FXUS61 KRLX 251124
AFDRLX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHARLESTON WV
725 AM EDT SUN JUL 25 2004
.AVIATION...
PATCHY 3-5KFT DECK AGAIN FORMED ON COOLING OF THE TOP OF THE MIXING
LAYER.  CRW STILL SOCKED IN WITH RADIATION FOG AND EKN JUST WENT
DOWN. THIS WILL BREAK INTO LOW CLOUDS NEXT HOUR AND THEN LIFT ABV
3KFT BY LATE MORNING.
SURFACE TROUGH SETS UP OVER AREA TURNING FLOW SE IN MOUNTAINS WHILE
REMAINING NORTHEAST OVER THE LOWLANDS.  THE PATCHY CLOUDS WILL AGAIN
EVOLVE INTO CU DECK FOR THE AFTERNOON.
A LOW PRESSURE CENTER WILL APPROACH FROM THE SOUTHWEST TONIGHT.
THERE IS THE CHANCE FOR SHOWERS AND THUNDERSTORMS AS FAR NORTHEAST
AS HTS-CRW-BKW LATE TODAY.  THIS IS OUT AHEAD OF THE APPROACHING
WEATHER SYSTEM AND MAY BE DIURNALLY DRIVEN TO A LARGE EXTENT...SO
SLIGHT CHANCE THUNDER ANYWHERE THIS EVENING THAN DECREASING CHANCE
TOWARD 6Z.  CHANCE THUNDER STILL TOO SMALL TO CODE IN EXPLICITLY AT
THIS TIME.
FLOW TONIGHT NE WEST OF OHIO AND VARIABLE EAST OF THERE WITH SURFACE
TROUGH ACROSS CENTRAL WV...SE GLOW IN THE MOUNTAINS.  EKN WILL AGAIN
RADIATE WITH MVFR ON VIS BY 6Z WHILE LOW (MVFR) CLOUDS ROLL BACK
INTO BKW ON SE FLOW.
INCREASING CHANCE FOR RAIN ALL SITES AFTER 6Z INTO MONDAY AS LOW
PRESSURE CENTER APPROACHES THE AREA.  CODED UP MOSTLY MVFR FOR THIS
LATER TONIGHT.  THE CHANCE FOR THUNDER WILL INCREASE AGAIN MONDAY.
&&
.PREVIOUS DISCUSSION...
THE FOLLOWING WAS ORIGINALLY ISSUED AT 428 AM EDT SUN JUL 25 2004
SHORT TERM (TODAY THROUGH MONDAY)...
SOME EVIDENCE OF CLOUD FORMATION AT TOP OF MIXING LAYER ON COOLING
ONCE AGAIN THOUGH NOT NEAR AS PREVALENT AS YESTERDAY.  RAN SKY FROM
ETA40 RH FROM LOW LEVELS FOR STARTERS TO ACCOUNT FOR THIS AS WELL AS
LOW LEVEL MOISTURE COMING AS FAR WEST AS BKW ON SOUTHEASTERLY FLOW
THIS MORNING AND AGAIN TONIGHT (MIXES INTO CU DECK THIS AFTERNOON).
MODELS DO NOT RESOLVE ALTOCU DECK APPROACHING FROM THE WEST WELL AND
HAD TO ACCOUNT FOR THIS TODAY.  WITH SOME SUNSHINE AND SOME CLOUDS
STAYED CLOSE TO GUIDANCE ON TEMPERATURES TODAY.
LOW PRESSURE CENTER APPROACHES FROM THE SOUTHWEST TONIGHT AND TRACKS
UP WEST OF AREA MONDAY.  ETA FARTHER WEST THAN GFS AND PLAYED A
COMPROMISE PER HPC.  INSTABILITY AND CONVERGENCE ZONE BEGINNING TO
SET UP OVER THE AREA CAN LEAD TO CONVECTION AS EARLY AS LATE TODAY
SOUTHWEST PART OF CWA.  THIS SPREADS NORTH AND EAST THIS EVENING
BEFORE ATMOSPHERE STABILIZES.  ROLLED WITH JUST SHOWERS FOR LATTER
HALF OF NIGHT.
