575 
FXUS63 KFSD 101725
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1225 PM CDT THU OCT 10 2013


.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 433 AM CDT THU OCT 10 2013

HIGH AMPLITUDE FLOW ACROSS THE NATION WITH DEEP WESTERN TROUGH AND 
STRONG PLAINS/MIDWEST RIDGE. MOISTURE ACROSS THE NATIONS MID SECTION 
IS LACKING...PRETTY MUCH LIMITED TO MID LEVEL SOURCE IN THE 
SOUTHWESTERN U.S. WEAK SYSTEM ALOFT PUSHING ALONG UPSTREAM SIDE 
THROUGH NEBRASKA THIS MORNING...BUT ONLY ENHANCING HIGH CLOUDS AT 
THE TIME. OVERALL...WARM SOUTHERLY FLOW WILL AGAIN DOMINATE THE AREA 
FOR ANOTHER DAY...AS THE LOW LEVEL GRADIENT AGAIN INCREASES A BIT 
WITH HIGH PLAINS FALLING PRESSURE IN ADVANCE OF THE MAJOR WESTERN 
TROUGH. WEAK BOUNDARY ACROSS THE WEST WILL START TO BECOME MORE 
DIFFUSE OR REORGANIZE FURTHER TO THE NORTHWEST. TEMPERATURES ALOFT 
SUGGEST HIGHS IN THE NEIGHBORHOOD OF THOSE FROM LAST COUPLE OF 
DAYS...AND AS LONG AS CIRRUS DIMINISHES WITH PASSAGE OF WAVE TO THE 
SOUTH...SHOULD SCRAPE UP ANOTHER DAY FROM THE MID 70S TO AROUND 
80... OR ABOUT 15 TO 20 DEGREES ABOVE NORMAL FOR MOST.

SHOULD GET A LITTLE DECOUPLING EARLY ON TONIGHT...BUT GRADIENT WILL 
REVERSE THE TREND AND KEEP WINDS UP TONIGHT...AS WELL AS LOW 
TEMPERATURES OVER THAT WHICH SOME OF THE RADIATIVELY COOLER SPOTS
HAVE ATTAINED THE LAST TWO NIGHTS. WITH APPROACH OF CLOSED LOW...A 
BAND OF STRONG PV ADVECTION WILL MOVE THROUGH THE WESTERN HALF OF 
THE CWA DURING THE LAST HALF OF THE OVERNIGHT. FAIRLY STRONG UPPER 
LEVEL FORCING AND 8 TO 9 C/KM MID LEVEL LAPSE RATES SHOULD OVERCOME 
THE OVERALL DRY ATMOSPHERE TO ALLOW BAND OF SHOWERS/ISOLATED THUNDER 
TO PRESS EASTWARD THE LAST HALF OF THE OVERNIGHT. INSTABILITY TRENDS
TO BE FAIRLY LIMITED...WITH A FEW HUNDRED J/KG ELEVATED CAPE. MOST 
HIGH RESOLUTION MODELS ALONG WITH SREF INDICATE A NARROW BAND OF 
PRECIPITATION...PERHAPS TOWARD THE I29 CORRIDOR TOWARD DAYBREAK.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 433 AM CDT THU OCT 10 2013

