853
FXUS63 KFSD 150326
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1026 PM CDT MON APR 14 2025
KEY MESSAGES
- WIDESPREAD SHOWERS WITH EMBEDDED THUNDERSTORMS WILL CONTINUE
TO MOVE SOUTHEAST INTO EARLY EVENING. ISOLATED GUSTS OVER 50
MPH AND SMALL HAIL CAN BE EXPECTED.
- TEMPERATURES WARM BACK ABOVE NORMAL THROUGH MID-WEEK.
- THUNDERSTORMS RETURN TO THE FORECAST BY THURSDAY AND CONTINUE
INTO FRIDAY. CONDITIONAL RISKS FOR SEVERE WEATHER REMAIN ON
THURSDAY, SO CONTINUE TO MONITOR THE FORECAST.
- SLIGHTLY COOLER TEMPERATURES INTO THE WEEKEND, WITH AN
INCREASING RISK FOR RAIN RETURNING BY SUNDAY AND MONDAY.
DISCUSSION
ISSUED AT 210 PM CDT MON APR 14 2025
THIS AFTERNOON: SATELLITE IMAGERY SHOWING A VIGOROUS UPPER
CIRCULATION MOVING THROUGH NORTH CENTRAL SOUTH DAKOTA EARLY THIS
AFTERNOON. FAIRLY WIDESPREAD SHOWERS WITH EMBEDDED THUNDERSTORM
ACTIVITY HAVE DEVELOPED AHEAD OF THIS WAVE. HIGH RESOLUTION CAMS
CONTINUE TO INDICATE POTENTIAL FOR HIGH POPS INTO EARLY EVENING,
WITH UPWARDS OF 200 TO 400 J/KG OF THIN CAPE IN SOUNDINGS. WHILE
FAIRLY SHARP 0-2KM LAPSE RATES HAVE DEVELOPED THIS AFTERNOON,
SURFACE TEMPERATURE NOT QUITE AS WARM AS PREVIOUSLY EXPECTED, WHICH
MAY LIMIT INTENSITY OF UPDRAFTS SLIGHTLY. NEVERTHELESS, WITH LOW
FREEZING LEVELS SMALL HAIL IS EXPECTED. SHARP LOW-LVL LAPSE RATES
AND SIZABLE T/TD SPREADS IN THE LOWEST 0-2KM RANGE WILL BE
CONDUCIVE TO SOME VERY LOCALIZED GUST POTENTIAL BETWEEN 50 AND
60 MPH WILL BE POSSIBLE.
TONIGHT: WITH THE LOSS OF DAYTIME HEATING, SCATTERED ACTIVITY WILL
SLOWLY DISSIPATE THIS EVENING, LEAVING CLEARING SKIES. WITH WINDS
WEAKENING TOWARDS DAYBREAK, CANNOT COMPLETELY RULE OUT PATCHY FOG,
BUT WILL NOT INCLUDE IN FORECAST AT THIS TIME.
TUESDAY-WEDNESDAY: MID-LVL RIDGING MOVES INTO THE PLAINS THROUGH MID-
WEEK, BRINGING A RETURN TO WARMER TEMPERATURES AND SLIGHT AFTERNOON
BREEZES. THE WARMEST HIGHS WILL BE ON WEDNESDAY, WITH 70S POSSIBLE
IN MANY AREAS.
THURSDAY: LONGWAVE TROUGHING WILL FORM OVER THE WESTERN CONUS LATE
WEDNESDAY, INDUCING SHARPER SOUTHWESTERLY FLOW THROUGH THE PLAINS
AND INDUCING RETURN FLOW. AN INITIAL SURGE IN MOISTURE ACCOMPANIED
BY A WEAK MID-LVL WAVE OF VORTICITY MOVING THROUGH THE FLOW COULD
INDUCE ELEVATED CONVECTION EARLY THURSDAY MORNING NEAR THE TRI-STATE
AREA. GIVEN THE ADVECTION OF NEARLY 1000 J/KG MUCAPE ANY STORM
LIFTING OFF THE 800MB LAYER COULD INDUCE MARGINALLY SEVERE HAIL.