ISENTROPIC LIFT BEGINS IN ERNEST LATE TONIGHT AS LOW APPROACHES.
GIVEN LOW TRACK...MOST OF WARM ADVECTION PRECIPITATION SHOULD TRACK
NORTHWEST OF THE AREA THOUGH CLIPPING OHIO COUNTIES.  FOR MONDAY
MORNING WENT WITH SHOWERS EAST AND SHOWERS AND THUNDERSTORMS WEST
CLOSER TO WARM SECTOR AND INSTABILITY.  BY LATE MONDAY MUCH OF AREA
IS IN WARM SECTOR WITH GOOD THETA E FEED AND INSTABILITY SO LIKELY
SHOWERS AND THUNDERSTORMS WARRANTED ALL ZONES BEFORE THE DAY IS OUT.
HIGH PW WITH THIS SYSTEM SUPPORTS POTENTIAL FOR HEAVY BUT NOT
NECESSARILY EXCESSIVE RAINFALL AS AREA SHOULD BE ABLE TO HANDLE IT
GIVEN SUMMER VEGETATION AND DRY JULY FOR THE MOST PART.
CLOSE TO GUIDANCE TEMPERATURES FOR TONIGHT.  GUIDANCE IS SPREAD
MONDAY AND THIS IS TIED TO DIFFERENCES IN TRACK OF LOW WHICH IN TURN
DETERMINES PROGRESS OF WARM SECTOR NORTHWARD INTO THE AREA.  WENT
WITH COMPROMISE HERE GIVEN COMPROMISE SOLUTION ACCEPTED ON LOW
TRACK.
POTENTIAL FOR STRONG THUNDERSTORMS EXISTS MONDAY AFTERNOON BUT CAPE
AND WIND FIELD COMBINATION FALLS SHY OF SEVERE THREAT.
PREVIOUS DISCUSSION...
THE FOLLOWING WAS ORIGINALLY ISSUED AT 316 AM EDT SUN JUL 25 2004
LONG TERM (MONDAY NIGHT THROUGH SATURDAY)...
IT STILL LOOKS LIKE A WET START TO THE LONG TERM WITH A SFC WARM
FRONT CROSSING MONDAY NIGHT THEN A COLD FRONT TUESDAY.  00Z NCEP
CHAIN HANDLING THINGS QUITE DIFFERENTLY WITH ETA HAVING A MORE
AMPLIFIED SOLUTION...WHICH GETS BACKING FM 12Z ECMWF...WHILE GFS
OFFERS A MORE PROGRESSIVE OUTPUT AND TRACKS SFC LOW 300 MILES
FARTHER E AND N THAN THE ETA.  OPTED FOR THE ETA MODEL SINCE IT HAS
RUN TO RUN CONTINUITY.
DRY CONVEYOR BELT WORKS IN TUESDAY AFTERNOON AND ALIGNS ITSELF ALONG
AND IMMEDIATELY BEHIND THE BAROCLINIC ZONE.  THIS WILL BE MONITORED
GIVEN A GOOD SHOT OF MID LEVEL DRYING OCCURS AS H5 DEWPOINTS FALL TO
-45 TO -50C.  THIS COULD LEAD TO GUSTY THUNDERSTORM WINDS WHEN THE
FRONT PASSES TUESDAY AFTERNOON AND EVENING EVEN THOUGH CONVECTIVE
PARAMETERS REMAIN MARGINAL FOR THIS TIME OF YEAR (LI/S OF -1C AND
SBCAPES RUN 0.7 KJ/KG).
