Area Forecast Discussion Issued by NWS Charleston, WV
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000
FXUS61 KRLX 191820
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
220 PM EDT SUN MAY 19 2013
.SYNOPSIS...
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UPPER TROUGH AXIS SLOWLY PASSES TONIGHT/MONDAY. NEW FRONT
APPROACHES LATE WEDNESDAY.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH MONDAY/...
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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 --
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.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
WEAK RIDGING REMAINS OVER THE EASTERN HALF OF THE US....AS UPPER
LEVEL LOW AND ASSOCIATED COLD FRONT ACROSS THE UPPER MIDWEST SLOWLY
SHIFTS EASTWARD TOWARD THE OHIO VALLEY. OVERALL...NOT MUCH CHANGE IN
THE SENSIBLE WEATHER FOR THE MID OHIO THROUGH THE PERIOD. INTRODUCED
SLIGHTLY WARMER TEMPS FOR TUESDAY FOLLOWING MOS TRENDS. HOWEVER...
AFTERNOON CLOUD DEVELOPMENT SHOULD HOLD TEMPS BACK SOME. THERE WILL
BE ENOUGH LOW LEVEL MOISTURE AROUND FOR DIURNALLY DRIVEN SHOWER
DEVELOPMENT THROUGH THE PERIOD...ESPECIALLY OVER THE EASTERN
MOUNTAINS. POP CHANCES INCREASE WEDNESDAY AS FRONT APPROACHES FROM
THE WEST.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HPC/ECMWF TRENDING TO GO WITH A STRONGER/FASTER UPPER TROUGH AND
COLD FRONT PUSHING ACROSS THE AREA THURSDAY. RAISED POPS TO CHANCE
WEDNESDAY AHEAD OF THE FRONT IN THE WARM MOIST AND UNSTABLE
AIR...AND UP TO LIKELY THURSDAY WHEN THE ACTUALLY FRONT CROSSES.
RAIN ENDS THURSDAY NIGHT WITH PASSAGE OF THE FRONT. STRONG HIGH
PRESSURE OVER CANADA RIDGES IN...WITH A CHILLY AIR MASS FILTERING IN
FRIDAY AND SATURDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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CONVECTION ONGOING AS HAS BEEN THE CASE OVER THE LAST FEW DAYS.
CARRY VCTS/VCSH FOR MOST LOCATIONS...WITH A FEW TEMPOS FOR
TERMINALS. BRIEF RESTRICTIONS DOWN TO MVFR POSSIBLE IN
SHRA/TSRA...AND KEEP THE OVERALL FORECAST CONSERVATIVE.
QUESTIONS ARISE OVER RIVER VALLEY FOG POTENTIAL OVERNIGHT. TREND
THE TERMINALS DOWN TO AT LEAST MVFR LATE IN THE OVERNIGHT
PERIOD...WITH IFR IN THE REALM OF POSSIBILITIES AT EKN/CKB/PKB.
UPPER RIDGE APPROACHES FOR MONDAY...AND HAVE REDUCED THE
CONVECTION CHANCES FOR THE WESTERN TERMINALS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: TEMPOS FOR SHRA/TSRA MAY NOT HAVE BEEN NEEDED
OVER THE AFTERNOON HOURS IN HIT OR MISS CONVECTION. QUESTIONS
LINGER ON FOG POTENTIAL TONIGHT.
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 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
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 H M
BKW CONSISTENCY H H H H M M M M M M M M
EKN CONSISTENCY H H H H H M M M M M M L
PKB CONSISTENCY H H H H H H H H M M M M
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 18Z MONDAY...
LATE IFR FOG POSSIBLE MONDAY NIGHT.-- End Changed Discussion --
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KMC/26
NEAR TERM...26
SHORT TERM...KMC
LONG TERM...JMV
AVIATION...26