000 
FXUS63 KFSD 170939
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA 
NATIONAL WEATHER SERVICE SIOUX FALLS SD
335 AM CST THU JAN 16 2008

.DISCUSSION...

THREE DIFFERENT SNOW CHANCES FOR THE NEXT 5 DAYS...AND OF COURSE 
TURNING MUCH COLDER AS PER PREV FCST. LIGHT SNOW STILL LINGERING IN 
NWRN IA THRU EARLY MRNG...AND REPORTS OF 1 TO 3 INCHES IN SERN PTNS 
OF AREA. THIS WILL PULL OUT THE EAST FLWD BY INITIALLY VERY COLD AIR 
MASS ASSCD WITH SFC RDG MOVG SEWD OVR CWA THIS MRNG. THIS COLD SFC 
RDG WILL MOVE OFF TO THE EAST THIS AFTN FLWD BY SWLY FLOW OF 
SOMEWHAT MILDER AIR ALOFT TO MIX DOWN CLOSE TO SFC WEST OF I29.
LOW LVLS IN ERN CWA SHOULD HAVE TOUGH TIME SEEING THIS MILDER AIR 
HOWEVER...ESP WITH NEW SNOW COVER IN NWRN IA. FAIRLY MIXED OUT TNGT 
WITH TROF AND ASSCD CLDS AND AREAS OF LGT SNW MOVG SEWD OVR CWA. NOT 
REALLY THAT MUCH DYNAMICS FOR MUCH ACCUM TNGT INTO FRI MRNG...MOSTLY 
DRIVEN BY COLD ADVECTION. MAIN SURGE OF ARCTIC AIR FRI THRU FRI NGT 
WITH TEMPS GRADUALLY FALLING. BEST MIXING AND NWLY WINDS FRI...WITH 
MOTHER LODE OF COLD AIR MOVG DOWN FRI NGT...SO THERE WILL EASILY BE 
WIND CHILL ISSUES THAT LATER SHIFTS WILL HAVE TO DEAL WITH. CLOUDS 
WILL ALSO HAVE TENDENCY TO BREAK UP FRI AFTN AND EVE AS VERY COLD 
DRY AIR TAKES OVER...BUT CIRRUS ON THE GROUND TYPE ICE CRYSTALS WILL
BE PSBL. MAIN CHANGE TO PREV FCST WAS TO HIT CHANCES OF SNOW MOVG 
EWD INTO CWA...MAINLY ALG AND SOUTH OF I90...LATER SAT NGT THRU SUN 
WITH GOOD WAVE SHOWN ON ALL MODELS. THIS SNOW WILL BE GENERATED ON 
THE MID LVL BOUNDARY AND COULD BE A NICE LITTLE SHOT OF FLUFF.

&&

.AVIATION...

IMPROVING CONDITIONS EXPECTED OVER THE AREA THROUGH THE MORNING 
HOURS AS LOW PRESSURE OVER IOWA CONTINUES TO PUSH AWAY FROM THE 
REGION. SCATTERED FLURRIES AROUND KSUX EARLY THIS MORNING...IN 
ASSOCIATION WITH ABOVE SYSTEM...WILL CONTINUE TO TAPER OFF...WITH 
VFR CONDITIONS ANTICIPATED THROUGH THE REMAINDER OF THE DAY. IN 
BETWEEN SYSTEMS...SKIES WILL BE MAINLY CLEAR AROUND THE KHON AND 
KFSD TAF SITES INTO EARLY AFTERNOON...BEFORE ANOTHER AREA OF LOW 
PRESSURE AND ASSOCIATED FRONTAL SYSTEM DROPS SOUTHWARD THROUGH SOUTH 
DAKOTA DURING THE LATE AFTERNOON. WITH THIS SYSTEM...CLOUDS WILL 
INCREASE AROUND KHON AFTER 21Z...WITH CEILINGS LOWERING INTO THE 
MVFR RANGE JUST AFTER 00Z THIS EVENING.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$
RSR/JM