-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 231651
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1251 PM EDT THU MAY 23 2013

.SYNOPSIS...
WEAK COLD FRONT EXITS FIRST THING THIS MORNING.  SECOND COLD FRONT
CROSSES THIS EVENING.  UPPER DISTURBANCE CROSSES EARLY FRIDAY
MORNING.  COOL CANADIAN HIGH PRESSURE ARRIVES TO START THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
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WATCHING BUBBLING CU FORMING ACROSS CWA ATTM WITH SHRA FORMING ALONG
A LLVL CONVERGENCE BOUNDARY ALONG OH RVR...WHICH WILL SHIFT E NEXT
SEVERAL HRS. HAVE LKLY POPS DEVELOPING WITH THIS AS IT WORKS INTO
CENTRAL LOWLANDS AND REMAINDER OF CWA EARLY THIS AFTN. MAY SEE SOME
MTN SHRA FORM AHEAD OF THIS ON DIFFERENTIAL HEATING. SHOULD SEE SOME
DEEPER CONVECTION FORM SHORTLY WITH SOME SFC HEATING. LATEST SPC
MESO DISCUSSION HAS PLACED MUCH OF WV ZONES IN POTENTIAL FOR WATCH.
NOT SURE HOW STRONG CONVECTION WILL BE WITH LESS SFC INSTABILITY
THAN PAST FEW DAYS. HOWEVER...FRZ LVLS ARE LWR AND BETTER UPR
SUPPORT WITH APPROACH OF UPR TROF. DEEPER SHEAR A LITTLE BETTER THAN
YESTERDAY AS WELL. DAMAGING WIND PROGS NOT AS IMPRESSIVE AS PAST FEW
DAYS WITH MDLS SHOWING MARGINAL DOWNDRAFT SIGNAL AS SFC TO H7 DELTA
THETA E NOT AT GREAT. OF PERHAPS MORE CONCERN IS WATER. CONCERNED S
PART OF THIS BOUNDARY MAY TRY TO TRAIN SOMEWHAT WITH THE BETTER PUSH
ACROSS SE OH/N LOWLANDS INITIALLY. ALREADY SEEING THIS HAPPENING
NEAR TRI STATE. 1 HR FFG HAS COME DOWN CONSIDERABLY WITH MUCH OF WV
ZONES 1 TO 1.25 INCHES AND N LOWLANDS LESS GETTING DOWN TO .75. THUS
WILL BE HOISTING A FLASH FLOOD WATCH FOR MUCH OF THE LOWLANDS AND N
MTNS. WILL END IT AT 00Z WITH PWS COMING DOWN TO 1 INCH.

MAY SEE A FEW BANDS OF SCT SHRA/TSRA BEHIND THIS UNTIL UPR TROF AXIS
AND COLD FRONT CROSSES THIS EVE. SHOULD SEE SOME POST FRONTAL
SHRA CONT ALONG AND E OF I79 OVERNIGHT WITH LOW STRATUS DEVELOPING
ELSEWHERE.

PREV DISCN...
A COLD FRONT WAS BARELY DISCERNIBLE AT THE SURFACE AS IT MOVED
ACROSS THE FCST AREA OVERNIGHT...STRETCHING FROM EASTERN OHIO
SOUTHWARD ACROSS CENTRAL WV EARLY THIS MORNING.  NONETHELESS...SFC
AND DEEP LAYER MOISTURE DECREASE A BIT FROM WED...SO ATMOSPHERE WILL
NOT BE QUITE AS UNSTABLE AS ON WED.  EVEN SO...WITH 35 KTS LOW-MID
LEVEL FLOW AND WBZ SLOWLY FALLING THROUGH 9KFT COULD STILL LEAD TO
GUSTY WINDS AND SMALL HAIL FROM THUNDERSTORMS THIS AFTERNOON INTO
THIS EVENING.

IT IS A SFC COLD FRONT DRIVEN BY A PAIR OF UPPER LEVEL DISTURBANCES
CROSSING THE AREA THIS AFTERNOON AND EVENING THAT WILL PROVIDE THE
FORCING MECHANISM FOR THE PRECIPITATION.  THE FIRST S/W TROF
ACTIVATES CONVECTION IN THE WESTERN PORTION OF THE FCST AREA BY
EARLY AFTERNOON...AND MOVES ON E ACROSS THE AREA DURING THE
AFTERNOON.  THERE WILL BE A LITTLE FURTHER DRYING TAKING PLACE ONCE
THAT S/W CROSSES.

SECOND S/W TROF FOLLOWS BEHIND SFC COLD FRONT TONIGHT...WITH A
SECOND ROUND OF CONVECTION LIKELY ALONG/AHEAD OF THE FRONT THIS
EVENING.  THE POTENTIAL FOR CONVECTION WILL END WITH THE PASSAGE OF
THE COLD FRONT...BUT ANAFRONT SHOWERS ARE LIKELY TO PERSIST BEHIND
THE FRONT OVERNIGHT...ESPECIALLY IN THE MOUNTAINS AS DAWN APPROACHES
FRI.

