127
FXUS63 KFSD 132326
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
626 PM CDT SUN APR 13 2025
KEY MESSAGES
- CRITICAL FIRE DANGER WILL CONTINUE INTO THE EVENING IN AREAS
ALONG AND WEST OF I-29.
- WINDS WILL INCREASE THROUGH THE EVENING HOURS WITH POTENTIAL
FOR WINDS TO PEAK NEAR ADVISORY LEVELS FOR A COUPLE HOURS
OVERNIGHT OVER THE ENTIRE FORECAST AREA. STRONGEST SUSTAINED
WINDS EXPECTED WEST OF I-29.
- COLDER WITH SCATTERED RAIN SHOWERS MONDAY AFTERNOON. WOULD
NOT RULE OUT ISOLATED LIGHTNING/TINY HAIL. VERY LOW (<20%)
POTENTIAL FOR SNOW TO MIX WITH RAIN IN THE HIGHEST ELEVATIONS.
- WINDS MAY AGAIN APPROACH ADVISORY LEVELS MONDAY AFTERNOON,
AND CONVECTIVE SHOWERS HAVE POTENTIAL TO BRING DOWN POCKETS OF
50+ MPH WINDS. ADDITIONAL WIND ADVISORIES MAY BE NEEDED.
- INCREASED RAIN CHANCES (30-50%) ARE SEEN BY THURSDAY-THURSDAY
NIGHT. HOWEVER, UNCERTAINTY IN TIMING PREVENTS GREATER DETAILS
AT THIS TIME. VERY CONDITIONAL SEVERE WEATHER RISK ALONG AND
SOUTH OF HIGHWAY 20.
DISCUSSION
ISSUED AT 224 PM CDT SUN APR 13 2025
THIS AFTERNOON: SURFACE TROUGH GRADUALLY SLIDING EAST THIS
AFTERNOON, PUSHING SURFACE WINDS TO THE WEST NORTHWEST IN MOST
AREAS. WINDS WILL BEGIN GUSTING UP TO ADVISORY LEVELS IN CENTRAL SD
THIS AFTERNOON AND WITH MIXING DEEPENING, WE'LL BEGIN TO FINALLY
PULL DRIER AIR DOWNWARD. FIRE DANGER REMAINS CRITICAL WEST OF I-29
INTO THE EVENING. PLEASE SEE SEPARATE FIRE WEATHER DISCUSSION FOR
DETAILS.
TONIGHT: STRONGER LOW-LVL COLD ADVECTION BEGINS TO ARRIVE THIS
EVENING, BRINGING A REINFORCING PUSH OF STRONGER WINDS FROM WEST TO
EAST ACROSS THE CWA. WHILE THE COMBINATION OF HIGHER SUSTAINED AND
GUSTS REMAINS ALONG AND WEST OF THE JAMES RIVER, THERE WILL BE
POTENTIAL FOR AN HOUR OR TWO OF NEAR ADVISORY GUSTS FURTHER EAST
INTO PORTIONS OF MINNESOTA AND IOWA OVERNIGHT. AT THIS TIME, GIVEN
THE BREVITY OF THE GUSTS, WILL HOLD OFF ON PUSHING THE ADVISORY
EAST, BUT WILL NEED TO MONITOR THIS EVENING.
MONDAY: A VERY PROGRESSIVE UPPER TROUGH SWINGS SOUTHEAST THROUGH THE
DAKOTAS ON MONDAY. WHILE WINDS WILL SUBSIDE SLIGHTLY AT SUNRISE, AN
INCREASING SPG WILL KEEP SUSTAINED WINDS UNDER ADVISORY LEVELS
THROUGH THE MORNING. THE INITIAL SURGE OF DPVA ASSOCIATED WITH
THE TROUGH MAY LEAD TO A LINEAR BAND OF LIGHT RAIN DEVELOPING
OVER EASTERN SODAK WITH THIS BAND OF RAIN SHIFTING INTO THE
BUFFALO RIDGE BY MID-DAY. MEANWHILE BEHIND THE PASSAGE OF THE
INITIAL SURGE OF VORTICITY, SURFACE LAPSE RATES WILL SHARPEN
QUICKLY AS LOW LVL COLD ADVECTION INTENSIFIES. WARMING AFTERNOON
TEMPERATURES SHOULD LEAD TO THE RAPID DEVELOPMENT OF CONVECTIVE
SHOWERS THROUGH THE AFTERNOON MOVING NW TO SE. SOUNDINGS
SUGGEST UPWARDS OF 100-300 J/KG MLCAPE (POTENTIALLY UP TO 500
J/KG FROM RAP SOUNDINGS), SO ANTICIPATING SOME LIGHTNING, AND
WOULDN'T BE SURPRISED TO SEE SMALL HAIL. AT TIMES, IF FREEZING
LEVELS FALL LOW ENOUGH, A FEW CLUSTERS OF SNOW MAY BE POSSIBLE
LATE IN THE DAY. THE DEEPENING LAPSE RATES WILL ALSO PROMOTE AN
INCREASED POTENTIAL TO SEE STRONG WIND GUSTS THROUGH THE
AFTERNOON NEAR ADVISORY LEVELS. IT'S NOT IMPOSSIBLE, BASED ON
CONVECTIVE MODEL SIMULATIONS, TO SEE ISOLATED GUSTS OVER 50 TO
55 MPH AS SHOWERS MOVE THROUGH. A WIND ADVISORY COULD CERTAINLY
BE ISSUED BY LATER SHIFTS, THOUGH IF WE INSTEAD SEE A DEEPENING
STRATO- CU LAYER THEN WIDESPREAD STRONG GUST POTENTIAL COULD BE
SUBDUED.
