Area Forecast Discussion
Issued by NWS Blacksburg, VA

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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 300620 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 220 AM EDT SAT APR 30 2016 .SYNOPSIS... LOW PRESSURE SHIFTS FROM THE SOUTHERN PLAINS INTO THE WESTERN OHIO VALLEY THROUGH SUNDAY. A WARM FRONT WILL MOVE NORTH AHEAD OF THIS SYSTEM AND ACROSS THE REGION BY SUNDAY...WITH THE COLD FRONT MOVING THROUGH MONDAY. && .NEAR TERM /THROUGH TODAY/...
-- Changed Discussion --
AS OF 200 AM EDT SATURDAY... WEDGE FRONT VERY WELL DEPICTED IN THE LAPS ANALYSIS AND GOES-R PROVING GROUND MVFR/IFR GRAPHIC...NOW NEAR A LWB-ROA-MWK. LOW CLOUDS SPREAD INTO THE REGION VERY QUICKLY BEHIND THE FRONT WITH A SHARP LINE NOTED FROM JUST OVC250 CIGS AT BCB/BLF/LWB TO CIGS AOB 100 ROA/DAN/LYH. MODELS CONTINUE TO MOVE WEDGE FRONT WEST THROUGH THE REST OF THE CWA BY THE 12Z-15Z TIME FRAME. AS THE WEDGE DEEPENS AND MID-LEVEL MOISTURE BEGINS TO SPREAD OVER TOP OF THE SHALLOW WEDGE...WOULD EXPECT -DZ TO EVOLVE...ESPECIALLY IN UPSLOPE AREAS ALONG THE BLUE RIDGE AND ALLEGHANY FRONT. BONAFIDE -RA OR -SHRA SHOULD BEGIN TO SPREAD INTO THE REGION LATER IN THE AFTERNOON AS THE FIRST OF SEVERAL SHORT WAVES EMANATING FROM A PERSISTENT UPPER LOW IN THE SOUTHWEST U.S. EJECT ENE-NE ACROSS THE REGION. THE WEDGE COULD POTENTIALLY BREAK LATE IN THE DAY TOWARD THE KBLF/KMKJ/KTNB AREA...BUT MOST LIKELY THIS WILL NOT OCCUR UNTIL AFT 00Z. T/TD GRIDS GENERALLY ON TARGET THIS HOUR. ADJUST POPS DOWNWARD OVERNIGHT...THEN WENT ALONG WITH ADVERTISED LIKELY POPS BY 15Z ACROSS MUCH OF THE REGION WEST OF THE BLUE RIDGE. EITHER HIGH OR LOW CLOUDS ENVELOPE MUCH OF THE REGION THIS HOUR...SO HAVE INCREASED CLOUDS TOWARD 100 PERCENT FROM THIS POINT FORWARD IN TIME. AS OF 845 PM EDT FRIDAY... SQUEEZE PLAY OF CLOUDS WILL OCCUR OVERNIGHT AS LOW LEVEL MOISTURE WITHIN THE PERSISTENT FAR EASTERN WEDGE OOZES BACK TOWARD THE BLUE RIDGE WHILE MID/HIGH CANOPY INCREASES FROM THE WEST AHEAD OF RETURN WARM ADVECTION TO THE SW. LATEST NAM ALSO QUITE MOIST WITH THE WEDGE ENHANCING OVERNIGHT IN THE WAKE OF PASSING SHORTWAVE ENERGY TO THE NORTH AND REINFORCING HIGH PRESSURE BUILDING SOUTH. FORECAST SOUNDINGS FROM OTHER SHORT TERM SOLUTIONS ALSO SHOW QUITE A BIT OF TRAPPED BOUNDARY LAYER MOISTURE