-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 192327
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
727 PM EDT SUN MAY 19 2013

.SYNOPSIS...
UPPER TROUGH AXIS SLOWLY PASSES TONIGHT/MONDAY. NEW FRONT MOVES
ACROSS WEDNESDAY AND THURSDAY. COOLER HIGH PRESSURE FRIDAY AND THE
WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
-- Changed Discussion --
720 PM UPDATE...REMAINING CONVECTION IS DECREASING AS IT DRIFTS
NORTH. DO HAVE AN OUTFLOW BOUNDARY N AND NW OF CHARLESTON...THAT IS
STILL POPPING SOME THUNDERSTORMS. ADJUSTED POPS FOR THE REST OF THE
EVENING...DECREASING THEM TO ISOLATED AND SCATTERED OVER THE NEXT
HOUR OR TWO.

PREVIOUS DISCUSSION...
UPPER TROUGH AXIS MOVING TO THE EAST AND AN AGONIZINGLY SLOW
RATE...AND HAS ALREADY SET OFF NUMEROUS SMALL SHOWERS WITH A FEW
THUNDERSTORMS. CLEARING THIS MORNING OVER THE TUG FORK VALLEY
EVENTUALLY SPREAD OUT OVER MOST OF THE AREA...ELIMINATING THE
CLOUD DEBRIS FROM THE ACTIVITY YESTERDAY AND THE SATURATED LOW
LEVELS OVERNIGHT WITH EARLY MIXING. BUT THIS EARLY HEATING HAS
ALREADY REACHED THE CONVECTIVE TEMPERATURES AND IN THE
END...ANOTHER DAY WITH SCATTERED CONVECTION IS ALREADY ONGOING.

NOT ANTICIPATING WATER ISSUES WITH THIS ROUND OF CONVECTION.

THE OTHER TRICK TO THE FORECAST...AS HAS BEEN WITH THE LAST FEW
DAYS...IS DETERMINING THE EXTENT OF THE CLOUD COVER OVERNIGHT.
PAST NIGHTS HAVE SEEN JUST ENOUGH CLEARING OVER WET SURFACES TO
GIVE STOUT RIVER VALLEY FOG. LAST NIGHT...MOST PLACES WERE
OVERCAST ELIMINATING THAT POSSIBILITY...AGAIN...LESS THE TUG FORK
VALLEY. FEELING IS SOME REDUCED VISIBILITIES ARE POSSIBLE AGAIN
FOR THE EARLY COMMUTE MONDAY MORNING.

UPPER RIDGE MOVES INTO THE WESTERN ZONES FOR MONDAY...REDUCING
CHANCES OF CONVECTION IN THAT AREA WITH SOME STABILITY ALOFT.
EXPECTING A WARM UP WITH RISES IN THE 850MB TEMPERATURES FROM THE
LOWER TO UPPER TEENS CELSIUS. BEST CHANCE OF CONVECTION ULTIMATELY
LIES OVER THE HIGHER TERRAIN MONDAY.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
WEAK RIDGING DOMINATES THE EASTERN THIRD OF THE U.S. THIS PERIOD AS
UPPER LEVEL LOW AND ASSOCIATED COLD FRONT ACROSS THE UPPER MIDWEST
SLOWLY SHIFTS EASTWARD TOWARD THE OHIO VALLEY. HIGH TEMPS FOR
TUESDAY NEAR 90 DEGREES FOLLOWING MOS TRENDS. THERE WILL STILL BE
ENOUGH LOW LEVEL MOISTURE AROUND FOR DIURNALLY DRIVEN SHOWER
DEVELOPMENT THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
APPROACHING LOW PRESSURE SYSTEM TRACKS ALONG THE GREAT LAKES
WEDNESDAY AND DRAGS ONE FRONT THRU WEDNESDAY NIGHT...FOLLOWED BY A
SECONDARY FRONT THURSDAY WHICH WILL BE THE LEADING EDGE OF A COOL
CANADIAN HIGH PRESSURE SYSTEM. MODELS IN MUCH BETTER AGREEMENT ON
THIS TWO PRONGED ATTACK OF THE PROGRESSIVE FRONTS. WITH LOTS OF
MOISTURE AND INSTABILITY WITH THE FIRST FRONT...WILL CONTINUE WITH
EXISTING HIGH POPS AND THUNDER. EVEN WITH THE SECOND FRONT ON
THURSDAY...DESPITE SOME LOSS OF MOISTURE...COOLING ALOFT AND STILL
GOOD DYNAMICS WITH THE FRONT WILL BRING ANOTHER ROUND OF HIGH POPS
WITH SOME THUNDER.

MUCH COOLER AND DRIER WILL FILTER IN FOR FRIDAY INTO THE WEEKEND AS
STRONG CANADIAN HIGH PRESSURE DROPS SOUTH OUT OF CENTRAL CANADA.

&&

.AVIATION /23Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
CONVECTION WINDING DOWN ACROSS THE FORECAST AREA...BUT STILL
INCLUDED SOME VCTS/CB AT PKB AS OUTFLOW BOUNDARY MOVING IN FROM THE
SOUTH IS STILL POPPING SOME THUNDERSTORMS. OTHERWISE...CLOUDS BEGIN
TO SCATTER OUT TONIGHT WHICH WILL ALLOW FOG TO FORM...ESPECIALLY
WHERE IT HAS RAINED RECENTLY. DESPITE NOT RAINING TODAY AT
EKN...STILL INCLUDED VALLEY FOG THERE AS WELL. FLY IN THE OINTMENT
WILL BE IF CLOUDS REMAIN MORE OVC/BKN IN ANY AREAS IN WHICH CASE FOG
WOULD BE LESS LIKELY. FOG SHOULD DISSIPATE AN HOUR OR TWO AFTER
SUNRISE. BEST CHANCE OF PRECIP WILL BE IN THE MOUNTAINOUS COUNTIES
TOMORROW...WITH A SCATTERED TO BROKEN 3-4KFT CLOUD DECK ACROSS THE
FORECAST AREA.

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

FORECAST CONFIDENCE...MEDIUM.

ALTERNATE SCENARIOS: STILL SOME UNCERTAINTY ON FOG DENSITY AND
LOCATIONS OVERNIGHT.

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

AFTER 00Z TUESDAY...
LATE IFR FOG POSSIBLE MONDAY NIGHT.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...JMV/26
NEAR TERM...MZ/26
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...MZ