318
FXUS63 KLSX 071748
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1148 AM CST SAT NOV 7 2009
DISCUSSION
/218 AM CST SAT NOV 7 2009/
MAIN CHALLENGE IS TEMPERATURE FORECASTING THE NEXT TWO DAYS.
FRIDAY'S HIGHS TURNED OUT TO BE UP TO 5 DEGREES WARMER THAN MAV/MET
GUIDANCE FROM 24 HOURS AGO AS THE ATMOSPHERE BECAME WELL MIXED TO
AROUND 900MB WITH TEMPERATURES AT THAT LEVEL BETWEEN 12-16C. THERE
WAS PLENTY OF SUNSHINE...ALBEIT THE RELATIVELY WEAK NOVEMBER SUN
WITH GUSTY SOUTH SOUTHWESTERLY WINDS WHICH ARE TYPICALLY GOOD FOR
A WARMUP. 900MB TEMP WILL BE SIMILIAR TODAY AND A DEGREE OR TWO
WARMER ON SUNDAY...SO WITH MIXING...CONTINUED S-SWLY SFC WINDS AND
SUNNY/MOSTLY SUNNY SKIES WILL GO ABOVE GUIDANCE BY 2-4 DEGREES
WHICH YIELD HIGHS IN THE LOWER TO MIDDLE 70S. TEMPERATURES WILL
FALL OFF A BIT ON MONDAY WITH MORE CLOUDS AND A FRONT MOVING SEWD
THROUGH THE AREA AND USED THE GFS MOS GUIDANCE.
STILL LOOKS DRY THROUGH SUNDAY NIGHT AS THE ATMOSPHERE REMAINS DRY
THROUGH A DEEP LAYER AND VARIOUS VORTS MOVING ACROSS THE AREA WILL
ONLY SUPPLY MINIMAL ASCENT IN THE ZONAL FLOW. THERE IS A COLD FRONT
OVER THE NRN PLAINS THAT WILL MOVE SEWD TODAY AS ITS ATTENDANT UPPER
TROUGH RACES QUICKLY EWD ACROSS THE GREAT LAKES. THERE IS GOOD
MODEL AGREEMENT THAT IT WON'T MAKE IT MUCH PAST THE MO/IA BORDER
BEFORE LIFTING BACK NORTHWARD EARLY ON SUNDAY. ANOTHER SHORTWAVE
TROUGH WILL ENTER THE PACIFIC NORTHWEST LATER TODAY AND MOVE ACROSS
THE NRN CONUS AT THE SAME TIME THAT UPPER LOW OVER BAJA CALIFORNIA
EJECTS NEWD. MODELS DO SHOW AGREEMENT THAT THESE FEATURES WILL
BEGIN TO PHASE OVER THE PLAINS BY LATE SUNDAY AND THEN MOVE EWD
ACROSS THE MIDWEST. ACCOMPANYING COLD FRONT WILL MOVE ACROSS THE
CWA LATE MONDAY INTO MONDAY NIGHT WHEN ASCENT FROM TROUGH AND
CONVERGENCE ALONG THE FRONT WARRANT KEEPING GOING CHANCE OF RAIN.
SUSIDENCE THEN SETS IN ON TUESDAY AS UPPER RIDGES BUILDS OVER THE
CNTRL CONUS.
BRITT
AVIATION
/1138 AM CST SAT NOV 7 2009/
FOR THE 18Z TAFS...
PRIMARY CONCERN FOR AVIATORS TODAY WILL BE 15-25KT WINDS FROM
230-250 DEGREES AHEAD OF A DECENT COLD FRONT WHICH WILL DRIFT INTO
NORTHERN MISSOURI BEFORE STALLING THIS EVENING. WINDS SHOULD DECREASE TO
5-7KTS BY 22-23Z THIS AFTERNOON AS THE PRESSURE GRADIENT SLACKENS.
RIVER FOG WILL BE A REAL POSSIBILITY LATE TONIGHT...THO SOUTHERLY
FLOW ISN'T AS FAVORABLE FOR ADVECTING FOG ONTO THE KSUS
TERMINAL...SO HAVE OPTED TO GO WITH VCFG RATHER THAN THE TEMPO
WHICH WAS IN PREVIOUS TAF. ELSEWHERE AND OTHERWISE...VFR
CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE NEXT 24-30 HOURS.
CARNEY
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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