ESPCLY NE. THEREFORE BEEFED UP CLOUDS AND INCLUDED SOME PATCHY DRIZZLE BACK WEST TO NEAR ROANOKE AFTER MIDNIGHT ALONG WITH PATCHY FOG. MAIN ASPECT WEST OF THE BLUE RIDGE WILL BE WITH DEEPENING CLOUD CANOPY ALTHOUGH APPEARS ENOUGH DRY AIR TO KEEP THINGS DRY OVERNIGHT ESPCLY GIVEN THE UPSTREAM MCS DIVING WELL TO OUR SOUTH. LATEST HRRR ABOUT THE ONLY GUIDANCE SHOWING ANY RAINFALL OVER THE FAR WEST LATE BUT APPEARS OVERDONE GIVEN ONLY WEAK FORECAST SOUTH/SE FLOW AND LITTLE SUPPORT ALOFT UNTIL SATURDAY. THUS WILL KEEP TREND OF BECOMING MOSTLY CLOUDY OVERNIGHT...BUT MAINLY DRY OUTSIDE OF DRIZZLE...WITH LOWS IN THE 50S...EXCEPT PERHAPS A FEW COOLER 40S WESTERN VALLEYS IF CLOUDS STAY THIN LONGER. PREVIOUS DISCUSSION AS OF 250 PM EDT FRIDAY... WEDGE STILL HOLDING ON OVER THE PIEDMONT MAINLY EAST OF LYNCHBURG AS FAR AS CLOUDS GO. TEMPERATURES RANGING WIDELY FROM AROUND 80 IN THE FOOTHILLS OF NORTH CAROLINA...AS WELL AS PORTIONS OF THE ROANOKE AND NEW RIVER VALLEY...TO AROUND 60 OUT TOWARD BUCKINGHAM TO KEYSVILLE. AS WE HEAD THROUGH THIS EVENING...SKIES WILL STAY CLEAR TO PARTLY CLOUDY EXCEPT MOSTLY CLOUDY NORTHEAST OF LYH. MODELS ARE FAVORING SOME TURNING TO THE SOUTHEAST OF THE WINDS OVERNIGHT WITH LOW CLOUDS MOVING WESTWARD AGAIN WELL AFTER MIDNIGHT. SOME PATCHY DRIZZLE POSSIBLE NEAR THE BLUE RIDGE...BUT UPSLOPE COMPONENT AND FORECAST SOUNDINGS DO NOT SUPPORT MUCH. WILL HAVE TO SEE WHERE THE MCS OVER WRN TN THIS AFTERNOON MOVES. MODELS TAKE IT EAST TO NORTHEAST TOWARD ERN KY BY 12Z SATURDAY...WEAKENING IT. SHOULD START TO SEE SHOWERS MOVE INTO THE MOUNTAINS OF WV/FAR SW VA AROUND 8-10AM...WITH LIGHT RAIN POSSIBLE IN THE WEDGE. THINK THE HIGH OVER GREAT LAKES BEHIND SHORTWAVE TONIGHT WILL BRING A STRONGER WEDGE TOWARD OUR AREA SATURDAY...AS EVIDENCED BY THE SFC LI FIELD IN THE MODELS. AS SUCH SHOULD SEE A COOLER DAY OVER MOST OF THE FORECAST AREA WITH HIGHS IN THE 60S. OUTSIDE THE WEDGE LOOKING FOR HIGHS IN THE LOWER 70S. MODELS FAVOR THE AFTERNOON WITH BETTER LOW LVL CONVERGENCE/UPPER DIVERGENCE MOVE ACROSS WV/FAR WRN VA ALONG THE FRONT. THEREFORE KEPT LIKELY TO LOW CATEGORICAL POPS GENERALLY ALONG/WEST OF THE BLUE RIDGE TO HIGH CHANCE EAST. THUNDER THREAT WILL BE CONFINED TO A FAR SW VA TO NW NC MTN LINE IN THE AFTERNOON...AND ISOLATED. NO SEVERE THREAT EXPECT TOMORROW DUE TO WEDGE.
