461
FXUS61 KRNK 191456
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1056 AM EDT SUN MAY 19 2013
SYNOPSIS
UPPER LEVEL ENERGY WILL MOVE SLOWLY ACROSS THE REGION TODAY AND
TONIGHT...THEN OFF THE MID ATLANTIC COAST BY TUESDAY. A LARGE LOW
PRESSURE SYSTEM WILL TRACK FROM THE CENTRAL PLAINS ON MONDAY
INTO THE GREAT LAKES BY THURSDAY. THIS SYSTEM WILL PUSH A COLD
FRONT THROUGH THE AREA ON FRIDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 1015 AM EDT SUNDAY...
SHOWER ACTIVITY IS LIGHT AND SPOTTY THIS MORNING AS INDICATED BY
RADAR...AND SATELLITE IMAGERY INDICATES CLOUD COVER BREAKING UP
ACROSS PORTIONS OF SOUTHEAST WEST VIRGINIA AND THE MOUNTAIN
EMPIRE. WITH DRIER AIR WORKING INTO THE MID AND UPPER LEVELS OF
THE ATMOSPHERE THROUGH THE DAY...EXPECT MORE HEATING COMPARED TO
YESTERDAY WHICH WILL RESULT IN SHOWERS AND THUNDERSTORMS
DEVELOPING BY AROUND NOON ACROSS ALL PARTS OF THE FORECAST AREA.
THE MAIN CONCERN WILL BE FOR THE POTENTIAL OF LOCALLY HEAVY RAIN
ACROSS THE AREA THIS AFTERNOON AND EVENING...AS INDICATED BY
CONVERGENCE ASSOCIATED WITH A STATIONARY FRONT ACROSS CENTRAL
VIRGINIA AND ABUNDANT MOISTURE IN THE LOW LEVELS...AND LIGHT
WINDS ALOFT RESULTING IN SLOW STORM MOVEMENT. THAT STATED...
WHILE THERE MAY BE SPOTS WITH HEAVY RAIN...OVERALL AMOUNTS
EXPECTED BY MONDAY MORNING ARE NOT EXCESSIVE...LESS THAN 2 INCHES
ON THE WPC DAY ONE FORECAST.
TONIGHT...SURFACE AND LOW LEVEL WINDS GRADUALLY TURN FROM THE
SOUTHEAST TO THE SOUTH THEN SOUTHWEST. 850 MB WINDS COME AROUND TO
THE WEST IN THE MOUNTAINS BY MORNING WITH SOME WARM AIR
ADVECTION. BUT MUCH OF THE NIGHT...EAST OF THE BLUE RIDGE WILL
STILL HAVE WEAK UPSLOPE SO ADDED PATCHY FOG. NO BIG CHANGES FROM
GUIDANCE FOR OVERNIGHT LOWS.
SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/
AS OF 346 AM EDT SATURDAY...
MONDAY IS QUITE WARM AND HUMID WITH THE EASTERLY COMPONENT ERASED
AND THE STATIONARY FRONT PUSHED BACK NORTH. SOME SUNSHINE BREAKING
OUT WILL PROBABLY LEAD TO SCATTERED STORMS ACROSS THE SOUTHERN BLUE
RIDGE MONDAY AFTERNOON. A GOOD CHUNK OF DRIER AIR ARRIVES AT H7
ACROSS SE WEST VA LATE DAY...POSSIBLY SHUTTING STORMS DOWN THERE.
LATE MONDAY AFTERNOON AND MONDAY NIGHT THE FOCUS WILL PROBABLY SHIFT
TO THE VA/NC PIEDMONT WITH SHOWERS AND STORMS POSSIBLY LASTING FOR A
GOOD PORTION OF THE NIGHT. EVEN MORE WIDESPREAD DRY AIR ALOFT ON
TUESDAY...SO PERHAPS THIS IS THE DRIEST DAY. SOME WEAK UPPER AIR
DISTURBANCES MAY ROTATE AROUND THE WESTERN PERIPHERY OF THE ATLANTIC
SURFACE HIGH...ADDING A LITTLE MORE MOISTURE ALOFT AND PROVIDING
SOME LIFT FOR MORE STORM COVERAGE ON WEDNESDAY.
LONG TERM /THURSDAY THROUGH SATURDAY/
AS OF 1215 PM EDT SATURDAY...
