336
FXUS63 KFSD 090341
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1041 PM CDT WED MAY 8 2024
KEY MESSAGES
- WIDESPREAD SHOWERS WITH EMBEDDED THUNDERSTORMS EAST OF I-29
WILL TRANSITION TO SCATTERED SHOWERS OVERNIGHT INTO THURSDAY
MORNING. SOME THREAT FOR LOCALIZED HEAVY RAINFALL RESULTING IN
ADDITIONAL RISES ON SOME RIVERS/STREAMS, MAINLY IN NORTHWEST
IOWA/SOUTHWEST MINNESOTA.
- WARMER AND MAINLY DRY CONDITIONS MOVE IN FOR THE WEEKEND.
CONTINUED WARM WITH RENEWED RAIN CHANCES BY MID WEEK.
DISCUSSION
ISSUED AT 239 PM CDT WED MAY 8 2024
SHOWERS AND THUNDERSTORMS SHOULD INCREASE IN COVERAGE ACROSS PARTS
OF NORTHWEST IA AND SOUTHWEST MN THROUGH THE AFTERNOON AS WELL AS
NEAR HIGHWAY 14. A SMALL AXIS OF INSTABILITY IS EXPECTED THIS
AFTERNOON IN THIS AREA. OVERALL INSTABILITY NOT THAT HIGH, BUT WITH
THE FREEZING LEVEL AROUND 6-7 KFT IT WILL BE PRETTY EASY TO GET SOME
SMALLER HAIL. STILL LOOKS LIKE AN ENVIRONMENT SUPPORTIVE OF HAIL UP
TO HALF DOLLAR SIZED WITH ONLY WEAK SHEAR EXPECTED. ONE OTHER THING
TO WATCH WILL BE THE POTENTIAL FOR FUNNELS AND LANDSPOUTS. STEEP LOW
LEVEL LAPSE RATES AND LIGHTER WINDS NEAR A SURFACE BOUNDARY MAY
SUPPORT THIS TYPE OF ACTIVITY. WITH ONLY MARGINAL INSTABILITY AND
WEAK SHEAR ANY ACTIVITY LIKE THIS SHOULD BE SHORT LIVED. WHILE SOME
STRONGER WINDS GUSTS WILL BE POSSIBLE THE HRRR AND HREF BOTH
INDICATING GUSTS SHOULD GENERALLY BE 50 MPH OR LOWER.
THE UPPER LEVEL LOW PRESSURE SHEARS OUT AND SAGS SOUTH TONIGHT INTO
THURSDAY. SCATTERED SHOWERS WILL REMAIN POSSIBLE DURING THIS TIME,
BUT INSTABILITY IS QUITE A BIT LESS SO EVEN LIGHTNING WILL LIKELY
DIMINISH QUITE A BIT AFTER ABOUT 10 PM. LOWS WILL BE SEASONALLY MILD
IN THE MID 40S.
WHILE THE MAIN SYNOPTIC FORCING SETTLES SOUTH, MODEL SOUNDINGS DO
SHOW SOME WEAK INSTABILITY NEAR THE TOP OF THE MIXED LAYER ON
THURSDAY WHICH MAY SUPPORT SOME ISOLATED SHOWERY ACTIVITY.
TEMPERATURES WILL ALSO BE A TOUCH COOLER AS WINDS TURN NORTHERLY AND
SOME DIURNALLY DRIVEN CLOUD COVER IS EXPECTED TO DEVELOP. HIGHS
SHOULD STILL BE IN THE 60S.
FRIDAY AND SATURDAY WILL BE DRY AND MILD AS NORTHWEST FLOW ALOFT
WEAKENS AND WESTERLY FLOW IN THE LOW LEVELS IS IN PLACE. BY SUNDAY A
WEAK WAVE IN THIS FLOW COULD BRING SOME ISOLATED ACTIVITY BUT FOR
NOW THIS LOOKS TO BE LOW IMPACT. HIGHS SHOULD GRADUALLY WARM FROM
THE LOWER 70S FRIDAY TO THE LOWER 80S BY SUNDAY.
WEST TO NORTHWEST FLOW ALOFT IS EXPECTED MONDAY AND TUESDAY WHICH
SHOULD LEAD TO A COUPLE OF WARM DAYS. WHILE THIS PATTERN WILL NOT BE
A WET ONE, SOME SPOTTY SHOWER AND THUNDERSTORM ACTIVITY WILL BE
POSSIBLE. THE MOST AGREEMENT APPEARS TO BE MONDAY NIGHT INTO TUESDAY
MORNING.
WEDNESDAY INTO THURSDAY THE MODELS ARE INDICATING A STRONG UPPER
LEVEL JET MAX DIVING INTO THE NORTHERN ROCKIES WHICH SHOULD TURN
UPPER LEVEL FLOW MORE SOUTHWESTERLY AND BRING A BETTER CHANCE FOR
SHOWERS AND THUNDERSTORMS.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1041 PM CDT WED MAY 8 2024
THUNDERSTORMS NEAR/EAST OF US HIGHWAY 59 IN NORTHWEST IOWA ARE
EXPECTED TO WEAKEN FURTHER THROUGH THE REMAINDER OF TONIGHT,
WITH THUNDER NOT EXPECTED TO IMPACT TAF LOCATIONS. MVFR CEILINGS
AND BRIEF MVFR VISIBILITY WILL BE ASSOCIATED WITH THE AREA OF
MORE PERSISTENT RAIN EAST OF I-29 THROUGH EARLY THURSDAY.
ADDITIONAL SCATTERED SHOWERS WILL SLIDE BACK TO THE SOUTH ACROSS
SOUTHEAST SD THROUGH THURSDAY MORNING, WITH MAINLY VFR CONDITIONS
EXPECTED. THE THREAT OF THUNDER WITH THIS ACTIVITY IS TOO LOW TO
INCLUDE IN TAFS, THOUGH IS NON-ZERO AND WILL BE MONITORED. ANY
SHOWERS MAY STILL PRODUCE GUSTY WINDS, THOUGH PREVAILING WINDS
WILL GENERALLY BE AT OR BELOW 15KT INTO THURSDAY MORNING, WITH
OCCASIONAL NORTH-NORTHWEST GUSTS TO AROUND 20KT DURING THE LATE
MORNING AND AFTERNOON.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...08
AVIATION...JH
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