-- End Changed Discussion --
&& .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... AS OF 300 PM EDT FRIDAY... UNSETTLED WEATHER WITH PERIOD OF SHOWERS AND THUNDERSTORMS EXPECTED FOR WEEKEND INTO EARLY NEXT WEEK. ALOFT...AN UPPER TROUGH DEVELOPS IN THE EAST. LOW PRESSURE WITH AN ASSOCIATED WARM FRONT EXTENDING EASTWARD AND COLD FRONT FRONT TRAILING SOUTH WILL MOVES OUT OF THE MISSISSIPPI VALLEY AND SLIDES INTO THE MID ATLANTIC REGION. A WARM FRONT WILL LIFT NORTH ACROSS THE REGION SATURDAY EVENING INTO SATURDAY NIGHT. WIDESPREAD SHOWERS AND THUNDERSTORMS WILL DAMPEN OUR SATURDAY EVENING INTO SUNDAY MORNING. LOW TEMPERATURES SATURDAY NIGHT WILL RANGE FROM THE LOWER 50S IN THE NORTH TO AROUND 60 DEGREES IN THE SOUTH. LOW PRESSURE WILL MOVE TO OUR NORTH SUNDAY INTO SUNDAY NIGHT. THERE ARE INDICATIONS THAT BY SUNDAY AFTERNOON...THE WEDGE WILL BE LOSING ITS GRIP ON THE AREA AND WE WILL ENTER THE UNSTABLE WARM SECTOR AHEAD OF THE COLD FRONT TRAILING THE LOW. DYNAMIC SUPPORT...WITH HEALTHY CAPES AND SOME SHEAR MAY BE ADEQUATE TO CREATE SOME ORGANIZED CONVECTION SUNDAY. THE DAY THREE CONVECTIVE OUTLOOK PLACED OUR AREA UNDER MARGINAL THREAT FOR SEVERE WEATHER. THERE IS ALSO THE POTENTIAL FOR HYDRO ISSUES AS PWATS WILL BE RUNNING WELL OVER ONE INCH AND LOCALLY HEAVY RAIN WILL BE ADDED TO OUR RECENT WET SPELL. TRAINING OF CELLS AND RAIN RATES WILL BE IMPORTANT WITH THESE STORMS WITH ANY FLOODING POTENTIAL. HIGH TEMPERATURES WILL TRICKY WITH CLOUD COVER AND PRECIPITATION. HIGHS ON SUNDAY WILL VARY FROM THE MID 60S IN THE NORTHWEST MOUNTAINS TO THE MID 70S IN THE SOUTH. A COLD FRONT WILL PUSH EAST THROUGH THE AREA SUNDAY NIGHT INTO MONDAY. LOW TEMPERATURES SUNDAY NIGHT WILL GENERALLY BE IN THE LOWER 50S IN THE WEST TO NEAR 60 DEGREES IN THE EAST. BY MONDAY AFTERNOON...THE FRONT WILL BE THROUGH THE REGION WITH GENERALLY IMPROVING CONDITIONS EAST OF THE BLUE RIDGE...BUT SOME LINGERING MOISTURE IN NORTHWEST UPSLOPE FLOW SUPPORTS ISOLATED SHOWERS TO THE WEST. HIGHS ON MONDAY WILL WARM INTO THE UPPER 50S IN THE NORTHWEST TO THE MID 70S IN THE PIEDMONT. HIGH PRESSURE WILL BUILD EAST OUT OF THE OHIO VALLEY INTO OUR AREA MONDAY NIGHT. LOW TEMPERATURES MONDAY NIGHT WILL DROP INTO THE LOWER 40S IN THE WEST TO THE LOWER 50S IN THE EAST. