970
FXUS63 KFSD 090943
AFDFSD
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
340 AM CST MON NOV 9 2009
DISCUSSION
DECENT DAY IN STORE OVER THE AREA AS UPPER LEVEL RIDGING BEGINS TO
BUILD INTO THE REGION AND SURFACE HIGH PRESSURE SLIDES ACROSS THE
NORTHERN PLAINS. THE CENTER OF THE HIGH MOVES RIGHT OVER OUR AREA
DURING THE DAY...RESULTING IN LIGHT WINDS...AND WITH SUBSIDENCE
UNDER THE HIGH...WILL MIX DOWN LOWER DEWPOINTS FROM
ALOFT...RESULTING IN A HIGH FIRE DANGER OVER OUR SOUTHWEST AND
NORTHEAST. WILL HAVE A DECENT AMOUNT OF HIGH CLOUDS STREAMING ACROSS
THE REGION TODAY...ESPECIALLY IN OUR SOUTH AND EAST...AND MAY KEEP
TEMPERATURES FROM REACHING THEIR MAXIMUM POTENTIAL. EVEN SO...IT
WILL STILL BE ABOVE NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE
UPPER 50S TO LOWER 60S.
WILL BEGIN TO LOSE SOME OF THE HIGH CLOUDS TONIGHT...AND WITH LIGHT
WINDS REMAINING...WENT ON THE LOW SIDE OF GUIDANCE WITH MINS FALLING
BACK TO LOWER TO MID 30S.
HIGH PRESSURE PUSHES INTO THE UPPER MIDWEST AND WESTERN GREAT LAKES
REGION ON TUESDAY...WITH WINDS PICKING UP BY AFTERNOON...ESPECIALLY
IN OUR WEST...IN AN INCREASING GRADIENT AS LOW PRESSURE BEGINS TO
ENCROACH ON THE WESTERN HIGH PLAINS. HIGH TEMPERATURES WILL WARM A
COUPLE OF DEGREES UNDER THE STRENGTHENING SOUTHERLY LOW LEVEL FLOW
AND A MOSTLY SUNNY DAY...THOUGH A FEW HIGH CLOUDS WILL BE POSSIBLE
IN OUR FAR WEST BY LATE AFTERNOON. WHILE DEWPOINTS WILL BE A LITTLE
HIGHER ON TUESDAY...WITH THE ABOVE NORMAL TEMPERATURES AND
BREEZY/WINDY CONDITIONS IN OUR WEST ON TUESDAY AFTERNOON...LOOKS
LIKE THE FIRE DANGER IN OUR SOUTHWEST WILL INCREASE INTO THE VERY
HIGH CATEGORY.
WILL BE A MUCH MILDER NIGHT ON TUESDAY NIGHT WITH SOUTHERLY WINDS
STAYING UP IN A EVER TIGHTENING GRADIENT. WILL ALSO HAVE AN INCREASE
IN CLOUDS WITH DECENT LOW LEVEL MOISTURE TRANSPORT AND WAA ON A
STRENGTHENING LOW LEVEL JET OVER OUR WEST DURING THE NIGHT. BOTH THE
GFS AND THE NAM PAINT ABUNDANT RH...GENERALLY BELOW 800
MB...BEGINNING TO PUSH ACROSS THE CWA BY EARLY ON WEDNESDAY...SO
THREW IN SOME DRIZZLE FOR MOST PLACES DURING THE DAY ON WEDNESDAY.
AT THIS POINT...DO NOT THINK IT WOULD BE MUCH MORE THAN THAT WITH
THE MIDLEVELS REMAINING VERY DRY. EVEN UNDER A SOUTHERLY FLOW...WITH
THE CLOUD COVER...EXPECTING A COOLER DAY FOR MOST OF THE FA...WITH
HIGHS IN THE LOWER TO MID 50S IN OUR CENTRAL AND EAST...TO NEAR 60
IN OUR WEST.
MODELS ARE WANTING TO KEEP RELATIVELY SHALLOW LOW LEVEL MOISTURE
TRAPPED UNDER AN INVERSION OVER OUR AREA INTO THURSDAY...SO MAY KEEP
A GOOD BIT OF CLOUD COVER UNTIL AT LEAST EARLY IN THE DAY...BEFORE
BETTER MIXING IS ACHIEVED IN ADVANCE OF A COLD FRONT APPROACHING THE
AREA FROM THE WEST BY LATE AFTERNOON. HIGHS WILL AGAIN BE IN THE 50S
TO LOWER 60S. /JM
AVIATION
HIGH THIN CIRRUS WILL PERIODICALLY BE OVER AREA DURING FORECAST
PERIOD AND THATS ABOUT IT. AS PREVIOUS SHIFT THOUGHT...WE COULD SEE
A LITTLE PATCHY FOG AT KHON THIS MORNING BUT IT SHOULD BE MINIMAL SO
HAVE DECIDED TO KEEP IT OUT OF TAF. WITH SURFACE RIDGE OVER THE
AREA...WINDS SHOULD REMAIN RELATIVELY LIGHT DURING PERIOD.
HEITKAMP
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
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