928
FXUS63 KFSD 031945
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
245 PM CDT THU APR 3 2025
KEY MESSAGES
- PRECIPITATION CHANCES RETURN TONIGHT THROUGH FRIDAY. ALTHOUGH
RAIN WILL BE THE DOMINANT PRECIPITATION TYPE, PERIODS OF A
RAIN/SNOW MIX OR ALL SNOW ARE EXPECTED.
- BENEFICIAL RAINFALL AMOUNTS ARE LIKELY WITH A 70+% CHANCE FOR
EXCEEDING A QUARTER OF AN INCH AND A 60+% CHANCE FOR EXCEEDING
A HALF AN INCH OF RAIN. SNOW ACCUMULATIONS OF LESS THAN AN
INCH.
- DRY WEATHER RETURNS FOR THE WEEKEND THROUGH THE MIDDLE OF NEXT
WEEK. NEAR TO ABOVE AVERAGE TEMPERATURES RETURN.
DISCUSSION
ISSUED AT 243 PM CDT THU APR 3 2025
CURRENTS-FRIDAY NIGHT: DREARY AND COOL CONDITIONS CONTINUE THIS
AFTERNOON AND INTO THE EVENING WITH STRATOCU OVER THE AREA.
TEMPERATURES ARE IN THE 40S, AND EXPECT SOME HIGHS IN THE 50S
WITH PEEKS OF SUNSHINE. LIGHT AND VARIABLE WINDS CONTINUE
TONIGHT.
NEXT SHORT WAVE MOVES THROUGH THE POSITIVELY TILTED UPPER LEVEL
TROUGH AND SPLIT MID LEVEL TROUGH TONIGHT THROUGH FRIDAY, ALONG WITH
AN UPPER LEVEL JET STREAK. CAMS AND OTHER DETERMINISTIC GUIDANCE
ARE STRUGGLING WITH THE EXACT TIMING AND EVOLUTION OF THE
PRECIPITATION - ESPECIALLY DURING THE DAY FRIDAY AND EAST OF THE
JAMES RIVER. MAIN QUESTION FOR TIMING AND COVERAGE COMES FROM WHERE
AND WHEN THE BETTER FORCING WILL LINE UP WITH THE BEST MOISTURE.
MOST OF THE PRECIPITATION SHOULD FALL AS RAIN TONIGHT WITH
TEMPERATURES IN THE 30S, ALTHOUGH SOME SNOW MIXES IN BRIEFLY NORTH
OF I-90 AND IN THE HIGHER ELEVATIONS.
PRECIPITATION CHANCES REMAIN SOMEWHAT UNCERTAIN DURING THE DAY AND
EVENING FRIDAY DUE TO MODEL VARIANCE IN TIMING. COLD FRONT/SECONDARY
TROUGH AXIS WILL MOVE THROUGH FRIDAY AFTERNOON INTO THE EVENING
HOURS (SLOWER THAN PREVIOUS FORECAST), WITH THE NORTHERN STREAM
TROUGH TRACKING EAST AS WELL. THIS SWINGS IN SOME COLDER AIR AS THE
PRECIPITATION SLIDES TO THE EAST. SOUNDINGS INDICATE THAT THIS
SHOULD BE A RELATIVELY "CLEAN" TRANSITION FROM RAIN TO SNOW AS THE
SATURATED COLUMN COOLS AT RELATIVELY THE SAME TIME/RATE. THUS, NOT
EXPECTING MUCH - IF ANY - SLEET OR FREEZING RAIN. IF THE FIRST WAVE
TAKES/EXPENDS MOST OF THE MOISTURE, THERE MAY BE LESS ACCUMULATIONS
WITH THE SECOND WAVE FRIDAY NIGHT. HIGHS FRIDAY IN THE 40S AND 50S
WITH LOWS IN THE 20S FRIDAY NIGHT.
