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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KRLX 201007
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
607 AM EDT MON MAY 20 2013

.SYNOPSIS...
UPPER TROUGH AXIS SLOWLY PASSES TODAY. NEW FRONT MOVES ACROSS
THURSDAY. COOLER HIGH PRESSURE FRIDAY AND THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
5H RIDGE AXIS TO NUDGE NORTHEASTWARD ALONG THE OHIO RIVER VALLEY
THROUGH THE PERIOD.  GENERAL FORECASTED TRENDS ARE ON TRACK. LOW TO
MID LEVEL MOISTURE WILL BE SHUNTED SLIGHTLY TO THE EAST TODAY WITH
DRYING OF THE ATMOSPHERIC COLUMN CONTINUING ON WESTERN PERIPHERY OF
UPPER RIDGE. ENOUGH MOISTURE WILL REMAIN ALONG A LINE FROM KEKN TO
KBKW AND POINTS TO THE EAST FOR ANOTHER ROUND OF DIURNALLY DRIVEN
SHOWERS AND THUNDERSTORMS. DRY AIR  WILL THEN WORK ITS WAY ACROSS
MOST OF THE AREA BY TONIGHT...BRINGING AN EARLIER END TO MOST SHOWER
ACTIVITY FOR THE OVERNIGHT HOURS AS WE HAVE SEEN FOR THE PAST FEW
DAYS. DID NOT STRAY TOO FAR FROM PREVIOUS FORECAST TEMP TRENDS AS
VALUES REMAIN ON TRACK WITH EXPECTED TRENDS.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
SHORT TERM PERIOD STARTS OUT WITH THE CWA IN THE WARM SECTOR OF LOW
PRESSURE SYSTEM THAT WILL PUSH EAST ACROSS THE GREAT LAKES REGION
DURING THE PERIOD...AND UPPER LEVEL RIDGE ACROSS THE EASTERN U.S. AS
A RESULT...EXPECTING RATHER WARM TEMPERATURES TO DEVELOP ACROSS THE
REGION IN THE SHORT TERM...PARTICULARLY ON TUESDAY...WHEN 500MB
HEIGHTS AROUND 582DAM AND 850MB TEMPS AVERAGING AROUND 17-18C.
EXPECTING TEMPERATURES ON TUESDAY TO RANGE IN THE UPPER 80S TO LOWER
90S FOR MANY LOCATIONS...AND THIS COMBINED WITH DEW POINTS IN THE
60S ACROSS MUCH OF THE AREA...WILL MAKE FOR A SOMEWHAT UNPLEASANT
DAY. WITH THE HUMID...UNSTABLE AIRMASS IN PLACE...STILL EXPECT A
CHANCE FOR THUNDERSTORMS TO DEVELOP IN DAYTIME HEATING...DESPITE
UPPER RIDGING IN PLACE.

ATTENTION THEN SHIFTS TO A COLD FRONT...ASSOCIATED WITH THE
AFOREMENTIONED LOW...WHICH WILL ENTER SOUTHEAST OHIO BY THURSDAY
MORNING. OUT AHEAD OF THE FRONT...PLENTY OF INSTABILITY AND DYNAMICS
WILL HELP TO GENERATE SHOWERS AND THUNDERSTORMS...SOME OF WHICH
COULD BE STRONG...PARTICULARLY IN SOUTHEAST OHIO/EASTERN KY/WV
COUNTIES NEAR TO THE OHIO RIVER. MODELS INDICATING 0-6KM SHEAR OF
AROUND 30+ KTS...AND A FREEZING LEVEL OF AROUND 10-11K FEET. HAIL
AND STRONG WINDS WILL BE FACTORS WITH ANY STORMS THAT ARE ABLE TO
DEVELOP. WILL PUT A MENTION OF SEVERE INTO THE HWO. OF
COURSE...CLOUD COVER...AND ANY CHANGES IN THE TIMING OF THE FRONTAL
BOUNDARY/ASSOCIATED UPPER TROUGH MAY END UP MITIGATING THE THREAT.

COLD FRONT WILL CONTINUE TO PUSH THROUGH THE REGION ON
THURSDAY...FOLLOWED BY A SECONDARY COLD FRONT THURSDAY NIGHT/EARLY
FRIDAY...WHICH WILL FINALLY USHER IN COOLER AND DRIER AIR INTO THE
REGION.

&&

.LONG TERM /FRIDAY 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 /10Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
EARLY MORNING CONVECTION SLIDING EAST ACROSS THE SOUTHERN
COALFIELDS COULD GET INTO KBKW TO START THE TAF PERIOD. ACTIVITY
IS ASSOCIATED WITH WEAK SHORTWAVE THAT IS PUSHING ACROSS SOUTHERN
AND EASTERN WV. OTHERWISE...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.
CONVECTION WILL BE MORE PREVALENT INVOF AFOREMENTIONED SHORTWAVE.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z 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       08   09   10   11   12   13   14   15   16   17   18   19
EDT 1HRLY       04   05   06   07   08   09   10   11   12   13   14   15
CRW CONSISTENCY  L    L    L    L    H    H    M    M    M    M    M    H
HTS CONSISTENCY  L    L    L    L    M    M    H    M    M    M    M    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    L    L    L    L    M    H    H    H    H    H    H
PKB CONSISTENCY  L    L    L    L    M    M    H    H    H    H    H    H
CKB CONSISTENCY  M    L    L    L    M    H    H    H    H    H    H    M

AFTER 12Z TUESDAY...
LATE IFR FOG POSSIBLE MONDAY NIGHT.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...KMC/SL
NEAR TERM...KMC
SHORT TERM...SL
LONG TERM...JMV
AVIATION...KMC