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 300 PM EDT FRIDAY... A WAVY FRONTAL BOUNDARY REMAINS STALLED TO OUR SOUTH TUESDAY INTO WEDNESDAY. AS SEVERAL LOW PRESSURE CENTER RIDE NORTHWARD ALONG THE BOUNDARY EXPECT ROUNDS OF SHOWERS AND A FEW THUNDERSTORMS. THE TIMING OF THE SIGNIFICANT SHORTWAVES AND ASSOCIATED MOISTURE LIFTING NORTHEAST ALONG THE UPPER FLOW REMAINS A CHALLENGE. LOOKS LIKE DEEPER MOISTURE PUSHES FAR ENOUGH NORTH WITH A LOW ON TUESDAY TO PROVIDE US WITH UNSETTLED WEATHER. THIS IS SUPPORTED BY GFS AND ECMWF...DESPITE THE DIFFERENCES IN LOW PRESSURE AND ITS TIMING ALONG WITH THE STRENGTH OF SHORTWAVE DIGGING SOUTH TO OUR WEST IN OHIO VALLEY. HIGH TEMPERATURES TUESDAY WILL VARY FROM THE UPPER 50S IN THE MOUNTAINS TO THE LOWER 70S IN THE PIEDMONT. DECIDED TO KEEP SCATTERED POPS FOR TUESDAY NIGHT. LOW TEMPERATURES TUESDAY NIGHT INTO WEDNESDAY MORNING WILL RANGE FROM THE MID 40S IN THE WEST TO THE LOWER 50S IN THE EAST. A COLD FRONT APPROACHES FROM THE WEST ON WEDNESDAY AND MOVES ACROSS REGION ON WEDNESDAY INTO THURSDAY. WITH UNCERTAINTY...HELD ON TO THE ISOLATED TO SCATTERED SHOWERS WITH THIS BOUNDARY. HIGHS ON WEDNESDAY AND THURSDAY WILL BE IN THE LOWER TO MID 60S IN THE WEST TO THE UPPER 60S TO LOWER 70S IN THE EAST. OVERNIGHT LOW TEMPERATURES WILL DROP TO AROUND 40 IN THE MOUNTAINS TO NEAR 50 IN THE PIEDMONT. DRIER AIR ARRIVE THURSDAY NIGHT INTO FRIDAY ON A WEST TO NORTHWEST FLOW. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
AS OF 200 AM EDT SATURDAY... WEDGE FRONT VERY WELL DEPICTED IN THE LAPS ANALYSIS AND GOES-R PROVING GROUND MVFR/IFR GRAPHIC...NOW NEAR A LWB-ROA-MWK. LOW CLOUDS SPREAD INTO THE REGION VERY QUICKLY BEHIND THE FRONT WITH A SHARP LINE NOTED FROM JUST OVC250 CIGS AT BCB/BLF/LWB TO CIGS AOB 100 ROA/DAN/LYH. MODELS CONTINUE TO MOVE WEDGE FRONT WEST THROUGH THE REST OF THE CWA BY THE 12Z-15Z TIME FRAME. AS THE WEDGE DEEPENS AND MID-LEVEL MOISTURE BEGINS TO SPREAD OVER TOP OF THE SHALLOW WEDGE...WOULD EXPECT -DZ TO EVOLVE...ESPECIALLY IN UPSLOPE AREAS ALONG THE BLUE RIDGE AND ALLEGHANY FRONT. BONAFIDE -RA OR -SHRA SHOULD BEGIN TO SPREAD INTO THE REGION LATER IN THE AFTERNOON AS THE FIRST OF SEVERAL SHORT WAVES EMANATING FROM A PERSISTENT UPPER LOW IN THE SOUTHWEST U.S. EJECT ENE-NE ACROSS THE REGION. THE WEDGE COULD POTENTIALLY BREAK LATE IN THE DAY TOWARD THE KBLF/KMKJ/KTNB AREA...BUT MOST LIKELY THIS WILL NOT OCCUR UNTIL AFT 00Z. CIGS STILL VFR AT KBLF/KLWB/KBCB. GIVEN THAT KROA IS ALREADY LIFR...WOULD EXPECT KBCB