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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 191823
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
223 PM 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 MONDAY/...
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.

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.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 150 PM EDT SUNDAY...

SCATTERED AFTERNOON AND EVENING THUNDERSTORMS WILL TAPER OFF MONDAY
NIGHT. THE GREATEST CHANCE OF SHOWERS AND THUNDERSTORMS WILL OCCUR
IN THE PIEDMONT. AFTER MIDNIGHT CUT BACK POPS TO SLIGHT CHANCE IN
THE EAST. WITH A SOUTHWEST FLOW...IT WILL BE MILD MONDAY NIGHT WITH
READINGS FROM THE MID 50S IN THE MOUNTAINS TO THE LOWER 60S IN THE
SOUTHEAST.

MID-LVL RIDGE BUILDS OVERHEAD TUESDAY AFTER THE SHORTWAVE TROUGH
EXITS THE REGION. WITH DRIER AIR ALOFT AND ABSENCE OF ORGANIZED LIFT
TRANSLATES TO LESS COVERAGE OF CONVECTION. PLAYED THE HIGHEST POPS
ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS. HIGHS TUESDAY WILL RANGE
FROM THE UPPER 70S IN THE MOUNTAINS TO THE UPPER 80S IN THE
PIEDMONT. WARM AND MUGGY TUESDAY NIGHT EXPECTED WITH LOWS IN THE
60S.

WEAK UPPER AIR DISTURBANCES ROTATING AROUND THE WESTERN PERIPHERY OF
THE ATLANTIC SURFACE HIGH...WILL PROVIDE SOME LIFT FOR SHOWERS AND
THUNDERSTORMS ON WEDNESDAY. ISOLATED TO SCATTERED CONVECTION WILL
LINGER INTO WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 150 PM EDT SUNDAY...

AN UPPER LEVEL CLOSED LOW WILL SPIN AROUND THE UPPER MISSISSIPPI
VALLEY THROUGH AT LEAST FRIDAY. IN ADVANCE OF THIS SYSTEM...PLENTY
OF MOISTURE WILL ADVECT NORTHWARD INTO OUR REGION.

PIECES OF ENERGY WILL SPIRAL EASTWARD FROM THE MAIN SYSTEM AND
COMBINE WITH DAYTIME HEATING TO CREATE SHOWERS AND THUNDERSTORMS.
HPC CONTINUES TO FAVOR A SLOWER TIMING OF THE COLD FRONT. THE FRONT
IS EXPECTED TO EXIT OUR AREA FRIDAY EVENING INTO FRIDAY NIGHT. ECMWF
REMAINS FASTER THAN GFS WITH TIMING OF COLD FRONT. DO NOT BELIEVE
THE SFC LOW THAT DEVELOPS OFF THE SOUTHEAST ON GFS. HIGH PRESSURE
WILL RIDGE SOUTH FROM THE GREAT LAKES ON SATURDAY AND SLIDE EAST ON
SUNDAY.

COOLING TREND EXPECT FOR FRIDAY AND SATURDAY. HIGHS ON FRIDAY
WILL RANGE FROM AROUND 70 DEGREES IN THE WEST TO NEAR 80 DEGREES
IN THE SOUTHEAST. SATURDAY HIGHS ONLY REACH THE MID 60S ACROSS
THE MOUNTAINS TO THE LOWER 70S ACROSS THE PIEDMONT. HIGHS FOR
SUNDAY WILL WARM A COUPLE OF DEGREES FROM THE MID 60S IN THE WEST
TO THE MID 70S IN THE EAST.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 155 AM EDT SUNDAY...

RADAR INDICATING SHOWERS DEVELOPING WITH AFTERNOON HEATING
AREAWIDE. CLOUD COVER ACROSS THE MOUNTAINS HAS BEEN LESS
WIDESPREAD AS DRIER AIR BUILDS IN FROM THE WEST...WHICH HAS LEAD
TO GREATER SURFACE HEATING. THEREFORE...WILL KEEPING AN EYE ON
STRONGER SHOWER ACTIVITY DEVELOPING IN THIS MORE UNSTABLE
ENVIRONMENT...WITH SHOWERS INTENSIFYING INTO THUNDERSTORMS DURING
THE AFTERNOON. THAT STATED... IF THE CIRRUS SHIELD FROM CONVECTION
OVER TENNESSEE CAN BUILD INTO THE AREA...EXPECT THAT WILL HAVE A
STABILIZING EFFECT AND LIMIT ADDITIONAL THUNDERSTORM DEVELOPMENT.
BUT CIRRUS DOES NOT LOOK LIKE IT IS IN A HURRY TO ENTER OUR AREA.

CEILINGS CONTINUE TO IMPROVE THIS AFTERNOON...HOWEVER WILL REMAIN
MVFR...POSSIBLY LOW END VFR AT BEST. SHOWER AND THUNDERSTORM
ACTIVITY WILL MOVE SLOWLY DUE TO LIGHT UPPER LEVEL WINDS...AND
HEAVY RAIN ASSOCIATED WITH THIS ACTIVITY WILL RESULT IN EXTENDED
PERIODS OF IFR VISIBILITIES...LESS THAN 1SM AT TIMES. GREATEST
RAINFALL COVERAGE WILL SHIFT EAST OF THE MOUNTAINS DURING EVENING
AS A SHORTWAVE PUSHES ACROSS THE AREA...WITH INTENSITY WANING BY
MIDNIGHT AS HEATING ENDS. LIGHT WINDS AND MOIST CONDITIONS WILL
RESULT IN ANOTHER ROUND OF PATCHY FOG OVERNIGHT...AS WELL AS
STRATUS DECKS BELOW 1KFT.

WITH AN UPPER LEVEL TROUGH SHIFTING EAST OVERNIGHT...EXPECT LOWER
COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY FOR MONDAY...WITH
BETTER COVERAGE IN THE EAST AS UPPER LEVEL RIDGING STARTS TO BUILD
ACROSS THE MOUNTAINS. 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.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...AMS
NEAR TERM...AMS/NF
SHORT TERM...KK
LONG TERM...KK
AVIATION...AMS/NF