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000
FXUS63 KFSD 222202
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
402 PM CST THU JAN 22 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM CST THU JAN 22 2015

AS STRATUS CONTINUES TO DEPART OUR EASTERN ZONES...TONIGHT WILL SHOW
AN INCREASE IN MID LEVEL CLOUDS MOVING NORTH TO SOUTH...BECOMING
CONSIDERABLY CLOUDY ACROSS THE FORECAST AREA BETWEEN 06Z AND 12Z
FRIDAY. WITH THE CLOUD COVER...COUPLED WITH SUBTLE WARM AIR
ADVECTION AND A SOUTH TO SOUTHWEST SURFACE FLOW...LOWS TONIGHT WILL
BE VERY MILD FOR THIS TIME OF YEAR WITH READINGS STAYING IN THE 20S.
THE LOW LEVEL JET IS RATHER STOUT WITH 925MB WINDS FORECAST TO
AVERAGE 35 TO 45 KNOTS FROM THE I 29 CORRIDOR AND POINTS EASTWARD...
THEREFORE PLACED A STRIPE OF GUSTY WINDS NEAR 35 MPH RIGHT ALONG THE
BUFFALO RIDGE IN SOUTHWEST MN.

ON FRIDAY...PUT IN SLIGHT CHANCE POPS FOR AREAS EAST OF THE JAMES
RIVER VALLEY. A SHORT WAVE MOVES THROUGH MINNESOTA WITH OUR FORECAST
AREA CAUGHT ON THE VERY WESTERN EDGE OF IT. BOTH THE NAM AND GFS
SHOW SATURATION INTO THE 800-750MB LAYER MOVING FROM NORTH TO SOUTH
FOR THESE LOCATIONS. WITH A DRY LAYER BELOW 800MB...ANY FALLING
PRECIPITATION WILL PROBABLY JUST BE SPRINKLES AND THUS DOUBTFUL TO
MEASURE A HUNDREDTH OF AN INCH. BUT A BIT OF A PROBLEM EXISTS IN
SOUTHWEST MN AND IMMEDIATE ADJACENT AREAS IN THE MORNING WHERE IF
ANY TRACE AMOUNTS OF PRECIP DOES FALL...IT WILL PROBABLY BE FREEZING
SPRINKLES...OR AT LEAST A MIX OF FREEZING SPRINKLES AND LIQUID. IN
THE AFTERNOON...BOTH THE NAM AND GFS CONTINUE TO SHOW SOME PROBABLE
STRATO CUMULUS DEVELOPMENT IN THE LOW LEVELS AFTER 18Z FRIDAY ALONG
AND EAST OF THE JAMES...SO SKIES MAY NOT BE REAL PRISTINE AT ANY
TIME OF THE DAY. WITH A MILD FLOW OF AIR HOWEVER AND STARTING SO
WARM IN THE MORNING...HIGHS SHOULD BE IN THE UPPER 30S TO MID 40S.


.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM CST THU JAN 22 2015

UPPER RIDGING OVER THE WESTERN UNITED STATES WILL PUT OUR REGION IN
NORTHWEST FLOW THIS WEEKEND INTO EARLY NEXT WEEK. THIS WILL
GENERALLY BE A WARM PATTERN...BUT TIMING OF SUBTLE WAVES AND FRONTS
ARE ALWAYS HARD TO PREDICT AND THUS SOME TEMPERATURE UNCERTAINTY
EXISTS. THERE IS AGREEMENT THAT ONE WAVE WILL SWING THROUGH THE AREA
SATURDAY AFTERNOON INTO SUNDAY. MODELS ARE HOWEVER STRUGGLING WITH
THE SPECIFICS OF THIS FEATURE. GFS IS WEAKER AND MORE DISORGANIZED
WITH THE SYSTEM...KEEPING MUCH OF THE PRECIPITATION TO OUR
NORTHEAST. THE ECMWF IS STRONGER AND DEEPER...RESULTING IN HIGHER
QPF ACROSS OUR AREA. THE GEM IS IN BETWEEN...BUT IS STILL MAINLY
DRY. THE ECMWF HAS BEEN MORE CONSISTENT...SO AT THIS TIME LEANING
TOWARDS A ECMWF AND GEM COMPROMISE. THUS WILL STICK WITH THE CHANCE
POPS SATURDAY AFTERNOON AND NIGHT. WITH THE TRACK OF THIS SYSTEM TO
OUR NORTH...STILL SEEMS LIKE MAINLY LIGHT RAIN...ALTHOUGH COULD SEE
SOME SNOW MIX IN SATURDAY NIGHT...ESPECIALLY SOUTHWEST MINNESOTA.
ACCUMULATIONS SEEM UNLIKELY AT THIS TIME. GIVEN MODEL
UNCERTAINTY...WILL NEED TO MONITOR TRENDS. WITH WARMING
TEMPERATURES ALOFT AND GOOD MIXING...EXPECTING 40S FOR HIGHS SATURDAY.

