Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 171115
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
615 AM CDT FRI OCT 17 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT FRI OCT 17 2014

LOW LEVEL COOL AIR CONTINUES TO FLOW IN WITH A SHALLOW MIXED
LAYER BELOW A STRENGTHENING INVERSION...AND THAT IS WHERE WE FIND
THE LOW CLOUD DECK WHICH HAS ALREADY BECOME SOLID OVER THE AREA.
THE INVERSION IS STRONG ENOUGH TO BE RESISTANT TO MID OCTOBER
WARMING AND THESE LOW CLOUDS ARE NOT GOING TO DISSIPATE OR GO
ANYWHERE VERY QUICKLY. THIS SHOULD MEAN A CLOUDY DAY FOR MOST OF
THE AREA BUT DO EXPECT CLEARING FAR SOUTHWEST THIS AFTERNOON WHERE
THE INFLOW AND INVERSION SHOULD ERODE SLOWLY.

PREVIOUS HIGH TEMPERATURES TODAY LOOK GOOD DESPITE LESS SURFACE
COOLING THAN EARLIER FORECAST...WHICH OF COURSE IS DUE TO THE
SHALLOW MIXED LAYER. WITH THE CLOUD COVER AND INVERSION...LOWER TO
MIDDLE 50S LOOK OK...WITH TEMPERATURES ALSO NOT GOING UP VERY MUCH
OR VERY QUICKLY. DRY AIR ABOVE ALL THIS ASSURES NO RAIN THREAT.

THE NORTHWEST WINDS WILL REMAIN STRONG BUT BELOW ADVISORY LEVELS.

THE NAM MAKES THE MOIST LAYER SHALLOWER TONIGHT BUT KEEPS THE
INVERSION. WILL ALLOW FOR A SLOW DECREASE IN CLOUDS FROM THE
SOUTHWEST WITH MOST CLOUDS REMAINING EAST THROUGH THE NIGHT. WINDS
WILL DECREASE AND MIXING WILL SUBSIDE TO ALLOW FOR COOLER
TEMPERATURES THAN CURRENT...ESPECIALLY WEST WHERE SKIES WILL
PROBABLY GO MOSTLY CLEAR.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 AM CDT FRI OCT 17 2014

A PROLONGED PERIOD OF DRY AND PLEASANT FALL WEATHER IS EXPECTED
THROUGH THE BULK OF THE MID TO LONG RANGE. WITH SURFACE HIGH
PRESSURE EXPANDING ACROSS THE NORTHERN AND CENTRAL PLAINS ON
SATURDAY...ANY PERSISTING STRATUS ACROSS OUR NORTHEASTERN HALF
SHOULD QUICKLY DISSIPATE THROUGH THE MORNING. WINDS WILL GRADUALLY
TURN SOUTH SOUTHEAST DURING THE DAY...BUT WITH THE CHILLY AIRMASS IN
PLACE...TEMPERATURES WILL REMAIN FAIRLY COOL...PARTICULARLY ACROSS
OUR EASTERN HALF WHERE HIGHS WILL BE IN THE MID 50S. FURTHER
WEST...HIGHS WILL TOP NEAR 60 IN SOUTH CENTRAL SD.

INCREASED SOUTHERLY WINDS ON SUNDAY WILL TURN
SOUTHWESTERLY...ALLOWING BETTER MIXING AND HIGHS TO IMPROVE AROUND
10 DEGREES. A DRY FRONTAL PASSAGE WILL BRING SOME PASSING MID TO
HIGH CLOUDS...HOWEVER THERE WILL BE ENOUGH FILTERED SUNSHINE FOR
HIGHS TO REACH THE MID 60S TO LOWER 70S.

SHARP UPPER LEVEL RIDGING WILL KEEP SUNNY SKIES AND PLEASANT FALL
TEMPERATURES IN THE PICTURE MONDAY THROUGH WEDNESDAY. MILD HIGHS
GENERALLY IN THE 60S TO LOWER 70S ARE EXPECTED EACH DAY. THE NEXT
PACIFIC WAVE POTENTIALLY DRIFTS INTO THE HIGH PLAINS WEDNESDAY NIGHT
INTO THURSDAY...ON A SLIGHTLY SLOWER PACE THAN PREVIOUS RUNS.
CONFIDENCE IN THIS TIMING OF THIS FEATURE REMAINS RATHER LOW WITH
SUCH A SOLID BLOCKING PATTERN IN PLACE ACROSS THE EASTERN UNITED
STATES. WILL CONTINUE TO SUGGEST SOME LOW END RAIN SHOWER POPS IN
OUR WEST WEDNESDAY NIGHT...SHIFTING EASTWARD ON THURSDAY. MILD
READINGS PERSIST.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 615 AM CDT FRI OCT 17 2014

WIDESPREAD CEILINGS 2-4K FEET WITH VFR TO MVFR FLUCTUATIONS
WITHIN THAT RANGE. 21Z-18/12Z VERY SLOW CLEARING FROM THE WEST TO
THE JAMES RIVER AREA/ HON TO YKN/ WITH CLOUDS BECOMING SCATTERED
2-4K FEET AGL. AFTER 18/09Z VERY PATCHY SHALLOW FOG MAY DEVELOP
IN THIS CLEARED AREA...BUT POSSIBILITY TOO LOW FOR NOW TO INCLUDE
SPECIFICALLY IN THE HON TAF. OCCASIONAL GUSTS TO 25-30 KNOTS FROM
THE NORTHWEST TO NORTH THROUGH 18/00Z.

&&

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

$$

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



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