017
FXUS61 KRLX 091838 CCA
AFDRLX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
1259 PM EST MON NOV 9 2009
SYNOPSIS
HIGH PRESSURE REMAINS IN CONTROL AS HIGH CLOUDS THICKEN. SOME HAZE
AND/OR POLLUTION INTO TUESDAY IN THE STABLE AIR. COLD FRONT CROSSES
LATE TUESDAY AS LOW PRESSURE PASSES WELL TO THE SOUTH.
NEAR TERM /THROUGH TUESDAY/
STABLE AIR MASS IN PLACE HAS GIVEN RISE TO SOME HAZE WHILE ALSO
LIMITING THE MIXING LAYER TO OR BELOW 2KFT...SCRUBBING SOME
PRESCRIBED BURNS TODAY. THE STABLE CONDITIONS AND LIGHT FLOW
THROUGH THE MID LEVELS CONTINUES INTO TUE BEFORE THE ATMOSPHERE
FINALLY STARTS TO BECOME BETTER MIXED. MIXING LAYER LOOKS EVEN
LOWER IF NOT NON-EXISTENT FOR TUE COMPARED WITH TODAY.
A MAJOR CHANGE IN THE FCST FOR TUE IS THE EXODUS OF THE REMNANTS OF
IDA TO OUR S AND E. IN ADDITION TO THE LATEST OPERATIONAL MODELS
ALL TRENDING THIS DIRECTION...ONLY 3/21 9Z SREF MEMBERS SHOW IDA
AFFECTING S HALF OF CWA AND ANOTHER 4 GRAZE S PORTION; OTHER 14
MEMBERS DRY. HAVE SCHC TO CHC LATE TUE FAR SE PORTION OF AREA AND
SCHC LATE NW BEHIND OLD FRONT DRIVEN BY NORTHERN STREAM SHORT
WAVE TROUGH. THIS IS THE FEATURE THAT WILL LEAD TO STEEPER LOW
LEVEL LAPSE RATES AND THE ERADICATION OF ANY HAZE.
WITH THE THICK HIGH CLOUD LAYER...SEEMS PRUDENT TO STICK CLOSE TO
CURRENT NUMBERS FOR LOWS TONIGHT AS THEY ARE CLOSEST TO THE HIGHER
MET. WITH DRIER FCST FOR TUE...APPEARS PRUDENT TO RAISE HIGHS ABOVE
THE MAV BUT NOT QUITE ALL THE WAY TO THE HIGH MET YET.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/
STILL A VARIETY OF MODEL SOLUTIONS REGARDING EVENTUAL FATE OF
APPROACHING WEAK COLD FRONT...PLUS REMNANT MOISTURE FROM IDA. THE
GFS IS THE STRONG OUTLIER...PHASING THE STREAMS ALONG THE ATLANTIC
COAST AND CREATING A STRONG CLOSED H500 LOW OVER THE APPALACHIANS BY
WEDNESDAY AFTERNOON. THE NAM WANTS TO SUPPRESS ALL OF THE TROPICAL
MOISTURE TO THE SOUTH...AND INSTEAD BRING ACROSS A WEAK MIDLEVEL
WAVE ASSOCIATED WITH THE COLD FRONT...AND WITH VIRTUALLY NO
PRECIPITATION. THE UKMET/GEM ALSO HAVE DIFFERING VIEWS. THE ECMWF
OFFERS MORE OF A COMPROMISE...WITH PHASING OCCURRING OFFSHORE OF THE
SOUTHEAST U.S...WHILE SKIMMING THE CWA WITH THE IDA REMNANT
MOISTURE. WENT WITH THIS SOLUTION...WHICH PRESERVE SOME MEASURE OF
CONTINUITY. STILL HAVE A DECENT GRADIENT IN THE POP GRIDS...RANGING
FROM LIKELY IN THE FAR SOUTH AND EAST TO LOW CHANCE IN THE
NORTHWEST. IN FACT...SOUTHEAST OHIO MAY WELL END UP GETTING ZERO
RAINFALL FROM THE STRUNG-OUT FRONT WHICH SINKS IN DURING THE DAY
TUESDAY. BULK OF THE TROPICAL MOISTURE ARRIVES AFTER 18Z TUESDAY IN
THE SOUTH AND EAST. ONE QUARTER TO ONE HALF INCH OF RAIN MAY FALL
IN SOUTHWEST VIRGINIA AND SOUTHEAST WEST VIRGINIA THROUGH 12Z
WEDNESDAY...WITH AMOUNTS DROPPING OFF TO THE NORTHWEST FAIRLY
QUICKLY.