THE NEXT SYSTEM THAT WILL IMPACT OUR REGION LATE WEDNESDAY NIGHT
THROUGH THE START OF THE NEXT WEEKEND. ALTHOUGH...WE CANNOT RULE
OUT ISOLATED TO SCATTERED SHOWERS OR EVEN A FEW STORMS DURING THE
TUESDAY NIGHT INTO WEDNESDAY TIME PERIOD. LOW LEVEL FLOW WILL
ALREADY BRINING ADDITIONAL MOISTURE INTO THE REGION FROM SOUTHWEST
IN ADVANCE OF THE NEXT SYSTEM.
OUR NEXT SYSTEM IS CURRENTLY PROGGED TO BE ASSOCIATED WITH AN UPPER
LEVEL CLOSED LOW THAT WILL PINWHEEL AROUND THE UPPER MISSISSIPPI
VALLEY THROUGH AT LEAST FRIDAY. PLENTY OF GULF OF MEXICO MOISTURE
WILL BE ADVECTED NORTHWARD INTO THE REGION IN ADVANCE OF THIS
SYSTEM. ALSO...PERIODIC BITS OF ENERGY WILL SPIRAL EASTWARD FROM
THE MAIN SYSTEM AND COMBINE WITH DAYTIME HEATING TO PROMOTE A
GENEROUS COVERAGE OF SHOWERS AND STORMS OVER THE REGION THROUGH AT
LEAST THE START OF THURSDAY NIGHT. MODEL GUIDANCE VARIES AS TO THE
SPEED OF THE ASSOCIATED SURFACE COLD FRONT. HPC GUIDANCE IS
FAVORING A SLOWER SOLUTION THAT IS MORE IN LINE WITH THE
OPERATIONAL 12Z/8AM GFS THAT DOESN/T HAVE THE FRONT EXITING THE
AREA UNTIL FRIDAY EVENING. HAVE FOLLOWED CLOSELY WITH THIS
SCENARIO.
TEMPERATURES THROUGH THIS PERIOD OF THE FORECAST WILL TREND
COOLER...WITH HIGHS ON SATURDAY EXPECTED TO BE IN THE LOW TO MID 60S
ACROSS THE MOUNTAINS WITH MID 60S TO NEAR 70 ACROSS THE PIEDMONT.
AVIATION /14Z SUNDAY THROUGH THURSDAY/
AS OF 155 AM EDT SUNDAY...
EXPECT GRADUAL IMPROVEMENT OF CEILINGS THIS MORNING FROM IFR/MVFR
TO MVFR/VFR...ALTHOUGH NOT CONFIDENT WITH TIMING. PRECIPITATION
HAS DECREASED IN COVERAGE. THIS BREAK IN THE RAIN WILL CONTINUE
THROUGH MID MORNING.
AS SHORT WAVE OVER THE TENNESSEE VALLEY SLOWLY APPROACHES THE
FORECAST AREA...HIGH CONFIDENCE OF MORE SHOWERS THIS AFTERNOON.
THE MOST LIKELY SITES FOR THUNDERSTORMS WILL BE DAN AND BLF BUT
THIS WILL BE LARGELY DEPENDENT IN GETTING SOME HEATING DURING THE
DAY. FLOW REMAINS SOUTHEAST TONIGHT SO EXPECT CEILINGS TO LOWER
BUT STAY IN THE MVFR TO IFR RANGE.
CONDITIONS LOOK TO IMPROVE MONDAY AS THE UPPER TROUGH MOVES TO
THE MID ATLANTIC COAST. EXPECT TUESDAY TO BE THE BEST BET FOR
DECENT FLYING CONDITIONS ALTHOUGH AN ISOLATED AFTERNOON AIRMASS
SHOWER OR THUNDERSTORM IS STILL POSSIBLE. NEXT FRONT APPROACHES ON
WEDNESDAY WITH MORE SHOWERS/STORMS DEVELOPING. THIS FRONT DOES NOT
APPEAR TO BE IN A BIG HURRY AND LOOKS TO BRING MVFR
CONDITIONS...POSSIBLY IFR AT NIGHT...TO TAF SITES FOR THE LATTER
HALF OF THE WEEK.
RNK WATCHES/WARNINGS/ADVISORIES
VA...NONE.
NC...NONE.
WV...NONE.
SYNOPSIS...AMS
NEAR TERM...AMS/NF
SHORT TERM...KM
LONG TERM...DS
AVIATION...AMS
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