Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 061759
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
159 PM EDT WED MAY 6 2015

.SYNOPSIS...
UPPER LEVEL HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY
THROUGH THURSDAY. A WEAK BACKDOOR COLD FRONT WILL DRIFT
SOUTH INTO THE AREA BY EARLY THURSDAY BEFORE DISSIPATING
THURSDAY NIGHT INTO FRIDAY. DEVELOPING LOW PRESSURE OFF THE
SOUTHEAST COAST SHOULD DRIFT NORTH TO ALONG THE COAST OF THE
CAROLINAS BY THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1250 PM EDT WEDNESDAY...

KFCX 88D RADAR STARTING DETECTING SOME ISOLATED SHOWERS ACROSS
PARTS OF THE AREA AROUND NOON. SINCE THAT TIME...COVERAGE HAS
GROWN ONLY SLIGHTLY WITH THE GREATEST CONCENTRATION ALONG THE
CREST OF THE BLUE RIDGE BETWEEN MEADOWS OF DAN AND FANCY GAP. MAY
CELLS ARE INCREASING IN HEIGHT...AND THEN SPREAD OUT ALOFT UPON
INTERSECTING AN INVERSION ALOFT. AS DAYTIME HEATING INCREASES...A
GREATER NUMBER WILL START TO BE ABLE TO MAKE HEADWAY ABOVE THAT
INVERSION LEVEL. HAVE MADE NO CHANGES TO THE CONFIGURATION OF THE
GREATER COVERAGE FOR THIS AFTERNOON WITH THE BLUE RIDGE...AND
NORTHERN AND WESTERN SECTIONS OF THE REGION HAVING THE GREATEST
POTENTIAL. SOUTHSIDE VIRGINIA INTO NORTH CENTRAL NORTH CAROLINA
WILL HAVE THE LEAST CHANCE. HAVE INCREASED VALUES FOR THE HIGH
TEMPERATURE FORECAST FOR SEVERAL AREAS WITH THE MOUNTAINS BY TWO
TO THREE DEGREES BASED UPON CURRENT OBSERVATIONS AND EXPECTED
TRENDS THE REMAINDER OF THE AFTERNOON.

AS OF 940 AM EDT WEDNESDAY...

NO MAJOR CHANGES WERE MADE TO THE OVERALL FORECAST PICTURE FOR
TODAY. HOWEVER...ONE ADJUSTMENT MADE WAS THE TREND OF THE CLOUD
COVER THE REMAINDER OF THE MORNING INTO EARLY AFTERNOON HOURS. A
SWATH OF ALTO-CU ACROSS THE NORTHERN HALF OF THE AREA HAS
PERSISTED ALL MORNING. WHILE WE DO EXPECT THIS CLOUD DECK TO MIX
OUT BY NOONTIME AS WE TRANSITION TO SURFACE BASED HEATING CUMULUS
CLOUDS...UNTIL THAT HAPPENS...THE FORECAST WARRANTS A GREATER
AMOUNT OF CLOUD COVER FORECAST IN THE NORTH THROUGH AT LEAST
MIDDAY.

AS OF 223 AM EDT WEDNESDAY...

UPPER LEVEL RIDGING WILL REMAIN IN PLACE ACROSS THE REGION INTO TONIGHT
AS A WEAK BACKDOOR COLD FRONT EDGES IN FROM THE NORTH/NE BY SUNRISE ON
THURSDAY. BOOST IN MOISTURE AHEAD OF THE FRONT WITH FORECAST PWATS
INCREASING TO AROUND 1.5 INCHES COMBINED WITH HIGHER 85H THETA-E OVER
THE MOUNTAINS SHOULD LEAD TO A BIT MORE CONVECTIVE COVERAGE THIS
AFTERNOON/EVENING. HOWEVER WITH RIDGING OVERHEAD AND MODEST CAPE VALUES
OF ONLY 500-1K J/KG MAINLY FAR WEST/NORTH...DEGREE OF SHRA/TSRA
COVERAGE REMAINS IFFY ESPCLY IN REGARDS TO ORGANIZATION UNDER SUCH WEAK
FLOW AND MAINLY LOW LEVEL FORCING. MOST MODEL SOLUTIONS DO DEVELOP
SCATTERED AFTERNOON COVERAGE...STARTING OVER THE FAR NW AROUND MIDDAY
AND THEN ALONG THE BLUE RIDGE PER WEAK SE FLOW CONVERGENCE. LATEST
HRRR/SPC WRF/GFS ARE THE WETTEST AND SPILL CONVECTION FARTHER EAST...
WHILE THE NAM/HIRES/EC SOLUTIONS REMAIN MORE SCATTERED NATURE AND
FARTHER NORTH WITH MORE ORGANIZED COVERAGE. THINK COULD BE A PERIOD OF
LIKELY COVERAGE NW AND RIDGES WHERE MORE LOCALIZED DIFFERENTIAL HEATING
GIVES A BOOST BUT FOR NOW HOLDING OFF...AND ONLY BOOSTING POPS TO
HIGHER CHANCE MAINLY NORTH-WEST. ISOLATED STRONGER TSRA POSSIBLE BUT
MORE OF AN ISOLATED HEAVY RAIN THREAT GIVEN LIGHT STEERING AND LIKELY
OUTFLOW DRIVEN REDEVELOPMENT. FAR SOUTH/SE LOCATIONS MAY END UP DRY FOR
THE MOST PART SO TRIMMED POPS THERE GIVEN LACK OF LIFT. OTRW PARTLY
SUNNY AND STILL QUITE WARM AHEAD OF THE FRONT WITH HIGHS MOSTLY UPPER
70S TO MID 80S.