POST FRONTAL AIRMASS REMAINS UNSTABLE WITH MID LEVEL LAPSE RATES OF
6.0 C/KM COURTESY OF H5 LOW REMAINING STATIONARY IN THE GREAT
LAKES.  TIME HEIGHTS AND BUFKIT SOUNDINGS ILLUSTRATE LLVL MSTR NEVER
CLEARS OUT...SO CONTINUED CHANCE OF RW/TRW...MAINLY DURING THE AFTN
AND EVENING.
INCREASED POPS TO LKLY MON NGT AND TUES AREA WIDE WITH LKLYS
EXTENDING INTO TUES NGT FOR HEADWATERS OF THE GREENBRIER RIVER AND
CENTRAL WV MTNS...CHC ELSW.  HIGHS TUESDAY WERE LOWERED ACCOUNTING
FOR A OVC SKY AND RA.
QPF TOTALS OFF THE GFS MON NGT THROUGH TUES NGT ARE PROGGED TO REACH
2.5 INCHES IN THE MOUNTAINS WITH 1.5 INCHES WEST OF THE OHIO RIVER.
PAST SYNOPTIC SETUPS SIMILAR TO THIS FAVOR AXIS OF HIGHER PRECIP
ALONG AND WEST OF THE OHIO RIVER...WHICH THE ETA SUGGEST.  RIGHT
NOW...NOT KEEN ON FFA POTENTIAL...HOWEVER IF TRAINING OCCURS AHEAD
OF THE WARM FRONT THEN THINGS WOULD CHANGE.
PREVIOUS DISCUSSION...
THE FOLLOWING WAS ORIGINALLY ISSUED AT 229 AM EDT SUN JUL 25 2004
AVIATION...
LIGHT NORTHEAST FLOW OVERNIGHT.  2-3.5KFT DECK AGAIN FORMING ON
COOLING OF THE TOP OF THE MIXING LAYER.  CRW ALREADY SOCKED IN WITH
RADIATION FOG.  THIS WILL ACTUALLY BREAK UP AT TIMES WITH
AFOREMENTIONED DECK ROLLING IN AND OUT OF THE AREA.  EKN BACK UP TO
5SM BUT WILL GO LIFR ON FOG AT TIMES OVERNIGHT.  AGAIN STRATOCU DECK
FORMING ABOVE THIS WILL KEEP EKN FROM STAYING LIFR.  MVFR TO IFR
DECK MAY SHOW UP AT BKW BEFORE DAWN ON SE FLOW.
SURFACE TROUGH SETS UP OVER AREA TURNING FLOW SE IN MOUNTAINS WHILE
REMAINING NORTHEAST OVER THE LOWLANDS.  PATCHY CLOUDS WILL AGAIN
EVOLVE INTO CU DECK FOR THE AFTERNOON.
A LOW PRESSURE CENTER WILL APPROACH FROM THE SOUTHWEST TONIGHT.
THERE IS THE CHANCE FOR SHOWERS AND THUNDERSTORMS AS FAR NORTHEAST
AS HTS-CRW-BKW LATE TODAY.  THIS IS OUT AHEAD OF THE APPROACHING
WEATHER SYSTEM AND MAY BE DIURNALLY DRIVEN TO A LARGE EXTENT...SO
DECREASING CHANCE TOWARD 6Z.  CHANCE TOO SMALL TO CODE IN EXPLICITLY
AT THIS TIME.
OTHERWISE NO CHANGE IN THE FLOW TONIGHT OTHER THAN DIMINISHING WIND
SPEEDS.  EKN WILL AGAIN RADIATE WITH MVFR ON VIS BY 6Z WHILE LOW
(MVFR) CLOUDS ROLL BACK INTO BKW ON SE FLOW.
INCREASING CHANCE FOR RAIN ALL SITES AFTER 6Z INTO MONDAY AS LOW
PRESSURE CENTER APPROACHES THE AREA.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
VA...NONE.
KY...NONE.
OH...NONE.
&&
$$
AVIATION...TRM
SHORT TERM...TRM
LONG TERM...FWM