Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 220347
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1047 PM CDT THU APR 21 2016

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 418 PM CDT THU APR 21 2016

SECONDARY FRONTAL BOUNDARY PUSHING THROUGH THE I 90 CORRIDOR AT MID
AFTERNOON. HAS HEATED OUT WELL IN ADVANCE INTO THE MID AND UPPER 60S
AND IN LAST HOUR OR TWO...ISOLATED SHOWERS HAVE DEVELOPED IN THE I
29 CORRIDOR TO COMPLIMENT THE RESIDUAL DEFORMATION BAND SHOWERS
LINGERING ACROSS NORTHWEST IOWA. THESE SHOWERS...AND EVEN AN
ISOLATED RUMBLE OF THUNDER...WILL CONTINUE TO PUSH SOUTH THROUGH THE
LOSS OF DIURNAL SUPPORT EARLY THIS EVENING.

FOR THE REMAINDER OF THE SHORT TERM...WILL BE QUIET. SURFACE RIDGE
WILL NOSE INTO THE REGION TONIGHT...WINDS WILL DIMINISH HEADING
THROUGH THE EVENING HOURS. CLEARING WILL CONTINUE TO PROGRESS
THROUGH THE AREA...BUT INDICATIONS ARE THAT SOME LOWER LEVEL
MOISTURE WILL HANG UP NEAR THE EASTERN BORDER WITH PERHAPS SOME
LOWER CLOUDS ATTEMPTING TO BACK INTO PARTS OF SW MN AND NW IA LATER
IN THE NIGHT.  A BIT TOO MUCH LINGERING GRADIENT REMAINS EAST OF I-
29 TO EXPECT TEMPERATURES TO BOTTOM OUT AT LOWEST POTENTIAL...BUT
WEST OF I-29 AND ESPECIALLY TOWARD THE MID JAMES VALLEY...LIKELY
COOLING TOWARD THE MID 30S COULD RESULT IN SOME PATCHY FROST.

SOUTHERLY WINDS WILL INCREASE ACROSS SOUTHEAST SOUTH DAKOTA ON
FRIDAY...BUT IN GENERAL WILL BE THE ONLY THING TO DIMINISH AN
OTHERWISE PLEASANT DAY. HIGHS WILL BE MILD...FROM LOWER 60S IN SW MN
AND NW IA...TO AROUND 70 IN SOUTH CENTRAL SD.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 418 PM CDT THU APR 21 2016

SATURDAY LOOKS LIKE A VERY WARM BUT WINDY DAY ACROSS THE REGION
AHEAD OF THE NEXT CUT OFF LOW MOVING INTO THE NORTHERN ROCKIES.
STRONG WARMING ALOFT...COPIOUS SUNSHINE AND MIXY SOUTHERLY SOUTHERLY
WINDS SHOULD ALLOW TEMPERATURES TO REACH WITHIN A FEW DEGREES ABOVE
OR BELOW 80. WIND SPEEDS WILL ALSO REACH NEAR ADVISORY LEVEL BY
AFTERNOON.

UPPER LOW SPINS INTO THE NORTHERN HIGH PLAINS ON SUNDAY...AND
WEAKENS AS IT MOVES EAST THROUGH THE REGION INTO MONDAY. MODELS ARE
IN DECENT AGREEMENT WITH THE TRACK OF THIS SYSTEM....WITH ONLY A FEW
SLIGHT DIFFERENCES. A WARM FRONT SETS UP ACROSS NORTHEAST SD SUNDAY
AFTERNOON...JUST NORTH OF THE FORECAST AREA. COULD SEE SOME ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS FORM IN THE WARM AIR
ADVECTION EAST OF I29 AND INTO THE HIGHWAY 14 CORRIDOR LATE SATURDAY
NIGHT INTO SUNDAY...HOWEVER MOISTURE IN THE LOW/MID LEVELS WILL BE
AN ISSUE. PRECIPITATION CHANCES INCREASE SUNDAY EVENING AND
OVERNIGHT AS THE LOW SHIFTS EASTWARD AND A COLD FRONT ARRIVES.

THE NEXT UPPER LEVEL CUT OFF LOW BARRELS INTO THE REGION MID
WEEK...AND WILL BRING YET ANOTHER ROUND OF WET WEATHER TO THE
NORTHERN PLAINS. MODELS ARE AGAIN IN DECENT AGREEMENT IN THE TIMING
AND TRACK OF THIS FEATURE...WHICH EMERGES IN THE HIGH PLAINS TUESDAY
EVENING AND SLOWLY WOBBLES EAST ACROSS THE REGION THROUGH AT LEAST
WEDNESDAY EVENING. THIS SYSTEM APPEARS TO BE A BIT COOLER AS
WELL...WHICH WILL KEEP HIGHS A LITTLE BELOW NORMAL. CLOUDS AND RAIN
SHOWERS WILL ACCOMPANY THIS SYSTEM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1041 PM CDT THU APR 21 2016

06Z TAFS ARE LIKELY GOING TO REFLECT VFR CONDITIONS WITH A COUPLE
OF CAVEATS. FIRST...STILL A LITTLE CONCERNED ABOUT PATCHY FOG
DEVELOPMENT IN THE JAMES RIVER VALLEY LATE TONIGHT AND EARLY
FRIDAY...RIGHT ALONG A SURFACE RIDGE AXIS WHICH WILL GIVE VERY
LIGHT WINDS IN THAT AREA. THEREFORE HEDGED WITH SOME MVFR TYPE FOG
FOR KHON...BUT AT THIS TIME DO NOT HAVE ENOUGH CONFIDENCE TO GO
ANY WORSE THEN THAT SINCE THE FOG MAY NOT FORM AT ALL. SECOND...
THERE ARE SOME INDICATIONS FROM THE LATEST NAM AND HRRR FIELDS
THAT THERE WILL BE ABUNDANT HUMIDITY IN THE VERY LOW LEVELS JUST
ABOVE THE SURFACE LATE TONIGHT THROUGH MID FRIDAY MORNING AT KSUX.
THE GROUND IS QUITE WET IN THAT AREA...SO IT MAY BE AN ARTIFACT OF
GROUND MOISTURE. BUT FOR A HEADS UP...DECIDED TO INCLUDE A
SCATTERED DECK AT 800 FEET JUST IN CASE SOME LOWER STRATUS FORMS
JUST BEFORE SUNRISE AND LINGERS INTO MID MORNING AT KSUX.

OTHERWISE CURRENTLY...UPPER END IFR TO MVFR STRATUS IS MOVING
SOUTHWARD ACROSS PARTS OF SOUTHWEST MN AND NORTHWEST IA. AT THIS
TIME...THE TRAJECTORY OF THESE CLOUDS SUGGEST THAT THEY WILL STAY
TOO FAR EAST TO IMPACT KSUX OR KFSD...BUT ESPECIALLY AT KSUX...IT
WILL BE CLOSE FOR A FEW HOURS.

&&

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

$$

SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...MJ



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