-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRNK 141105
AFDRNK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
705 AM EDT TUE MAY 14 2013

.SYNOPSIS...
SURFACE HIGH PRESSURE WILL SHIFT SOUTHEAST OF THE AREA TODAY
ALLOWING A WARMER RETURN SOUTHWEST FLOW TO TAKE SHAPE. AN UPPER
LEVEL RIDGE BUILDS OVER THE REGION TONIGHT INTO WEDNESDAY
RESULTING IN ABOVE NORMAL TEMPERATURES FOR MID WEEK. A FRONTAL
BOUNDARY WILL APPROACH THE AREA ON THURSDAY AND STALL OVER OR NEAR
THE REGION INTO THE START OF THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM EDT TUESDAY...

TRANSITION BETWEEN THE LAST OF THE COLD MORNINGS AND MORE
SUMMERLIKE WEATHER WILL TAKE PLACE OVER THE NEXT 24 HOURS AS HIGH
PRESSURE SLIPS OFF TO THE SE ALLOWING STRONG WARM ADVECTION TO
TAKE SHAPE LATER TODAY. AHEAD OF THIS WARMING...EXPECT TO SEE SOME
MID CLOUDS WITH A FAINT VORT NOW ACROSS THE SRN LAKES DROP SE IN
THE LINGERING NW FLOW ALOFT WHICH MAY MAKE FOR PERIODS OF CLOUD
COVER ESPLCY NORTH/WEST INTO THE AFTERNOON. HOWEVER GIVEN WEAKER
LAPSE RATES PER THE EXODUS OF THE COLD POOL ALOFT AND DRIER LOW
LEVELS...NOT EXPECTING ANY -SHRA SO OVERALL PC NORTH TO MAINLY
SUNNY ELSW TODAY. OTRW WILL CONTINUE TO LET THE GOING FROST/FREEZE
HEADLINES ROLL EARLY ON WITH FROST MORE VALLEY CONFINED OUTSIDE OF
THE FAR NW ATTM. 85H TEMPS LOOK TO REBOUND A GOOD 5-10 DEGREES
FROM CURRENT VALUES THIS AFTERNOON AIDED BY INCREASING LOW LEVEL
SW FLOW. WARMEST AIR ALOFT WILL BE OVER THE WEST WHICH SHOULD EVEN
OUT HIGHS MAINLY IN THE UPPER 60S TO LOWER 70S EXCEPT A CAT OR SO
COOLER AT ELEVATION.

WARM FRONT ASSOCIATED WITH THE CORE OF THE WARMEST 85H AIR
WILL BE LIFTING NE THROUGH THE OHIO VALLEY OVERNIGHT PRECEDED BY
A BAND OF SHRA THAT LOOKS TO SCRAPE BY JUST TO THE NORTH LATE.
SINCE LATEST MODELS HAVE TRENDED FARTHER NORTH WITH ANY LIGHT
PRECIP PER BUILDING HEIGHTS...ADJUSTED POPS DOWN SLIGHTLY...BUT
LEFT IN A LOW POP FROM THE GREENBRIER VALLEY EAST TO NW OF LYH
OVERNIGHT PER LATEST ENSEMBLES. THIS MAY ALSO ALLOW FOR A SHARP
CLOUD GRADIENT WITH MORE CLOUDS I-64 AND POINTS EAST...WITH MAINLY
CLEAR SKIES HEADING SOUTH TOWARD THE VA/NC BORDER. JET ALOFT WILL
REALLY RAMP UP LATE AS +17C 85H TEMPS SURGE IN FROM THE WEST ON
40+ KT WEST/NW WINDS. SOUNDINGS HESITANT TO MIX MUCH OF THAT TO
THE SURFACE IN A WARM ADVECTION PATTERN BUT COULD SEE CLOSE TO
ADVISORY LEVELS HIGHER PEAKS ACROSS THE SW LATE. LOW TEMPS MUCH
MILDER WITH MIXING KEEPING THE RIDGES ABOVE 55-60...WHILE VALLEYS
PERHAPS DECOUPLE ENOUGH FOR A FEW 40S...WITH MAINLY 50-55 ELSW
GIVEN A MAV/MET BLEND.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EDT TUESDAY...

A WEAK SHORTWAVE DROPS SOUTHEAST WEDNESDAY MORNING AND MOVES INTO
THE ATLANTIC OCEAN BY WEDNESDAY AFTERNOON. SUMMER RETURNS WITH A
JUMP IN 850 MB TEMPERATURES TO NEAR 19 DEGREES AND A DOWNSLOPING
WESTERLY SURFACE FLOW. INCREASED WIND SPEEDS IN THE MOUNTAINS
TOWARDS NAM. WENT WITH THE HIGHER ADJMET FOR HIGHS ON WEDNESDAY WITH
VALUES FROM THE UPPER 70S IN THE MOUNTAINS TO THE UPPER 80S IN THE
SOUTHEAST. KEPT IT DRY WEDNESDAY NIGHT...BUT CLOUDS INCREASE ACROSS
THE NORTH ESPECIALLY AFTER MIDNIGHT. LOWS WEDNESDAY NIGHT WILL DROP
INTO MID 50S IN THE WEST TO AROUND 60 DEGREES IN THE EAST.

