749 
FXUS63 KFSD 221158
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
652 AM CDT FRI AUG 22 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT FRI AUG 22 2014

MAIN FOCUS IN THE SHORT TERM WILL BE A FAIRLY POTENT WAVE EXPECTED 
TO IMPACT THE FORECAST AREA BEGINNING THIS EVENING. LARGE TROUGH 
OVER THE INTERMOUNTAIN WEST THIS MORNING WILL EJECT A SHORTWAVE FROM 
THE FOUR CORNERS REGION INTO THE CENTRAL HIGH PLAINS THIS AFTERNOON. 
MEANWHILE SURFACE LOW PRESSURE DEEPENS IN WESTERN KANSAS AND LIFTS 
NORTHWARD INTO NEBRASKA IN THE EVENING. AN ATTENDANT WARM FRONT WILL 
ALSO LIFT NORTHWARD TOWARDS THE MISSOURI VALLEY LATE TONIGHT.

MUGGY CONDITIONS WILL PERSIST TODAY...WITH MID TO UPPER 60S 
DEWPOINTS INCREASING THROUGH THE DAY TODAY AS FLOW CONTINUES TO TAP 
INTO MOISTURE. EXPECT DEWPOINTS WELL INTO THE LOW OR MID 70S ACROSS 
OUR SOUTHEASTERN HALF BY THIS AFTERNOON. WITH HIGH TEMPERATURES 
WARMING ONCE AGAIN INTO THE 80S...HEAT INDEX VALUES WILL REACH THE 
MID TO UPPER 90S IN PARTS OF NORTHWEST IOWA AND FAR SOUTHEAST SOUTH 
DAKOTA. COULD SEE A FEW INITIAL HIGH BASED CONVECTION FIRE EARLIER 
IN THE DAY IN NEBRASKA AND CLIP OUR SOUTHERN BORDER. HOWEVER...LATER 
THIS EVENING AS THE LOW LEVEL JET BEGINS INCREASING AND THE FRONT 
STARTS LIFTING NORTHWARD...CONVECTION WILL SLOWLY BUILD NORTHWARD 
INTO THE MISSOURI VALLEY...BECOMING CATEGORICAL ACROSS OUR 
SOUTHWESTERN HALF OVERNIGHT. MAIN CHANGE WAS TO SLOW DOWN THE TIMING 
SEVERAL HOURS WITH NEARLY EVERY MODEL SUPPORTING A SLOWER 
PROGRESSION OF THE BOUNDARY LIFTING NORTH. STRONG INSTABILITY 
ESPECIALLY IN OUR SOUTH COULD BUMP CAPE VALUES TO 2500 J/KG...WITH 
INITIAL MEAGER SHEAR INCREASING OVERNIGHT AS THE LLJ INCREASES. A 
FEW ISOLATED EMBEDDED SEVERE STORMS WILL BE POSSIBLE LATE TONIGHT 
NEAR THE MISSOURI VALLEY AS THE FRONT NEARS THE AREA...HOWEVER THE 
BULK OF THE THREAT WILL REMAIN SOUTH OF THE CWA. MAIN SEVERE THREAT 
WOULD BE MARGINAL HAIL AND GUSTS TO 65 MPH. LOWS TONIGHT WILL BE IN 
THE MID 60S TO NEAR 70.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 406 AM CDT FRI AUG 22 2014

IN GENERAL...00Z GFS RUN IS MUCH MORE PROGRESSIVE THAN THE OTHER 
SOLUTIONS...AND GIVEN ITS OUTLYING SOLUTION...HAVE DISCOUNTED IT AND 
HAVE ATTEMPTED TO REDUCE THE BLENDS INFLUENCE.  WARM AND MUGGY 
PATTERN CONTINUES THIS WEEKEND AHEAD OF A SLOW MOVING TROUGH MOVING 
OUT OF THE PACIFIC NORTHWEST INTO THE NORTHERN ROCKIES.  LEADING 
SHORTWAVE LIFTING INTO THE REGION IN SOUTHWEST FLOW APPEARS TO 
MAINLY BE FOCUSED WEST...AND WHILE THE EAST REMAINS UNSTABLE...LACK 
OF FORCING AND STRONG ENOUGH CAP SHOULD LIMIT CONVECTION SPREADING 
EAST.  AS SUCH...HAVE SCALED BACK POPS EAST OF I-29 THROUGHOUT THE 
DAY ON SATURDAY.  AS PREVIOUS FORECAST MENTIONED...PWAT VALUES ARE 
NEAR 2 INCHES...WHICH IS AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. 
WITH STRONG WARM AIR ADVECTION THROUGHOUT THE DAY SATURDAY...THERE 
IS THE POTENTIAL FOR REGENERATING CELLS ALONG THE WARM FRONT LIFTING 
NORTH THROUGH THE AREA.  CLOSER TO THE CENTER OF THE SHORT 
WAVE...CLOUDS AND CONVECTION WILL KEEP TEMPERATURES DOWN...WHILE 
FURTHER TO THE EAST TEMPERATURES WILL APPROACH 90. 

ON SATURDAY NIGHT INTO SUNDAY...UPPER LOW APPROACHES FROM THE WEST 
BUT RIDGE TO THE EAST IS FAIRLY STRONG SO THE LOW LIFTS MORE NORTH 
THAN TRANSLATING EAST. WITH THE FOCUS FURTHER TO THE WEST...HAVE CUT 
POPS BACK SOME ESPECIALLY THROUGHOUT THE DAY ON SUNDAY.  COLD FRONT 
MOVES THROUGH ON SUNDAY WITH MUCH COOLER AND DRIER AIR WORKING INTO 
THE REGION BEHIND THE FRONT. TEMPERATURES APPEAR TO REMAIN BELOW 
NORMAL THROUGH THE BETTER PORTION OF NEXT WEEK...WITH THE BEST 
CHANCE OF PRECIPITATION ON WEDNESDAY AS WEAK UPPER LEVEL TROUGH 
MIGRATES THROUGH THE AREA. 

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY NIGHT) ISSUED AT 
652 AM CDT THU AUG 21 2014

PATCHY SHALLOW FOG EARLY THIS MORNING WILL QUICKLY LIFT BY 
13Z...WITH VFR CONDITIONS EXPECTED THROUGH 00Z. CONVECTION LIKELY TO 
DEVELOP THIS EVENING NEAR THE MISSOURI RIVER AND VERY SLOWLY LIFT 
NORTHEAST THROUGH THE END OF THE TAF PERIOD. MVFR AND IFR VISIBILITY 
AND CEILINGS WILL BE POSSIBLE IN THUNDERSTORMS WITH HEAVY RAINS. 
EXPECT ACTIVITY IN KSUX AFTER 03Z...POSSIBLE MAKING IT AS FAR NORTH 
AS KFSD AND KHON AFTER 06Z.


&&

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

$$

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