Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
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 180213 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1015 PM EDT SUN AUG 17 2014 .SYNOPSIS...
-- Changed Discussion --
A SERIES OF UPPER LEVEL DISTURBANCES IN NORTHWEST FLOW ALOFT WILL CROSS THE REGION THIS WEEK.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 1015 PM SUNDAY... ISOLATED SHOWERS WHICH DEVELOPED ALONG WEAK LOW LEVEL CONVERGENCE BOUNDARIES IN THE SANDHILLS AND OVER THE NW PIEDMONT DISSIPATED WITH LOSS OF HEATING. A MODERATELY MOIST AIR MASS REMAINS IN PLACE AS SFC DEWPOINTS RANGED FROM THE MID 60S NW TO THE LOWER 70S SE. ALOFT...CONVECTIVE DEBRIS ASSOCIATED WITH CONVECTION OCCURRING OVER SECTIONS OF THE LOWER OH AND TN VALLEYS WILL CONTINUE TO STREAM EAST- SE ACROSS THE CAROLINAS. THIS INCREASE IN MID-HIGH LEVEL CLOUDINESS COUPLED WITH A MODIFYING AIR MASS SHOULD YIELD MIN TEMPS OVERNIGHT AS WARM IF NOT A DEGREE OR TWO WARMER THAN LAST NIGHT. MIN TEMPS NEAR 70-LOWER 70S. CLOSER TO DAYBREAK...CANNOT RULE OUT THE POSSIBILITY OF A STRAY SHOWER OR TWO CROSSING THE PIEDMONT...MAINLY WEST OF RALEIGH. THESE SHOWERS WILL BE ASSOCIATED WITH THE APPROACH OF A MODERATELY STRONG S/W. THIS FEATURE WILL ENHANCE THE POSSIBILITY OF SHOWERS AND A FEW THUNDERSTORMS BY LATE MORNING IN THE WEST...AND AREAWIDE MONDAY AFTERNOON.
-- End Changed Discussion --
&& .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 330 PM SUNDAY... WILL INCREASE PRECIP CHANCES TO LIKELY (60-70%) ON MONDAY AS THE POTENT SHORTWAVE CURRENTLY IN THE TN VALLEY TRACKS ACROSS VA/NC DURING THE DAY...BEGINNING 12-15Z IN THE TRIAD AND BY EARLY/MID AFTERNOON (~18Z) IN THE EAST. WITH INCREASE PRECIP CHANCES AND AN EARLIER ONSET... EXPECT MUCH COOLER HIGHS THAN PREVIOUSLY ANTICIPATED...IN THE LOWER/MID 80S NW TO NEAR 90F SE. EXPECT A POTENTIAL FOR LOCALLY HEAVY RAINFALL AND FLASH FLOODING...PRIMARILY IN URBAN AREAS AND LOCATIONS THAT HAVE RECEIVED RECENT HEAVY RAINFALL. ANTICIPATE PRECIP CHANCES TO DECREASE FROM WEST-EAST IN ASSOC/W A PERIOD OF SUBSIDENCE IN THE WAKE OF THE SHORTWAVE TRACKING EAST ACROSS THE AREA DURING THE LATE AFTERNOON AND EARLY EVENING...THOUGH SOME CHANCE FOR SHOWER ACTIVITY MAY PERSIST OVERNIGHT AS ADDITIONAL SMALL AMPLITUDE DISTURBANCES TRACK ACROSS THE REGION IN WNW FLOW ALOFT. LOWS MON NIGHT NEAR OR ABOVE NORMAL IN THE 70- 74F RANGE. -VINCENT && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 320 PM SUNDAY... THE UPPER AIR PATTERN AT THE BEGINNING OF THE LONG TERM PERIOD INCLUDES A GENERAL WESTERLY FLOW WITH A WEAK SHEAR AXIS EXTENDING FROM NORTH TO SOUTH ACROSS THE MID ATLANTIC. DURING THE REMAINDER OF THE LONG TERM PERIOD THE PATTERN EVOLVES AS BOTH THE GFS AND THE ECMWF DEVELOP A LARGE RIDGE ACROSS THE LOWER MISSISSIPPI VALLY ON THURSDAY WITH 5950M HEIGHTS THAT PERSISTS INTO EARLY SATURDAY. GUIDANCE DIVERGES A BIT AT THAT TIME AS THE RIDGE IN THE ECMWF WEAKENS AND A BROAD TROUGH SWEEPS ACROSS THE NORTHERN ROCKIES AND NORTHERN PLAINS ON SUNDAY WHILE THE GFS HOLDS ONTO A STRONGER RIDGE. REGARDLESS... CENTRAL NC WILL BE IN A NORTHWEST FLOW ALOFT FOR MUCH OF THE PERIOD WITH A THREAT OF SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS EACH DAY. NEAR TO ABOVE AVERAGE HIGH TEMPERATURES WILL COOL DOWN TO NEAR TO BELOW AVERAGE AS A COLD FRONT PUSHES SOUTH THROUGH THE REGION. ONE SHORTWAVE TROUGH AND AN ASSOCIATED SURFACE LOW WILL MOVE OFFSHORE TUESDAY MORNING BEFORE ANOTHER DISTURBANCE ALOFT MOVES INTO THE REGION FROM THE WEST LATE TUESDAY. CONVECTIVE COVERAGE SHOULD BE MUCH LESS ON TUESDAY THAN ON MONDAY WITH THE GREATEST COVERAGE IN THE EAST AHEAD OF THE BEST FORCING AND IN THE REGION OF DEEPEST MOISTURE. NOT TOO EXCITED ABOUT SIGNIFICANT SEVERE WEATHER WITH THE SREF SUGGESTING A WEAK TO MODERATELY UNSTABLE AIR MASS WITH BULK SHEAR VALUES PEAKING AROUND 20- 25KTS. BUT THE FLOW HIGHS SHOULD RANGE IN THE UPPER 80S TO LOWER 90S. GUIDANCE DEPICTS A SIMILAR PATTERN ACROSS THE CAROLINAS FOR THE MID TO END OF THE LONG TERM PERIOD AS A NORTHWEST FLOW ALOFT DRIVES MULTIPLE IMPULSES ACROSS THE REGION. DEEP LAYER MOISTURE IS MORE LIMITED ON WEDNESDAY AND THURSDAY BUT INCREASES MARKEDLY ON FRIDAY INTO THE WEEKEND WITH PRECIPITABLE WATER VALUES ON SAT AND SUN RANGING FROM NEAR 2.1 ACROSS THE COASTAL PLAIN TO 1.8 ACROSS THE WESTERN PIEDMONT. A WEAK COLD FRONT IS PROGGED TO MOVE SOUTH ACROSS THE REGION ON FRIDAY AND SATURDAY AND LIKELY LINGER IN A WEST TO EAST ORIENTATION ACROSS GA/SC AND SOUTHERN NC PROVIDING A FOCUS FOR CONVECTION. ITS DIFFICULT TO PLACE MUCH SPECIFICITY IN THE FORECAST BUT WEDNESDAY AND THURSDAY WOULD APPEAR TO HAVE LESS CONVECTIVE COVERAGE WITH INCREASING CHANCES OF CONVECTION ON FRIDAY INTO THE WEEKEND. HIGH TEMPERATURES IN THE LOWER 90S ON WEDNESDAY AND THURSDAY WILL COOL DOWN A BIT ON FRIDAY AND SHOULD BE NOTICEABLY COOLER FOR SATURDAY AND SUNDAY WITH HIGHS IN THE LOWER TO MID 80S. MORNING LOWS WILL COOL SLIGHTLY FROM THE UPPER 60S TO LOWER 70S AROUND MID WEEK TO THE UPPER 60S TO AROUND 70 BY THE WEEKEND. -BLAES && .AVIATION /00Z MONDAY THROUGH FRIDAY/... AS OF 815 PM SUNDAY... 24-HR TAF PERIOD: VFR CONDITIONS ARE EXPECTED TO CONTINUE THIS EVENING INTO EARLY MONDAY MORNING. HOWEVER... A BRIEF GENERAL VFR SHOWER OR TWO WILL BE POSSIBLE AT KGSO/KINT/KFAY EARLY THIS EVENING THROUGH 02/03Z. EXPECT SUB-VFR CONDITIONS ASSOCIATED WITH SCATTERED TO WIDESPREAD SHOWERS AND STORMS BEGINNING BY 12/13Z IN THE WEST (INT/GSO) AND 15/16Z ELSEWHERE (RDU/FAY/RWI) AS A POTENT SHORTWAVE TRACKS INTO THE REGION FROM THE WEST. CHANCES FOR CONVECTION WILL DECREASE BY LATE AFTERNOON TO EARLY EVENING...THOUGH SOME POTENTIAL FOR SHOWERS WILL PERSIST MON NIGHT... ALONG WITH A CHANCE FOR FOG OR LOW CEILINGS DUE TO ENHANCED LOW-LEVEL MOISTURE IN PLACE ALONG WITH RECENT RAINFALL. FOR NOW HAVE ADDED A PROB30 GROUP FOR THE THREAT FOR STORMS WITH SUB-VFR CONDITIONS AND GUSTY WINDS FROM THE MID/LATE MORNING TIME FRAME TO LATE AFTERNOON/EVENING MONDAY. LOOKING AHEAD: EXPECT A CLIMATOLOGICAL POTENTIAL FOR AFT/EVE SHOWERS AND STORMS THROUGH MID TO LATE WEEK... ALONG WITH POSSIBLY SOME PRE- DAWN SUB-VFR CONDITIONS FOR LOCATIONS THAT SEE CONVECTION FROM THE PRIOR AFTERNOON/EVENING. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...WSS SHORT TERM...VINCENT LONG TERM...BLAES AVIATION...BSD/VINCENT

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