-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 171952
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
343 PM EDT FRI MAY 17 2013

.SYNOPSIS...
STATIONARY FRONT REMAINS OVER THE AREA INTO THE WEEKEND.
UPPER LEVEL SHORTWAVE PASSES SOUTH. NEW FRONT APPROACHES WEDNESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
LCL AND HI RES MDLS ARE IN DECENT AGREEMENT ON DEVELOPING
CONVECTION ALONG A RESIDUAL LLVL BOUNDARY THIS AFTN AND WILL ROLL
WITH THE CONSENSUS. THIS BOUNDARY IS DEPICTED ON THE SFC MOISTURE
CONVERGENCE AND LLVL WIND FIELD UP TO AT LEAST H925. LOCATION OF
THIS ALONG AND JUST S OF I64 CORRIDOR. ACTUAL OLD COLD FRONT
APPEARS TO HAVE FIZZLED OUT ACROSS N OH AND S PA...STILL CAN SEE A
GOOD DWPT GRADIENT UP THAT WAY THOUGH.

TRICKY FCST FOR REMAINDER OF AFTN. WILL TRY TO HONE IN ON THE
AFOREMENTIONED BOUNDARY FOR DETERMINISTIC POPS...WITH SOME LKLY POPS
DEVELOPING. HOWEVER...APPEARS DRIER AIR MAY HAVE MADE IT A LITTLE
FURTHER SW THIS MORNING THAN MDLS WERE INDICATING...ESSENTIALLY
CAPPING OFF CU DEVELOPMENT. HOWEVER...FEEL WITH APPROACH OF UPR
WAVE...MOISTURE ADV SHOULD STILL ALLOW THINGS TO FIRE IN NEXT FEW
HRS. SO...HAVE THINGS POPPING IN NEXT COUPLE OF HRS NE KY TO COAL
FIELDS AND S WV PLATEAU WITH RIDGETOP DEVELOPMENT IN N MTNS. THIS
SHOULD SLOWLY PUSH TO N AND NE TO ALONG I 64 METRO CORRIDOR AND
INTO MORE OF THE MTNS BY 21Z...IF NOT A LITTLE SOONER. THIS
APPEARS TO GET ITS PUSH FROM APPROACHING UPR LVL WAVE ACROSS TN
VALLEY AMID AN OTHERWISE WEAKENING FLOW. WILL TAKE THIS INTO NORTH
CENTRAL LOWLANDS...SE OH...AND N MTNS BEFORE DISSIPATING ARND
SUNSET. WILL ONLY BE ABLE TO MAKE IT SO FAR NORTH THOUGH. WILL
KEEP PERRY TO MORGAN AND EXTREME N WV LOWLANDS MAINLY DRY TDY WITH
SOME DRIER AIR THRU MUCH OF THE COLUMN. DECENT SFC HEATING TO
EARLY AFTN WILL AID IN SFC DESTABILIZATION ALLOW CAPE VALUES ARND
1500 J/KG TO ACT ON IN ADDITION TO BOUNDARY FOCUS AND SOME MID LVL
LIFT. PW STILL ARND 1.5 INCHES S HALF OF CWA. SAW SOME 1 TO 2
INCHES OF STREAKY RAIN YESTERDAY FROM GREENUP TO PUTNAM...PT
PLEASANT TO N KANAWHA AND S WV PLATEAU. 1 HR FFG HAS COME DOWN TO
1.25 TO 1.5 ACROSS MUCH OF THE LOWLANDS AND MTNS THAT ARE EXPECTED
TO GET HIT TDY. WHILE SOME TRAINING IS POSSIBLE...THINK SLOW
MOVEMENT TO NE WILL HELP TO KEEP WATER PROBLEMS CONFINED TO ISO
AREAS IN HEAVIER CONVECTION. WILL HAVE TO KEEP A CLOSE EYE ON
THOUGH.

ASSUMING FCST DOES NOT BUST...LEFT CHC POPS IN ACROSS S HALF OF
CWA WITH APPROACH OF UPR LVL WAVE. FG TRICKY TONIGHT AND WILL
DEPEND ON WHO GETS RAIN AND EXTENT OF CLD COVER. MDLS INDICATE
ENOUGH CLDS TO PREVENT DENSE FG FOR AREAS THAT ARE EXPECTED TO SEE
SOME RAIN.

UPR LVL SYS MOVES INTO AREA ON SAT WITH SHRA AND SOME
TSRA...GREATEST COV IN AFTN. HAVE LKLY POPS ACROSS NE KY...S
WV...SW VA BY AFTN.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
-- Changed Discussion --
LOOKING MORE LIKE AN EARLY SUMMER PATTERN. WEAK BUT BROAD UPPER LOW
CURRENTLY OVER THE LOWER AND MIDDLE MISSISSIPPI VALLEY IS FORECAST
BY THE MODELS TO DRIFT BASICALLY EAST THIS WEEKEND...EXITING THE
AREA BY MONDAY. WITH A MOIST AND CONDITIONALLY UNSTABLE ATMOSPHERE
IN PLACE...THE THREAT OF SHOWERS AND THUNDERSTORMS CONTINUES THROUGH
THE WEEKEND...BUT MAINLY ON A DIURNAL BASIS AND MAINLY ACROSS THE
SOUTH HALF WHERE THE BEST OF ANY WEAK UPPER DYNAMICS WILL OCCUR.
THERE WILL BE A VERY WEAK EAST TO WEST FRONT WILL MEANDERING ACROSS
THE AREA BEFORE LIFTING NORTH BY MONDAY...BUT AREAS AND INTENSITY OF
THE ACTIVITY WILL BE DETERMINED MORE BY PREVIOUS OUTFLOW BOUNDARIES
AND WHERE SUNSHINE THROUGH LOTS OF CLOUDS THIS WEEKEND CAN REALLY
BOOST THE TEMPERATURES. THUS...GIVEN UNCERTAINTY OF THE FRONTAL
POSITION AND OUTFLOW BOUNDARIES...AND AREAS WHERE CLOUDS UNDER THE
UPPER LOW CAN BREAK FOR SUNSHINE...WE WILL KEEP HIGHEST POPS IN THE
HIGH CHANCE RANGE. STILL...WHERE THERE ARE HEAVIER STORMS...SOME
LOCALIZED MINOR FLOODING MAY OCCUR IN THOSE AREAS.

