FXUS63 KSGF 281735
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1135 AM CST SAT NOV 28 2009

...UPDATE TO AVIATION...

.DISCUSSION...

SOUTHERLY BREEZES KEPT THE ATMOSPHERE MIXED OVERNIGHT...MITIGATING 
TEMPERATURES FROM FALLING OUT OF THE UPPER 40S AND LOWER 50S.  THE 
ANIMATED MOISTURE CHANNEL INDICATED BROAD CYCLONIC FLOW OVER THE 
SOUTHERN AND CENTRAL PLAINS.  THIS AIRMASS IS VERY DRY...AND CLOUD 
COVER WAS QUITE LIMITED IN THIS REGION OF WEAK SYNOPTIC SCALE LIFT.  
OBSERVATIONS ACROSS THE PLAINS SUGGEST THAT CLOUDS ARE IN THE FORM 
OF CIRRUS...WHICH WILL PASS OVER THE OZARKS REGION TODAY.  THIS 
SCATTERED CLOUD COVER WILL HAVE LITTLE IMPACT ON TEMPERATURES...AS 
READINGS MAY BE A DEGREE OR TWO WARMER THAN YESTERDAY.  THEREFORE 
LOOK FOR ANOTHER FANTASTIC DAY...AS AFTERNOON TEMPERATURES WARM INTO 
THE UPPER 60S AND LOWER 70S.

HEADING INTO TONIGHT AND SUNDAYS PERIODS...MODELS STILL SEEM TO BE 
INCREASING MOISTURE LEVELS TOO QUICKLY OVER SOUTHEAST KANSAS AND 
SOUTHERN MISSOURI.  OBSERVATIONS AS FAR SOUTH AS INTERSTATE 20 OVER 
TEXAS AND LOUISIANA ARE MEASURING DEW POINTS IN THE 30S AND 40S.  
THE FORT WORTH 00Z RAOB MEASURED A PRECIPITABLE WATER VALUE OF 0.32 
INCHES.  DESPITE THIS EXTREMELY DRY AIR THAT EXISTS OVER A LARGE AREA 
OF THE CENTRAL AND SOUTHERN CONUS...MODELS BRING MID TO UPPER 40 DEW 
POINTS INTO THE OZARKS BY THIS AFTERNOON AND TONIGHT.  HAVE LOWERED 
GRIDDED DEW POINTS SEVERAL DEGREES FROM MOS THROUGH TODAY AND THIS 
EVENING.  

DUE TO THIS EXCESS IN MOISTURE...I ALSO THINK THAT QPF VALUES ARE 
OVERDONE ON SUNDAY.  WHILE A FEW ISOLATED TO SCATTERED LIGHT RAIN 
SHOWERS WILL LIKELY DEVELOP ALONG AND BEHIND A COLD 
FRONT...WIDESPREAD RAINFALL MAY BE DIFFICULT TO COME BY.  
TEMPERATURES WILL COOL BEHIND THE PASSAGE OF THE FRONT...AS A 
NORTHERN PLAINS AIRMASS SPREADS IN.  LOOK FOR OVERNIGHT LOWS ON 
SUNDAY NIGHT AND EARLY MONDAY MORNING TO DROP BACK INTO THE LOWER 
30S.

DRY AND MILD WEATHER IS EXPECTED FOR THE MONDAY - WEDNESDAY TIME 
FRAME.  A CUTOFF UPPER LEVEL LOW PRESSURE SYSTEM WILL GRADUALLY 
APPROACH FROM THE WEST.  THERE IS SOME MAJOR DIFFERENCES IN MODEL 
OUTPUT REGARDING THE TRACK OF THIS LOW...WHICH WILL HAVE SERIOUS 
IMPACTS ON OUR SENSIBLE CONDITIONS DEPENDING ON HOW THIS SITUATION 
MATERIALIZES. 

THE 00Z ECMWF...SHOWS THE UPPER LOW TO TRACK ACROSS ARKANSAS...WHICH 
PUTS AREAS OF THE OZARKS WITHIN A FAVORABLE POSITION FOR 
PRECIPITATION.  THERE ARE SEVERAL OTHER MODELS THAT SUPPORT THIS 
NORTHERN TRACK OF THE LOW.  ON THE OTHER HAND...THE GFS SHOWS THE 
LOW CENTER TO TRACK CLOSER TO THE INTERSTATE 20 CORRIDOR...CONFINING 
ALL IMPACTS WELL INTO THE DEEP SOUTH.  DUE TO THE MODEL 
DISCREPANCY...I'VE DECIDED TO NOT CHANGE MUCH FROM THE ONGOING 
FORECAST...UNTIL THESE MEDIUM RANGE SOLUTIONS BEGIN TO SHOW SOME 
AGREEMENT AND CONSISTENCY.

CRAMER

&&

.AVIATION...

FOR THE 18Z TAF PACKAGE...VFR CONDITIONS WILL CONTINUE THROUGH AT
LEAST THIS EVENING WITH AN INCREASE IN HIGH LEVEL CLOUDS EXPECTED.
THE LOW LEVEL JET WILL ONCE AGAIN LEAD TO WIND SHEAR CONCERNS
TONIGHT. THIS WILL ALSO ACT TO BRING MOISTURE NORTHWARD...WHICH
WILL GRADUALLY RESULT IN MVFR CIGS BY DAYBREAK SUNDAY. A COLD
FRONT WILL MOVE THROUGH THE AREA ON SUNDAY. RAIN LOOKS TO BE
SPOTTY AT FIRST...WITH BETTER CHANCES SUNDAY AFTERNOON.

GAGAN

&&

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

$$