Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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575
FXUS63 KFSD 291950
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
250 PM CDT FRI APR 29 2016

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 250 PM CDT FRI APR 29 2016

AN UPPER LEVEL LOW OVER COLORADO WILL SLOWLY LIFT INTO NEBRASKA BY
SATURDAY. OUT AHEAD OF THE FEATURE WILL SEE INCREASING MIDLEVEL
THETA E ADVECTION AND DEVELOPING FRONTOGENESIS IN AREAS GENERALLY
FROM THE INTERSTATE 90 CORRIDOR AND SOUTHWARD FOR LATE TONIGHT INTO
SATURDAY. THERE WILL BE A PRETTY SHARP CUT OFF TO THE PRECIPITATION
TO THE NORTH...ESPECIALLY INTO SATURDAY AFTERNOON AS MOISTURE FIGHTS
A DRY NORTHEASTERLY FLOW IN THE MIDLEVELS. PRECIPITATION AMOUNTS
LOOK TO BE FAIRLY GENEROUS INTO SATURDAY EVENING THROUGH THE
MISSOURI RIVER CORRIDOR...AVERAGING AROUND 1.5 TO 2 INCHES THROUGH
THE AREA...TAPERING DOWNWARD TO JUST UNDER AN INCH ALONG THE I90
CORRIDOR. TO THE NORTH...RAINFALL AMOUNTS WILL BE MUCH
LESS...RUNNING ONLY NEAR A TENTH THROUGH THE HIGHWAY 14 CORRIDOR. IN
ADDITION TO THE RAINFALL...WINDS WILL BEGIN TO INCREASE LATE TONIGHT
AS THE GRADIENT INCREASES AS LOW PRESSURE WINDS UP TO THE
SOUTH...BECOMING FAIRLY WINDY ON SATURDAY AS MIXED LAYER WINDS
INCREASE TO 35 TO 40 KTS.

AS FOR TEMPERATURES FOR TONIGHT AND TOMORROW...IT WILL REMAIN FAIRLY
MILD TONIGHT WITH THE CLOUD COVER AND LOWS DROPPING INTO THE LOWER
TO MID 40S. HIGHS ON SATURDAY WILL STILL BE BELOW NORMAL WITH
CLOUDS/SHOWERS AND A COOL NORTHEASTERLY  SURFACE FLOW...TOPPING OUT IN
THE 50S THROUGH THE HIGHWAY 14 CORRIDOR WHERE THE RAIN POTENTIAL IS
LESS...TO MID 40S TO NEAR 50 THROUGH THE REMAINDER OF THE FORECAST
AREA.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 250 PM CDT FRI APR 29 2016

RAIN WILL GRADUALLY COME TO AN END ON SATURDAY NIGHT AS UPPER LEVEL
SUPPORT SHIFTS EAST AND MID LEVEL MOISTURE ERODES FROM THE NORTH.
MOST OF THE RAINFALL WILL BE SOUTH OF INTERSTATE 90 AND BY SUNDAY
MORNING SHOULD BE IN SOUTHERN PARTS OF NORTHWEST IOWA...BEFORE
EXITING LATE MORNING. WITH WINDS AND CLOUDS IN PLACE THROUGH THE
NIGHT WENT CLOSEST TO THE CONSRAW OUTPUT...SO MAINLY UPPER 30S NORTH
TO 40 TO 45 FROM INTERSTATE 90 SOUTH.

SUNDAY SHOULD PROVE TO BE A PRETTY NICE DAY AS CLOUDS ERODE FROM THE
NORTH AND WINDS AVERAGE ABOUT 10 TO 20 MPH. HIGHS WILL LIKELY BE IN
THE UPPER 50S TO LOWER 60S.

SUNDAY NIGHT INTO MONDAY WILL SEE A WEAK RIDGE OF HIGH PRESSURE MOVE
THROUGH WITH GOOD WESTERLY MIXING WINDS ON MONDAY. THIS SHOULD LEAD
TOWARDS LOWS IN THE MID TO UPPER 30S WHILE HIGHS ON MONDAY CLIMB
INTO THE MID 60S...MAYBE EVEN CLOSE TO 70 IN CENTRAL SOUTH DAKOTA.

IN THE OUTER PERIODS (TUESDAY THROUGH FRIDAY)...DEEP TROUGHING OVER
NORTH CENTRAL CANADA WILL GRADUALLY EXTEND SOUTH AND EAST INTO THE
OHIO VALLEY AS RIDGING BUILDS ACROSS THE ROCKIES AND THE WESTERN
HIGH PLAINS. THIS SHOULD SUPPORT DRY CONDITIONS AND MILD
TEMPERATURES...LIKELY FAIRLY CLOSE TO OR A BIT ABOVE THE SEASONAL
NORMALS. WITH DECENT AGREEMENT AMONGST THE MODELS AM NOT SEEING ANY
BIG CHANGES TOT HE GOING FORECAST. SO BASICALLY PLANNING FOR HIGHS
MAINLY IN THE 60S AND LOWS MAINLY IN THE 40S. WHILE THE WIND IS NOT
EXPECTED TO BE EXCESSIVELY STRONG...LIKELY GOING TO SEE GUSTS AROUND
25 MPH EACH DAY. THE ONLY THING TO REALLY WATCH DURING THIS TIME
FRAME WILL BE IF THE MODELS CAN COME IN TO SOME SORT OF AGREEMENT ON
THE NEAR SURFACE PATTERN. SOME VARIATIONS IN HANDLING SOME BACK DOOR
COLD FRONT POTENTIAL. ONE CASE IS THURSDAY WHERE THE GFS AT 925MB IS
+25 C NEAR KFSD WHILE THE ECMWF IS ABOUT +16...TURNING INTO A
DIFFERENCE OF SURFACE TEMPERATURE OF 80 TO 85 ON THE GFS TO NEAR 70
FOR THE ECMWF.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1201 PM CDT FRI APR 29 2016

MVFR STRATUS WILL REMAIN ACROSS MUCH OF THE AREA THROUGH THE TAF
PERIOD...THOUGH KHON MAY SCATTER OUT THROUGH THE AFTERNOON AND
EVENING. RAIN WILL BEGIN TO LIFT FROM THE SOUTH LATER
TONIGHT...AFFECTING KSUX AFTER 06Z AND KFSD BY MID MORNING ON
SATURDAY.

&&

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

$$

SHORT TERM...JM
LONG TERM...08
AVIATION...JM



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