Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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093
FXUS63 KFSD 051139
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
639 AM CDT THU MAY 5 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 337 AM CDT THU MAY 5 2016

ANOTHER SPECTACULAR DAY IN STORE ACROSS THE AREA. IT WILL FEATURE
JUST AS MUCH SUNSHINE...AND EVEN WARMER TEMPERATURES AS A SOUTH TO
SOUTHWEST AIR FLOW SETS UP ACROSS THE AREA. SOMEWHAT STRONGER WINDS
ARE EXPECTED FROM SOUTH CENTRAL SD ARCING ALONG THE HIGHWAY 14
CORRIDOR...BUT EVEN THERE LIKELY ONLY REACHING 10 TO 20 MPH. HIGHS
WILL VARY FROM PLEASANT MID 70S IN NORTHWEST IOWA...TO DOWNRIGHT
WARM LOWER 80S WEST FROM THE JAMES VALLEY WESTWARD. WILL AGAIN SEE
AFTERNOON RELATIVE HUMIDITY FALLING TO 25 TO 32 PERCENT.
CONTINUATION OF SOUTH TO SOUTHWEST GRADIENT OVERNIGHT...WITH
INDICATIONS IN SEVERAL MODELS OF A FAIRLY MODEST SOUTHWESTERLY LOW
LEVEL JET. THE STRONGER WINDS ALOFT MAY HELP TO KEEP TEMPS A BIT
WARMER AT HIGHER ELEVATIONS AROUND THE CWA...BUT HAVE SIDED A BIT
CAUTIOUS WITH DRY AIRMASS TO ALLOW TEMPS TO FALL GENERALLY TO THE
LOWER TO MID 50S.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 337 AM CDT THU MAY 5 2016

WELL ABOVE NORMAL TEMPERATURES SETTLE OVER THE REGION AS A WELL
AMPLIFIED UPPER RIDGE AXIS SLIDES EAST ACROSS THE PLAINS. SOUTHWEST
WINDS INCREASE TO 15 TO 25 KT DURING THE DAY AHEAD OF AN APPROACHING
COLD FRONT...ALLOWING STRONG MIXING TO OCCUR. MID LEVEL TEMPERATURES
ARE EXPECTED TO BE QUITE WARM...IN THE UPPER TEENS CELSIUS AT 850MB.
THE GEM IS THE WARMEST...WHILE THE ECMWF IS SURPRISINGLY COOL. WITH
STRONG MIXING...WENT CLOSER TO THE GFS/NAM TEMPERATURES...WHICH
SHOULD MIX INTO THE MID 80S TO NEAR 90.

THE COLD FRONT DROPS SOUTH THROUGH THE REGION FRIDAY NIGHT. STRONG
CAPPING...WEAK CONVERGENCE AND MEAGER MOISTURE WILL MAKE CONVECTION
DEVELOPMENT PROBLEMATIC. HOWEVER WILL LEAVE IN SLIGHT CHANCE MENTION
FRIDAY EVENING IN OUR NORTH AND OVERNIGHT IN OUR SOUTH. GUSTY
NORTHERLY WINDS ALSO ARRIVE BEHIND THE FRONT ALONG WITH MODEST COLD
AIR ADVECTION...LEADING TO COOLER...BUT SEASONAL TEMPERATURES FOR
THE WEEKEND. SATURDAY AND SUNDAY WILL BE LARGELY DRY...WITH ONLY A
FEW STRAY SHOWERS OR THUNDERSTORMS POSSIBLE NEAR THE MISSOURI VALLEY
ON SUNDAY THAT MAY LIFT INTO THE AREA FROM CONVECTION DEVELOPING
WELL TO OUR SOUTH. HIGHS WILL GENERALLY BE IN THE MID 60S TO LOWER
70S.

A MORE UNSETTLED WEATHER PATTERN DEVELOPS EARLY NEXT WEEK INTO MID
WEEK AS A PAIR OF BROAD UPPER LOWS EMERGE FROM THE INTERMOUNTAIN
WEST. AS BEFORE...STILL QUITE A BIT OF UNCERTAINTY IN HOW THESE TWO
FEATURES WILL PLAY OFF OF EACH OTHER...WITH FORECAST MODELS SHOWING
SOME PRETTY SIGNIFICANT DIFFERENCES...ESPECIALLY MOVING INTO THE MID
WEEK TIME FRAME. THE INITIAL UPPER LOW LIFTS NORTHEAST OUT OF THE
FOUR CORNERS REGION SUNDAY AND WOBBLES INTO THE CENTRAL HIGH PLAINS
SUNDAY NIGHT. EXPECT PRECIPITATION CHANCES TO INCREASE SUNDAY NIGHT
INTO MONDAY...WITH LIKELY POPS ALONG AND SOUTH OF I90 ON MONDAY.
CHANCE POPS SEEM REASONABLE HEADING INTO TUESDAY MORNING...BUT WITH
THE INITIAL WAVE POTENTIALLY SLIDING OFF THE EAST...THERE SHOULD BE
SOME DECREASE AHEAD OF THE SECOND WAVE. NOT MUCH OF ANY CONFIDENCE
IN THIS TIMING...SO WILL LEAVE POPS AS IS FOR NOW.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 638 AM CDT THU MAY 5 2016

CONDITIONS EXPECTED TO REMAIN VFR THROUGH 12Z FRI. INCREASING
OFF SURFACE WINDS TONIGHT WILL PRODUCE NON CONVECTIVE LOW LEVEL
WIND SHEAR CONDITIONS GENERALLY AFTER 06Z AT KHON AND KFSD.
THERE MAY ALSO BE SOME AVIATION IMPACT DUE TO AN ELEVATED SMOKE
LAYER FROM CANADIAN FIRES.

&&

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

$$

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



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