COOLER AIR MOVES SOUTH BEHIND THE WAVE FOR SUNDAY. BASED ON THE
ECMWF AND GEM PREFERENCE MENTIONED ABOVE...DID CUT BACK HIGHS
SOME...BUT STILL LOOKING AT 30S AND 40S. COULD BE A LITTLE LINGERING
LIGHT RAIN OR SNOW EAST OF INTERSTATE 29...BUT NOT EXPECTING ANY
ACCUMULATION. DO NOT HAVE ANY POPS LATER SUNDAY INTO SUNDAY NIGHT AT
THIS TIME...BUT LATEST MODELS SUGGEST ANOTHER WAVE WAVE MAY TRAVERSE
THE AREA. IF FUTURE RUNS CONTINUE TO SHOW THIS...MAY END UP NEEDING
A CHANCE OF LIGHT SNOW OR RAIN...BUT ANYTHING WOULD BE VERY LIGHT.

THE STORY MONDAY INTO WEDNESDAY WILL BE THE WELL ABOVE NORMAL
TEMPERATURES. SEEMS LIKE READINGS IN THE 40S TO AROUND 50 ARE LIKELY
EACH DAY. ECMWF ENSEMBLE MOS SPREAD IS HIGH THOUGH...SUGGESTING SOME
UNCERTAINITY IN WEAK FRONTAL TIMING AND LOW LEVEL THERMAL FIELDS.
THUS STAYED ON THE WARMER SIDE OF GUIDANCE...BUT DID NOT GO TOO
EXTREME. NOT OUT OF THE QUESTION ETHER TUESDAY OR WEDNESDAY SEES
WIDESPREAD 50S. AT THIS TIME LOOKS LIKE COOLER AIR WILL FILTER IN BY
THURSDAY AS TROUGHING MOVES EAST. THIS COULD BRING OUR NEXT LIGHT
SNOW POTENTIAL BY FRIDAY...BUT THIS IS A WAYS OUT SO NOT CONFIDENT
AT THIS TIME.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1128 AM CST THU JAN 22 2015

PATCH OF IFR STRATUS IS NOW ERODING IN EAST CENTRAL SD...BUT HAS
CLEARED OUT OF KHON AND WILL NOT AFFECT ANY TAF SITES IN THE SIOUX
FALLS FORECAST AREA EARLY THIS AFTERNOON. OTHERWISE THE MAIN AREA
OF MVFR CLOUDS CONTINUES TO MOVE EASTWARD ALONG AND EAST OF
INTERSTATE 29...WITH SOME STRATOCUMULUS DEVELOPMENT ON THE BACK
SIDE OF THE CLOUDS. THEREFORE WILL LIKELY BE A SLOW REDUCTION OF
CLOUD COVER THROUGH THE AFTERNOON HOURS EAST OF I 29 FROM MVFR TO
VFR CONDITIONS. WENT WITH A TEMPO MVFR SCENARIO FOR KSUX THROUGH
20Z AS THE STRATOCUMULUS DEVELOPMENT COULD KEEP THEM WITH A
CEILING OFF AN ON. BUT BOTH THE NAM AND GFS SHOW MOISTURE
DECREASING AT KSUX BY 20Z TO 21Z THIS AFTERNOON. TONIGHT AND
FRIDAY MORNING...MID LEVEL CLOUDS WILL MOVE INTO THE FORECAST AREA
WITH VFR CONDITIONS.


&&

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

$$

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