THURSDAY AFTERNOON BECOMES A BIT MORE INTERESTING AS AN ELONGATED
SURFACE TROUGH EXTENDS ACROSS THE TRI-STATE AREA, WHILE A SURFACE
LOW MAY TRY TO DEVELOP OVER NORTHERN NEBRASKA. CONSIDERABLE
UNCERTAINTY REMAINS ON WHERE THESE SURFACE FEATURES MAY FALL, AND
HOW STRONG THE EML WILL BE THROUGH THE EASTERN HALF OF THE CWA.
SEVERAL AI BASED CONVECTIVE FORECASTS ALL SUGGEST AN INCREASED
POTENTIAL FOR STRONG TO SEVERE STORMS ALONG AND EAST OF THIS
BOUNDARY (MOSTLY EAST OF I-29) IN THE AFTERNOON AND EVENING. ONLY
THE ECMWF SEEMS TO REALIZE THE POTENTIAL SURFACE BASED CONVECTION
WITH OTHER MODELS SUGGESTING MORE ELEVATED STORMS. THIS WILL
CERTAINLY BE A TIME PERIOD TO CONTINUE MONITORING.
FRIDAY: A COLD FRONT SWEEPS SOUTHEAST BY FRIDAY, LEAVING COOLER
TEMPERATURES AND LINGERING SHOWERS THROUGH THE DAY.
SATURDAY-MONDAY: OUR EYES THEN TURN TOWARDS AN UPPER LOW THAT BEGINS
TO MOVE OUT OF THE FOUR CORNERS REGION FRIDAY NIGHT AND INTO THE
PLAINS BY THE END OF THE WEEKEND. MEDIUM RANGE MODEL CONTINUE TO
STRUGGLE WITH THE EXACT TRACK OF THIS DEEPENING UPPER LOW, WITH
BASICALLY 50% OF THE EC/GEFS/CME MODEL TAKING THE UPPER LOW TOWARDS
A DIRECT IMPACT TO THE CWA, WITH THE OTHER 50% TAKING THE LOW
FURTHER SOUTHEAST. THEN THERE ARE TIMING DIFFERENCES WITH SOME
IMPACTING THE CWA AS EARLY AS SUNDAY MORNING, AND OTHERS CLOSER TO
MONDAY MORNING. IF THIS STORM IMPACTS THE AREA, IT WOULD LIKELY
BRING MODERATE RAINFALL TOTALS, CONSIDERABLE WIND, AND SOME LOW END
POTENTIAL FOR A CHANGEOVER TO SNOW. THE BOTTOM LINE IS...IF YOU
HAVE PLANS FOR SUNDAY OR MONDAY, CONTINUE TO MONITOR YOUR
FORECAST.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1025 PM CDT MON APR 14 2025
VFR CONDITIONS ARE EXPECTED FOR THE TAF PERIOD. NORTHWEST WINDS HAVE
WEAKENED LATE THIS EVENING AND WILL STAY LIGHT THROUGH THE OVERNIGHT
HOURS. MARGINALLY BREEZY NORTHWEST WINDS ARE EXPECTED TOMORROW
AFTERNOON. ONCE WINDS WANE DURING THE LATE AFTERNOON AND EVENING
HOURS, WINDS WILL BEGIN TO FLIP TO OUT OF THE EAST. THE LIGHT EAST
WINDS WILL FINISH OUT THE TAF PERIOD.
FIRE WEATHER
ISSUED AT 210 PM CDT MON APR 14 2025
WINDS CONTINUE TO INCREASE THIS AFTERNOON, LIKELY BREAKING THE
40 MPH MARK THROUGH THE MISSOURI RIVER VALLEY REGIONS. DEW
POINTS HAVE BEEN A BIT SLOWER TO MIX DOWNWARD, AND THE ADDITION
OF SCATTERED SHOWERS MAY LIMIT THE FIRE DANGER RISK SLIGHTLY
INTO EARLY EVENING. HOWEVER, GIVEN THE INTENSE WINDS, AND EVEN
POTENTIAL FOR A ROGUE LIGHTNING STRIKE AS AN IGNITION SOURCE,
WILL CONTINUE RED FLAG WARNING.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...DUX
AVIATION...MEYERS
FIRE WEATHER...DUX
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