Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 262016
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
316 PM CDT SUN OCT 26 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 316 PM CDT SUN OCT 26 2014

LOW LEVEL MOISTURE WILL CONTINUE TO SPREAD IN FROM THE SOUTH
TONIGHT...THOUGH MODELS HAVE BEEN WAY TOO FAST BRINGING IT IN. THE
BAND OF HIGHER BASED LOW CLOUDS HAS MOVED OUT OF THE AREA...LEAVING
TONIGHT WITH A MOSTLY CLEAR START WITH SOME CIRRUS SPREADING OVER
FROM THE SOUTHWEST. LATER TONIGHT...STILL EXPECT A LOWER STRATUS
DECK TO DEVELOP AND SPREAD INTO THE NORTHWEST IA AND SOUTHWEST MN
PARTS OF OUR FORECAST AREA. THE STRONG WINDS...WHICH IN CONTRAST
WERE WELL HANDLED BY THE MODELS...WILL DROP OFF EARLY AS A BROAD
SURFACE TROUGH MOVES IN FROM THE WEST. A DECENT UPPER WAVE COMING IN
BEHIND THE SURFACE TROUGH AND COLD FRONT WILL START TO INCREASE
MIDDLE AND HIGH CLOUDS FROM THE WEST LATE TONIGHT. HAVE KEPT A LIGHT
SHOWER CHANCE SOUTHWEST FOR VERY LATE TONIGHT. LOW TEMPERATURES
SHOULD BE IN THE MID 40S NORTHWEST TO THE LOWER 50S SOUTHEAST.

THE STRENGTH OF THE APPROACHING WAVE ASSURES THERE WILL BE A BAND
OF POSTFRONTAL SHOWERS MOVING ACROSS PART OF THE AREA MONDAY. THIS
BAND IS LIKELY TO BE FAIRLY NARROW AND START TO SWING MORE NORTHEAST
AS THE UPPER SYSTEM DOES THE SAME. BECAUSE OF THAT AND THE MARGINAL
MOISTURE ADVECTION AT MID LEVELS...WILL KEEP POPS FOR MONDAY IN THE
HIGH CHANCE AREA...50 PERCENT...IN AN AREA JUST WEST OF FSD WITH
LOWER CHANCE OR SLIGHT CHANCES SOUTHEAST AND OVER THE NORTHWEST
CORNER. THE BEST SHOWER CONCENTRATION SHOULD MOVE OUT TO THE
NORTHEAST DURING THE DAY WITH A LESSER COVERAGE OF SHOWERS
LINGERING SOUTHEAST THROUGH THE AFTERNOON.

COOLER AIR WILL BEING TO SPREAD IN ON NORTHWEST WINDS...BUT THE
COOLEST AIR WILL NOT COME IN DURING THE DAY AHEAD OF AN APPROACHING
SECONDARY WAVE. HIGHS ARE EXPECTED TO BE IN THE UPPER 50S TO LOWER
60S.


.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 316 PM CDT SUN OCT 26 2014

COOL AND DRY NORTHWEST FLOW ARRIVES BEHIND THE EXITING SHORTWAVE AND
PERSISTS THROUGH THE END OF THE WORK WEEK. LOW TO MID LEVEL
STRATOCUMULUS IS LIKELY MONDAY NIGHT ACROSS THE NORTHERN FORECAST
AREA...EXPANDING INTO ALL BUT SOUTH CENTRAL SD INTO TUESDAY. DECENT
COLD AIR ADVECTION PUSH WILL BRING ABOUT BRISK NORTHWEST WINDS ON
TUESDAY AROUND 15 TO 20 MPH WITH HIGHER GUSTS THROUGHOUT THE DAY.
MONDAY NIGHT WILL SEE CHILLY LOW TEMPERATURES NEAR FREEZING IN THE
MID TO UPPER 30S. HIGHS ON TUESDAY WILL ONLY REACH THE UPPER 40S TO
LOWER 50S BUT WILL FEEL CHILLY WITH THE GUSTY WINDS. DESPITE THE
WINDY CONDITIONS...THE COOLER TEMPERATURES AND HIGHER HUMIDITY
VALUES WILL KEEP FIRE CONDITIONS BELOW RED FLAG WARNING.

MODELS CONTINUE TO BRING A WEAK WAVE THROUGH THE AREA ON WEDNESDAY
EVENING OR NIGHT...BUT THE SUPPORT IS LACKING AND CONDITIONS SHOULD
REMAIN DRY WITH INCREASED MID AND HIGH CLOUDS. RIDGING SHARPENS OVER
THE ROCKIES LATER IN THE WEEK...WHILE TROUGHING DIGS INTO THE GREAT
LAKES. THIS AMPLIFIED PATTERN BRINGS ANOTHER SHOT OF COOLER AIR INTO
THE NORTHERN PLAINS ON THURSDAY NIGHT AND FRIDAY. THE GEM AND TO A
LESSER EXTENT THE ECMWF...NUDGE THE UPPER RIDGE AXIS FURTHER EAST
INTO THE HIGH PLAINS THAN THE GFS ON FRIDAY...RESULTING IN A
SLIGHTLY WARMER PATTERN FOR OUR EASTERN HALF...AND MUCH WARMER IN
THE FAR WEST. WILL CONTINUE WITH THE CONSERVATIVE ALLBLEND VALUES
WITH HIGHS IN THE MID 40S TO LOWER 50S UNTIL A GREATER CONSENSUS CAN
BE REACHED.  TEMPERATURES ARE ON A WARMING TREND FOR THE WEEKEND AS
THE RIDGE SLIDES SLOWLY EASTWARD. DRY CONDITIONS CONTINUE.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1231 PM CDT SUN OCT 26 2014

VFR THROUGH 27/06Z. A FEW SURFACE GUSTS TO 25 KNOTS NORTHERN PART
OF THE FORECAST AREA UNTIL 26/22Z. 27/06Z-18Z VFR WILL CONTINUE
NORTHWEST OF A SUX/MWM LINE WITH SLOWLY LOWERING CEILINGS AND
DEVELOPING SCATTERED -SHRA...WHILE CEILINGS LOWER TO 1-3K FEET
ALONG AND SOUTHEAST OF THE SUX/MWM LINE. AREAS OF VISIBILITY 3-5SM
IN LIGHT FOG/BR WILL BE POSSIBLE IN THIS AREA 27/09Z-15Z.


&&

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

$$

SHORT TERM...
LONG TERM...
AVIATION...



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