Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 182340
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
640 PM CDT FRI APR 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 247 PM CDT FRI APR 18 2014

VERY WINDY INTO THE EVENING MOST AREAS...ESPECIALLY WEST OF
INTERSTATE 29. WILL KEEP THE WIND ADVISORY IN PLACE THROUGH 8PM AND
ALMOST COULD HAVE ADDED THE INTERSTATE 29 CORRIDOR BUT WITH WINDS
JUST NEAR ADVISORY AND THOSE STRONGEST WINDS LIKELY DIMINISHING A
BIT TOWARDS 7PM WILL JUST CONTINUE WITH 20 TO 35 MPH. THE REMAINDER
OF THE NIGHT WILL REMAIN FAIRLY BREEZY AS WELL WITH WINDS AVERAGING
ABOUT 15 TO 30 MPH IN MOST LOCATIONS. THEY SHOULD WEAKEN A BIT IN
THE FAR WESTERN CWA TOWARDS SUNRISE AS THE INCOMING FRONT MOVES IN.
WILL CONTINUE THE THREAT FOR ISOLATED TO SCATTERED SHOWERS MAINLY
NORTH OF INTERSTATE 90 AFTER MIDNIGHT. INSTABILITY PRETTY SMALL AND
MID LEVEL CONVERGENCE NOT REAL STRONG SO A VERY ISOLATED LIGHTNING
STRIKE NOT IMPOSSIBLE BUT SHOULD BE LESS THAN 20 PERCENT COVERAGE.
WILL LEAN TOWARDS THE MILD SIDE OF GUIDANCE AS WELL WITH LOWS MAINLY
48 TO 53. IF WINDS ARE AS STRONG AS EXPECTED AND CLOUDS ARE A LITTLE
THICKER THAN EXPECTED LOWS COULD BE ANOTHER COUPLE OF DEGREES WARMER.

ON SATURDAY THE FRONT WILL GRADUALLY WORK THROUGH THE CWA. WITH THE
MAIN UPPER LEVEL WAVE SHEARING OFF TO THE NORTHEAST FORCING ALONG
THE FRONT REMAINS WEAK THROUGH THE DAY. THE EXCEPTION WILL BE LATE
AFTERNOON IN THE FAR SOUTHERN CWA WHERE A WAVE IS EXPECTED TO MOVE
THROUGH NEBRASKA AND INTERSECT THE BOUNDARY. INSTABILITY LIKELY
ENOUGH TO PRODUCE A FEW THUNDERSTORMS BUT NOT ENOUGH TO PRODUCE ANY
SEVERE THUNDERSTORMS. TEMPERATURES FAIRLY DEPENDENT UPON CLOUD COVER
AND ISOLATED SHOWER COVERAGE SO WILL MAINTAIN MID TO UPPER 60S OVER
WESTERN AND NORTHERN PARTS OF THE CWA WHILE MUCH OF NORTHWEST IOWA
WILL STAY ON THE WARM SIDE OF THE FRONT AND FROM SIOUX CITY TO STORM
LAKE THE MID TO UPPER 70S WILL BE LIKELY.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 247 PM CDT FRI APR 18 2014

AS THE UPPER LOW DRIVING THE SATURDAY FRONT LIFTS NORTHEAST INTO
CANADA...A SOUTHWESTERLY UPPER FLOW WILL REMAIN IN PLACE OVER THE
SOUTHEAST PART OF THE FORECAST AREA. INCREASING LOW AND MID LEVEL
MOISTURE POOLING NEAR THE FRONTAL AND SHORT WAVE BOUNDARIES WILL BE
LEFT HANGING AS THE WAVE PULLS NORTHEAST. MEANWHILE ANOTHER WEAK
WAVE APPROACHES FROM THE SOUTHWEST...SO RAINFALL OVER NORTHWEST IOWA
AND FAR SOUTHEAST SOUTH DAKOTA SHOULD CONTINUE TO SLOWLY DEVELOP
SATURDAY NIGHT INTO SUNDAY. WHILE SUPPORT DOES NOT APPEAR TO BE
ENOUGH FOR WIDESPREAD RAIN...THE AVAILABLE MOISTURE AND SOME DEGREE
OF INSTABILITY IS LIKELY TO TRIGGER SCATTERED TO NUMEROUS SHOWERS
AND A FEW THUNDERSTORMS. AM TARGETING SATURDAY NIGHT THROUGH SUNDAY
NIGHT RAINFALL TO STAY LESS THAN AN INCH OVER THE FAR SOUTHEAST
CORNER OF THE AREA...TOPPING OUT AT ABOUT 0.80 INCH AS OF NOW.
STRONGER THAN EXPECTED UPPER SUPPORT COULD DRIVE THAT MAXIMUM TO A
BIT OVER AN INCH.

TEMPERATURES WILL BE MILD WITH THE WARMER SATURDAY NIGHT LOWS AND
THE COOLER SUNDAY HIGHS LOGICALLY IN THE SOUTHEAST WHERE CLOUDS AND
SOME RAINFALL WILL RULE. THE SYSTEM MOVING OUT LATE SUNDAY NIGHT
SHOULD GIVE WAY TO A DRY AND MILD COUPLE OF DAYS UNDER SOME UPPER
RIDGING BETWEEN SYSTEMS. DEVELOPING WESTERN UPPER TROUGH APPROACHES
TO BRING SHOWERS AND STORMS BY WEDNESDAY...WITH POTENTIALLY MORE
RAINFALL IN A STRONGER SYSTEM WEDNESDAY THROUGH THURSDAY.
TEMPERATURES WILL STILL BE MILD. THE APPROACH OF A STRONG SURFACE
SYSTEM WEDNESDAY IS LIKELY TO LEAD TO A PRETTY WINDY DAY. THE SYSTEM
THEN WILL PASS BY LATE THURSDAY AND BRING COOLER WEATHER FOR FRIDAY.
AT THIS TIME IT LOOKS LIKE SHOWERS MAY LINGER FRIDAY AS THIS
STRONGER SYSTEM WILL NOT SET ANY SPEED RECORDS MOVING EAST. HOWEVER
CURRENT TIMING SUGGESTS THAT THE FOLLOWING WEEKEND...WHICH IS BEYOND
THE FORECAST PERIOD...IS LIKELY TO BE DRY AND MILD OR WARM...AS
UPPER RIDGING TAKES OVER IN THE PLAINS WHILE THE NEXT MAJOR TROUGH
DEVELOPS CLOSE TO THE PACIFIC COAST.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 637 PM CDT FRI APR 18 2014

VFR WILL PREVAIL OVER THE AREA THROUGH SATURDAY. THE BIGGER
CONCERN IS THE SOUTHERLY WINDS. THEY WILL BE QUITE STRONG
TONIGHT...ESPECIALLY ALONG AND WEST OF THE INTERSTATE 29 CORRIDOR.
IN THESE AREAS EXPECT FREQUENT GUSTS TO AROUND KNOTS THROUGH 06Z
SATURDAY...THEN THEY WILL BEGIN SLOWLY SUBSIDE.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 1 AM CDT TONIGHT FOR SDZ038-039-050-
     052>054-057>060-063>065-068.

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

$$

SHORT TERM...08
LONG TERM...
AVIATION...MJ






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