755 
FXUS63 KFSD 132002
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
302 PM CDT MON OCT 13 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 258 PM CDT MON OCT 13 2014

DEEP LONGITUDINAL TROUGH EXTENDING THE LENGTH OF THE MISSISSIPPI 
RIVER VALLEY IS ONLY SLOWLY INCHING EAST.  AS A RESULT...MUCH OF THE 
EASTERN HALF OF THE FORECAST AREA REMAINS COVERED IN CLOUDS. THE
CLOUDS HAVE KEPT THE ATMOSPHERE FROM MIXING AND ALBEIT
BREEZY...WINDS HAVE NOT BEEN AS STRONG AS ANTICIPATED. COULD SEE A
FEW LIGHT SHOWERS THROUGH THE AFTERNOON HOURS ACROSS NORTHWEST
IOWA AS UPPER LEVEL TROUGH LIFTS NORTH...HOWEVER...AS IT DOES SO
THE SYSTEM SHIFTS EVER SO SLIGHTLY EAST SHIFTING THE FOCUS EAST OF
THE ENTIRE FORECAST AREA BY LATE THIS AFTERNOON. ATMOSPHERE WILL
TRY TO GRADUALLY CLEAR FROM WEST TO EAST THROUGH THE
OVERNIGHT...BUT IT WILL BE A VERY SLOW PROCESS. LOW LEVEL COLD AIR
ADVECTION WILL KEEP THINGS SLIGHTLY MORE MIXED IN THE EASTERN
PORTION OF THE FORECAST AREA. HAVE INCREASED WINDS SLIGHTLY...AND
KEPT SIMILAR LOWS IN THE EAST. IN THE JAMES RIVER VALLEY AND
WEST...CONDITIONS WILL HAVE A BETTER CHANGE OF RADIATING
BETTER...AND HAVE SIDED AT OR SLIGHTLY BELOW GUIDANCE VALUES FOR
LOWS.

TUESDAY SHOULD BE A RELATIVELY QUIET DAY AS HIGH PRESSURE BUILDS 
INTO THE AREA.  WITH UNIDRECTIONAL FLOW...SHOULD BE A FAIRLY MIXY 
DAY AND SIDED WITH HIGHS A FEW DEGREES ABOVE CLIMATOLOGICAL NORMS IN 
THE MID 60S.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 258 PM CDT MON OCT 13 2014

GENERALLY QUIET WEATHER IS EXPECTED THROUGH THE MID AND EXTENDED 
RANGE FORECAST. MID-LVL RIDGING WILL PEAK ACROSS THE AREA ON 
WEDNESDAY AND THURSDAY AS SLOW MOVING UPPER LOW DRIFTS INTO THE 
GREAT LAKES.  DOWNSTREAM BLOCKING WILL PREVENT THIS UPPER LOW FROM 
COMPLETELY EJECTING EASTWARD BY THE END OF THE WEEK...WITH LATEST 
GUIDANCE INDICATING THAT IT WILL STALL AND AID IN THE DEVELOPMENT OF 
MORE BROAD SCALE LONG WAVE TROUGH INTO THE WEEKEND.

AT THE SURFACE...RIDGE AXIS WILL GRADUALLY SLIDE EAST OF THE AREA LATE
ON WEDNESDAY ALLOWING TEMPERATURES TO WARM ABOVE NORMAL. ON
THURSDAY...A QUICK MOVING UPPER TROUGHING WILL LIFT NORTHEAST
THROUGH THE REGION...PUSHING A FRONTAL BOUNDARY THROUGH THE AREA.
TEMPERATURES ARE EXPECTED TO WARM BEHIND THIS FRONTAL BOUNDARY
GIVEN A SHARP DOWNSLOPE COMPONENT...BUT WILL QUICKLY FALL AS A
COLDER AIRMASS REACHES THE AREA OVERNIGHT.

AN UNCERTAIN FORECAST REMAINS FOR THE UPCOMING WEEKEND...AS 
GFS/ECMWF DIFFER SIGNIFICANTLY ON THE DEGREE OF TROUGHING ACROSS
THE EASTERN CONUS. THE ECMWF WITH AGREEMENT FROM THE GEM...REMAIN
MUCH COLDER FOR FRIDAY-SUNDAY...WITH SUBSTANCIAL CLOUD COVER AND
EVEN A FEW SHOWERS OVER SW MINNESOTA. HAVE TRENDED SLIGHTLY COOLER
AND IN LINE WITH THE MORE CONSISTENT ECMWF. REGARDLESS OF
SOLN...NO LARGE SCALE PRECIPITATION CHANCES IN THE FUTURE INTO
EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1223 PM CDT MON OCT 13 2014

MVFR CONDITIONS MAINLY CONFINED TO NORTHWEST IOWA AND AREAS EAST
WILL CONTINUE TO STEADILY IMPROVE THROUGH THE AFTERNOON HOURS AS
UPPER LOW SLOWLY INCHES EAST. BREEZY NORTHWEST WINDS WILL PREVAIL
THROUGH THE AFTERNOON HOURS...AND WITH BRISK FLOW ALOFT...WILL
STRUGGLE TO SETTLE DOWN THIS EVENING ESPECIALLY EAST OF I-29.
MARGINALLY BREEZY CONDITIONS WILL DEVELOP DURING THE DAYLIGHT
HOURS ON TUESDAY...ESPECIALLY ACROSS NORTHWEST IOWA.
ELSEWHERE...TO THE NORTH AND WEST...THE GRADIENT WILL BE LESS AND
THEREFORE THE WINDS WILL BE LESS AS WELL.


&&

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

$$

SHORT TERM...
LONG TERM...DUX
AVIATION...