Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 220921
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
321 AM CST THU JAN 22 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 311 AM CST THU JAN 22 2015

STRATUS SITUATED ACROSS THE AREA THIS MORNING IS EXPECTED TO ERODE
FROM WEST TO EAST THROUGH THE DAY AS 925 MB WINDS TRANSITION TO A
DRIER SOUTHWESTERLY FLOW. ALL MODELS ARE SUPPORTIVE OF THIS...THOUGH
DO LINGER THE CLOUDS IN OUR FAR EAST INTO LATE THIS AFTERNOON.
OTHERWISE...AS WINDS BECOME SOUTHWESTERLY BEHIND EXITING HIGH
PRESSURE TO THE SOUTHEAST...WILL HAVE A MODERATION IN TEMPERATURES
OVER YESTERDAY. THIS WILL PLAY OUT WITH HIGHS INTO THE UPPER 30S TO
NEAR 40 THROUGH MUCH OF THE SOUTH AND WEST...TAPERING BACK TO LOWER
30S FROM EAST CENTRAL SOUTH DAKOTA THROUGH SOUTHWESTERN MINNESOTA
INTO THE SPENCER/STORM LAKE CORRIDOR WHERE CLOUDS MAY HANG A LITTLE
LONGER AND THERMAL PROFILES ARE COOLER.

WARM AIR ADVECTION WILL CONTINUE THROUGH TONIGHT IN THE
SOUTHWESTERLY LOW LEVEL FLOW OUT AHEAD OF AN APPROACHING SURFACE
TROUGH. IN RESPONSE...IT WILL BE A RELATIVELY MILD NIGHT FOR THIS
TIME OF YEAR WITH LOWS MAINLY MID AND UPPER 20S.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 311 AM CST THU JAN 22 2015

ABOVE NORMAL TEMPERATURES CONTINUE THROUGHOUT THE MEDIUM AND
EXTENDED PORTIONS OF THE FORECAST. THE ONLY WEATHER CONCERNS WILL BE
FOCUSED ON FRIDAY AND AGAIN SATURDAY NIGHT AS SHORTWAVE ENERGY
PASSES THROUGH THE REGION.

FRIDAY...MODEL CONSENSUS BRINGS A WEAK SHORTWAVE THROUGH THE AREA
DURING THE DAY ON FRIDAY. LOW-LVL WARM ADVECTION WILL BRING THE
THERMAL RIDGE OVERHEAD BY FRIDAY AFTERNOON AHEAD OF A WEAK SFC
TROUGH. BARRING ANY SUBSTANCIAL IMPACT FROM INCREASING MID-UPR
LVL CLOUDS...MOST AREAS SHOULD REACH INTO THE 40S. GFS REMAINS THE
MOST SATURATED SOLUTION AS THIS SHORTWAVE MOVES
THROUGH...PRODUCING LIGHT QPF EAST OF I-29. GIVEN TRAJECTORY AND
PACIFIC MOISTURE FLOW...DRIER SOLUTIONS MAY BE MORE CORRECT.
REGARDLESS...WOULD NOT BE SHOCKED TO HEAR OF A FEW SPRINKLES.

SATURDAY AND SUNDAY...YET ANOTHER SHORTWAVE WILL CREST THE WESTERN
CONUS RIDGE AND TRACK SOUTHEASTWARD THROUGH THE REGION SATURDAY
NIGHT AND SUNDAY. MODELS GUIDANCE HAS DRIFTED A BIT FURTHER APART
TONIGHT WITH TRACK AND INTENSITY OF THE WAVE...BUT GENERALLY
STILL ADVERTISE A WEAK AND SOMEWHAT DISORGANIZED SYSTEM. GIVEN THE 150
KNOT JET STREAK PUSHING THIS WAVE SOUTHEAST...AND LEFT EXIT REGION
OF THAT JET PLANTED NEARBY...LIGHT QPF LATE SATURDAY INTO SUNDAY
SEEMS LIKELY...BUT WHETHER IT IS NEARBY OR JUST NORTH AND EAST OF
THE CWA REMAINS IN QUESTION. GIVEN TEMPERATURES REMAINING ABOVE
NORMAL AS THIS WAVE MOVES THROUGH...A LIGHT MIXTURE OF RAIN/SNOW
WOULD BE EXPECTED.

MONDAY THROUGH WEDNESDAY...THE BROAD WESTERN RIDGE WILL TRY TO
EXPAND EASTWARD EARLY NEXT WEEK PUSHING WARMER AIR INTO THE AREA.
IN FACT...THE WARMEST READINGS MAY ARRIVE BY NEXT TUESDAY AND
WEDNESDAY...BUT THE DEGREE OF WARMING IS IN QUESTION.  925MB TEMPS
OFF THE GFS ARE ONLY IN THE 0 TO +3 RANGE...WHILE THE ECMWF AND EVEN
THE GEM ARE MUCH MUCH WARMER...WITH INCREDIBLE 925MB TEMPS OF +10
TO +13C! IT IS A BIT EARLY TO GET TOO EXCITED ABOUT THE DEGREE OF
POTENTIAL WARMTH ON DAY 7 GIVEN HOW DIFFICULT IT CAN BE TO
MAXIMIZE THIS TYPE OF POTENTIAL GIVEN MODEL VARIABILITY IN THE
EXTENDED PORTIONS OF THE FORECAST. REGARDLESS SOMETHING TO KEEP AN
EYE ON AS WE HEAD INTO THE WEEKEND.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1054 PM CST WED JAN 21 2015

SWATH OF MVFR CEILINGS ARE EXPECTED TO BEGIN DISSIPATING FROM WEST
TO EAST OVERNIGHT AS LOW LEVEL WINDS SHIFT WESTERLY AND DRIER AIR
BEGINS WORKING INTO THE REGION. STILL A BIT OF UNCERTAINTY WITH
THE NAM HOLDING ONTO LOW CEILINGS INTO THE DAY ON THURSDAY...WHILE
THE GFS AND HRRR SUPPORTS THE DRYING SOLUTION. AM STILL FAVORING
THE DRYING SOLUTION AS SKIES BEGIN CLEARING JUST WEST OF THE
FORECAST AREA. WINDS WILL BE TURNING LIGHT THEN SOUTHWESTERLY AT
THE SURFACE BUT SHOULD REMAIN LESS THAN 15 KT DURING THE DAY
THURSDAY.


&&

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

$$

SHORT TERM...JM
LONG TERM...DUX
AVIATION...


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