332
FXUS63 KFSD 061119
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
619 AM CDT TUE MAY 6 2025
KEY MESSAGES
- PREDOMINANTLY DRY CONDITIONS PERSIST THIS WEEK. LOW (< 20%)
CHANCES OF LIGHT RAIN EXIST ACROSS THE MISSOURI RIVER VALLEY
THIS AFTERNOON AND FOR THE MISSOURI RIVER VALLEY AND
NORTHWESTERN IOWA WEDNESDAY INTO THURSDAY.
- NEAR TO ABOVE AVERAGE TEMPERATURES PREVAIL WITH HIGHS MOSTLY
IN THE 70S, WARMING TO THE 80S BY THE END OF THE WEEK.
- WARM, BREEZY, AND MOSTLY DRY CONDITIONS EXPECTED THIS WEEKEND
INTO EARLY NEXT WEEK. MOST OF THE AREA WILL SEE HIGHS IN THE
80S BY EARLY NEXT WEEK (GREATER THAN A 60% CHANCE).
DISCUSSION
ISSUED AT 319 AM CDT TUE MAY 6 2025
CURRENTS THROUGH TONIGHT: PLEASANT MORNING WITH JUST A FEW CLOUDS
ACROSS THE AREA. TEMPERATURES THROUGH 3 AM CDT ARE IN THE UPPER 40S
TO MID 50S. OMEGA BLOCK BREAKS DOWN TODAY AS THE LOW PRESSURES MOVE
EAST, WITH THE LOW OVER THE SOUTHWEST SHIFTING INTO THE SOUTHERN
PLAINS. THIS WILL KEEP MOSTLY DRY CONDITIONS OVER THE AREA, WITH A
MIX OF CLOUDS AND SUN.
CAMS ARE SHOWING THE POTENTIAL FOR SOME SHOWERS ALONG AND WEST OF
THE MO RIVER VALLEY IN TO SOUTH CENTRAL SD THIS AFTERNOON AND
EVENING. THIS IS DUE TO SOME WEAK INSTABILITY (LESS THAN 100 J/KG)
ALONG WITH AN AREA OF WAA AND VORTICITY ADVECTION. EXPECT AT LEAST
DIURNALLY DRIVEN CUMULUS TO DEVELOP IN THIS AREA; HOWEVER, DRY SUB
CLOUD LAYER LEADS TO LOW CONFIDENCE IN PRECIP POTENTIAL (LESS THAN
15% CHANCE) SO WILL OMIT MENTION FOR NOW. CONTEMPLATED ADDING
SPRINKLE MENTION, BUT AGAIN, THINK THAT PRECIP WILL STRUGGLE WITH
OVER 6KFT OF A DRY LAYER TO OVERCOME.
OTHERWISE, LIGHT AND SOMEWHAT VARIABLE WINDS THIS MORNING WILL
BECOME NORTHEASTERLY THIS AFTERNOON, AROUND 5-10 MPH AND OCCASIONAL
GUSTS TO 20 MPH AS WEAK SURFACE LOW MOVES EAST OVER THE AREA. WARMED
HIGHS A DEGREE OR TWO FROM PREVIOUS (DESPITE INCREASING CLOUD COVER)
GIVEN OUR OVER-PERFORMANCE THE LAST COUPLE OF DAYS. HIGHS IN THE MID
70S TO LOWER 80S. LOWS TONIGHT AROUND 50.
WEDNESDAY-THURSDAY: WITH THE MID/UPPER LOW MOVING THROUGH THE
SOUTHERN PLAINS, REX BLOCK PATTERN SETS UP FOR THE MIDDLE OF THE
WEEK. PRECIPITATION CHANCES GENERALLY REMAIN TO THE SOUTH OF OUR
AREA WHERE THE BETTER MOISTURE IS FOCUSED WITH LOW PRESSURE, BUT
AREAS TOWARD US HWY 20 AND THE MO RIVER VALLEY MAY AGAIN SEE SOME
ISOLATED SHOWERS. CHANCES FOR MEASURABLE PRECIPITATION DURING THIS
TIME REMAIN LOW TO MODERATE (LESS THAN 45%).
