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000
FXUS61 KRLX 200528
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
128 AM EDT MON MAY 20 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 TODAY/...
10 PM UPDATE...LAST OF THE SHOWERS STILL DRIFTING NE JUST EAST OF
THE OHIO RIVER FROM MASON TO TYLER COUNTY WV. THIS ACTIVITY SHOULD
DECREASE OVER THE NEXT COUPLE HOURS...SO DECREASED POPS THROUGH
THE OVERNIGHT.

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.

&&

.SHORT TERM /TONIGHT 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 /05Z MONDAY THROUGH FRIDAY/...
CLOUDS CONTINUING TO SCATTER OUT THIS MORNING AND EXPECTING SOME
PATCHY FOG TO DEVELOP. MOST FAVORABLE AREAS FOR FOG DEVELOPMENT
WILL BE WHERE RAIN FELL RECENTLY. SINCE LOW LEVEL MOISTURE QUITE
SHALLOW...FOG SHOULD DISSIPATE SHORTLY AFTER SUNRISE AS LOW LEVEL
BOUNDARY LAYER MIXES OUT. DIURNAL TREND OF CONVECTIVE DEVELOPMENT
WILL OCCUR AGAIN TODAY WITH MID LEVEL MOISTURE BEING SHUNTED
SLIGHTLY TO THE EAST AS SOME DRYING FROM THE WEST OCCURS. CONDITIONS
REMAIN MOSTLY VFR MONDAY NIGHT.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...

FORECAST CONFIDENCE...MEDIUM.

ALTERNATE SCENARIOS: 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.

DATE                              MON 05/20/13
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  H    H    L    L    L    L    H    H    M    M    M    M
HTS CONSISTENCY  M    M    L    L    L    L    M    M    H    M    M    M
BKW CONSISTENCY  M    M    M    M    M    H    H    H    H    H    H    H
EKN CONSISTENCY  M    L    L    L    L    L    L    M    H    H    H    H
PKB CONSISTENCY  M    M    L    L    L    L    M    M    H    H    H    H
CKB CONSISTENCY  M    M    M    L    L    L    M    H    H    H    H    H

AFTER 06Z TUESDAY...
LATE IFR FOG POSSIBLE MONDAY NIGHT.

&&

.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...KMC