Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 180448
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1148 PM CDT THU APR 17 2014

.UPDATE...
ISSUED AT 857 PM CDT THU APR 17 2014

HAVE BEEN CARRYING SOME SPRINKLES THIS EVENING UNDER THE MID CLOUD
DECK AS IT MOVES FROM WEST TO EAST ACROSS OUR FORECAST AREA
THROUGH MIDNIGHT. MITCHELL AND WINNER BOTH REPORTED TRACE AMOUNTS
SO THERE IS A FEW SPRINKLES REACHING THE GROUND.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 357 PM CDT THU APR 17 2014

HIGH PRESSURE WILL SLIP EAST OF THE AREA TONIGHT ALLOWING FOR A
STRONG SOUTHERLY FLOW TO DEVELOP. ALOFT FORCING WILL INCREASE AS THE
RETURN FLOW SETS UP. INSTABILITY PRETTY MUCH NON EXISTENT BUT WITH
DECENT MID LEVEL MOISTURE AND DECENT FORCING SUSPECT ISOLATED
SHOWERS WILL BE POSSIBLE. WHILE TEMPERATURES WILL LIKELY RISE
OVERNIGHT...AS THE LIGHT RAIN POTENTIAL MOVES INTO NORTHERN AND
NORTHEASTERN PARTS OF THE CWA A BRIEF PERIOD OF LIGHT FREEZING RAIN
OR FREEZING SPRINKLES WILL BE POSSIBLE. AT THIS TIME WITH THE WARMER
GROUND AND THE VERY LIGHT AMOUNT EXPECTED NOT PLANNING ON ANY
SLIPPERY ROADS OR WALKWAYS. BY MID MORNING ON FRIDAY TEMPERATURES
SHOULD BE ABOVE FREEZING. DID LOWER LOWS A BIT IN THE NORTHEAST
CWA...INTO THE MID 20S WHILE INCREASING JUST A TOUCH TO NEAR 40 IN
SOUTH CENTRAL SD WHERE THE RETURN FLOW SETS UP THIS EVENING. HAVE
MOST SIGHTS BOTTOMING OUT BEFORE OR AROUND MIDNIGHT THEN CLIMBING
AFTER THAT.

BY FRIDAY A FEW LIGHT SHOWERS WILL REMAIN POSSIBLE OVER SOUTHWEST MN
BUT CLOUDS SHOULD CLEAR THROUGH THE DAY LEADING TOWARDS A MOSTLY
SUNNY...ALBEIT WINDY AFTERNOON. WILL LIKELY APPROACH WIND ADVISORY
CRITERIA IN SOUTH CENTRAL SD BUT WILL HOLD OFF FOR NOW.
HOWEVER...NOT PLANNING ON A FIRE WEATHER WATCH AT THIS TIME AS EVEN
WITH THE INCREASED WINDS...LOWERED DEW POINTS AND INCREASED
HIGHS...AFTERNOON RH VALUES STILL CLOSE TO 30 PERCENT...SO A VERY
HIGH FIRE DANGER FOR CENTRAL PARTS OF SD. WILL HAVE HIGHS RANGING
FROM THE MID 50S IN SOUTHWEST MN TO THE MID TO UPPER 70S IN SOUTH
CENTRAL SD.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 357 PM CDT THU APR 17 2014

