386 
FXUS63 KFSD 261726
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1220 PM CDT FRI OCT 26 2012


.DISCUSSION.../ISSUED AT 1040 AM CDT/
BIGGEST CHALLENGE TODAY REMAINS TO BE CLOUD COVER ACROSS THE AREA. 
CURRENT SATELLITE IMAGE SHOWING MUCH OF THE REGION SOCKED IN WITH 
STRATUS. THE RUC CONTINUES TO LOOK LIKE THE MODEL OF CHOICE WITH 
REGARD TO LOW LEVEL RH FIELDS...SO FOLLOWED THIS IN KEEPING CLOUDS 
OVER THE AREA THROUGH AT LEAST LATE THIS AFTERNOON OR EVENING. WITH 
THE THOUGHT THAT LITTLE SUNSHINE WILL BE REALIZED...LOWERED HIGHS A 
DEGREE OR TWO. UPDATES OUT.

&&

.AVIATION.../FOR THE 18Z TAF ISSUANCE/
LOW CLOUD DECK LOOKS TO REMAIN ACROSS THE AREA AT LEAST INTO THIS 
EVENING...AND EXPECT CEILINGS TO BE WITHIN THE LOWER VFR RANGE. 
CONFIDENCE IS LOW WITH REGARD TO WHETHER CEILINGS WILL BREAK UP 
TONIGHT WITH MODELS HANDLING LOW LEVEL RELATIVE HUMIDITY FIELDS 
POORLY. SOMEWHAT GUSTY NORTHWESTERLY WINDS TODAY WILL DROP OFF THIS 
EVENING...BECOMING VARIABLE TRENDING TOWARD SOUTHERLY OVERNIGHT.

&&


.PREV DISCUSSION.../ISSUED AT 336 AM CDT/
MAIN FORECAST PROBLEM TODAY WILL BE THE CLOUD COVER. MODELS HAVE 
HANDLED THE LOW CLOUD COVER VERY POORLY. DRIER H85 AIR OVER MN AND 
IOWA HAVE BROUGHT SOME CLEARING TO SECTIONS OF NORTHWEST IOWA AND 
THIS DRIER AIR IS PROGGED TO BACK WEST TO NEAR I29 THIS 
MORNING...AND THEN INCREASE AGAIN DURING THE AFTERNOON FROM THE 
WEST. SO WILL LIKELY SEE MORE SUNSHINE EAST OF I29 TODAY WHILE 
WESTERN CWA REMAINS MOSTLY CLOUDY. HOW FAR WEST ANY CLEARING GETS 
TODAY IS AN ISSUE. AS FAR WEST AS I29 MAY BE OPTIMISTIC BASED ON 
CURRENT TRENDS MOST AREAS WILL LIKELY STAY MOSTLY CLOUDY THROUGH THE 
DAY WITH SOME CLEARING DURING THE NIGHT. WILL BE ANOTHER COLD DAY 
WITH HIGHS ONLY IN THE UPPER 30S TO MID 40S.

FOCUS THEN SHIFTS TO SATURDAY AND WAVE DROPS SOUTHEAST IN NORTHWEST 
FLOW ALOFT. ASSOCIATED WEAK INVERTED TROF MOVES INTO WESTERN CWA 
SATURDAY AND THEN WEAKENS SATURDAY NIGHT. AM EXPECTING SOME LIGHT 
PRECIPITATION TO DEVELOP ACROSS WESTERN CWA SATURDAY IN THE FORM OF 
LIGHT RAIN OR LIGHT SNOW. THIS PRECIPITATION MAY HAVE A HARD TIME 
GETTING MUCH FURTHER EAST OF I29 SATURDAY NIGHT AS SOMEWHAT OF A 
KEEWATIN HIGH KEEPS LOWER LEVELS DRY TO THE EAST OF I29 AND THUS 
WILL BE HARD TO SATURATE LOW LEVELS AS WEAK WAVE MOVES EAST OF I29 
LATER SATURDAY NIGHT. SO WILL KEEP HIGHEST PRECIPITATION CHANCES 
WEST OF I29 SATURDAY NIGHT WITH ONLY A CHANCE OF LIGHT SNOW TO THE 
EAST. COULD SEE AN INCH OR SO OF SNOW WEST OF I29 SATURDAY LIGHT 
WITH PERHAPS LITTLE IF ANY SNOW TO THE EAST. WITH INCREASING CLOUD 
COVER AND LOW LEVEL COLD SOUTHEAST FLOW...HIGH TEMPERATURES WILL 
STRUGGLE TO CLIMB THROUGH THE 40S...ALTHOUGH HIGHS COLD TOP NEAR 50 
ALONG THE MISSOURI RIVER.

AS SYSTEM PULLS AWAY...CWA IS LEFT IN LOW LEVEL SOUTHEAST FLOW AND 
CLOUD COVER ON SUNDAY MAY BE HARD TO CLEAR AS STRATUS MAY BE FAIRLY 
WIDESPREAD AGAIN. DRIER AIR DOES MOVE INTO WESTERN CWA DURING THE 
DAY...BUT THE QUESTION IS IF THIS WILL BE ENOUGH TO SCOUR OUT LOWER 
CLOUDS. FOR NOW WILL BE A LITTLE MORE PESSIMISTIC AND ONLY HAVE 
SKIES BECOME PARTLY CLOUDY ACROSS THE WEST. TEMPERATURES WILL REMAIN 
COLD WITH HIGHS AGAIN ONLY IN THE 40S MOST PLACES.

BELOW NORMAL TEMPERATURES WILL PERSIST ON MONDAY WITH BLOCKING 
PATTERN OFF EAST COAST KEEPS COOLER AIR FUNNELING SOUTHEAST ACROSS 
CWA.

TUESDAY AND WEDNESDAY SHOULD BE A BIT WARMER...BUT THAT WILL BE 
DEPENDENT ON HOW STORM OFF EAST COAST EVOLVES. WITH RETROGRADING 
LOW...COOLER TEMPERATURES LIKELY TO REMAIN IN PLACE ACROSS THE CWA 
AND NOT AS PROGRESSIVE EAST AS MODEL MAY INDICATE. SO NOT 
SIGNIFICANTLY WARMER MONDAY TUESDAY THROUGH THURSDAY. WILL LEAVE 
FORECAST DRY AFTER SATURDAY NIGHT...BUT A WEAK WAVE DROPPING 
SOUTHEAST TUESDAY COULD PRODUCE SOME LIGHT RAIN...MAINLY OVER 
WESTERN CWA AS HIGH PRESSURE OVER THE WESTERN GREAT LAKES REGION 
BLOCKS PROGRESSION FURTHER EAST.   

&&


.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$