Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 291133
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
633 AM CDT MON JUN 29 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 419 AM CDT MON JUN 29 2015

JET MAX ROUNDING THE TOP OF THE WEST COAST RIDGE WILL WORK ACROSS
THE AREA TODAY AND SHOULD BRING AT LEAST ISOLATED TO LOW SCATTERED
THUNDERSTORMS. INSTABILITY AND SHEAR REALLY NOTHING TO GET CONCERNED
ABOUT SO NOT PLANNING ON ANY SEVERE BUT WITH THE DRY SOUNDINGS AND
THE UNIDIRECTIONAL NORTHWEST SHEAR SOME STRONGER WIND GUSTS TO 50
MPH NOT OUT OF THE QUESTION. AHEAD OF THIS POTENTIAL CONVECTION
TEMPERATURES WILL WARM NICELY AND DEW POINTS WILL REMAIN MARGINALLY
DRY FOR THIS TIME OF YEAR...AVERAGING THE MID 50S TO LOWER 60S.
HIGHS WILL BE MAINLY IN THE MID TO UPPER 80S.

THE THUNDERSTORM THREAT WILL LINGER INTO THE EVENING AND OVERNIGHT
HOURS IN THE FAR EASTERN CWA. OTHERWISE SKIES WILL CLEAR AND ANOTHER
PLEASANT EVENING WILL BE IN STORE FOR THE AREA WITH LOWS IN THE
LOWER 60S.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 419 AM CDT MON JUN 29 2015

FAR FROM A PERIOD OF HIGH CERTAINTY IN THE SHORTER TO INTERMEDIATE
TERM...WITH NORTHWEST FLOW ACROSS THE AREA FEATURING WAVES OF
GREATLY DIFFERENT TIMING...MOSTLY WEAK...WITH SOME FOCUSED MID
LEVEL BOUNDARY REMAINING AT LEAST IN PROXIMITY. AS A RESULT OF THE
UNCERTAINTY...TENDENCY FOR THE FORECAST IS TO END UP SOMEWHAT MORE
PESSIMISTIC IN TERMS OF PRECIPITATION THAN WHAT WILL ACTUALLY
OCCUR.

WHILE CANNOT FULLY RULE OUT PRECIPITATION BY EARLY TUESDAY
MORNING...LINGERING MID LEVEL TAIL OF MOISTURE AND WEAK THERMAL
ADVECTION SEEMS HIGHLY UNLIKELY TO PRODUCE ANY PRECIPITATION GIVEN
THE SLIGHTLY STABLE PROFILE. INITIAL WEAK WAVE WILL APPROACH FROM
THE NORTHWEST DURING THE MIDDAY AND AFTERNOON...WITH MORE
SUBSTANTIAL WAVE SLATED TO PUSH DOWN LATER TUESDAY NIGHT. LEADING
WAVE WILL HAVE LITTLE INSTABILITY TO WORK WITH...AND WHILE DEEPER
LAYER CERTAINLY SHOWS A STRONG DIRECTIONAL CHANGE TO WIND...
PARAMETERS DO NOT LINE UP TO SUGGEST ANY SEVERE WEATHER THREAT
WITH THE SIGNIFICANT LACK OF INSTABILITY AS SCATTERED SHOWERS AND
A FEW RUMBLES SLIP SOUTHEAST THROUGH THE HEART OF THE CWA IN THE
AFTERNOON. MAIN LOWER LEVEL BAROCLINIC BOUNDARY SHOULD REMAIN
LOCKED UP ACROSS NEBRASKA DURING THE DAY...WITH A BIT COOLER EAST
TO NORTHEAST WIND OVER THE AREA KEEPING HIGHS FROM AROUND 80
NORTHEAST...TO THE MID TO PERHAPS UPPER 80S MISSOURI VALLEY.
BETTER CHANCE OF RAINFALL WILL COME WITH SECOND WAVE ON TUESDAY
NIGHT...AND ALSO CLOSER TO THE BAROCLINIC ZONE ACROSS NORTHEAST
NEBRASKA INTO NORTHWEST IOWA. FAIRLY FRONTOGENETIC BOUNDARY ALONG
THE SOUTHERN EDGE OF THE CWA WILL PRESENT AN ENHANCED OPPORTUNITY
FOR CONVECTIVE DEVELOPMENT ALONG INSTABILITY GRADIENT DURING THE
EVENING AS LOW LEVEL JET INCREASES AHEAD OF THE APPROACHING WAVE.
MORE GENERAL SHOWERS/EMBEDDED THUNDER WILL SPREAD IN LATER IN THE
NIGHT FROM THE NORTH/WEST WITH DEEPER SYNOPTIC FORCING.