FRONTAL BOUNDARY DROPS SOUTH ON THURSDAY FROM THE MASON-DIXON LINE
INTO OUR CWA. GFS AND ECMWF ARE QUICKER THAN NAM WITH THE PROGRESS.
TRICKY FORECAST: CONVECTIVE COMPLEXES ALONG THE FRONT MAY MOVE THE
BOUNDARY...ZONAL FLOW DOES NOT SEEM FAVORABLE FOR MUCH OF A SOUTHERN
PUSH. WITH RECENT RAINS...ANOTHER ISSUE TO CONSIDER IS THE POTENTIAL
FOR TRAINING OF THUNDERSTORMS WITH HEAVY RAINS. GFS AND ECMWF
PLACED THE HIGHEST QPF OVER WEST VIRGINIA THURSDAY AFTERNOON INTO
THURSDAY NIGHT. PLACED THE HIGHEST POPS IN THE NORTHWEST. WENT WITH
HIGHS THURSDAY FROM LOWER 70S IN THE MOUNTAIN TO THE MID 80S IN THE
SOUTHEAST. WITH CLOUDS AND SHOWERS THURSDAY NIGHT...PLAYED LOWS FROM
THE MID 50S TO LOWER 60S.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 345 PM EDT MONDAY...

TIMING OF THE SHORT WAVE COMING OUT OF THE SOUTHERN PLAINS SOMEWHAT
SIMILAR TO PAST FEW RUNS BRINGING SOME ENHANCED LIFT INTO THE AREA
THURSDAY NIGHT AND FRIDAY. CHALLENGING TO NARROW DOWN BEST CHANCE OF
PRECIPITATION FRIDAY NIGHT THROUGH SUNDAY NIGHT. LITTLE CHANGE IN THE
AIR MASS AND DAILY HIGHS AND LOWS THROUGH SUNDAY.

NEXT LONG WAVE UPPER TROF DIGGING INTO THE CENTRAL UNITED STATES ON
SUNDAY AND MONDAY. THIS PUSHES A COLD FRONT INTO THE REGION ON
MONDAY. SO HAVE A HIGHER PROBABILITY OF PRECIPITATION FOR MONDAY AND
MONDAY NIGHT.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
AS OF 645 AM EDT TUESDAY...

SEEING LOCALIZED VLIFR CONDITIONS IN FRZG FOG/STRATUS AT KLWB
ATTM THAT SHOULD ERODE QUICKLY WITH THE ONSET OF HEATING. OTRW
MAINLY VFR CONDITIONS LOOK TO CONTINUE DURING THE VALID TAF PERIOD
WITH SOME INCREASE IN MID CLOUDS BY THIS AFTERNOON AS A WEAK
DISTURBANCE SLIDES SE FROM THE GREAT LAKES. THIS MAY MAKE FOR A
PERIOD OF 8-12K FT CIGS ACROSS THE SE WVA SITES BY MIDDAY AND ELSW
THIS AFTERNOON/EVENING. A WARM FRONT APPROACHING FROM THE WEST
OVERNIGHT WILL BRING AN AXIS OF SOMEWHAT DEEPER MOISTURE WITH A
PERIOD OF LOWER STRATO- CU POSSIBLE AROUND KLWB TONIGHT AND EAST
TO KLYH OVERNIGHT. HOWEVER STILL APPEARS MOST WILL STAY VFR INTO
EARLY WEDNESDAY WITH ANY -SHRA ALSO REMAINING JUST NORTH OF THE
TAF SITES. WEST WINDS WILL TURN MORE SW AND BECOME GUSTY OVER THE
HIGHER RIDGES THIS AFTERNOON ESPCLY AROUND KBLF WHERE A FEW GUSTS
TO OVER 20 KTS APPEAR LIKELY THIS AFTERNOON. WINDS NEAR THE
SURFACE WILL DIMINISH THIS EVENING BUT INCREASE ALOFT AS THE SURGE
OF MUCH WARMER AIR ARRIVES. LATEST MODELS SHOW A 35-45 KT JET JUST
OFF THE SURFACE AFTER MIDNIGHT SO INCLUDED A PERIOD OF LLWS AT ALL
SITES EXCLUDING KDAN LATE.

OUR NEXT CHANCE OF ORGANIZED PRECIPITATION AND AREAS OF SUB-VFR
CONDITIONS WILL BE LATE THURSDAY THROUGH SATURDAY WHEN A FRONTAL
SYSTEM MOVES INTO AND THEN STALLS NEAR THE REGION.
-- End Changed Discussion --
&&

.CLIMATE...
-- Changed Discussion --
LOW TEMPERATURES THIS MORNING WILL FLIRT WITH RECORD LOW
TEMPERATURES AT ALL CLIMATE LOCATIONS. THE FOLLOWING ARE THE
CURRENT RECORD LOW TEMPERATURES FOR MAY 14 ALONG WITH THE YEAR OF
THAT RECORD.

MAY 14
ROA...37...1996
LYH...33...1997
RNK...31...1996
DAN...38...2007
BLF...33...1996
-- End Changed Discussion --

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR VAZ019-020-024.
     FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR VAZ023-034-035-
     044>047-058-059.
NC...NONE.
WV...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR WVZ045.
     FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR WVZ043.

&&

$$
SYNOPSIS...DS/JH
NEAR TERM...JH
SHORT TERM...KK
LONG TERM...AMS
AVIATION...DS/JH/KM
CLIMATE...CF/DS