Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 240350
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1050 PM CDT TUE SEP 23 2014

.UPDATE...
ISSUED AT 952 PM CDT TUE SEP 23 2014

THE OVERALL FORECAST TREND IS ON TARGET. INCREASED POPS FOR THIS
EVENING A FEW HOURS AGO FOR OUR EASTERN ZONES...AS AN AREA OF
CONVECTION DEVELOPED IN EXTREME NORTHWEST IA ALONG SOME WARM AIR
ADVECTION LATE TUESDAY AFTERNOON. THIS CONVECTION THEN FILLED IN
SOME AS IT LIFTED SLOWLY NORTHEASTWARD. THE OTHER AREA OF PRECIP
WHERE WE ALREADY HAD FAIRLY HIGH POPS IS IN OUR SOUTHERN ZONES
ALONG THE NEXT VORT MAX. THAT RAINFALL WILL LAST INTO THE
OVERNIGHT HOURS...WITH ONLY SMALL CHANCES FOR RAIN ELSEWHERE IF
ANY AT ALL.

WITH THE EXPANSE OF CLOUD COVER EXPECTED...LOWS STILL DO NOT LOOK
TOO BAD WITH WIDESPREAD MID 50S IN STORE. SOME LATE NIGHT CLEARING
COULD ALLOW SOME PATCHY FOG TO DEVELOP IN OUR WESTERN ZONES.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 249 PM CDT TUE SEP 23 2014

VORTICITY LOBE PRESENTLY LIFTING THROUGH THE REGION THIS
AFTERNOON...WITH PRECIPITATION SLOWLY PULLING OFF TO THE NORTH AND
EAST AS EXPECTED. ANTICIPATE THIS TREND TO CONTINUE THROUGH THE
EVENING HOURS...BEFORE REDEVELOPMENT OCCURS LATER TONIGHT AS A
SECONDARY VORT LOBE SWINGS AROUND THE BASE OF AN APPROACHING UPPER
LEVEL TROUGH. LOOKS LIKE THE BETTER FORCING WITH THIS FEATURE WILL
SWING ACROSS THE SOUTHERN PORTIONS OF THE CWA OVERNIGHT...BRINGING
THE BETTER RAIN CHANCES INTO THE LOWER MISSOURI RIVER CORRIDOR AND
LOWER NORTHWESTERN IOWA ZONES. THERE DOES APPEAR TO BE BETTER
ELEVATED INSTABILITY TONIGHT...WITH ELEVATED MUCAPE VALUES HOVERING
AROUND 500 J/KG...SO INCLUDED ISOLATED THUNDER IN THE FORECAST. DO
EXPECT SOUTHEASTERLY WINDS TO FALL OFF IN OUR WEST TONIGHT...AND
WITH THE POTENTIAL FOR SOME CLEARING OVER THAT AREA INTRODUCED
PATCHY FOG OVER THERE FOR LATE TONIGHT INTO MID MORNING ON
WEDNESDAY. ANOTHER MILD NIGHT EXPECTED WITH LOWS IN THE MID AND
UPPER 50S.

ON WEDNESDAY THE VORT LOBE PULLS OFF TO THE EAST...WITH RAIN CHANCES
DIMINISHING THROUGH THE MORNING HOURS. THERE WILL BE DECREASING
CLOUDS THROUGH THE DAY...AND WITH THIS AND WARMING PROFILES IT WILL
BE A MUCH NICER DAY...WITH HIGHS AROUND 70 IN THE EAST TO AROUND 80
IN THE FAR WEST.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 249 PM CDT TUE SEP 23 2014

THURSDAY AND FRIDAY LOOK WARM WITH AN INCREASING SOUTHERLY
WIND...LIKELY BECOMING A BIT BREEZY ON FRIDAY. BOTH DAYS...FRIDAY
BEING A BIT WARMER...WILL SEE HIGHS MAINLY IN THE 80S WITH LOWS IN
THE 50S TO LOWER 60S.

IN THE OUTER PERIODS (SATURDAY THROUGH TUESDAY)...ABOVE NORMAL
TEMPERATURES THROUGH THE PERIOD WITH ONLY A SMALL CHANCE FOR
THUNDERSTORMS ON TUESDAY. FAR ENOUGH OUT THE CONFIDENCE IS PRETTY
SMALL...ESPECIALLY GIVEN A CHANCE THAT THE WAVE COULD WRAP UP TO THE
WEST AND PUSH NORTHWARD. BEYOND THIS SMALL CHANCE A VERY STRONG
UPPER LEVEL RIDGE THAT ENCOMPASSES THE EASTERN PORTION OF THE
ROCKIES INTO THE WESTERN ATLANTIC OCEAN WILL KEEP ALMOST SUMMER LIKE
TEMPERATURES IN THE FORECAST. IN FACT THIS RIDGE LOOKS A BIT LIKE
THE ONE THAT SET UP CAMP FOR A MONTH OR SO BACK IN MARCH OF 2012. IF
THE DEEP WEST COAST TROUGH IS SLOWER TO EJECT OR EJECTS IN MORE OF A
NORTHWARD FASHION AROUND THE PERIFERY OF THE HUGE RIDGE WE COULD SEE
AN EXTENDED PERIOD OF ABOVE NORMAL TEMPERATURES...BUT FOR NOW THE
ABOVE NORMAL CONDITIONS APPEAR AS THOUGH THEY WILL BEGIN TO BERAK
DOWN ON TUESDAY INTO WEDNESDAY AS A PIECE OF ENERGY EJECTS ONTO THE
NORTHERN PLAINS FROM THE DEEP WEST COAST TROUGH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1050 PM CDT TUE SEP 23 2014

SHOWERS WILL BE AFFECTING THE SOUTHEAST/ FAR EAST PART OF THE AREA
THROUGH 12Z...FROM FSD NORTHEAST EAST AND SOUTH. SOUTHEASTERLY
INFLOW OF LOW LEVEL DRY AIR APPEARS STRONGER THAN MODELS ARE
SHOWING AND NOW EXPECT LIMITED LOWERING TO AREAS OF MVFR CEILINGS
IN AND BEHIND THE SHOWER AREA. FURTHER WEST...CLEARING AREA STILL
LOOKS PRIMED FOR SOME FOG DEVELOPMENT AFTER 09Z AND WILL KEEP SOME
LOWERING TO IFR IN KHON. AFTER 14Z STEADY IMPROVEMENT FROM THE
WEST TO VFR 14Z-17Z. VFR SHOULD PREVAIL 18Z-25/06Z WITH SKIES
BECOMING CLEAR.

&&

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

$$

UPDATE...MJ
SHORT TERM...JM
LONG TERM...08
AVIATION...


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