THE WEEKEND STILL LOOKS WARM ACROSS THE AREA...ALTHOUGH IT MAY NOT
BE COMPLETELY DRY. SPLIT FLOW ACROSS THE AREA...WITH A NORTHERN
STREAM WAVE MOVING TO OUR NORTH ON SATURDAY...AND A SOUTHERN STREAM
WAVE MOVING TO OUR SOUTH LATER SATURDAY INTO SUNDAY. THE NORTHERN
STREAM WAVE WILL DRAG A COLD FRONT INTO THE AREA LATER FRIDAY NIGHT
INTO SATURDAY. WITH THE BEST FORCING STAYING NORTH...AND ONLY VERY
MARGINAL INSTABILITY OVERHEAD...NOT THINKING WE SEE TOO MUCH IN THE
WAY OF SHOWER ACTIVITY. SATURDAY WILL THUS GENERALLY BE MOSTLY
CLOUDY WITH JUST A FEW SHOWERS AND MAYBE AN ISOLATED THUNDERSTORM
AROUND. MODELS COMING INTO BETTER AGREEMENT ON SATURDAY NIGHT INTO
SUNDAY...TRENDING TOWARDS THE ECMWF SOLUTION. THIS SOLUTION RESULTS
IN THE FRONT STALLING OVER NORTHWEST IOWA...WITH THE SOUTHERN STREAM
WAVE INTERACTING WITH IT. THIS RESULTS IN AN AREA OF SHOWERS AND A
FEW THUNDERSTORMS SATURDAY NIGHT INTO SUNDAY. STILL SOME UNCERTAINTY
ON EXACTLY HOW FAR WEST THIS RAIN MAKES IT. BUT DID GO AHEAD AND
INCREASE POPS...ESPECIALLY ALONG AND SOUTHEAST OF A YANKTON TO SIOUX
FALLS TO MARSHALL LINE. WILL NEED TO MONITOR TRENDS...BUT THIS AREA
MAY END UP HAVING MORE OF A WET SUNDAY THAN DRY ONE...SO SOMETHING
TO KEEP AN EYE ON. SHEAR AND INSTABILITY SHOULD NOT BE HIGH ENOUGH
FOR ANY SEVERE WEATHER...BUT A FEW THUNDERSTORMS ALONG WITH THE
SHOWERS ARE CERTAINLY A POSSIBILITY. HIGH TEMPERATURES BOTH DAYS ARE
A BIT TRICKY DUE TO CLOUD COVER AND SHOWER CONCERNS...BUT 60S AND
70S SEEM LIKELY. STAYED CLOSE TO CONSENSUS FOR NOW...BUT IF IT ENDS
UP SUNNIER ON ONE OF THE DAYS HIGHS WILL LIKELY BE WARMER THAN
FORECAST.

MONDAY SHOULD BE MOSTLY SUNNY AS THE WAVE EXITS TO THE EAST WITH
HIGHS IN THE UPPER 60S TO LOW 70S. WE BEGIN TO GET A BIT MORE
UNSETTLED TUESDAY INTO THURSDAY. A STRONG TROUGH WILL ENTER THE WEST
COAST AND MOVE TOWARDS THE PLAINS. MOST OF TUESDAY SHOULD BE
DRY...BUT AS THE WARM FRONT LIFTS NORTH AND THETAE ADVECTION
INCREASES...COULD SEE SOME SHOWERS AND A FEW THUNDERSTORMS DEVELOP
MAINLY TUESDAY NIGHT INTO EARLY WEDNESDAY. QUESTION THEN BECOMES HOW
QUICKLY THE WARM FRONT LIFTS NORTH AND WHETHER WE GET INTO THE WARM
SECTOR. THE 12Z ECMWF HAS BACKED OFF ON THE PROGRESSION OF THE WARM
FRONT...MORE TOWARDS THE GFS SOLUTION. THIS WILL PLAY A BIG FACTOR
ON TEMPERATURES. GIVEN THE 12Z ECMWF AND GFS TREND...BACKED OFF A
BIT MORE TOWARDS CONSENSUS VALUES FOR HIGHS WEDNESDAY...BUT
UNCERTAINTY REMAINS HIGH. AS FORCING AND MOISTURE INCREASES...SHOWER
AND THUNDERSTORM THREAT WILL INCREASE WEDNESDAY INTO WEDNESDAY NIGHT
AHEAD OF THE COLD FRONT. THERE IS A SEVERE WEATHER THREAT WITH SHEAR
EXPECTED TO BE HIGH. QUESTION BECOMES HOW MUCH INSTABILITY WE CAN
GET THIS FAR NORTH. SO WILL JUST NEED TO KEEP AN EYE ON MODEL TRENDS
OVER THE COMING DAYS. THURSDAY WILL BE BEHIND THE COLD FRONT WITH
HIGHS IN THE 60S. DEPENDING ON THE TRACK OF THE UPPER LOW...WE COULD
STAY DRY...OR GET SOME INSTABILITY SHOWERS AND THUNDERSTORMS AS THE
COLD AIR ALOFT MOVES IN WITH THE UPPER LOW AND TROUGH AXIS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1148 PM CDT THU APR 17 2014

VFR CONDITIONS WILL PREVAIL FOR THE REMAINDER OF THE NIGHT AND ON
FRIDAY. WIND SPEEDS ON FRIDAY WILL BE PRETTY STRONG. THEY WILL BECOME
SOUTH TO SOUTHEAST AND FREQUENTLY GUST FROM AROUND 30 TO 35 KNOTS
ACROSS THE AREA BY LATE MORNING AND AFTERNOON.

&&

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

$$

UPDATE...MJ
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...MJ






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