849
FXUS61 KRLX 042005
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
405 PM EDT SAT JUL 4 2009
SYNOPSIS
AN APPROACHING LOW PRESSURE SYSTEM WILL SPREAD SHOWERS AND
THUNDERSTORMS INTO THE REGION TONIGHT AND TOMORROW. HIGH PRESSURE
BUILDS IN BEHIND LOW FOR DRIER WEATHER MONDAY THROUGH MID WEEK.
NEAR TERM /THROUGH SUNDAY/
PRECIPITATION FROM AN APPROACHING LOW PRESSURE SYSTEM AND ASSOCIATED
WARM FRONT IS GRADUALLY WORKING ITS WAY INTO THE REGION. ISOLATED
THUNDERSTORMS WILL BE POSSIBLE LATER THIS EVENING AND TONIGHT AS THE
SYSTEM CONTINUES TO MOVE INTO THE REGION...HOWEVER...THE BULK OF
INSTABILITY ASSOCIATED WITH THIS SYSTEM WILL REMAIN WELL SOUTH AND
WEST OF THE FORECAST AREA. NOT REAL IMPRESSED WITH CHANCES FOR
THUNDER ACROSS THE CWA. THINKING BEST CHANCES FOR ISOLATED THUNDER
WILL BE OVER EXTREME SOUTHERN PARTS OF THE CWA WHERE BETTER DYNAMICS
EXIST...AND HAVE THEREFORE TAKEN THUNDER OUT OF MUCH OF THE NORTHERN
ZONES. AS WITH THE PREVIOUS FORECAST...HAVE CONTINUED TO TREND THE
FORECAST MORE TOWARDS THE GFS WITH KEEPING AT LEAST CHANCE OF POPS
UP NORTH. LOW PRESSURE SYSTEM WILL GRADUALLY MOVE OFF TO THE EAST ON
SUNDAY FOR A GRADUAL DECREASE IN POPS SUNDAY AFTERNOON AND
EVENING...BUT EXPECTING QUITE A BIT OF LOW CLOUD COVER TO LINGER
ACROSS THE REGION. HAVE THEREFORE KEPT TEMPERATURES TOMORROW ON THE
COOL SIDE...AND TRENDED THEM SLIGHTLY COOLER FROM THE PREVIOUS
FORECAST ACROSS MUCH OF THE REGION.
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/
LOW PRESSURE SYSTEM EXITING SUNDAY NIGHT LEAVES LOW CLOUDS IN ITS
WAKE BUT ONLY FOR A TIME AS MODELS INSIST ON DRY ADVECTION LIMITING
MOISTURE TO JUST THE BOUNDARY LAYER LASTER IN THE NIGHT. THIS THEN
WOULD FAVOR POST RAIN FOG THOUGH KICKED THE CAN ON INCLUSION FOR
NOW. HIGH PRESSURE AND STABLE AIR TAKE OVER FOR THE BALANCE OF THE
PERIOD.
USED AN AVERAGE OF THE NUMBERS FOR LOWS SUN NT WITH A LARGE
DISPARITY AT EKN A FUNCTION OF WHETHER IT CLEARS. HIGHS MON LOOKED
GOOD FROM PREV PACKAGE AND LATEST NUMBERS. DROPPED LOWS A LITTLE
TOWARD THE LOWER MAV MON NT AS THERE SHOULD BE LITTLE OR NO
IMPEDIMENT TO RADIATIVE COOLING. ALSO LOWERED HIGHS TUE PER LOWER
MEX WITH COOL CANADIAN AIR IN CONTROL BUT MEX IS TOO LOW TUE NT IF
NAM12 IS RIGHT WITH WSW FLOW AHEAD OF STRONG SHORT WAVE TROUGH
APPROACHING FROM THE N...STUCK WITH PREV FCST. OTHER MODELS ARE DRY
COMPARED WITH MOISTURE LADEN LOOK OF THE NAM12.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
WENT MOSTLY WITH ECMWF PER HPC AND ISC. NW FLOW REGIME PERSISTS
OVERALL THROUGH THE PERIOD WITH UPPER RIDGE MAINLY OVER SOUTHERN
ROCKIES INTO SOUTHERN PLAINS. CONTINUED WITH DRY SOLN FOR NOW WITH
VIGOROUS SHORT WAVE TROUGH MOVING SE...MOST OF ITS ENERGY PASSING NE
OF THE FCST AREA. HIGH PRESSURE BRINGS DRY WEATHER FOR THE
BALANCE OF THE WORK WEEK AS HEIGHTS BUILD SOMEWHAT. NEXT FRONT
APPROACHES SAT DAY 7 PER ECMWF.
TEMPERATURES WERE MOSTLY A BLEND OF ONGOING...GFS AND HPC...WITH THE
DRY WEATHER ACTUALLY ALLOWING FOR HIGHS MORE TYPICAL OF SUMMER
DESPITE THE NW FLOW ALOFT...BECAUSE THE HEIGHTS COME UP. THE NIGHTS
REMAIN TOLERABLE FOR THIS TIME OF YEAR EXCEPT FRI NT AHEAD OF THE
NEXT COLD FRONT.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
18Z SATURDAY THROUGH 18Z SUNDAY...
MID AND HIGH CLOUDS WILL CONTINUE TO INCREASE ACROSS THE REGION AS
THE NEXT SYSTEM MOVES INTO THE REGION. RAIN SHOWERS WILL SPREAD INTO
THE REGION AFTER 20Z. EXPECT WIDESPREAD MVFR AND ISOLATED IFR
CONDITIONS TO DEVELOP IN RAIN SHOWERS AFTER 00Z. BULK OF
PRECIPITATION AND MVFR CONDITIONS WILL BE ALONG AND SOUTH OF A LINE
FROM KI43 TO KEKN. LIGHT SURFACE WINDS WITH MODERATE WESTERLY WINDS
ALOFT. PRECIPITATION WILL DECREASE IN COVERAGE AND INTENSITY AFTER
15Z BUT MVFR CIGS ARE EXPECTED TO LINGER ACROSS THE REGION BEHIND
THE EXITING LOW PRESSURE SYSTEM.
AFTER 18Z SUNDAY...
NO WIDESPREAD IFR CONDITIONS EXPECTED.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
SYNOPSIS...SL/TRM
NEAR TERM...SL
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...SL
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