704
FXUS63 KFSD 022330
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
530 PM CST SUN FEB 2 2025
KEY MESSAGES
- LIGHT PRECIPITATION WILL WORK NORTHWARD LATER THIS AFTERNOON
AND EVENING, HOWEVER TRENDS CONTINUE TO PLACE GREATEST
POTENTIAL FOR SNOW JUST NORTH OF HIGHWAY 14.
- SOME FOG REDEVELOPMENT IS POSSIBLE IN NORTHWEST IOWA AND
NORTHEASTERN NEBRASKA LATER TONIGHT. UNCERTAINLY LINGERS ON IF
DENSE FOG CAN DEVELOP. RISK SHOULD QUICKLY MINIMIZE
- COOLER THAN NORMAL TEMPERATURES SETTLE INTO THE AREA FOR MUCH
OF THE UPCOMING WEEK.
- TWO PRECIPITATION CHANCES TO WATCH FOR THIS WEEK. CHANCE FOR
LIGHT FREEZING RAIN TO SNOW WEDNESDAY AFTERNOON AND NIGHT, AND
PERHAPS A SLIGHTLY HIGHER RISK FOR SNOW SATURDAY.
PROBABILITIES OF BOTH EVENTS REMAIN IN THE 30 TO 50% RANGE.
DISCUSSION
ISSUED AT 216 PM CST SUN FEB 2 2025
THIS AFTERNOON: COLD FRONT BISECTING THE CWA THIS AFTERNOON, WITH
TEMPERATURES IN THE 30S NORTH OF THE FRONT, BUT AREAS SOUTH OF THE
FRONT IN SLIGHT CLEARING SURGING TOWARDS THE 50S. WE CONTINUE TO
SEE THICKENING BAND OF MID-LVL CLOUDS DEVELOP FROM THE BLACK HILLS
REGION SOUTHEAST ACROSS NORTHERN NEBRASKA. THESE CLOUDS ARE
ASSOCIATED WITH INCREASING MID-LVL FRONTOGENESIS THAT WILL LIFT
NORTHWARD THROUGH THE AFTERNOON AND EVENING. GENERALLY THERE
REMAINS A CONSIDERABLE AMOUNT OF SUB-CLOUD DRY AIR WITH SOME
REINFORCING DRY AIR ADVECTION MOVING IN FROM THE NORTH. THAT SAID,
THE GREATEST POTENTIAL FOR ANY MEASURABLE PRECIPITATION MAY TAKE
PLACE CLOSER TO HIGHWAY 14 AFTER SUNSET.
TONIGHT: GOOD AGREEMENT REMAINS WITH SHORT TERM MODEL GUIDANCE
PUSHING FRONTAL FORCING NORTH OF THE CWA AND INTO FAR NORTHERN SOUTH
DAKOTA AND SOUTHERN NORTH DAKOTA LATER THIS EVENING. THIS SHOULD
KEEP MOST OF THE CWA OUT OF MEASURABLE SNOW CHANCES WELL INTO THE
NIGHT. THE ARRIVAL OF A MID-LVL VORTICITY MAX SHOULD LEAD TO THIS
PRECIPITATION INTENSIFYING SLIGHTLY AFTER MIDNIGHT, BUT AGAIN,
MINIMAL IMPACT LOCALLY. FURTHER SOUTH, THE RESIDUAL AIRMASS SOUTH
OF THE AFOREMENTIONED FRONT REMAINS MOIST WITH DEW POINTS IN
THE LOWER TO MIDDLE 30S. GIVEN FOG DEVELOPMENT SUNDAY MORNING IN
A LIGHT WIND AND STRONG RADIATIONAL COOLING ENVIRONMENT, A
SIMILAR SITUATION COULD DEVELOP INTO MONDAY MORNING. WHILE
HREF/NBM PROBABILITIES INDICATE LOWER RISKS FOR DENSE FOG
DEVELOPMENT GIVEN PERSISTENT CIRRUS, WILL AT LEAST INDICATE SOME
MINOR FOG POTENTIAL. THE EVENTUAL PUSH OF DRY NORTHERLY AIR BY
12Z SHOULD QUICKLY ERODE ANY FOG THAT DOES DEVELOP.
MONDAY: COLDER AIR ATTEMPTS TO SPILL SOUTHWARD ON MONDAY, WITH VERY
LITTLE DIURNAL RISE IN TEMPERATURES EXPECTED. LOWER STRATUS THAT
BUILDS SOUTHWARD OVERNIGHT MAY EVENTUALLY RESIDE IN A COLD ENOUGH
ENVIRONMENT TO PRODUCE OCCASIONAL FLURRIES MONDAY AFTERNOON OR
EVENING.
TUESDAY: WINDS WEAKEN TUESDAY MORNING AS HIGH PRESSURE DRIFTS INTO
NORTHWESTERN MINNESOTA. WE SHOULD START THE DAY RATHER CHILLY WITH
LOWS IN THE SINGLE DIGITS IN MOST LOCATIONS. BROAD LOW LEVEL WARM
ADVECTION BEGINS BY THE AFTERNOON HOURS AS WINDS TURN TO THE EAST.