BY SUNRISE WEDNESDAY...MOST OF THE MOISTURE HAS PULLED OFF TO THE
EAST. SOME LIGHT RAIN MAY LINGER IN THE MOUNTAINS DURING THE
MORNING...BUT NORTHEAST FLOW AROUND THE LOW TO THE SOUTHEAST MEANS
NO BACKSIDE UPSLOPE. LARGE SURFACE HIGH BUILDS IN BEHIND...WITH
CLEARING SKIES AND COOLER TEMPERATURES.
LEANED TOWARDS THE COOLER SIDE OF MOS TUESDAY IN THE SOUTHEAST WITH
THICKER CLOUDS AND RAIN...AND MORE MIDDLE-OF-THE-ROAD TO THE
NORTHWEST. MET/MAV BLEND TUESDAY NIGHT. PREFERRED COOLER VALUES
WEDNESDAY WITH THE NORTHEAST FLOW BRINGING IN 1-3C H850 AIR.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
MODELS CONTINUE TO DIFFER WITH THE HANDLING OF THE REMNANTS OF
HURRICANE IDA. 12Z NAM APPEARS TO BE TRENDING TOWARDS A DRIER
SOLUTION FOR THURSDAY...AS IT INDICATES THE LOW PRESSURE SYSTEM OVER
THE SE U.S....AND ITS ASSOCIATED MOISTURE WILL CONTINUE TO MOVE
SOUTH OF THE REGION. 12Z GFS CONTINUES TO INDICATE THE REMNANTS OF
HURRICANE IDA WILL MOVE NORTHEAST OVER THE REGION EARLY THIS
WEEK...WITH PRECIPITATION CONTINUING TO WRAP AROUND THE BACK SIDE OF
THE LOW INTO THE REGION FOR THURSDAY. 00Z RUN OF THE ECMWF ALSO
INDICATED THE LOW PRESSURE CENTER WOULD MOVE NORTHEAST OVER THE
REGION...BUT WOULD MOVE OFFSHORE BY THURSDAY. HOWEVER...12Z RUN OF
THE ECMWF NOW SEEMS TO BE MORE IN LINE WITH THE 12Z NAM...TRENDING
TOWARDS A DRIER SOLUTION ON THURSDAY AS THE LOW PRESSURE CENTER
REMAINS OVER THE SE U.S....BEFORE SLIDING OFF TO THE SOUTH AND EAST
LATE WED. FOR NOW HAVE TRENDED THE FORECAST MORE TOWARDS THAT OF
HPC...ECMWF...AND NAM...WHICH KEEPS THE FORECAST REGION DRY FOR
THURSDAY. HIGH PRESSURE THEN TAKES CONTROL FOR MUCH OF THE REMAINDER
OF THE FORECAST PERIOD...FOR DRY CONDITIONS AND A GRADUAL WARM UP IN
TEMPERATURES. UNSETTLED WEATHER RETURNS TO THE FORECAST AREA LATE IN
THE PERIOD AS ANOTHER LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT
MOVE IN FROM THE WEST.
AVIATION /18Z MONDAY THROUGH SATURDAY/
VFR FCST WITH LIGHT FLOW SFC AND ALOFT. HAZE IN THE STABLE AIR MASS
MAY DROP VSBYS TOWARD MVFR /5 MI/. THIS IS MOST LIKELY AT EKN
DURING THE MORNING HOURS.
AFTER 18Z TUESDAY...
NO SIGNIFICANT WEATHER EXPECTED AT THIS TIME.
RLX WATCHES/WARNINGS/ADVISORIES
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
SYNOPSIS...KTB/CL/TRM
NEAR TERM...TRM
SHORT TERM...CL
LONG TERM...SL
AVIATION...TRM
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