TO TREND THAT WAY WITHIN THE NEXT TWO HOURS. SHOULD TAKE UNTIL 08Z-10Z TO REACH KLWB...AND PROBABLY 12Z-13Z FOR KBLF. ONE THE WEDGE EVOLVES THE REGION FROM THE EAST...EXPECT IFR-LIFR CIGS TO HOLD UNTIL 18Z OR SO...THEN BECOME MOSTLY LOW END MVFR. VSBYS SHOULD DROP INTO THE MVFR CATEGORY BY DAYBREAK...EXPECT POSSIBLY KBLF...WHICH SHOULD HOLD ONTO VFR UNTIL LATER IN THE DAY. -DZ SHOULD EVOLVE IN UPSLOPE AREAS NEAR THE BLUE RIDGE/ALLEGHANY FRONT BY EARLY TO MID-MORNING...THEN -RA OR-SHRA BY 18Z AND BEYOND AS NOTED ABOVE. STILL DO NOT FORESEE MUCH WORSE THAN MVFR VSBYS THROUGH THIS TAF VALID PERIOD. WINDS LIGHT/VARIABLE WEST OF THE WEDGE. OTHERWISE...NORTHEAST 6-9KTS EAST OF THE BLUE RIDGE...EAST-SOUTHEAST TO SOUTHEAST 7-10KTS WEST OF THE BLUE RIDGE...WITH LOW END GUSTS DEVELOPING DURING THE MORNING KBLF VICINITY...AND POSSIBLY OTHER LOCATIONS...ESPECIALLY EAST OF THE BLUE RIDGE. MEDIUM TO HIGH CONFIDENCE IN CIGS THROUGH THE TAF VALID PERIOD. MEDIUM CONFIDENCE IN VSBYS THROUGH THE TAF VALID PERIOD. MEDIUM TO HIGH CONFIDENCE IN WIND DIR/SPD THROUGH THE TAF VALID PERIOD. EXTENDED AVIATION DISCUSSION... WIDESPREAD SHOWERS WITH MVFR INCLUDING LOCALLY IFR CONDITIONS PERSIST OVERNIGHT INTO SUNDAY MORNING...LIKELY IMPROVING TO MVFR/VFR BY AFTERNOON AS THE WEDGE ERODES...SHIFTS NORTHEAST AND THE REGION MOVES INTO THE WARM SECTOR. SUNDAY AFTERNOON BRINGS THE POTENTIAL FOR SCATTERED CONVECTION...SOME POSSIBLY STRONG TO SEVERE AS SHORT WAVE ENERGY TRACKS NORTHEAST ACROSS THE REGION IN THE WARM/UNSTABLE AIR MASS. SITUATION APPEARS SOMEWHAT SIMILAR TO WHAT WAS OBSERVED THURSDAY ACROSS THE REGION...BUT PERHAPS MORE ACTIVITY NORTH-WEST OF THE BLUE RIDGE THIS TIME AROUND THAN WHAT WAS OBSERVED SUNDAY. SFC LOW PRESSURE TRACKS NORTHEAST ACROSS GA/SC/NC SUN NIGHT-TUE...LIKELY PROLONGING SUB-VFR CIGS AND POTENTIALLY LEAVING SOME LIGHT PRECIPITATION ACROSS THE REGION...ESPECIALLY EAST OF THE BLUE RIDGE. FOR THE MID AND LATER PART OF NEXT WEEK...A DEEP UPPER LOW IS EXPECTED TO DROP DOWN ACROSS THE GREAT LAKES INTO THE APPALACHIANS AND MID-ATLANTIC REGION...WHICH WILL LEAVE THE REGION WITH VARIABLE CLOUDINESS...SHOWERS...AND PERIODS OF SUB-VFR CONDITIONS.
-- End Changed Discussion --
&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WP NEAR TERM...JH/RAB/WP SHORT TERM...KK LONG TERM...KK AVIATION...DS/RAB/WP

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