555 
FXUS63 KFSD 101021
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
421 AM CST WED DEC 10 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 418 AM CST WED DEC 10 2014

COMPLICATED FORECAST AGAIN TODAY AS SMATTERING OF CLOUDS ACROSS THE 
REGION WHICH WILL IMPACT POTENTIAL WARMING. CURRENTLY...WARM FRONT 
IS ACROSS THE FAR WESTERN EDGE OF SOUTH DAKOTA...AND A LARGE PART OF 
THE WARM AIR WILL REMAIN BOTTLED UP WEST OF THE FORECAST AREA TODAY. 
STRATUS ACROSS SOUTHWEST MINNESOTA EARLY THIS MORNING IS EXPECTED TO 
RETREAT TO THE NORTHEAST THROUGH THE MORNING TODAY...HOWEVER...AM 
ALSO CONCERNED ABOUT AREA OF CLOUDS EXPANDING ACROSS EASTERN 
NEBRASKA.  SOUTHERLY FLOW IN THE LOW LEVELS SUGGESTS THAT THIS AREA 
OF CLOUD COVER WILL LIFT NORTHWARD THROUGH THE DAY IMPACTING ANY 
POTENTI9AL WARMING ALONG AND EAST OF I-29.  SHORT TERM HI-RES MODELS 
SHOW CLOUD COVER BREAKING APART THIS AFTERNOON....BUT AM NOT 
COMPLETELY CONVINCED THIS WILL OCCUR...SO HAVE SKY COVER TRENDING 
TOWARDS A PARTLY CLOUDY SKY THROUGHOUT THE DAY.  WITH SKY COVER 
CONCERNS...HAVE CONTINUED THE TREND DOWNWARD...ESPECIALLY ACROSS THE 
EAST. 

MODELS SUGGEST THERE WILL BE A RESURGENCE OF LOW CLOUDS ACROSS THE 
EASTERN HALF OF THE FORECAST AREA TONIGHT.  WITH CLOUDS ACROSS THE 
AREA...KEPT FORECAST LOWS N THE EAST WARMER THAN IN THE WEST...WITH 
LOWS IN THE 20S. GIVEN THE STRATUS WILL BE AROUND...AM NOT EXPECTING 
DENSE FOG TO DEVELOP OVERNIGHT...BUT COULD BE SOME 4-6 SM 
VISIBILITIES FLOATING AROUND.


.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 418 AM CST WED DEC 10 2014

CONTINUED CONCERN FOR THE LATER HALF OF THE WEEK WILL BE THE
IMPACT OF STRATUS ON THE UNSEASONABLY WARM TEMPERATURES. LARGE
SCALE UPPER RIDGING OVER THE WESTERN PLAINS CONTINUES TO SLOWLY
SHIFT EASTWARD DURING THIS PERIOD. MID LEVEL TEMPERATURES SOAR
THURSDAY AND THURSDAY NIGHT...WITH 850MB TEMPS WELL INTO THE LOW
TO MID TEENS CELSIUS. WITH LOW LEVEL SOUTH TO SOUTHWEST
WINDS...MOISTURE BELOW THIS TEMPERATURE INVERSION WILL
INCREASE...BUT IT LOOKS LIKE THE BEST POTENTIAL FOR PROLONGED
STRATUS WILL BE ACROSS OUR SOUTHEASTERN THIRD OF THE FORECAST AREA
- PRIMARILY NORTHWEST IOWA AND SOUTHWEST MINNESOTA. THIS LAYER
LOOKS TO BE EXTREMELY SHALLOW WITH EXTREMELY DRY AIR ABOVE...WHICH
SHOULD PREVENT ANY DRIZZLE DEVELOPMENT. IT ALSO SHOULD ALLOW FOR
SOME DISSIPATION DURING THE AFTERNOON HOURS ON THURSDAY FOLLOWED
BY A SLIGHT INCREASE THURSDAY NIGHT. HIGHS WILL BE IN THE 40S TO
MID 50S THURSDAY AND WARM FURTHER INTO THE MID 40S TO LOWER 60S ON
FRIDAY. WARMEST TEMPERATURES WILL BE IN SOUTH CENTRAL SD WHERE
SUNSHINE IS MOST LIKELY TO BE ABUNDANT.

