Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 191743
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1143 AM CST FRI DEC 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 319 AM CST FRI DEC 19 2014

IN THE SHORT TERM...THE MAIN CONCERN IS THE CLOUDS AND ASSOCIATED
CLEARING LINE.  AREAS IN EXTREME WESTERN PORTION OF THE CWA MAY SEE
A LITTLE SUN TODAY AS CLEARING LINE SLIDES EVER SO SLOWLY EAST.
HOWEVER...MOST OF THE ENTIRE FORECAST AREA WILL ONCE AGAIN BE LOCKED
IN STRATUS TODAY...TONIGHT AND INTO THE WEEKEND.  THERE IS A SLIGHT
CHANCE FOR A LITTLE FREEZING DRIZZLE TODAY BUT MOISTURE ISN`T SO
DEEP RIGHT NOW BUT MODELS DO SHOW A LITTLE DEEPENING WITH TIME
ACROSS AREAS OF NORTHWEST IOWA AND SOUTHWEST MINNESOTA.  AT THIS
TIME...I DECIDED NOT TO INCLUDE THE MENTION OF FREEZING DRIZZLE DUE
TO THE UNCERTAINTIES.  DEFINITELY ANOTHER GREY FORECAST PERIOD.
HIGHS WILL BE WARMER THAN THOSE OF YESTERDAY AND THE UPWARD CLIMB
WILL BE TEMPERED BY THE CLOUDS.  SO MORE SEASONAL HIGHS.

AS WE HEAD INTO TONIGHT...THE MAIN ISSUE WITH THE FORECAST IS AGAIN
THE CHANCES FOR FREEZING DRIZZLE BUT WILL LET LATER SHIFTS TAKE A
LOOK AT WHETHER THE MOISTURE IS TRULY DEEPENING OR IS IT A MODEL
ANOMALY.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 319 AM CST FRI DEC 19 2014

WEAK SOUTHERLY FLOW LINGERS ACROSS THE REGION FOR SATURDAY AND
SUNDAY WITH SURFACE RIDGING TO OUR EAST. WITH A MOIST 935 MB FLOW
CONTINUING TO STREAM INTO THE AREA FROM THE SOUTH...EXPECTING
STRATUS TO HOLD STRONG AT LEAST INTO EARLY ON SUNDAY...ESPECIALLY
FROM THE INTERSTATE 29 CORRIDOR EASTWARD. THERE WILL BE A BETTER
POTENTIAL FOR SOME BREAKS IN OUR WEST ON SUNDAY AS THE LOW LEVEL
FLOW TAKES ON A MORE WEST/SOUTHWESTERLY COMPONENT. SIGNALS FOR
DRIZZLE WITH THE LOW LEVEL MOISTURE LOOKED EVEN LESS IMPRESSIVE IN
MOST RECENT MODEL RUNS...SO CONFINED DRIZZLE CHANCES TO OUR EXTREME
SOUTHEASTERN IOWA ZONES FOR SATURDAY NIGHT AND EARLY SUNDAY MORNING.
HIGHS ON SATURDAY LOOK TO RUN GENERALLY LOWER TO MID 30S...THEN AS
925 MB TEMPERATURES WARM ON SUNDAY OUT AHEAD OF A DEEPENING TROUGH
OVER THE NORTHERN ROCKIES/WESTERN HIGH PLAINS...HIGHS WILL RESPOND
IN KIND TOPPING OUT IN THE MID AND UPPER 30S ON THAT DAY.

WELL ADVERTISED UPPER LEVEL TROUGH BEGINS TO DEEPEN OVER THE CENTRAL
CONUS BY SUNDAY NIGHT...AS SHORTWAVE ENERGY BEGINS TO ENCROACH ON
OUR AREA. STILL SOME MODEL DIFFERENCES ON SPECIFICS...BUT THE
GENERAL TREND IS FOR THE BETTER PRECIPITATION CHANCES TO BE IN OUR
EAST ON SUNDAY NIGHT WHERE THE BEST THETA E ADVECTION WILL BE
SITUATED AND THE DEEPER MOISTURE WILL RESIDE. AGAIN THERE ARE
VARIATIONS IN MODEL THERMAL PROFILES...BUT THERE DOES APPEAR TO BE A
WARM LAYER ALOFT ON SUNDAY NIGHT INTO AT LEAST EARLY ON
MONDAY...WHICH WILL LEAD TO PRECIPITATION TYPE ISSUES. FOR SUNDAY
NIGHT THE MAIN PRECIPITATION TYPES WOULD BE RAIN/FREEZING RAIN/OR
SLEET...THOUGH FORTUNATELY IT APPEARS THAT AREAS THAT HAVE THE BEST
POTENTIAL FOR PRECIPITATION MAY REMAIN ABOVE FREEZING THROUGH THE
NIGHT ON SUNDAY. THE MAIN WAVE SLIDES THROUGH THE REGION ON MONDAY
AND MONDAY NIGHT...WITH SLOWLY COOLING THERMAL PROFILES AND
PRECIPITATION TYPE TRANSITIONING TO SNOW...WITH SOME RAIN IN THE
SOUTH WHERE IT WILL STILL BE RELATIVELY MILD ON MONDAY AFTERNOON
WITH HIGHS IN THE UPPER 30S THROUGH THAT AREA.

BY MONDAY NIGHT THERMAL PROFILES WILL HAVE COOLED SUFFICIENTLY THAT
ANY PRECIPITATION WOULD BE ALL SNOW...WITH THE LIGHT SNOW POTENTIAL
LINGERING INTO TUESDAY AS THE TROUGH DEEPENS THROUGH THE MISSISSIPPI
VALLEY. FOR THE REMAINDER OF THE EXTENDED...LOOKS TO DRY OUT FOR
WEDNESDAY AND THURSDAY AS THE SYSTEM PULLS AWAY AND BRIEF UPPER
LEVEL RIDGING BUILDS INTO THE REGION. TEMPERATURES THROUGH THE
PERIOD WILL BE FAIRLY TYPICAL FOR THIS TIME OF YEAR WITH HIGHS IN
THE 20S AND LOWER 30S AND LOWS IN THE TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1140 AM CST FRI DEC 19 2014

POOR AVIATION CONDITIONS EXPECTED TO CONTINUE THROUGH THE PERIOD.
GENERALLY WENT WITH A PERSISTENT FORECAST KEEPING CIGS VERY
SIMILAR TO WHERE THEY ARE NOW INTO TOMORROW MORNING. THINGS TO
WATCH WILL BE WHETHER CIGS ARE ABLE TO LOWER A FEW HUNDRED MORE
FEET TONIGHT...AND WHETHER WE SEE ANY DENSE FOG DEVELOPMENT.

&&

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

$$

SHORT TERM...HEITKAMP
LONG TERM...JM
AVIATION...CHENARD



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