RAISED TEMPERATURES A BIT TODAY TO REFLECT THE LATEST GUIDANCE.
LITTLE CHANGE NEEDED ON LOWS TONIGHT BUT FINESSED HOURLY
TEMPERATURES TO REFLECT PASSAGE OF THE COLD FRONT.  HAVE SNOWSHOE
DROPPING TO THE MID 30S BY DAWN SAT HAS H85 TEMPERATURES DROP TOWARD
0C.
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&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
DRIER...COOLER WEATHER TO SET UP ACROSS THE REGION BEHIND THE
EXITING UPPER TROUGH. 850MB TEMPS WILL DROP INTO THE SINGLE DIGITS
FRIDAY NIGHT...SOME OF THE COOLEST AIR WE HAVE SEEN IN A FEW WEEKS.
THIS...ALONG WITH HIGH PRESSURE SETTLING INTO THE REGION...AND A
CLEARING SKY...WILL SEE GOOD RADIATIONAL COOLING FRIDAY NIGHT...AND
FROST/FREEZE HEADLINES MAY BE NEEDED IN MANY
LOCATIONS...PARTICULARLY ACROSS THE NORTH. IN MOUNTAINOUS
COUNTIES...THIS WOULD MAINLY AFFECT SHELTERED VALLEYS...AS NOCTURNAL
LLJ SHOULD PREVENT FROST FORMATION. WILL HIGHLIGHT THE POTENTIAL FOR
FROST/FREEZE IN THE HWO. FLY IN THE OINTMENT HOWEVER WILL BE THE
POTENTIAL FOR MID AND HIGH CLOUDS MOVING INTO THE AREA FROM AN UPPER
DISTURBANCE. THIS MAY PREVENT FROST FORMATION PARTICULARLY ACROSS
EASTERN KY...SOUTHWEST VA...AND SOUTHERN COAL FIELDS OF WV.

COULD SEE A SLIGHT CHANCE FOR SHOWERS SUNDAY MORNING ACROSS SOUTHERN
ZONES...BUT FOR NOW...MUCH OF THE ENERGY AND MOISTURE ASSOCIATED
WITH THIS LOOKS TO REMAIN OFF TO OUR WEST...SO FOR NOW WILL MAINTAIN
A DRY FORECAST SUNDAY MORNING.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
HAVE GENERALLY FOLLOWED WPC THINKING FOR THIS PORTION OF THE
FORECAST.

HIGH PRESSURE WILL BE IN CONTROL OF THE WEATHER ACROSS THE AREA INTO
SUNDAY NIGHT.  HOWEVER...MODELS SUGGEST A FEW WEAK MID-LEVEL
SHORTWAVE MAY MOVE SOUTHEAST.  BELIEVE AREA SHOULD REMAIN DRY...WITH
A FEW MORE CLOUDS BEGINNING SATURDAY NIGHT

A WARM FRONT WILL THEN DEVELOP AND APPROACH THE REGION ON MONDAY. AS
A RESULT...THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY AND
TUESDAY...MAINLY DURING THE AFTERNOON AND EVENING HOURS.

TEMPERATURES ON SATURDAY SHOULD BE NEAR NORMAL WITH DAYTIME HIGHS IN
THE 70S ACROSS THE LOWLANDS...WITH 60S ACROSS THE HIGHER
ELEVATIONS.  AS THE HIGH PUSHES EAST ON SUNDAY...EXPECT TEMPERATURES
TO WARM TO SLIGHTLY ABOVE NORMAL VALUES MONDAY AND TUESDAY.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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PATCHY MVFR/IFR STRATUS MIDDLE OHIO VALLEY FIRST THING THIS MORNING
MAY ALSO IMPACT THE CENTRAL APPALACHIANS...BEFORE MIXING
HIGHER...ALLOWING FOR VFR MID TO LATE MORNING.

ANOTHER FRONT APPROACHING FROM THE W THIS AFTERNOON WILL GIVE RISE
TO CONVECTION AGAIN THIS AFTERNOON AND EVENING...BRINGING MVFR AND
LOCALIZED IFR CONDITIONS...AND POSSIBLY GUSTY WINDS.

LIGHT SW FLOW THIS MORNING WILL BECOME W AND A BIT GUSTY THIS
AFTERNOON...AS A SURFACE TROUGH MOVES THROUGH...AND THEN W TO NW AND
GUSTY TONIGHT...AS A COLD FRONT MOVES THROUGH.  LIGHT SW FLOW ALOFT
THIS MORNING WILL BECOME W LATE TODAY...AND THEN MODERATE NW
OVERNIGHT TONIGHT.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...

FORECAST CONFIDENCE...MEDIUM TO HIGH.

ALTERNATE SCENARIOS: FORMATION...EXTENT AND THEN BREAKING UP OF
STRATUS THIS MORNING COULD VARY.  TIMING AND DEGREE OF FLIGHT
RESTRICTIONS DUE TO CONVECTION THIS AFTERNOON INTO THIS EVENING
COULD VARY.  TIMING AND EXTENT OF MVFR /OR LOWER/ STRATOCU FORMING
LATER TONIGHT COULD ALSO VARY.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
EDT 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
CRW CONSISTENCY  M    H    H    H    H    M    H    H    H    M    M    M
HTS CONSISTENCY  M    H    H    H    M    H    H    H    M    M    M    M
BKW CONSISTENCY  M    M    M    H    H    H    H    M    H    H    M    M
EKN CONSISTENCY  H    M    M    H    H    H    H    H    H    H    M    M
PKB CONSISTENCY  H    H    H    H    H    M    H    H    H    M    M    H
CKB CONSISTENCY  H    M    H    H    H    H    H    H    H    H    M    M

AFTER 18Z FRIDAY...
IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING.
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&&

.RLX WATCHES/WARNINGS/ADVISORIES...
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WV...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR WVZ008>011-
     013>020-025>032-038>040-046-047.
OH...NONE.
KY...NONE.
VA...NONE.
-- End Changed Discussion --

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...TRM/30
SHORT TERM...SL
LONG TERM...ARJ
AVIATION...TRM