DECREASED HIGHS BY A COUPLE OF DEGREES FROM PREVIOUS ON WEDNESDAY
GIVEN THE MORE DOMINANT EASTERLY LOW AND STRONGER INVERSION LEADING
TO LESS EFFICIENT MIXING. STILL ABOVE AVERAGE THOUGH IN THE 70S TO
NEAR 80. LOWS IN THE MID 40S TO NEAR 50 ONCE AGAIN. MORE OF THE SAME
ON THURSDAY. WEDNESDAY WILL BE BREEZIER THAN THURSDAY THANKS TO THE
COMPRESSED SPG WITH GUSTS AGAIN AROUND 20 MPH.
FRIDAY-THE WEEKEND: FLOW PATTERN GETS A BIT MESSY FOR THE END OF THE
WEEK AND INTO THE WEEKEND, WITH A QUASI REX BLOCK PATTERN OVER THE
PLAINS - STAGNANT MID/UPPER LEVEL LOW OVER EASTERN TX/LA WITH HIGH
PRESSURE AND RIDGING THROUGH THE NORTHERN PLAINS. COULD SEE SOME
LIGHT SHOWERS WITH A WEAK SURFACE LOW AND BOUNDARY MOVING THROUGH ON
FRIDAY; WILL LEAVE NBM POPS (15% OR LESS) FOR NOW GIVEN LOW
CONFIDENCE IN MOISTURE RETURN AND PLACEMENT/TIMING OF THE FROPA.
OUTSIDE OF THOSE LOW CHANCES, RIDGING KEEPS US DRY. BREEZY AND WARM
CONDITIONS PREVAIL DUE TO PREVAILING SOUTHERLY FLOW. HIGHS THROUGH
THE WEEKEND CLIMB INTO THE 80S FOR MOST - WARMEST ON SUNDAY. MILD
LOWS IN THE UPPER 40S AND 50S.
EARLY NEXT WEEK: BREEZY SOUTHERLY WINDS HELP KEEP WELL ABOVE AVERAGE
CONDITIONS IN PLACE TO START THE WORK WEEK, WITH MODERATE TO HIGH
(60+%) CHANCES OF HIGHS ABOVE 80 DEGREES AND MODERATE (40-60%)
CHANCES OF HIGHS ABOVE 85. LOWS IN THE 50S TO LOWER 60S. RIDGING
BREAKS DOWN THROUGH THE EARLY TO MID PART OF THE WEEK, ALTHOUGH
GUIDANCE VARIES IN THE DETAILS OF WHEN. COULD SEE A COUPLE OF SHORT
WAVES MOVE THROUGH EARLY IN THE WEEK, BUT MORE DEFINED LOW LOOKS TO
MOVE INTO THE PLAINS MID NEXT WEEK - BRINGING THE RETURN OF AT LEAST
LOW END RAIN CHANCES.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 615 AM CDT TUE MAY 6 2025
VFR CONDITIONS THROUGH THE PERIOD, ALTHOUGH COULD SEE SOME VERY
PATCHY MVFR FOG IN RIVER VALLEYS THIS MORNING (WITH KYKN AT 5SM
AT THE TIME OF THIS DISCUSSION. LIGHT AND VARIABLE WINDS BECOME
NORTHEASTERLY THIS AFTERNOON AND EARLY EVENING, WITH GUSTS
AROUND 15-20 KNOTS TONIGHT INTO WEDNESDAY MORNING.
ISOLATED SHOWERS ARE POSSIBLE ALONG THE MO RIVER VALLEY IN SOUTH
CENTRAL SD, WITH LESS THAN A 20% CHANCE DUE TO VERY DRY AIR
BELOW THE CLOUD BASES. ANY ACTIVITY SHOULD STAY TO THE WEST OF
KHON IF IT DEVELOPS THIS AFTERNOON AND EVENING.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...SG
AVIATION...SG
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