COVERAGE MAY LINGER MOUNTAINS WITH PERHAPS SOME OF THIS SPILLING EAST
OF THE BLUE RIDGE EARLY THIS EVENING IF A CLUSTER ORGANIZES BEFORE
FADING WITH LOSS OF HEATING BEFORE MIDNIGHT. THEREFORE KEPT IN SOME LOW
POPS MAINLY NORTH HALF THIS EVENING BEFORE TURNING PC WITH PATCHY FOG
OVERNIGHT. LOWS MOSTLY IN THE MUGGY 50S WITH SOME SPOTS ALONG THE
RIDGES LIKELY STAYING ABOVE 60 OVERNIGHT.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 315 AM EDT WEDNESDAY...

AN AREA OF WEAK HIGH PRESSURE WILL REMAIN OVER THE MID ATLANTIC
THROUGH THE DAY THURSDAY. THIS SHALLOW WEDGE MAY LINGER OVER THE
AREA THURSDAY NIGHT WITH THE HELP OF A SUB-TROPICAL LOW WOBBLING OFF
THE SOUTHEAST COAST. EASTERLY FLOW FROM BOTH SYSTEMS WILL BRING AN
INCREASE IN MOISTURE INTO THE AREA EACH PERIOD. THE MORE MOISTURE
THE BETTER CHANCE FOR SHOWERS. HOWEVER...WE WILL KEEP POPS LOW (20-
30 PERCENT) THROUGH THE FORECAST PERIOD FOR A COUPLE OF REASONS. THE
FIRST REASON IS THAT THE EASTERN PORTION OF FORECAST AREA WILL BE
UNDER A SUBSIDENCE REGION OF THE SOUTHEAST COASTAL LOW THURSDAY AND
THURSDAY NIGHT. THE MOUNTAINS WILL BE JUST OUTSIDE OF THIS REGION
AND COULD SEE HIT AND MISS SHOWERS THURSDAY AFTERNOON...FADING IN
THE EVENING. THE SECOND REASON TO KEEP POPS LOW IS CONFIDENCE. WITH
A STUBBORN UPPER LEVEL RIDGE OVER THE MID ATLANTIC...THE COASTAL
LOW`S FORECAST TRACK IS UNCERTAIN AND COULD WOBBLE AROUND THE
CAROLINAS OVER THE WEEKEND. THE THIRD REASON IS TIMING OF SHOWERS.
IF THIS LOW TRACKS INLAND...TIMING FEEDER-BANDS TRACKING ACROSS THE
AREA WILL BE DIFFICULT. THE NAM BRING THE FIRST BAND ACROSS
SOUTHSIDE LATE THURSDAY NIGHT...WHILE THE GFS TIMING IS LATE IN THE
DAY FRIDAY. DRY AIR ENTRAINING INTO THE LOW FRIDAY AND FRIDAY NIGHT
COULD ALSO KEEP SHOWERS CLOSER TO THE CENTER AND NOT ENTER THE
FORECAST AREA AT ALL.

TEMPERATURES WILL ALSO BE TRICKY THROUGH THE PERIOD. WITH WEAK
STEERING FLOW AND A SHALLOW WEDGE...TEMPERATURES WILL WARM TO NEAR
80F ACROSS THE AREA THURSDAY. ON FRIDAY...MORE CLOUDS AND CONTINUED
EASTERLY FLOW WILL KNOCK DOWN DAYTIME TEMPERATURES INTO THE MID TO
UPPER 70S. DEPENDING ON SHOWER ACTIVITY...TEMPERATURES COULD BE
COOLER. DESPITE SHOWERS OR NOT...DEW POINTS WILL INCREASE THROUGH
THE PERIOD SO PREPARE YOURSELF FOR MUGGY SUMMER-LIKE CONDITIONS.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 345 PM EDT TUESDAY...

UPPER LEVEL RIDGING ACROSS THE SOUTHEAST AND MID ATLANTIC IS
EXPECTED TO MOVE LITTLE THROUGH THE WEEKEND INTO THE BEGINNING OF
THE NEXT WORKWEEK. AS SUCH...EXPECT THE TREND OF SUMMERLIKE WEATHER
TO CONTINUE. THE MAIN CONCERN THROUGH THE PERIOD REMAINS THE TRACK
OF A LOW APPROACHING THE CAROLINA COAST...POTENTIALLY PUSHING A
PLUME OF TROPICAL MOISTURE ACROSS OUR AREA WHICH DAYTIME-HEATING
DRIVEN SHOWERS AND THUNDERSTORMS MAY FEED OFF OF. THE THREAT FOR ANY
SEVERE THUNDERSTORMS REMAIN ISOLATED DURING THIS TIME...HOWEVER
ABUNDANT MOISTURE AND LIGHT UPPER LEVEL WINDS INDICATE A THREAT FOR
SLOW MOVING CELLS CAPABLE OF PRODUCING LOCALLY HEAVY RAIN. SHOULD
THE LOW REMAIN OFFSHORE...FURTHER AWAY FROM OUR AREA...THE HEAVY
RAIN THREAT WILL BE REDUCED. WEATHER FORECAST MODELS ARE STILL
TRYING TO GET A HANDLE ON WHAT TRACK THE LOW WILL TAKE...SO THE
SITUATION WILL BE MONITORED CLOSELY OVER THE NEXT FEW DAYS.