STILL, A COOLER THAN NORMAL TEMPERATURE DAY IS EXPECTED WITH SOME
INCREASING MID-UPPER CLOUDS.
WEDNESDAY-WEDNESDAY NIGHT: PERHAPS A TIME PERIOD THAT BEARS A BIT
MORE WATCHING FOR IMPACTS AS MID-LVL ZONAL FLOW TURNS SLIGHTLY MORE
SOUTHWEST IN NATURE. EARLY WEDNESDAY SIGNALS CONTINUE TO SHOW
INCREASING LOW-LVL WARM ADVECTION IN RESPONSE TO MID-LVL TROUGHING
MOVING INTO THE PLAINS FROM THE SOUTHWEST. MEANWHILE, A SECONDARY
AREA OF VORTICITY TRAVELS THROUGH NORTH DAKOTA LATER IN THE EVENING.
GFS CONTINUES TO FOCUS ALL OF THE QPF ON WEDNESDAY NORTH OF THE CWA
FOCUSED MORE WITH THE STRONGER SYNOPTIC WAVE AND RIGHT ENTRANCE OF
THE UPPER JET. HOWEVER, FURTHER SOUTH WE CONTINUE TO SEE QPF
GENERATED WITHIN THE LOW-LVL WARM ADVECTION ZONE AND MESSY 700
MB VORTICITY TRAIL IN THE ECMWF/CMC/NAM THROUGH THE EASTERN
HALF OF THE TRI-STATE AREA. DIGGING A BIT DEEPER INTO SOUNDINGS
REVEALS SATURATION FROM THE BOUNDARY LAYER TO 750MB WITH A
GENERAL LACK OF ICE PRESENT. THE IMMEDIATE LAYER ABOVE THE
SATURATED LAYER ALSO SUGGESTS SOME MINOR INSTABILITY. THE LACK
OF ICE PRESENT IS MOST LIKELY WHY WE'RE SEEING FREEZING
RAIN/DRIZZLE GENERATION FROM SEVERAL ENSEMBLES (AS HIGH AS 50%
FROM THE ECMWF) AND NBM FREEZING RAIN PROBABILITIES ARE
APPROACHING 20-40%. FOR NOW WILL CONTINUE FREEZING RAIN MENTION,
AND ACTUALLY SPREAD THAT MENTION A BIT FURTHER WEST TOWARDS
TOWARDS A STALLED FRONTAL BOUNDARY THROUGH THE JAMES RIVER
VALLEY. WITH TEMPERATURES AT THE SURFACE BETWEEN 27-30F,
CERTAINLY A TIME PERIOD TO MONITOR FOR IMPACTS.
THURSDAY-SATURDAY: A COLD FRONT PLUNGES SOUTHEAST BY THURSDAY
MORNING BRINGING ANOTHER ROUND OF SLIGHTLY BELOW NORMAL
TEMPERATURES TO THE REGION. NO PRECIPITATION IS ANTICIPATED
THROUGH THE END OF THE WEEK. WE'LL CONTINUE TO KEEP A CLOSE EYE
ON NEXT SATURDAY INTO SUNDAY, AS SIGNALS FOR A PROGRESSIVE OPEN
WAVE CONTINUE TO REMAIN IN MEDIUM RANGE AND ENSEMBLE GUIDANCE.
ENSEMBLE PROBABILITIES HAVE ACTUALLY JUMPED CONSIDERABLY TOWARDS
THE 60-80% PROBABILITY OF 0.01" OF QPF, WITH A MATCHING
INCREASE IN 0.10" QPF. LOOKING AT INDIVIDUAL MEMBER SOLUTIONS
REVEALS MUCH LESS UNCERTAINTY ON IF PRECIPITATION WERE TO
DEVELOP, BUT MORESO ON TIMING AND TRACK.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 520 PM CST SUN FEB 2 2025
VFR CONDITIONS WILL TRANSITION TO MOSTLY MVFR CEILINGS THIS TAF
PERIOD AS STRATUS RETURNS OVERNIGHT. TAKING A LOOK AT SATELLITE
IMAGERY, MID TO HIGH LEVEL CLOUDS CONTINUE TO SIT OVER MOST
AREAS THIS EVENING WITH A FEW POCKETS OF FLURRIES. AS THIS
DEVELOPING ACTIVITY CONTINUES TO PROGRESS NORTHEASTWARDS, COULD
SEE A TEMPORARY CLEARING DEVELOP ACROSS AREAS SOUTH OF I-90
BEFORE MORE MVFR STRATUS REDEVELOPS ACROSS THE AREA OVERNIGHT.
OTHERWISE, EASTERLY TO NORTHEASTERLY WINDS TONIGHT WILL BECOME
MORE NORTHERLY BY MONDAY TO END THE TAF PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...DUX
AVIATION...GUMBS
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