Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 230851
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
351 AM CDT SUN AUG 23 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CDT SUN AUG 23 2015

CORE OF INTENSE UPPER LEVEL LOW SLIPPING EASTWARD ACROSS NORTHERN
MINNESOTA...WRAPPING BAND OF LOWER CLOUDINESS SOUTHWARD ACROSS
EASTERN SOUTH DAKOTA AND SOUTHWEST MINNESOTA. STRONG GRADIENT IN
PLACE...AS SECONDARY BAND OF PRESSURE RISES BEHIND UPPER TROUGH OF
2-3 HPA/3H PUSH THROUGH NORTHEASTERN SD IN THE PREDAWN HOURS.

BRISK WINDS WILL CONTINUE TO BE THE FOCUS OF THE SHORT TERM. HAVE
HAD DIFFICULTY GETTING MORE THAN A COUPLE OF SITES TO WIND ADVISORY
CRITERIA IN THE OVERNIGHT HOURS. GREATEST INSTABILITY OF THE LOWER
LEVELS REMAINS BELOW THE CLOUD DECK AS IT PUSHES THROUGH THE I-29
CORRIDOR...KEEPING GREATEST COUPLING TOWARD THE 35-40 KNOT WINDS AT
THE TOP OF THE MIXED LAYER. FROM RAP/HRRR AND VARIOUS SHORT RANGE
MODELS...THE BAND OF STRONGER WINDS JUST OFF SURFACE IS FORECAST TO
CONTINUE TO PUSH EAST AND LIFT NORTHEAST THROUGH THE REMAINDER OF
THE OVERNIGHT AND EARLY MORNING HOURS...MUCH AS THE AREA OF
CLOUDINESS WHICH MAINTAINS THAT EXTRA BIT OF DESTABILIZATION. FOR
THESE REASONS...HAVE NEITHER EXPANDED ADVISORY THROUGH THE NORTHERN
BUFFALO RIDGE LOCATIONS IN SW MN NOR EXTENDED ACROSS THE EXTREME
EAST CENTRAL PORTIONS OF SD...AS EXPECT CONDITIONS WILL REMAIN
MARGINAL WITH SUSTAINED WINDS 25 TO 30 MPH AND GUSTS TO AROUND 40
MPH. REMAINDER OF LOCATIONS HAVE CANCELLED THE WIND ADVISORY WITH
THREAT OF STRONGEST WINDS PASSED.

ONCE BAND OF CLOUDS PUSHES THROUGH...SHOULD BE A SUNNY DAY ACROSS
THE AREA...WITH PERHAPS A FEW RAGGED CUMULUS NEAR THE EASTERN BORDER
OF THE CWA. TEMPS RUNNING ABOUT A MONTH AHEAD...CORRESPONDING TO THE
FIRST DAY OF AUTUMN...WITH UPPER 60S TO LOWER 70S.  WITH VERY DRY
AIR AND DIMINISHED WINDS WITHIN THE RIDGE AXIS TONIGHT AS IT DRIFTS
OVER THE WESTERN HALF OF THE CWA TONIGHT...LIKELY TO SEE SOME FAIRLY
CHILLY TEMPERATURES...ESPECIALLY LOWER ELEVATIONS WEST OF I 29...AND
NOT OUT OF THE QUESTION TO GET INTO SHOUTING DISTANCE OF A FEW
RECORD LOW TEMPERATURES WHEN TEMPS DIP TO LOWER TO MID 40S.


.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 348 AM CDT SUN AUG 23 2015

A QUIET START TO THE WORK WEEK WITH HIGH PRESSURE DOMINATING ACROSS
THE REGION FOR MONDAY AND TUESDAY. THIS WILL PLAY OUT TO DRY
CONDITIONS AND BELOW NORMAL TEMPERATURES BOTH DAYS. HIGHS WILL BE
MAINLY 70S...APPROACHING 80 IN OUR SOUTH CENTRAL SD ZONES. LOWS ON
MONDAY NIGHT WILL BE MID 40S TO LOWER 50S.

THE SURFACE RIDGE BEGINS TO PUSH OFF TO THE EAST ON WEDNESDAY...WITH
A SOUTHERLY LOW LEVEL FLOW RETURNING TO THE REGION ON THE BACKSIDE
OF THE HIGH. THIS WILL RESULT IN SUBTLE WARMING ON WEDNESDAY WITH
HIGHS INTO THE MID 70S TO LOWER 80S.

FOR THURSDAY THROUGH SUNDAY...UPPER LEVEL RIDGING OVER THE CENTRAL
CONUS WILL BE THE OVERALL THEME...WITH MODEL DIFFERENCES IN THE
HANDLING OF SHORTWAVES PUSHING THROUGH THE RIDGE. MODEL CONSENSUS
WOULD SUGGEST THAT THE BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS
WOULD COME SOMETIME IN THE THURSDAY TO FRIDAY TIME FRAME...WITH
LESSER CHANCES FOR THE UPCOMING WEEKEND. TEMPERATURES THROUGH THE
PERIOD WILL BE CLOSE TO NORMAL FOR THIS TIME OF YEAR FOR THURSDAY
INTO SATURDAY...WITH HIGHS JUST EITHER SIDE OF 80 AND LOWS JUST
EITHER SIDE OF 60. MAY CLIMB TO JUST ABOVE NORMAL BY THE END OF THE
PERIOD WITH RISING UPPER LEVEL HEIGHTS AS THE RIDGE NUDGES EASTWARD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1033 PM CDT SAT AUG 22 2015

GUSTY WEST-NORTHWEST WINDS WILL BE PRIMARY AVIATION CONCERN THROUGH
THIS PERIOD. GUSTS 20-30KTS WILL BE MOST PREVALENT THROUGH THE
PERIOD...THOUGH A PERIOD OF STRONGER WINDS IS EXPECTED DURING THE
OVERNIGHT AS SECONDARY PUSH OF COLD ADVECTION MIXES SOME STRONGER
WINDS TO THE SURFACE IN THE 05Z-10Z WINDOW. STRONGEST WINDS WITH
THIS SURGE WILL AFFECT THE NORTHERN PORTIONS OF THE FORECAST AREA...
INCLUDING KHON...WHERE A PERIOD OF MVFR CEILINGS AND SPOTTY LIGHT
SHOWERS MAY ALSO OCCUR. WINDS MAY DIMINISH AGAIN DURING THE EARLY
MORNING...BUT DIURNAL MIXING WILL BRING GUSTS BACK INTO 20-35KT
RANGE BY MID-LATE SUNDAY MORNING. STRONGEST DAYTIME WINDS SHOULD
IMPACT LOCATIONS FROM EAST CENTRAL SD INTO SOUTHWEST MN...MAINLY
NORTHEAST OF TAF LOCATIONS.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 7 AM CDT THIS MORNING FOR SDZ039-040-055.

MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...CHAPMAN
LONG TERM...JM
AVIATION...JH



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