Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 251908 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 310 PM EDT SAT APR 25 2015 .SYNOPSIS...A WARM FRONT WILL STALL ACROSS CENTRAL NC THIS AFTERNOON AND REMAIN STATIONARY OVERNIGHT AS AN AREA OF LOW PRESSURE TRAVERSES WEST-TO-EAST ACROSS THE REGION. A COLD FRONT WILL CROSS THE AREA ON SUNDAY. && .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 310 PM SATURDAY... TONIGHT... MAIN FORECAST CHALLENGE IS IF/WHEN SCATTERED CONVECTION MAY AFFECT CENTRAL NC LATE TONIGHT. EARLY THIS AFTERNOON...A STALLED SFC BOUNDARY STRETCHED WEST-TO-EAST ACROSS CENTRAL NC IN VICINITY OF HIGHWAY 64. MID-UPPER DISTURBANCE RESPONSIBLE FOR THE LIGHT RAIN THIS MORNING HAS PUSHED EAST AND TAKEN MOST OF THE STEADY LIGHT RAIN WITH IT. FOR THE REMAINDER OF THE AFTERNOON...EXPECT PATCHES OF LIGHT RAIN TO LINGER DUE TO FAVORABLE LOW LEVEL ISENTROPIC UPGLIDE OVER THE REGION. TEMPS WILL VARY FROM NEAR 50-LOWER 50S NORTH OF THE BOUNDARY TO THE LOW-MID 60S SOUTH OF THE BOUNDARY. ATTENTION TURNS TO THE WEST-NW OF THE REGION WHERE SCATTERED STRONG/ISOLATED SEVERE CONVECTION EXPECTED TO DEVELOP THIS AFTERNOON IN ASSOCIATION WITH A DISTURBANCE AND ATTENDANT SFC WAVE. MOST NEAR TERM MODELS SUGGEST THIS SYSTEM WILL GLIDE TO THE EAST-SE. IF THIS VERIFIES...SHOULD SEE AN INCREASE IN SCATTERED CONVECTION ACROSS THE NORTHERN PIEDMONT BETWEEN 11 PM-2 AM...WITH SCATTERED CONVECTION DRIFTING EAST INTO THE COASTAL PLAIN AND SANDHILLS DURING THE PRE- DAWN HOURS. BULK SHEAR IN EXCESS OF 50KTS SHOULD MAINTAIN STORM ORGANIZATION THOUGH LOW LEVEL INSTABILITY WILL BE LACKING. MID LEVEL LAPSE RATES AVERAGE 7-7.5 DEG C/KM. THIS SUGGEST BULK OF CONVECTION WILL BE ELEVATED WITH STRONGER CELLS LIKELY PRODUCING SOME HAIL AND LOCALIZED STRONG GUSTY WINDS. BETTER CHANCE FOR SURFACE-BASED CONVECTION WILL BE ACROSS THE SOUTHERN COUNTIES THOUGH LIFTING MECHANISM IN THIS REGION NOT AS STRONG AS TO THE NORTH. FOR NOW WILL HAVE SOLID CHANCE/LOW END LIKELY POPS...MAINLY ACROSS THE NORTHERN COUNTIES..LATE THIS EVENING INTO THE OVERNIGHT. OVERNIGHT TEMPS WILL VARY FROM THE UPPER 40S/LOWER 50S NORTH TO THE MID-UPPER 50S SOUTH.
-- End Changed Discussion --
&& .SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
-- Changed Discussion --
AS OF 310 PM SATURDAY... SUNDAY... SHEAR AXIS AND ATTENDANT SURFACE COLD FRONT WILL PROGRESS SOUTH ACROSS CENTRAL NC. THIS FEATURE WILL SUPPORT SCATTERED SHOWERS...MAINLY ACROSS THE NORTH DURING THE MORNING HOURS...AND FOCUS MORE IN THE SOUTH DURING THE AFTERNOON. OVERCAST SKIES AND SCATTERED RAIN SHOWERS WILL LIMIT DIURNAL TEMP RECOVERY TO NO MORE THAN 8-12 DEGREES. NLY LOW LEVEL WINDS BEHIND THE EXITING WAVE WILL FILTER DRIER STABLE AIR INTO CENTRAL NC. THUS SHOULD SEE A DWINDLING POP TREND NORTH-TO SOUTH LATE SUNDAY. MAX TEMPS SUNDAY MID-UPPER 50S FAR NE TO THE LOWER 70S FAR SW. SUNDAY NIGHT... NORTHERLY FLOW WILL CONTINUE TO FUNNEL THE DRIER STABLE AIR MASS INTO OUR REGION. OVERCAST SKIES MAY PERSIST A GOOD PART OF THE EVENING...THEN DIMINISH NORTH-TO-SOUTH. IF THIS CLEARING TREND DOES OCCUR OVERNIGHT...COULD SEE POCKETS IF DENSE FOG EARLY MONDAY MORNING. MIN TEMPS MID-UPPER 40S.