RAINFALL AND INCREASED CLOUD COVER ALSO HAS THE POTENTIAL TO AFFECT
DAYTIME TEMPERATURES...AND THEREFORE AFTERNOON HIGHS ALSO REMAIN
SOMEWHAT IN QUESTION. WITH THIS AFTERNOON`S FORECAST PACKAGE...HAVE
AFTERNOON HIGHS RANGING FROM THE MID/UPPER 70S WEST TO THE LOW 80S
EAST EACH DAY...WHILE OVERNIGHT LOWS WILL BE IN THE UPPER 50S AND
LOW 60S. INCREASED RAINFALL HAS THE POTENTIAL TO KEEP AFTERNOON
HIGHS A FEW DEGREES LOWER ON SATURDAY HOWEVER.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 135 PM EDT TUESDAY...

FORECAST CONFIDENCE IS MODERATE TO HIGH THROUGH MIDDAY THURSDAY.

ISOLATED TO SCATTERED SHOWERS ARE DEVELOPING IN AREAS ALONG AND
WEST OF THE BLUE RIDGE...IN CONJUNCTION WITH HEATING OF THE DAY
AND THE APPORACH A BACKDOOR COLD FRONT. CIGS ARE MAINLY VFR ACROSS
THE AREA. BRIEF...LOCALIZED SUB-VFR CONDITIONS WILL BE POSSIBLE
UNDER THE HEAVIER SHOWERS/STORMS. THE SHOWERS AND STORMS WILL
DISSIPATE AFTER SUNSET.

OVERNIGHT...THE BACKDOOR COLD FRONT WILL MAKE PROGRESS INTO THE
REGION AND BRING LOW LEVEL WINDS AROUND TO THE NE-E. SOME GUIDANCE
IS ALLOWING FOR THE POTENTIAL FOR SOME MVFR CIGS TO ARRIVE IN
MAINLY NORTH AND EASTERN PARTS OF THE AREA. PATCHY LIGHT FOG WILL
ALSO BE POSSIBLE...ESPECIALLY IN AREAS THAT RECEIVED RAIN
TODAY...AND ALSO IN SOME OF THE MOUNTAIN AND RIVER VALLEYS.

ON THURSDAY...ISOLATED TO SCATTERED SHOWER AND STORM DEVELOPMENT
WILL AGAIN BE POSSIBLE ALONG THE LEADING EDGE OF THE BACKDOOR
FRONT AND DURING THE PEAK HEATING OF THE DAY. THIS WOULD PLACE THE
GREATEST COVERAGE ACROSS SOUTHEAST WEST VIRGINIA...SOUTH INTO THE
NORTHERN MOUNTAINS OF NORTH CAROLINA.

FORECAST CONFIDENCE THURSDAY AFTERNOON THROUGH SATURDAY IS
MODERATE.

AFTERNOON AND EARLY EVENING SHOWERS AND STORMS WILL BE COMMON
THROUGH SATURDAY...BUT THE TREND FOR THE AXIS OF BEST COVERAGE
WILL SLOWLY WORK ITS WAY WEST OF THE REGION. CONDITIONS WILL
MAINLY BE VFR EXCEPT FOR SOME LATE NIGHT AND EARLY MORNING PATCHY
LIGHT FOG AND SUB-VERSION PATCHY MVFR CLOUDS.

FORECAST CONFIDENCE SATURDAY NIGHT INTO MONDAY IS LOW.

MODEL GUIDANCE IS STILL SHOWING A DECENT AMOUNT OF VARIABILITY IN
THEIR SOLUTIONS REGARDING THE ROUTE A SLOW MOVING UPPER LOW ALONG
THE COAST OF THE CAROLINAS WILL TAKE LATE THIS WEEKEND INTO EARLY
NEXT WEEK. ACCORDINGLY...THE TIMING AND APPROACH OF A COLD FRONT
FROM THE MID-MISSISSIPPI VALLEY WILL BE IMPACTED BY THE POSITION
OF THE LOW AS WELL. A CONSENSUS FORECAST PLACES INCREASING
COVERAGE OF SHOWERS AND STORMS OVER THE AREA DURING THIS PERIOD
WITH A MIX OF MVFR AND VFR CONDITIONS WITH THE BEST COVERAGE ON
MONDAY.



&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...DS/JH
NEAR TERM...DS/JH
SHORT TERM...RCS
LONG TERM...NF
AVIATION...DS


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