Tuesday, September 28, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 290448
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1148 PM CDT TUE SEP 28 2010

..UPDATE TO AVIATION...

DISCUSSION...

PATCHY STRATOCUMULUS CLOUDS HAS DEVELOPED OVER MUCH OF THE
FORECAST AREA THIS AFTERNOON AS DAYTIME MIXING LIFTS WHAT LITTLE
MOISTURE WE HAVE OVER THE REGION. EXPECT THESE CLOUDS TO DISSIPATE
AROUND SUNSET WITH TEMPERATURES FALLING QUICKLY THROUGH THE 60S
AND MID 50S THROUGH THE EVENING. TEMPERATURES ARE EXPECTED TO DROP
INTO THE UPPER 40S TO LOWER 50S BY SUNRISE...ABOUT 5 DEGREES LOWER
THAN MID AFTERNOON CROSS-OVER TEMPERATURES. ALSO...WIND SPEEDS
WILL DROP TO LIGHT AND VARIABLE AS THE SURFACE RIDGE AXIS OVER THE
UPPER MIDWEST SETTLES OVER THE OZARKS. SO EXPECT TO SEE SOME
PATCHY FOG DEVELOP LATE TONIGHT AND EARLY WEDNESDAY.

THE LATEST MODEL GUIDANCE CONTINUES TO BRING A DRY COLD FRONT
ACROSS THE REGION LATE WEDNESDAY NIGHT AND EARLY THURSDAY. MEAN RH
VALUES AROUND 40-50 PERCENT WILL WARRANT INCREASING CLOUD COVER
AND KEEPING MIN TEMPS SEVERAL DEGREES WARMER WEDNESDAY NIGHT.
THEREAFTER A REINFORCING SHOT OF CANADIAN AIR WILL MAKE ITS WAY
INTO THE REGION.

THE OVERALL UPPER AIR PATTERN WILL REMAIN VERY MERIDIONAL WITH
RIDGING OVER THE WESTERN CONUS AND TROUGHING OVER THE MID-ATLANTIC
REGION. THIS WILL KEEP OUR AREA IN NORTHWEST FLOW ALOFT THROUGH
EARLY NEXT WEEK. AN UPPER LEVEL DISTURBANCE PROGGED BY THE ECMWF
TO MOVE ACROSS THE REGION ON SATURDAY MAY BRING A FEW MORE CLOUDS
BUT WILL CONTINUE WITH A DRY FORECAST THROUGH THE WEEKEND.

BY SATURDAY NIGHT AND SUNDAY...A 1030 MB SURFACE HIGH OVER THE
NORTHERN PLAINS AND UPPER MIDWEST WILL BUILD SOUTHWARD TOWARD THE
OHIO VALLEY. SOME OF THE COLDEST AIR SO FAR THIS SEASON MAY CLIP
OUR EASTERN AND CENTRAL COUNTIES. FOR NOW...HAVE DROPPED MIN TEMPS
INTO THE LOWER AND MID 40S EAST OF HIGHWAY 65 ON SUNDAY NIGHT AND
MONDAY NIGHT. WOULD NOT BE SURPRISED IF THESE NEED TO BE LOWERED
MORE...ESPECIALLY IF THE TROUGH DROPS FURTHER TO THE SOUTHWEST.

TERRY

&&

AVIATION...

FOR THE 06Z TAFS...WIND HAS DIMINISHED TO CALM AT FORECAST POINTS
ACROSS THE AREA WITH SURFACE RIDGE OVERHEAD. WITH A CLEAR SKY...NO
WIND AND DEW POINTS DEPRESSIONS APPROACHING ZERO...WILL LIKELY SEE
SOME FOG DEVELOP OVERNIGHT. FOR NOW HAVE DROPPED IT GRADUALLY TO
MVFR AFTER A COUPLE OF HOURS FROM THE ONSET OF THE TAFS...THEN
INTO IFR AFTER 10Z. SHOULD BECOME VFR AFTER 15Z.

LINDENBERG

&&

SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

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