862 
FXUS63 KFSD 271733
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA 
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1230 PM CDT FRI JUL 27 2012

.DISCUSSION.../ISSUED AT 1000 AM CDT/
LOW CLOUDS ROTATING THRU SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND 
PORTIONS OF SOUTHEAST SOUTH DAKOTA THIS MORNING WILL GRADUALLY PULL 
OFF TO THE EAST AND DISSIPATE AS THE ATMOSPHERIC MIXING BEGINS.  
GRIDS LOOK TO BE IN GOOD SHAPE WITH SLIGHTLY LOWER HIGHS AND 
DEWPOINTS THAN YESTERDAY.  SHOULD BE A PRETTY COMFORTABLE DAY AROUND 
THE AREA WITH LIGHT NORTHERLY FLOW.  WILL TAKE A CLOSER LOOK THIS 
AFTERNOON AT TONIGHTS PRECIP CHANCES.  ATTM...PRESENT FORECAST OF 30 
TO 40 POPS LOOKS GOOD AS MOISTURE LOOKS TO BE THE LIMITING FACTOR.
/HEITKAMP

&&

.AVIATION.../FOR THE 18Z TAF ISSUANCE/
STRATUS DECK DISSIPATING DUE TO MIXING AND ALSO UPPER LOW PRESSURE 
SYSTEM PULLING OFF TO THE EAST.  NOT MUCH WEATHER OVER ROUTES 
THROUGH 03Z.  AFTER THAT PERIOD...UPPER LEVEL STORM SYSTEM BEGINS TO 
AFFECT FORECAST AREA.  MENTIONED A CHANCE FOR SCATTERED -SHRA AT 
KHON AFTER 06Z.  -SHRA WILL GRADUALLY MOVE EAST TO AFFECT KFSD 
TOWARDS DAWN.  ATTM...NOT TO CONFIDENT THAT SHOWER ACTIVITY WILL 
REACH KSUX BEFORE END OF TAF PERIOD. THEREFORE DID NOT MENTION IN 
THE TAF.
/HEITKAMP

&&

.PREVIOUS DISCUSSION.../ISSUED AT 430 AM CDT/
A RATHER PLEASANT SUMMER DAY IS ANTICIPATED TODAY AS AN UPPER RIDGE 
BUILDS INTO THE WESTERN PLAINS AND SURFACE HIGH PRESSURE SETTLES IN 
OVER THE REGION. WINDS WILL BE RELATIVELY LIGHT AND GRADUALLY SWITCH 
TO THE SOUTHEAST INTO SOUTH CENTRAL SOUTH DAKOTA AS WARM AIR 
ADVECTION BEGINS WORKING BACK INTO THE NORTHERN HIGH PLAINS. A SWATH 
OF STRATUS OVER NORTHERN MINNESOTA IS FINALLY BEGINNING TO CREEP 
INTO OUR NORTHEASTERN TIER OF COUNTIES THIS MORNING AND SHOULD 
SPREAD ACROSS SOUTHWEST MINNESOTA THIS MORNING BEFORE DISSIPATING 
LATE MORNING. OTHERWISE...SKIES WILL BE MOST SUNNY WITH HIGHS IN THE 
LOWER 80S IN SOUTHWEST MINNESOTA TO NEAR 90 IN THE MISSOURI VALLEY. 

THE FIRST OF TWO SHORTWAVES WILL DIP INTO THE NORTHERN HIGH PLAINS 
FRIDAY EVENING...COINCIDING WITH THE INCREASING WARM AIR ADVECTION. 
SCATTERED THUNDERSTORMS WILL LIKELY POPS OVER WESTERN SOUTH DAKOTA 
AND COULD POTENTIALLY TRACK INTO OUR WESTERN COUNTIES OVERNIGHT. 
MODELS ARE IN FAIRLY GOOD AGREEMENT WITH TRACKING THE WAVE SOUTHEAST 
THROUGH THE CWA THROUGH SUNDAY MORNING. A BROADER WAVE IS QUICK TO 
FOLLOW THE FIRST WAVE AND SHOULD FOLLOW A SIMILAR TRACK AND BRING 
THE BEST POTENTIAL FOR ADDITIONAL SHOWERS AND THUNDERSTORMS TO AREAS 
EAST OF INTERSTATE 29. STILL...EVEN WITH THESE TWO WAVES IT DOES NOT 
APPEAR AT THIS TIME TO BE A WIDESPREAD RAIN EVENT OR A PARTICULARLY 
HEAVY RAINFALL PRODUCER. TEMPERATURES ARE TRICKY FOR THIS TIME FRAME 
AND WILL BE LARGELY DEPENDENT ON THE AMOUNT OF RAINFALL AND CLOUD 
COVERAGE STICKING AROUND IN THE DAYLIGHT HOURS ON SATURDAY AND 
SUNDAY. WITH THE BETTER POTENTIAL FOR WET CONDITIONS ACROSS OUR 
EAST...HAVE KEPT READINGS IN THE COOLER UPPER 70S AND LOWER 80S 
WHILE THE MID 90S ARE EXPECTED IN OUR EXTREME WESTERN COUNTIES.

FOR THE EXTENDED RANGE...MODELS CONTINUE TO SHOW DISCREPANCIES FOR 
THE EARLY TO MID PORTIONS OF NEXT WEEK. NORTHWESTERLY UPPER FLOW 
BECOMES A BIT FLATTER DURING THIS PERIOD...HOWEVER THE LARGER 
DIFFERENCES ARE IN THE PLACEMENT OF THE RIDGE AXIS...WITH THE GFS BY 
FAR THE FARTHEST WEST. AS A RESULT...THE GFS BRINGS SEVERAL WAVES 
OVER THE TOP OF THE RIDGE AND THROUGH OUR FORECAST AREA DURING THIS 
PERIOD...WHILE THE ECMWF AND FOR THE MOST PART THE GEM ARE DRIER 
DURING THIS PERIOD. AM THINKING THAT THE BEST ROUTE OF ATTACK IS TO 
KEEP THINGS DRY IN THE EXTENDED WITH SO LITTLE CONFIDENCE IN THE 
TIMING AND TRACK OF THESE WEAK WAVES. THERE SEEMS TO BE SLIGHTLY 
MORE AGREEMENT IN BRINGING A SOMEWHAT MORE ROBUST WAVE INTO THE 
REGION MID WEEK...SO WILL LEAVE LOW CHANCE MENTION WEDNESDAY NIGHT 
AND THURSDAY.

&&

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

&&

$$