Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 072333
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
633 PM CDT MON JUL 7 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 336 PM CDT MON JUL 7 2014

CONVECTIVE TRENDS THROUGH THE LATER AFTERNOON AND EVENING ARE THE
PRIMARY CONCERN OF THE SHORT TERM. CURRENTLY...THE CWA IS MAINLY
BETWEEN THE BETTER DYNAMIC FORCING TO THE NORTH ASSOCIATED WITH
STRONG MID LEVEL WAVE AND THE BETTER THERMODYNAMIC AIR MASS WHICH
HAS FOR THE MOST PART BEEN FORCED SOUTHWARD BY COOL AIR POOL FROM
EARLIER SOUTHERN SD/NORTHERN NE CONVECTION. STILL REMAINS A FAIR MID
LEVEL INSTABILITY CLOSER TO SOUTHERN CWA...AND SOMEWHAT STRONGER LOW
LEVEL INSTABILITY TO THE NORTH. COLD FRONT ARCING ACROSS EXTREME
NORTHWEST CORNER OF THE CWA WILL BE PUSHED STEADILY SOUTHEAST
THROUGH THE LATE AFTERNOON AND EVENING. CONVERGENCE ZONE IN HIGH
RESOLUTION SOLUTIONS WORKING ACROSS NORTH OF I 90 IS THE PRIMARY
FOCUS OF STRONGER UPDRAFTS MID TO LATE AFTERNOON. PREDOMINANT WEST
TO SOUTHWEST FLOW AT THE LOW LEVELS HAS REDUCED THE LOW LEVEL
SHEAR...AND TO SOME DEGREE THE DEEPER SHEAR. IF ANY SEVERE STORMS TO
OCCUR...AT THIS TIME WOULD LOOK TO FAVOR SOUTHWEST MINNESOTA TOWARD
THE IOWA GREAT LAKES AREA...AND THREAT WOULD BE LIKELY LIMITED TO
SOME MARGINAL SEVERE HAIL AND WIND...WITH A SLIGHTLY GREATER THREAT
JUST NORTH/EAST OF THE CWA.

THE SHOWER AND THUNDER THREAT ENDS FAIRLY QUICKLY DURING THE EVENING
AS WAVE CONTINUES TO SHEAR OFF TO THE NORTHEAST OF THE AREA AND THE
ADDED HELP FROM DIURNAL DESTABILIZATION AND CONVERGENCE WITH
BOUNDARY ALL START TO DWINDLE.

BOUNDARY LAYER MOISTURE LOOKS A BIT TOO HIGH IN THE COUPLE OF MODELS
THAT ACTUALLY PRODUCE SOME HEATING BASED SPRINKLES/LIGHT SHOWERS
ACROSS THE NORTHEAST HALF OF CWA TOMORROW AFTERNOON...AND PREFER TO
KEEP DRY WITH JUST A DIURNAL INCREASE IN CUMULUS. WELL MIXED
ENVIRONMENT AND HAVE PUT HIGHS MID TO HIGH RANGE SUGGESTED BY MODEST
MIXING.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 336 PM CDT MON JUL 7 2014

TUESDAY NIGHT INTO WEDNESDAY MORNING WILL BE QUIET A SEASONALLY COOL
AS A WEAK RIDGE OF HIGH PRESSURE MOVES INTO THE REGION. LOWERED LOWS
A TOUCH AND AIMING FOR MAINLY LOWER TO MID 50S.

WEDNESDAY INTO WEDNESDAY NIGHT WILL SEE GRADUALLY INCREASING
INSTABILITY BUT FOR NOW THE BETTER INSTABILITY AND BETTER CHANCES
FOR THUNDERSTORMS SHOULD REMAIN MAINLY WEST OF INTERSTATE 29. NO
MAJOR THREAT FOR SEVERE THUNDERSTORMS AT THIS TIME.

THURSDAY WILL ONLY SEE A SMALL CHANCE FOR THUNDERSTORMS DURING THE
DAY AS DEEP STRONG SOUTHERLY FLOW DEVELOPS. SHOULD BE QUITE A BIT OF
CLOUD COVER AND INCREASING LOW LEVEL MOISTURE SO WILL AIMING FOR
MAINLY AROUND 80 TO THE MID 80S FOR HIGHS.

IN THE OUTER PERIODS(FRIDAY THROUGH MONDAY)...THE MODELS ARE IN OK
AGREEMENT WITH THE LARGE SCALE BUT DIFFERING QUITE A BIT ON THE
STRENGTH OF THE TROUGH OVER SOUTHERN CANADA EXTENDING INTO THE GREAT
LAKES AREA. A FEW OF THE RUNS OF BROUGHT IN A MUCH DEEPER TROUGH
WHICH SWINGS TEMPERATURES WELL BELOW NORMAL BUT FOR NOW WILL NOT
BUY INTO 850MB TEMPERATURES COOLER THAN 10 DEGREES C. SO BASICALLY
AIMING FOR HIGHS IN THE 80S WITH MID 70S TO LOWER 80S ON MONDAY.
WHILE THERE IS A GOOD CHANCE SHOWER SHOWERS AND THUNDERSTORMS
THURSDAY NIGHT THE REMAINDER OF THE PERIOD SHOULD SEE MAINLY
ISOLATED TO SCATTERED THUNDERSTORMS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 633 PM CDT MON JUL 7 2014

LEADING EDGE OF A COLD FRONT IS EXTENDING FROM THE EASTERN
SECTIONS OF SOUTHWEST MN...SOUTHWESTWARD TO BETWEEN SIOUX FALLS
AND SIOUX CITY EARLY THIS EVENING. THIS FRONT WILL CONTINUE TO
RAPIDLY MOVE EASTWARD THIS EVENING. ISOLATED TO SCATTERED
CONVECTION IS POSSIBLE ALONG THE WIND SHIFT MAINLY THROUGH MID
EVENING...THEN THE WEATHER SHOULD QUIET DOWN RAPIDLY. WITH THE
CONVECTION NOT WIDESPREAD...TOOK OUT THE CHANCES FOR TSRA IN THE
KSUX TAF SITE...AND THE BOUNDARY IS ALREADY THROUGH KFSD AND KHON.
THEREFORE LOOKING FOR VFR CONDITIONS THROUGH TUESDAY...BUT THERE
COULD BE OCCASIONAL GUSTS AROUND 25 KNOTS FROM THE NORTHWEST LATE
MORNING AND AFTERNOON TUESDAY.

&&

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

$$

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






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