FRIDAY APPEARS TO BE A VERY WINDY DAY ACROSS THE FORECAST AREA AS AN 
AREA OF LOW PRESSURE DRIFTS FROM CENTRAL SOUTH DAKOTA INTO NORTHWEST 
MINNESOTA.  WITH THE AID OF MIXING...WINDS WILL PICK UP RAPIDLY 
THROUGH THE MORNING HOURS AND WITH 30-35 KNOTS OF FLOW AT 925 HPA... 
MAY APPROACH ADVISORY CRITERIA IN THE EAST. ANY SHOWER ACTIVITY 
MOVING THROUGH MAY TEMPORARILY STABILIZE THE NEAR SURFACE LAYER 
KEEPING THE STRONG WINDS ALOFT. UPPER LEVEL SUPPORT QUICKLY SHIFTS 
NORTHEAST THROUGH THE MORNING HOURS...AND APPEARS TO STABILIZE ON 
THE BACKSIDE OF THE WAVE.  THEREFORE...MAY NOT BE MANY SHOWERS 
AROUND THROUGH THE AFTERNOON HOURS WITH STRONG WINDS CONTINUING TO 
SURFACE.  MODELS SUGGEST COLD FRONT WILL PUSH INTO THE WESTERN EDGE 
OF THE FORECAST AREA...AND STRONG COLD AIR ADVECTION MAY LEAD TO 
WIND GUSTS APPROACHING HIGH WIND CRITERIA.  HAVE ISSUED A SMALL 
ADVISORY FOR AREAS IN THE WEST...BUT EXPECT ADVISORY WILL BE NEEDED 
TO BE EXPANDED FURTHER EAST.  IN ADDITION...THERE IS A CHANCE THAT 
WINDS IN SOUTH CENTRAL SOUTH DAKOTA COULD REACH HIGH WIND WARNING 
CRITERIA...ESPECIALLY IN BRULE...CHARLES MIX AND GREGORY COUNTIES.  
FUTURE SHIFTS WILL NEED TO KEEP AN EYE ON THESE LOCATIONS FOR 
POTENTIAL UPGRADE TO THE HEADLINES. 

VERY DRY AIR WORKS INTO THE FORECAST AREA BEHIND THE FRONT FRIDAY 
EVENING INTO SATURDAY.  WITH LOW LEVEL COLD AIR ADVECTION CONTINUING 
THROUGH THE NIGHT FRIDAY NIGHT...KEPT WIND ADVISORY GOING THROUGH 
05Z BUT COULD NEED TO KEEP THE ADVISORY LINGERING LONGER IN THE EAST 
IF IT IS EXPANDED.  WITH WINDS CONTINUING THROUGH MUCH OF THE 
NIGHT...SHOULD BE A WARM AND WINDY NIGHT ACROSS THE AREA. 

SATURDAY WILL BE A MIXY DAY WITH UNIDIRECTIONAL NORTHWEST FLOW.  
HAVE UNDERCUT DEW POINTS WITH DRY AIR ALOFT. WITH SURFACE RIDGE 
BUILDING INTO THE AREA...EXPECT WINDS TO RAPIDLY DECREASE SATURDAY 
EVENING ONCE MIXING CEASES.  

WITH DRY AIR REMAINING ACROSS THE AREA AS SURFACE RIDGE MOVES ACROSS 
THE AREA...HAVE UNDERCUT GUIDANCE TEMPERATURES SATURDAY NIGHT.  MAY 
NEED TO ADD FROST WORDING TO THE FORECAST...BUT WITH 925 HPA 
TEMPERATURES IN THE 3-5 C RANGE...DO NOT EXPECT HARD FREEZE QUITE 
YET.  

NEXT SYSTEM APPEARS TO MOVE INTO THE FORECAST AREA SUNDAY NIGHT INTO 
MONDAY BEFORE EXITING ON TUESDAY.  HAVE CONTINUED TO INCREASE POPS 
WITH THIS SYSTEM....AND WITH LIMITED INSTABILITY KEPT PRECIP AS RAIN 
SHOWERS FOR NOW. 

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1220 PM CDT THU OCT 10 2013

GENERAL VFR CONDITIONS THROUGH THE TAF PERIOD. MODERATE
SOUTHEASTERLY WINDS THROUGH TONIGHT WILL BEGIN TO RAMP UP AFTER
14Z ON FRIDAY. WITH A LOW LEVEL JET DEVELOPING OVER THE AREA
TONIGHT...WILL HAVE LOW LEVEL WIND SHEAR AT KFSD AND KSUX DURING
THE OVERNIGHT HOURS. MAY ALSO HAVE A BRIEF PERIOD OF SHOWERS MOVE
ACROSS THE AREA AFTER 10Z TONIGHT...WITH BETTER CHANCES NORTH OF
INTERSTATE 90.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 1 PM FRIDAY TO MIDNIGHT CDT FRIDAY NIGHT FOR 
     SDZ050-052-057>059-063>065-068-069.

MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

UPDATE...CHAPMAN
SHORT TERM...CHAPMAN
LONG TERM...
AVIATION...JM