OVERALL, BENEFICIAL RAINFALL AMOUNTS ARE EXPECTED, WITH PROBABILITY
OF AREAS WEST OF THE JAMES RIVER SEEING OVER 0.25" OF LIQUID
EQUIVALENT IN 24 HOURS MORE THAN 70% AND OVER 0.5" OVER 60% NEAR THE
MO RIVER IN SOUTH CENTRAL SD. AS FOR SNOWFALL, AMOUNTS WEST OF THE
JAMES WILL BE HIGHLY DEPENDENT ON WHEN THE COLD AIR MOVES IN. WITH
THE SLOWER PROGRESSION OF THIS, ACCUMULATION MAY BE HARD TO COME BY.
GENERALLY LESS THAN AN INCH OF SNOW EXPECTED FOR THE HIGHER
ELEVATION AREAS. MOST OF THE ACCUMULATION COMES FRIDAY EVENING AND
NIGHT.
SATURDAY-MONDAY: UPPER TROUGH CONTINUES TO MOVE THROUGH SATURDAY.
HIGHS RECOVER INTO THE 40S, SO ANY SNOW ACCUMULATION FRIDAY NIGHT
WILL BE SHORT LIVED. LOWS IN THE 20S. SLIGHTLY WARMER ON SUNDAY
AHEAD OF THE NEXT WAVE AND COLD FRONT WHICH WILL SWING THROUGH
SUNDAY NIGHT INTO MONDAY. BRIEF WARM UP SUNDAY BRINGS TEMPERATURES
IN THE 50S, RETURNING TO THE UPPER 30S AND 40S TO START THE WORK
WEEK. LACK OF MOISTURE WITH THIS WAVE KEEPS DRY WEATHER IN PLACE.
MOST OF NEXT WEEK: BY EARLY TO MID NEXT WEEK, WEAK RIDGING BUILDS
ACROSS THE WESTERN CONUS, SLIDING EASTWARD. SHORT WAVE MOVES THROUGH
THE OVERALL PATTERN MID NEXT WEEK, BUT MODEL GUIDANCE CURRENTLY
VARIES SIGNIFICANTLY ON TIMING OF THIS FEATURE. BETTER MOISTURE
APPEARS TIED TO THE SURFACE LOW TO THE SOUTH, SO NOT EXPECTING MUCH
IN THE WAY OF PRECIPITATION. MODEL PROBABILITIES OF A TENTH OF AN
INCH OF RAIN DURING THIS PERIOD ARE LOW (LESS THAN 30%).
MORE ROBUST RIDGING MOVES INTO THE ROCKIES TOWARD THE END OF NEXT
WEEK LEADING TO PREVAILING NORTHWESTERLY FLOW ALOFT. GUIDANCE HAS
BEEN TRENDING DOWNWARD ON HOW WARM WE'LL BE WITH THE NORTHERN JET
STREAM STALLED JUST TO OUR EAST, BUT STILL EXPECT ABOVE NORMAL
TEMPERATURES (HIGHS IN THE 50S AND 60S AND LOWS IN THE 30S TO 40S).
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1228 PM CDT THU APR 3 2025
MVFR STRATUS HAS BEEN HANGING ON A BIT LONGER THIS AFTERNOON,
WITH MVFR STRATOCU DEVELOPING AS WELL. MODELS ARE STRUGGLING TO
HANDLE THIS OVERALL, BUT HAVE GONE A BIT MORE PESSIMISTIC IN
TIMING TO THE RETURN OF VFR CEILINGS THIS AFTERNOON AND EVENING.
FURTHER REFINEMENT MAY BE NEEDED DEPENDING ON THE COVERAGE OF
THE STRATOCU.
WINDS BECOME LIGHT AND VARIABLE BEFORE SHIFTING TO THE
EAST/SOUTHEAST BY THE END OF THE PERIOD. PRECIPITATION, MOSTLY
RAIN, WILL EXPAND IN COVERAGE THROUGH FRIDAY MORNING AND
AFTERNOON, MAINLY IMPACTING AREAS WEST OF I-29 DURING THIS
FORECAST CYCLE. EXPECT A RETURN TO MVFR AND LOWER CONDITIONS AS
PRECIPITATION MOVES EAST.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...SG
AVIATION...SG
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