WAVE WILL STILL BE LINGERING OVER THE EASTERN CWA COME WEDNESDAY
MORNING...BUT OVERALL AREA WILL BE BATTLING A MORE STABLE AND
DRIER EASTERLY COMPONENT AS IT WORKS EAST LATER TUESDAY NIGHT AND
WEDNESDAY MORNING. HAVE MAINTAINED SOME MODERATE CHANCE POPS ON
WED MORNING...BUT TRENDED DOWNWARD DURING THE AFTERNOON AND
EVENING IN WAKE OF THIS WAVE...WHICH LEAVES BEHIND THE MID LEVEL
BOUNDARY. ECMWF IS MUCH MORE PESSIMISTIC WITH LINGERING
PRECIPITATION MUCH OF THE DAY...AND FAIRLY OUT ON THE PERIPHERY
WITH THAT SOLUTION COMPARED TO THE GREATER SET. AGAIN...MODELS
INDICATE A STRONGER WAVE POTENTIAL AROUND THE LATER WEDNESDAY
NIGHT INTO THURSDAY EVENING WINDOW. AGAIN...THERE IS NOT MUCH
POTENTIAL FOR ANY APPRECIABLE INSTABILITY TO WORK INTO THE
REGION...AND AGAIN SHOULD KEEP SEVERE WEATHER THREAT AT A MINIMUM
LEVEL WITH THIS LATTER WEEK SYSTEM...DESPITE FLOW TRANSITIONING
FROM EASTERLY TO SOUTHEASTERLY AT LOW LEVELS...TO NORTHWESTERLY
IN MID LEVELS. TEMPS WILL TAKE A BIT MORE OF A TREK DOWNWARD FOR
MIDWEEK HIGHS...WITH A LOT OF HIGHS IN THE MID TO UPPER 70S
THROUGH THURSDAY...MODERATING A FEW DEGREES EACH FRIDAY AND
SATURDAY AS WORK TOWARD SOME RIDGING TO START THE HOLIDAY WEEKEND.

AS IS USUALLY THE CASE...GFS IS APPRECIABLY QUICKER WITH STRONGER
IMPULSE MOVING ALONG THE CANADIAN BORDER AND SLIDING TOWARD THE
GREAT LAKES BY LATER SATURDAY NIGHT/SUNDAY COMPARED TO ECMWF...
WHICH IS LESS AMPLIFIED AND DELAYS UNTIL LATER SUNDAY. SHOULD BE
ABLE TO SQUEAK OUT A PLEASANT INDEPENDENCE DAY FOR ALL...WITH SMALL
POPS IN THE WEST SATURDAY NIGHT AND AREA WIDE ON SUNDAY REFLECTING
THE TIMING UNCERTAINTY AS A COLD FRONT WILL BE TRANSITING THE
AREA OVER THE LATTER HALF OF THE WEEKEND...WITH BOTH WARMER AIR
AND GREATER INSTABILITY AHEAD OF FEATURE. AN ECMWF TIMING WOULD
SUGGEST NEED FOR AT LEAST 5 TO 10 DEGREES WARMING ON SUNDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 633 AM CDT MON JUN 29 2015

VFR THROUGH THE PERIOD. THERE COULD BE A FEW THUNDERSTORMS OVER
MAINLY PARTS OF SOUTHWEST MINNESOTA BETWEEN ABOUT 22Z AND 5Z.

&&

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

$$

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



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