Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 292330
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
630 PM CDT WED OCT 29 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 327 PM CDT WED OCT 29 2014

FAIRLY STRONG UPPER LEVEL WAVE WILL PUSH ACROSS THE AREA TONIGHT...A
120 KNOT JET STREAK DIVING FROM THE PACIFIC NW TOWARD THE CENTRAL
PLAINS ON THURSDAY. RESULT IS STRONG BUT GRADUALLY SHEARING DYNAMICS
FOR LIFT SPREADING ACROSS THE AREA...MOST CONCENTRATED THROUGH THE
NORTH...BUT THE OVERALL MOISTURE PROFILES ARE QUITE LACKING.
CURRENTLY A MASS OF SHOWERS PRESSING ACROSS SOUTHWEST NORTH DAKOTA
AND NORTHWEST SOUTH DAKOTA MOVING EAST SOUTHEAST WITHIN AREA OF
FORCING. THIS AREA OF LIFT WILL FIND BEST CHANCE FOR SHOWERS
EVOLVING BETWEEN 03Z AND 06Z ACROSS EAST CENTRAL SD INTO SW
MN...WITH LESSER CHANCES TO THE SOUTH. MUCH OF THE PRECIPITATION
COULD END UP AS VIRGA OR SPRINKLES AS IT PROGRESSES INTO THE
INCREASINGLY DRY LOW LEVEL AIR MASS...BUT STILL WARRANTS A LOW
COVERAGE POP...HIGHEST IN THE NORTHEAST.

ALONG WITH THE WAVE...A WIND SHIFT WILL PUSH ACROSS THE AREA FROM
THE WEST LATE EVENING AND EARLY OVERNIGHT. THIS WILL BRING A BRIEF
PASSAGE INTO THE WARMER SECTOR OF SYSTEM...SOON FOLLOWED BY
SOUTHEASTWARD CRASHING OF COLD FRONT ON THURSDAY MORNING. NORTHERLY
WINDS WILL BECOME A QUITE BLUSTERY 20 TO 30 MPH...AS LOW CLOUDS
INCREASE WITHIN STRONG COLD ADVECTION ZONE.  QUITE LIKELY THAT TEMPS
WILL TAKE A SIDESTEP MOST AREAS BY AFTERNOON...AND EVEN A FEW
DEGREES DROP WITH STRENGTH OF LOW LEVEL COLD ADVECTION AND CLOUDS.
NO DOUBT A BLUSTERY DAY THAT WILL REMIND MANY OF TUESDAY.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT WED OCT 29 2014

SURFACE HIGH PRESSURE BEGINS TO BUILD INTO THE REGION ON THURSDAY
NIGHT...WITH THE RIDGE AXIS BEING LOCATED THROUGH OUR WESTERN AREAS
BY 12Z ON FRIDAY. THIS WILL ALLOW WINDS TO DROP OFF THROUGH THE
JAMES RIVER VALLEY...AND WITH COLD AIR ADVECTION CONTINUING LEANED
TOWARD THE COLDEST GUIDANCE WITH LOWS DROPPING TO AROUND 20 OVER
THAT AREA. TO THE EAST...THERE WILL STILL BE ENOUGH OF A GRADIENT
THAT WINDS WILL NOT DROP OFF AS MUCH...SO WENT WITH LOWS IN THE MID
AND UPPER 20S.

CHILLY AIR WILL BE ENTRENCHED ACROSS THE REGION BY FRIDAY WITH 850
MB READINGS AVERAGING IN THE RANGE OF -2 TO 3 C IN THE
AFTERNOON...AND LOOKING AT HIGHS ONLY IN THE UPPER 30S TO LOWER 40S.
FORTUNATELY WINDS WILL REMAIN IN CHECK AS THE SURFACE RIDGE AXIS
SLIDES THROUGH THE REGION. AS HIGH PRESSURE MOVES EASTWARD A
TIGHTENING GRADIENT WILL RESULT IN WINDS PICKING UP IN OUR WEST ON
FRIDAY NIGHT...AND TEMPERATURES WILL STEADY OUT OR RISE DURING THE
OVERNIGHT THROUGH THAT AREA. EARLY LOWS WILL BE IN THE MID/UPPER 20S
THROUGH THE JAMES RIVER VALLEY...WHILE TEMPERATURES WILL STILL BE
CHILLY IN OUR EAST WITH LOWS IN THE LOWER 20S.

A STRONG SOUTHERLY FLOW DEVELOPS ON SATURDAY BEHIND THE EXITING HIGH
PRESSURE...AND WITH A TIGHTENING GRADIENT AND WINDS AROUND 40 KTS AT
THE TOP OF THE MIXED LAYER IT WILL BE A WINDY DAY. IN A WARM AIR
ADVECTION REGIME...IT WILL BE WARMER WITH HIGHS MID 40S TO LOWER 50S.

WITH AN UPPER LEVEL RIDGE OVERHEAD...SUNDAY WILL BE THE WARMEST OF
THE NEXT FEW. STILL BREEZY WITH HIGHS 50S TO NEAR 60. BY THE
BEGINNING OF NEXT WEEK AN UPPER LEVEL TROUGH PUSHES EASTWARD FROM
THE WESTERN CONUS...WITH SOME RAIN CHANCES IN OUR EAST FOR SUNDAY
NIGHT AND MONDAY IN A SPLIT FLOW PATTERN. TEMPERATURES APPEAR TO
REMAIN JUST ABOVE NORMAL THROUGH THE MIDDLE OF NEXT WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 630 PM CDT WED OCT 29 2014

VFR THROUGH 30/15Z WITH ISOLATED -SHRA BASED ABOVE 5K FEET. FROM
15Z TO 31/00Z CEILINGS 2-3K FEET AND SURFACE GUSTS TO 25 KNOTS
FROM THE NW OR N WILL SPREAD OVER THE AREA FROM THE NORTHWEST...
EXCEPT CONDITIONS REMAINING VFR SOUTHWEST OF A 9V9 TO PKS LINE.

&&

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

$$

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



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