-- End Changed Discussion --
&& .LONG TERM /MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
AS OF 310 PM SATURDAY... MONDAY THROUGH TUESDAY: A DEEP MID/UPPER LEVEL LOW WILL CONTINUE TO LINGER OFF THE NORTHEAST/NEW ENGLAND COAST MONDAY INTO TUESDAY... WITH A SERIES OF S/W DISTURBANCES TRACKING THROUGH THE CYCLONIC FLOW ALOFT ACROSS THE MID-ATLANTIC INTO NC ON MONDAY. HOWEVER... CENTRAL NC WILL BE REMOVED ENOUGH FROM THE DEEP MOISTURE... SO DRY CONDITIONS ARE EXPECTED TO CONTINUE... WITH PERHAPS JUST AN INCREASE IN CLOUD COVER ON MONDAY (ESPECIALLY ACROSS THE NORTHEAST PORTION OF CENTRAL NC). THUS... EXPECT A CONTINUATION OF BELOW NORMAL HIGH TEMPS EARLY NEXT WEEK... GENERALLY IN THE 60S TO NEAR 70 SOUTH. LOWS MONDAY NIGHT IN THE 40S. TUESDAY NIGHT THROUGH SATURDAY: UNCERTAINTY STILL REIGNS SUPREME IN THE MID TO LATE WEEK FORECAST. THE DEEP MID/UPPER LEVEL VORTEX OFF THE NORTHEAST/NEW ENGLAND COAST WILL SLOWLY SHIFT/LIFT NORTHEASTWARD... SLOWER THOUGH ON THE ECMWF. THE SLOWER DEPARTURE OF THE DEEP MID LEVEL LOW APPEARS TO HAVE RAMIFICATIONS WITH THE EVOLUTION OF THE MID LEVEL FLOW AND RESULTANT SURFACE PATTERN AND POP/TEMP FOR MID TO LATE WEEK ACROSS CENTRAL NC. A MID LEVEL LOW INVOF THE FOUR CORNERS REGION ON SUNDAY IS EXPECTED TO SHIFT EASTWARD EARLY TO MID NEXT WEEK. MEANWHILE A NORTHERN STREAM DISTURBANCE IS EXPECTED TO DROP SOUTH TO SOUTHEASTWARD OUT OF CANADA AND TOWARDS THE MID-ATLANTIC. HOW THESE LATTER TWO FEATURES INTERACT OR DONT INTERACT WILL PLAY A HUGE ROLE IN DETERMINING THE SENSIBLE WEATHER ACROSS CENTRAL NC FROM AT LEAST WEDNESDAY THROUGH FRIDAY. THE LATEST ECMWF ALLOWS THE SOUTHERN STREAM OPENING MID LEVEL LOW TO SPREAD ACROSS THE AREA... WITH THE NORTHERN STREAM S/W ENERGY DIVING SOUTHWARD OUT OF CANADA AND AMPLIFYING THE MID LEVEL FLOW OVER THE CAROLINA HELPING TO DEVELOP A SIGNIFICANT COASTAL LOW WITH GENERALLY WET AN COOL CONDITIONS ACROSS OUR AREA DEVELOPING WEDNESDAY AND LINGERING INTO FRIDAY. MEANWHILE... THE GFS IS FASTER WITH THE NORTHERN STREAM ENERGY DIVING SOUTHEASTWARD FROM CANADA...WHICH HELPS TO DRIVE THE NORTHERN STREAM TROUGH THROUGH THE AREA FASTER... THANKS IN PART BY THE FASTER DEPARTURE OF THE CURRENT MID/UPPER LOW NEAR THE NEW ENGLAND COAST. THIS WOULD RESULT IN LESS PRECIP ON WEDNESDAY AND DRY FOR THE REMAINDER OF THE FORECAST PERIOD... WITH RESULTANT WARMER TEMPS... YET STILL GENERALLY SIGHTLY BELOW NORMAL HIGH TEMPS. FOR NOW HAVE TRENDED A CLOSE TO WPC... KEEPING POPS IN THE CHANCE CATEGORY FOR WEDNESDAY THROUGH THURSDAY... WITH HIGH TEMPS A COUPLE OF CATEGORIES BELOW NORMAL.
-- End Changed Discussion --
&& .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 120 PM SATURDAY... HIGH LIKELIHOOD THAT AVIATION CONDITIONS WILL DETERIORATE TO IFR/LIFR CEILINGS BY LATE THIS AFTERNOON...PERSISTING THROUGH EARLY SUNDAY MORNING. AREAS OF RAIN WILL DIMINISH FROM THE WEST THIS AFTERNOON WITH PATCHES OF FOG AND/OR DRIZZLE IN ITS WAKE. THERE IS LESS THAN A 1-IN-5 CHANCE OF A THUNDERSTORM THIS EVENING THROUGH THE OVERNIGHT HOURS ACROSS THE SOUTHERN COUNTIES. THIS CHANCE APPEARS BEST (BUT STILL NO MORE THAN 1:5) NEAR OR SOUTH OF KFAY. AVIATION CONDITIONS WILL BE SLOW TO IMPROVE SUNDAY WITH WIDESPREAD IFR/MVFR CEILINGS AND THE POSSIBILITY OF A FEW SHOWERS IN THE AFTERNOON-EARLY EVENING...MAINLY ACROSS THE NORTHERN COUNTIES INCLUDING KRWI...KRDU...AND THE TRIAD TERMINALS. CONDITIONS SHOULD IMPROVE SUNDAY NIGHT INTO MONDAY AS A DRIER MORE STABLE AIR MASS INFILTRATES THE REGION. THE VFR CONDITIONS SHOULD PERSIST INTO TUESDAY. A LOW PRESSURE SYSTEM APPROACHING FROM THE SW WILL BRING THE NEXT CHANCE FOR SUB VFR CONDITIONS TO CENTRAL NC WEDNESDAY INTO THURSDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS LONG TERM...BSD AVIATION...WSS

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.