERDO THESE GRADIENT WINDS. WILL CAP WIND GUSTS AT 30KT FOR NOW. TEMPS MAY COOL INTO THE UPPER 40S ACROSS THE NORTH SUNDAY EVENING BUT WILL LIKELY RISE BACK INTO THE 50S SUNDAY NIGHT AHEAD OF THE FRONT. GUIDANCE SUGGESTS THE COASTAL PLAIN MAY REACH THE 60S BY EARLY MONDAY...BUT MOST AREAS WILL SEE TEMPS FALLING THROUGH THE DAY ON MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS OF 332 PM SATURDAY... DEEPENING AREA OF LOW PRESSURE WILL CONTINUE MOVING NORTHEASTWARD AWAY FROM THE MID ATLANTIC COAST... AND WINDS WILL DIMINISH OVERNIGHT AS HIGH PRESSURE OVER THE OHIO VALLEY MOVES EASTWARD OVER THE AREA ON MONDAY NIGHT INTO TUESDAY. THIS HIGH WILL MOVE OFF THE COAST ON WEDNESDAY... PROVIDING COMPARATIVELY WARMER TEMPS IN SOUTHWESTERLY FLOW. MEANWHILE... UPPER LEVEL LOW OVER THE SOUTHWEST WILL GRADUALLY BEGIN TO OPEN INTO A WAVE AS IT MOVES EASTWARD TO THE WESTERN GULF OF MEXICO... WHERE SURFACE LOW PRESSURE FORMS OVER THE NORTHERN GULF. PROGRESSION OF THIS SYSTEM STILL REMAINS QUITE UNCERTAIN... WITH CONSIDERABLE VARIATION AMONGST MODEL SOLUTIONS IN HANDLING THE PRIMARY SOUTHERN STREAM ENERGY... AND THE TRAILING NORTHERN STREAM WAVE. ECMWF REMAINS SUPPRESSED WITH THE SOUTHERN STREAM UPPER LEVEL WAVE AND MUCH WEAKER WITH THE SECOND NORTHERN STREAM ONE... AND PUSHES THE LOW EASTWARD OUT TO SEA WITH NO LOCAL IMPACTS... WHILE THE GFS BRINGS THE LOW ALONG THE SOUTHEAST COAST AS STRONGER NORTHERN STREAM ENERGY DIVES INTO THE AREA... RESULTING IN WIDESPREAD RAIN THURSDAY. WITH NO STRONG CONSENSUS TO DRIVE A DEVIATION FROM THE CURRENT FORECAST... WILL CONTINUE WITH SLIGHT TO CHANCE POPS ON THURSDAY... WITH DRY CONDITIONS FRIDAY AND SATURDAY. TEMPS WILL REMAIN BELOW NORMAL THURS THROUGH SAT. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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AS OF 1230 AM SUNDAY... 24-HR TAF PERIOD: HIGH PRESSURE CENTERED OVER THE AREA WILL SHIFT OFF THE SE COAST THIS AFTERNOON...IN ADVANCE OF A POTENT UPPER LEVEL WAVE AND ATTENDANT SFC LOW TRACKING EASTWARD FROM THE CENTRAL PLAINS INTO THE OH VALLEY. THIS WILL SECURE VFR CONDITIONS THROUGH 21-00Z WITH LIGHT VARIABLE WINDS BECOMING S/SW AT 10 TO 15KTS BY THE AFTERNOON. AS LOW-LEVEL MOISTURE INCREASES VIA STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF AN APPROACHING COLD FRONT. SHOWERS AND MVFR/IFR CEILINGS WILL DEVELOP AT THE INT/GSO TERMINALS BETWEEN 00- 06Z MON...SPREADING EASTWARD ACROSS ALL THE AREA BETWEEN 06 TO 12Z. LOOKING AHEAD: RAIN AND MVFR/IFR CEILINGS WILL SCATTER OUT WEST TO EAST ACROSS THE AREA BETWEEN 15 TO 18Z AS THE FRONT EXITS THE AREA. WINDY CONDITIONS ARE EXPECTED IN THE WAKE OF THE FRONT MONDAY AFTERNOON WITH DANGEROUS W/NW CROSSWINDS WITH SUSTAINED WINDS OF 15 TO 20KTS AND GUSTS AS HIGH AS 35 KTS. A NW BREEZE AT 10-15 KT WILL PERSIST MON NIGHT AS HIGH PRESSURE BUILDS TOWARD THE REGION FROM THE WEST. VFR CONDITIONS WILL RULE THROUGH MID-WEEK AS DRY HIGH PRESSURE BUILDS OVER THE CAROLINAS.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT NEAR TERM...BADGETT SHORT TERM...BLS LONG TERM...SEC AVIATION...CBL/VINCENT

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