Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 231953
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
253 PM CDT WED JUL 23 2014

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 423 AM CDT WED JUL 23 2014

EXPECTING A PRETTY NICE DAY ACROSS THE REGION WITH SURFACE HIGH
PRESSURE REMAINING IN CONTROL OF OUR WEATHER. SOME WEAK MID LEVEL
LIFT MAY ALLOW FOR SCATTERED MID LEVEL CLOUDINESS AT TIMES...AND
CONVECTION TO OUR WEST MAY SPILL SOME CIRRUS INTO THE REGION AS
WELL...BUT STILL THINKING WE END UP IN THE PARTLY TO MOSTLY SUNNY
CATEGORY WITH DRY CONDITIONS PREVAILING. NOT MUCH CHANGE TO THE HIGH
TEMPERATURE FORECAST...GENERALLY UPPER 70S TO MID 80S.

WEATHER SHOULD BECOME MORE ACTIVE AS WE HEAD INTO LATER
TONIGHT INTO THURSDAY. AS THE LOW LEVEL JET INCREASES AND WINDS VEER
MORE TO THE SOUTH AND WEST ALOFT...WE WILL SEE PRETTY IMPRESSIVE
THETAE ADVECTION AND ISENTROPIC LIFT ENCOMPASS THE AREA...ALONG WITH
INCREASING ELEVATED INSTABILITY. SEEMS LIKE A GOOD SETUP FOR
ELEVATED THUNDERSTORMS AFTER MIDNIGHT INTO THE DAY THURSDAY. STORM
MOTION WILL BE NORTHWEST TO SOUTHEAST...SO IT IS POSSIBLE THAT
STORMS THAT FORM WEDNESDAY EVENING ACROSS EASTERN MONTANA AND
WESTERN NORTH DAKOTA ROUND THE RIDGE AND DIVE SOUTHEAST INTO OUR
AREA...SUCH AS SHOWN BY THE 0Z HI RES ARW...4KM OPERATIONAL NAM AND
ECMWF. ALSO SEEMS PROBABLE THAT ADDITIONAL STORMS WILL GET GOING
OVERHEAD AS THE BETTER LIFT MOVES ACROSS.

SO WHILE THE EXACT CONVECTIVE EVOLUTION REMAINS UNCERTAIN...SEEMS
LIKE A DECENT CHANCE OF GETTING SOMETHING...SO INCREASED POPS ACROSS
THE AREA. ELEVATED INSTABILITY SHOULD INCREASE TO AROUND 1000 TO 1500
J/KG...WITH SOME SHEAR PRESENT AS WELL. SO WHILE NOT EXPECTING
ANYTHING SIGNIFICANT...SEEMS PLAUSIBLE THAT THESE STORMS COULD
PRODUCE SMALL HAIL...WITH A FEW POTENTIALLY MARGINALLY SEVERE...SO
SOMETHING TO KEEP AN EYE ON. FOLLOWED SOMETHING CLOSE TO THE ECMWF
AND SREF FOR POPS...AS THEY WERE IN GOOD AGREEMENT. THIS KEEPS THE
THREAT ALONG AND WEST OF INTERSTATE 29 THROUGH 12Z...SHIFTING EAST
THROUGH THE DAY THURSDAY. CLOUD COVER IS A CONCERN FOR HIGHS ON
THURSDAY...BUT IT WILL BE WARMING ALOFT. SO FOR NOW WILL KEEP 70S IN
THE EAST...BUT DID RAISE HIGHS INTO THE 90S ACROSS SOUTH CENTRAL
SOUTH DAKOTA WHERE SUNSHINE AND WARMER TEMPS ALOFT SEEM MOST
PROBABLE.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 423 AM CDT WED JUL 23 2014

SEEMS LIKELY THAT WE SEE ANOTHER AREA OF ELEVATED CONVECTION BLOSSOM
THURSDAY EVENING INTO THE OVERNIGHT AS THE LOW LEVEL JET PICKS UP
AGAIN. SEEMS LIKE THE MOST LIKELY LOCATION FOR THIS IS THE FAR
EASTERN PORTION OF OUR CWA AND EAST INTO SOUTHERN MINNESOTA AND
NORTHERN IOWA. THIS IS WHERE THE BETTER CONVERGENCE ON THE NOSE OF
THE JET SHOULD BE. AGAIN FAVORED A SOLUTION CLOSE TO THE ECMWF AND
SREF. STILL SOME UNCERTAINTY ON WHERE EXACTLY THIS DEVELOPS...SO
SOMETHING TO WATCH. BUT THINKING THE MAJORITY OF THE ACTION WILL
STAY EAST OF OUR FORECAST AREA THURSDAY NIGHT INTO FRIDAY. SO WITH
PARTLY TO MOSTLY SUNNY SKIES...FRIDAY SHOULD SEE HIGHS IN THE 80S
WITH A STRONG CAP KEEPING ANY SURFACE BASED CONVECTION AT BAY.

MODELS NOW SHOWING ANOTHER AREA OF LIFT ASSOCIATED WITH A JET MAX
COMING ACROSS THE NORTHERN PLAINS ON FRIDAY NIGHT INTO EARLY
SATURDAY. NAM...SREF AND ECMWF ACTUALLY IN GOOD AGREEMENT ON
DEVELOPING CONVECTION WITH THIS FEATURE ACROSS SOUTHERN SOUTH
DAKOTA. WILL INTRODUCE LOW CHANCE POPS INTO THE FORECAST...IF
CONSISTENCY ON THIS FEATURE CONTINUES...POPS WILL NEED TO BE
INCREASED. OTHERWISE SATURDAY WILL BE ONE LAST DAY WITH NEAR NORMAL
HIGHS IN THE 80S.

A STRONG UPPER WAVE MOVING ACROSS THE CANADIAN BORDER AND THEN
DIVING INTO THE GREAT PLAINS REGION WILL PUSH A COLD FRONT THROUGH
OUR AREA SATURDAY NIGHT. THIS WILL RESULT IN A RETURN TO BELOW NORMAL
TEMPERATURES SUNDAY INTO EARLY NEXT WEEK. LOOKING AT MID 70S TO LOW
80S ON SUNDAY AND MONDAY...WITH MAYBE SOME SLOW WARMING BEGINNING ON
TUESDAY. MODELS HAVE TRENDED COOLER SO DID LOWER HIGHS SOME FOR THIS
PERIOD. THE 850 MB TEMPS OFF THE 0Z SUITE OF MODELS SUGGEST THESE
HIGHS ON SUNDAY AND MONDAY MAY STILL BE A FEW DEGREES TOO WARM...BUT
MODELS HAVE BEEN INCONSISTENT WITH THIS FEATURE THE PAST SEVERAL
DAYS...SO WILL WAIT FOR SOME BETTER RUN TO RUN CONSISTENCY BEFORE
DECREASING HIGHS MORE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 251 PM CDT WED JUL 23 2014

SCATTERED ELEVATED SHOWERS AND STORMS WILL MOVE FROM WEST TO EAST
ACROSS OUR FORECAST AREA LATE TONIGHT AND THURSDAY MORNING.
THEREFORE TRIED TO TIME THE BEST CHANCES FOR THIS CONVECTION IN
THE THREE TAF SITES. DUE TO THE ELEVATED NATURE OF THE PRECIP...
CONDITIONS WILL LIKELY REMAIN VFR THROUGH THE TAF PERIOD.

&&

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

$$

SHORT TERM...CHENARD
LONG TERM...CHENARD
AVIATION...MJ






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