A STRONGER SURGE OF MOISTURE BUILDS BACK INTO THE AREA LATER FRIDAY 
AFTERNOON INTO FRIDAY NIGHT. WITH A SLIGHTLY MORE SUBSTANTIAL CLOUD 
DECK...SOME PATCHY FOG AND DRIZZLE MAY DEVELOP ACROSS OUR EASTERN 
HALF LATE FRIDAY NIGHT AND PERSIST THROUGH MUCH OF SATURDAY AS THE 
CLOUD COVER INCREASES TO BLANKET MUCH OF THE FORECAST AREA. WILL 
CONTINUE WITH SOME LIGHT RAIN CHANCES EXPANDING ACROSS THE FORECAST 
AREA SATURDAY NIGHT AND SUNDAY WITH A SHORTWAVE LIFTING INTO THE 
FORECAST AREA DURING THIS PERIOD. HIGHS ON SATURDAY WILL BE MILD IN 
THE 50S DESPITE THE INCREASED CLOUD COVERAGE.

ALL MODELS BEGIN TO PAINT A DEEP CUT OFF LOW EMERGING FROM THE 
ROCKIES INTO THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY. MODELS SHOW 
SOME PRETTY SIGNIFICANT DIFFERENCES IN THE IMPACT OF THIS SYSTEM FOR 
OUR FORECAST AREA. WHILE THE GFS AND GEM TRACK THE STACKED LOW 
CENTER NEAR THE KANSAS AND OKLAHOMA BORDER...THE ECMWF HAS COME IN 
FURTHER NORTH CLOSER TO THE NEBRASKA BORDER. AS A RESULT...THERE ARE 
SOME MAJOR DIFFERENCES IN WHERE THE THERMAL BOUNDARY WILL SET UP 
SUNDAY NIGHT AND MONDAY. THE GEM HAS VERY LITTLE IMPACT ON OUR 
FORECAST AREA...WHILE THE GFS BRINGS SOME PRECIPITATION IN THE 
MISSOURI VALLEY AND NORTHWEST IOWA. THE ECMWF HOWEVER BRINGS AS MUCH 
AS 1" OF QPF INTO THE HEART OF OUR FORECAST AREA. WITH COOLER AIR 
RETURNING TO THE FORECAST AREA...MUCH OF THIS PRECIPITATION COULD BE 
SNOWFALL OR RAIN TURNING TO SNOWFALL. STILL...SO MUCH UNCERTAINTY 
DURING THE TIME SO WILL LEAVE ONLY CHANCE POPS WHICH ARE HIGHEST IN 
NORTHWEST IOWA.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1044 PM CST TUE DEC 9 2014

FOR THE REMAINDER OF THE NIGHT...THERE WILL BE SCATTERED MVFR
CEILINGS ACROSS SOUTHWEST MN AND THE EASTERN SECTIONS OF EAST
CENTRAL SD. SOME OF THIS STRATUS MAY BE CLOSE TO THE KFSD TAF
SITE...THEREFORE KEPT A MENTION OF SCATTERED MVFR CLOUDS IN FOR
KFSD AS A HEDGE. OTHERWISE WITH A MOIST SOUTHERLY FLOW...WOULD NOT
BE SURPRISED TO SEE SOME MVFR FOG AROUND SUNRISE WEDNESDAY
MORNING. AFTER THAT...WILL LEAN TOWARD VFR CONDITIONS...BUT NOTING
THAT THERE COULD BE STRATUS NOT TOO FAR EAST OF I 29 WEDNESDAY
AFTERNOON AND EVENING. THEREFORE THAT WILL NEED MONITORED FOR THE
KFSD AND KSUX TAF SITES.


&&

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

$$

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