HIGH TEMPERATURES AS A WHOLE LOOK TO BE NEAR NORMAL WHILE LOWS WILL
BE ABOVE NORMAL.
-- End Changed Discussion --

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
DID NOT CHANGE MUCH WITH THE NEXT SYSTEM MID WEEK...WITH MORE WET
WEATHER COMING BACK IN AND SLOW TO LEAVE.

LOOKS TO BE A RELATIVE BREAK IN THE WET PATTERN MONDAY AND
TUESDAY...BEING BETWEEN EXITING UPPER LOW AND A FRONTAL SYSTEM
FORECAST TO BEGIN AFFECTING US FROM THE WEST WEDNESDAY. STILL...LOTS
OF MOISTURE AND MORE SUNSHINE UNDER THE WEAK UPPER RIDGE WILL STILL
BRING A THREAT FOR A FEW STORMS MONDAY AND TUESDAY. TEMPERATURES
WILL RESPOND WITH SUNSHINE...LIFTING INTO THE 80S MONDAY AND TUESDAY.


PREVIOUS DISCUSSION...
EXTENDED PERIOD BEGINS WITH CWA IN NE PORTION OF AN UPPER
RIDGE...HOWEVER A SW TROUGH RESIDES ON ERN PERIPHERY OF THIS RIDGE
AND IS SLOW TO PUSH EAST. THIS SHOULD KEEP OUR AREA IN DISTURBED
WEATHER THROUGH DAY 4...WITH PRIMARILY DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS IN THE WV MOUNTAINS. LITTLE BREAK...IF ANY...IN THE
AGITATED WEATHER PATTERN AS NEXT SYSTEM IS QUICK TO MOVE IN FROM
THE WEST TUESDAY. GFS AND ECMWF DIVERGE SOLNS WITH THE HANDLING OF
THE UPPER LEVEL LOW TRACK THROUGH THE GREAT LAKES. RELUCTANT TO GO
ANY HIGHER THAN CHC POPS WITH TIMING DIFFERENCES BETWEEN OPERATIONAL
GUIDANCE. STAYED NEAR WPC GUIDANCE WITH TEMPS THROUGH THE EXTENDED
SAVE FOR LOCAL ADJUSTMENTS.
-- End Changed Discussion --

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
BULK OF CONVECTION ACTIVITY SHOULD GENERALLY BE ALONG AND SOUTH
OF AN AREA FROM KHTS TO KCRW TO KEKN AND SOUTH. EXPECT MVFR/IFR
CONDITIONS IN VICINITY OF STORMS. HAVE SOME TEMPO IFR GROUPS CODED
UP TO HANDLE.

MAJORITY OF CONVECTIVE ACTIVITY WILL DIE DOWN AFTER 00Z. APPROACH
OF UPR LVL WAVE MAY KEEP ENOUGH MID/HI CLDS ARND TO KEEP DENSE FG
AT BAY...LIMITING TERMINALS TO MVFR VSBY. PLAYED IT CONSERVATIVE
FOR THIS PACKAGE WITH FG TONIGHT. SOME LOW STRATUS EXPECTED ON E
SLOPES OF POCAHONTAS AND RANDOLPH IN WEAK SSE FLOW. KEPT OUT OF
KEKN FOR NOW.

SHRA AND SOME TSRA AGAIN ON SATURDAY...AS UPR WAVE MOVES JUST S OF
AREA. GREATEST COVERAGE APPEARS TO BE ACROSS SAME AREAS AS
EXPECTED TDY AND MAXIMIZED IN AFTN. HAVE SOME VICINITY SHRA/TSRA
IN AT THIS DISTANCE THOUGH.

OVERALL LIGHT SURFACE WINDS DURING THE TAF PERIOD.

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


FORECAST CONFIDENCE...LOW TO MEDIUM

ALTERNATE SCENARIOS: CONVECTION MAY NOT BE AS WIDESPREAD AS FCST
THIS AFTN. DEVELOPMENT OF FOG AFTER 03Z SATURDAY MAY BE MORE
WIDESPREAD AND WORSE THAN FORECAST.

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    H    H    H    M    M    M    M
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
BKW CONSISTENCY  M    M    M    M    M    H    H    H    H    H    M    M
EKN CONSISTENCY  H    H    H    H    H    H    H    H    M    M    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z SATURDAY...
BRIEF/INTERMITTENT IFR POSSIBLE IN HEAVIER SHOWERS/THUNDERSTORMS
THROUGH THE WEEKEND. IFR FOG POSSIBLE IN OVERNIGHT HOURS.
-- End Changed Discussion --

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...JS/SL
NEAR TERM...30
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...30