Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 040843
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
343 AM CDT SAT JUL 4 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CDT SAT JUL 4 2015

MAIN FOCUS TODAY WILL BE ON THE POTENTIAL FOR ISOLATED TO SCATTERED
CONVECTION DEVELOPING THIS AFTERNOON AND EVENING IN OUR WESTERN
COUNTIES. SOUTHERLY LOW LEVEL FLOW WILL ALLOW FOR MODEST MIXING AND
WARMING OF TEMPERATURES SEVERAL DEGREES FROM YESTERDAY. HIGHS WILL
BE IN THE 80S AND MAY APPROACH 90 IN SOUTH CENTRAL SD. WITH THE
SOUTHERLY LOW LEVEL WINDS...SMOKE FROM THE CANADIAN FIRES SHOULD
HAVE LESS OF AN IMPACT AT THE SURFACE TODAY AND TONIGHT.

MODELS SUGGEST THAT WE WILL SEE A SLIGHT MOISTURE INFLUX INTO THE
AFTERNOON. WITH A BROAD MID LEVEL WAVE SLOWLY MOVING EASTWARD
THROUGH THE DAKOTAS AND A SURFACE TROUGH DEEPENING IN THE HIGH
PLAINS...WE COULD SEE A FEW STORMS POP BY MID AFTERNOON IN SOUTH
CENTRAL SOUTH DAKOTA AND THE NEBRASKA PANHANDLE. MUCAPE VALUES
REACHES 1500 TO 2500 J/KG WEST OF THE JAMES RIVER WITH SHEAR VALUES
AROUND 40 KT. CANNOT RULE OUT A FEW STORMS BECOMING STRONG TO SEVERE
WITH LARGE HAIL...WHILE THE INVERTED V SOUNDINGS ALSO SUGGEST A
SEVERE WIND THREAT AS WELL. MOST RECENT CAMS DO PAINT SCATTERED
STORMS WITH UPDRAFTS BY AROUND 21Z IN SOUTH CENTRAL SD JUST WEST OF
THE FORECAST AREA...HOWEVER THIS ACTIVITY DOES NOT SHOW MUCH
EASTWARD MOVEMENT THROUGH THE EVENING. MODEL CONSENSUS KEEPS STORMS
WEST OF I29 IN OUR REGION...PRIMARILY WEST OF THE JAMES RIVER
VALLEY. ANY STORMS THAT DO MANAGE TO DEVELOP WILL WEAKEN LATE
EVENING AND DIMINISH OVERNIGHT. LOWS WILL BE IN THE 60S.


.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 342 AM CDT SAT JUL 4 2015

SUNDAY LOOKS TO BE A WARM AND HUMID DAY IN A MODERATE SOUTHERLY FLOW
OUT AHEAD OF A DEVELOPING SURFACE TROUGH OVER THE WESTERN HIGH
PLAINS. WITH HIGHS IN THE MID 80S TO LOWER 90S AND DEWPOINTS IN THE
UPPER 60S TO AROUND 70 IT WILL FEEL FAIRLY UNPLEASANT. THINK THAT
MOST OF THE DAY WILL BE DRY IN A CAPPED ATMOSPHERE...THEN WILL MOST
LIKELY SEE THUNDERSTORMS DEVELOP IN THE LATE AFTERNOON AND EVENING
IN OUR NORTH AND WEST AS THE AFOREMENTIONED TROUGH/FRONTAL BOUNDARY
PUSHES EASTWARD AND A SHORTWAVE SLIDES INTO THE REGION. WITH CAPE
VALUES AROUND 2500 J/KG AND EFFECTIVE SHEAR NEAR 40 KTS IN THE LATE
AFTERNOON AND EVENING...SEVERE STORMS WILL BE A POSSIBILITY WITH
LARGE HAIL AND DAMAGING WINDS...ALONG WITH HEAVY RAIN. THE SYSTEM
WILL PUSH EASTWARD ON SUNDAY NIGHT...WITH THUNDERSTORMS FOLLOWING
SUIT...WITH THE MAIN THREAT TRANSITIONING TO STRONG WINDS/HEAVY RAIN
AS THE STORMS SPREAD ACROSS THE CWA OVERNIGHT. OUT AHEAD OF THE
SYSTEM...IT WILL BE A MILD NIGHT WITH LOWS AROUND 70...WHILE ON THE
BACKSIDE OF THE FRONT LOWS WILL DROP INTO THE LOWER 60S IN OUR FAR
WEST.

SHOWERS AND THUNDERSTORMS WILL LINGER IN OUR EAST ON MONDAY MORNING
AS THE FRONT FINALLY PUSHES THROUGH THE AREA BY MID TO LATE MORNING.
IT WILL BE A COOLER DAY WITH COLD AIR ADVECTION INTO THE AREA AND
HIGHS MID AND UPPER 70S. TUESDAY LOOKS TO BE DRY AS HIGH PRESSURE
BUILDS INTO THE NORTHERN PLAINS...WITH HIGHS ONCE AGAIN MID AND
UPPER 70S.

FOR THE REMAINDER OF THE EXTENDED...FAIRLY BENIGN WEATHER IN A LESS
AMPLIFIED UPPER LEVEL FLOW. WHILE TEMPERATURES WILL REMAIN JUST
BELOW NORMAL FOR MID WEEK...THERE WILL BE A SUBTLE WARMING TREND
EACH DAY THROUGH THE END OF NEXT WEEK. WHILE LOW END POPS ARE
WARRANTED FOR THE WEDNESDAY TO THURSDAY TIME FRAME...NO SIGNIFICANT
SYSTEMS ARE ON THE HORIZON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1105 PM CDT FRI JUL 3 2015

MAINLY VFR CONDITIONS AND VERY LIGHT WINDS EXPECTED TONIGHT AS
SURFACE HIGH PRESSURE SLOWLY SHIFTS EAST. WILL LIKELY SEE SOME AREAS
OF MVFR VISIBILITY AS SMOKE FROM CANADIAN FOREST FIRES SEEPS TO THE
SURFACE...BUT TIMING FOR THIS TO OCCUR IS UNCERTAIN. WILL HOLD ON TO
A PERIOD OF MVFR VISIBILITY IN SMOKE AT KHON THROUGH THE EARLY
MORNING UNTIL SLIGHTLY STRONGER SOUTHERLY FLOW SHOULD HELP DISPERSE
THE SMOKE PARTICLES AND BRING SOME IMPROVEMENT. UNCERTAINTY IS TOO
HIGH TO BRING VISIBILITY BELOW VFR AT KFSD/KSUX BUT WILL CERTAINLY
MONITOR TRENDS AND AMEND IF NEEDED.

KEEPING TAFS PRECIP-FREE THROUGH THIS PERIOD...THOUGH ISOLATED
STORMS MAY DEVELOP IN WESTERN PARTS OF THE AREA LATE IN THE PERIOD.


&&

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

$$

SHORT TERM...
LONG TERM...JM
AVIATION...JH


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