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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 232245
AFDRLX

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

.SYNOPSIS...
SECOND COLD FRONT CROSSES THIS EVENING. UPPER DISTURBANCE CROSSES
EARLY SATURDAY AND SUNDAY NIGHT. COOL CANADIAN HIGH PRESSURE
ARRIVES TO START THE WEEKEND.

&&

.NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --
615 PM UPDATE...CANCELLED FLASH FLOOD WATCH AS CONVECTION IS
DECREASING WITH LOSS OF HEATING. ADDITIONAL LIGHT SHOWERS WILL CROSS
THE AREA OVERNIGHT WITH A TRUE BLUE COLD FRONT...BUT WILL NOT CAUSE
A CONCERN FOR FLOODING.

PREVIOUS DISCUSSION...
SHRA/TSRA ALONG A LLVL CONVERGENCE BOUNDARY IN C WV...WHICH WILL
SHIFT E NEXT SEVERAL HRS. HAVE LKLY POPS WITH THIS AS IT WORKS
INTO REMAINDER OF CWA LATER 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. ISSUED FLASH FLOOD WATCH EARLIER 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.

CAA COMMENCES IN EARNEST LATE WITH H85 TMPS BOTTOMING OUT CLOSE TO
0Z. NOT OUT OF THE QUESTION FOR SNOWSHOE TO SEE SOME WET
SNOWFLAKES ARND DAWN. AS TROF AXIS PULLS E COLUMN COLUMN DRIES OUT
CONSIDERABLY AND WILL ALLOW MORNING STRATUS TO MIX OUT IN MORNING
WITH JUST SOME FLAT CU IN AFTN HEATING. WENT CLOSER TO MET FOR
HIGHS WITH LWR 60S AND SOME 40S IN HIGHEST ELEVATIONS...DEFINITELY
NOT INDICATIVE OF LATE MAY.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES FRIDAY NIGHT TO
PROVIDE DRY AND COLDER AIR UNDER NORTHERLY FLOW. DRY WEATHER
CONTINUES THROUGH THE WEEKEND AS CALM FLOW UNDER HIGH PRESSURE
SYSTEM EXTENDS INTO OH VALLEYS AND WV.

CLEAR SKIES...CALM FLOW AND SOME COLD ADVECTION AT H850 WILL BRING
TEMPERATURES AT OR BELOW FREEZING POSING A WIDESPREAD THREAT FOR
GROWING VEGETATION TO FROST OR FREEZE INTO EARLY SATURDAY MORNING.

KEPT POTENTIAL FOR FROST/FREEZE IN THE HWO.

HIGH PRESSURE MOVES ACROSS THE AREA INTO TUESDAY TO PROVIDE MOSTLY
DRY WEATHER. SOME CLOUDS WILL BE COMMON...AND A SHORTWAVE AT H5 BRINGS
VORT MAXES SATURDAY NIGHT.

WENT CLOSER TO SIMILAR MET/MAV NUMBERS FOR TEMPERATURES THROUGH
THE PERIOD.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE REMAINS IN CONTROL TO AT LEAST EARLY WEDNESDAY
PROVIDING DRY WEATHER WITH A SLOW WARMING TREND.

ANOTHER MID LEVEL SHORTWAVE WILL MOVE THROUGH SUNDAY NIGHT FOR LOW
CHANCE FOR RAIN SHOWERS INTO MONDAY.

A WARM FRONT DEVELOPS AS IT APPROACHES 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.

FOR SATURDAY...TEMPERATURES SHOULD BE NEAR NORMAL WITH DAYTIME
HIGHS IN THE 70S ACROSS LOWLANDS...WITH 60S ACROSS THE HIGHER
ELEVATIONS. TEMPERATURES WILL CONTINUE TO CLIMB IN THE UPPER TO
MID 80S BY THE END OF THE WEEK. LOWS WILL RANGING IN THE 60S.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
LLVL CONVERGENCE BOUNDARY SERVING AS FOCUS FOR SHRA/TSRA THIS AFTN
WHICH WILL SHIFT GREATEST COVERAGE INTO MTNS BY 21Z...BRINGING MVFR AND
LOCALIZED IFR CONDITIONS...AND POSSIBLY GUSTY WINDS. HAVE SOME
TEMPO GROUPS TO TRY AND COVER WITH VCSH AND VCTS IN THE
PREDOMINATE GROUP. MAY SEE ANOTHER BAND OF SHRA AND ISO THUNDER
WITH ARRIVAL OF UPR TROF AND COLD FRONT AFTER 00Z.

EXPECT SOME POST FRONTAL SHRA TO LINGER OVERNIGHT...MAINLY IN
MTNS. MVFR STRATUS TO DEVELOP AS WELL AT ALL TAF SITES WITH
PERHAPS SOME IFR BASES IN MTNS. THIS WILL SCT OUT FROM W TO E IN
THE MORNING WITH JUST SOME SCT FLAT CU FOR AFTN.

W FLOW 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 WILL BECOME W LATE
TODAY...AND THEN MODERATE NW OVERNIGHT TONIGHT.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...

FORECAST CONFIDENCE...MEDIUM TO HIGH.

ALTERNATE SCENARIOS: FORMATION...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       20   21   22   23   00   01   02   03   04   05   06   07
EDT 1HRLY       16   17   18   19   20   21   22   23   00   01   02   03
CRW CONSISTENCY  H    H    H    H    H    M    M    H    H    M    M    M
HTS CONSISTENCY  H    H    H    H    H    H    M    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    M    M    H    L    M    M
EKN CONSISTENCY  H    H    H    H    H    H    H    H    L    L    M    M
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    M    M    M    M    M

AFTER 00Z SATURDAY...
IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING.
-- End Changed Discussion --

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
-- End Changed Discussion --

&&

$$
SYNOPSIS...ARJ/30
NEAR TERM...JMV/30
SHORT TERM...ARJ
LONG TERM...ARJ
AVIATION...30