MONDAY NIGHT: THE UPPER TROUGH MOVES EAST OVERNIGHT, ALLOWING SKIES
TO CLEAR INTO TUESDAY. TEMPERATURES THROUGH MAY BE QUITE COOL,
WITH LOWS FALLING INTO THE UPPER 20S TO LOWER 30S.
TUESDAY-WEDNESDAY: RIDGING MOVES INTO THE PLAINS BY TUESDAY,
SIGNALING A RETURN OF WARM ADVECTION AND ALSO WARMER TEMPERATURES.
WE'LL LIKELY SEE A RETURN OF TEMPERATURES INTO THE UPPER 50S
AND 60S. MID-LVL CLOUDS MAY BE ON THE INCREASE BY WEDNESDAY AS A
SUBTLE WEAKNESS MOVES THROUGH THE MID-LVL FLOW. THE PRESENCE OF
THIS CLOUD LAYER LIKELY WON'T IMPACT TEMPERATURES, WITH HIGHS
BY WEDNESDAY AFTERNOON RISING INTO THE 70S OVER MUCH OF THE
AREA.
THURSDAY-FRIDAY: TROUGHING WILL INCREASE OVER THE WESTERN CONUS BY
THE MIDDLE OF THE WEEK, ALLOWING FLOW THROUGH THE CENTRAL AND
NORTHERN PLAINS TO TURN SOUTHWESTERLY. MOST MEDIUM RANGE
GUIDANCE CONTINUES TO INDICATE MOISTURE TRANSPORT FROM THE GULF
NORTHWEST INTO THE OKLAHOMA PANHANDLE AND THEN SHIFTING FURTHER
NORTH INTO THE PLAINS ON A 50 KNOT LLJ BY THURSDAY MORNING. AS
AN EMBEDDED SHORTWAVE IN THE SOUTHWESTERLY FLOW ARRIVE, ELEVATED
CONVECTION IS LIKELY TO DEVELOP AT TIMES LATE WEDNESDAY NIGHT
INTO THURSDAY MORNING, POTENTIALLY CONTINUING THROUGH THE DAY
NORTH OF A STALLED WARM FRONT. AI BASED GUIDANCE CONTINUES TO
HINT AT THE POTENTIAL FOR STRONGER STORMS INTO EASTERN NEBRASKA
AND PORTIONS OF WESTERN/NORTHWESTERN IOWA IN THE AFTERNOON AND
EVENING HOURS OF THURSDAY SOUTH OF THIS AFOREMENTIONED BOUNDARY,
THOUGH THERE THE DEGREE OF CAPPING REMAINS PROBLEMATIC. COLDER
AIR SINKS INTO THE REGION FOR FRIDAY WITH TEMPERATURES FALLING
BACK INTO THE 50S AND 60S WITH CONSIDERABLE CLOUDS.
SATURDAY-SUNDAY: MEDIUM RANGE GUIDANCE HAS SETTLED INTO A SOLUTION
THAT WILL KEEP THE MAJORITY OF NEXT WEEKEND DRY. HOWEVER WE'LL KEEP
AN EYE ON AN UPPER LOW TRACKING INTO THE PLAINS FROM THE FOUR
CORNERS REGION. THIS SYSTEM HAS THE POTENTIAL TO SPREAD WIDESPREAD
RAIN INTO THE AREA TO START NEXT WEEK. IN FACT, NBM/LREF
PROBABILITIES FOR >0.10" ARE ALREADY OVER 50% FOR MOST OF THE
AREA.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 626 PM CDT SUN APR 13 2025
VFR CONDITIONS BEGIN THE TAF PERIOD. GUSTY NORTHWEST WINDS PERSIST
ACROSS THE AREA WITH GUSTS AS HIGH AS 35-40 KNOTS. THESE WINDS WILL
PERSIST THROUGH THE EVENING HOURS BEFORE SLOWLY WEAKENING DURING THE
OVERNIGHT HOURS. AT THE SAME TIME, MVFR STRATUS WILL PUSH INTO THE
AREA TONIGHT AS WELL. THE MVFR CEILINGS WILL CONTINUE THROUGH THE
MORNING HOURS TOMORROW BEFORE LIFTING BACK TO VFR LEVELS DURING THE
AFTERNOON HOURS. THIS IS THE SAME PERIOD OF TIME SCATTERED SHOWERS
WILL OVERSPREAD THE AREA. AT THIS TIME, HAVE ONLY ADDED PROB30
GROUPS TO ALL TAFS GIVEN THE SCATTERED NATURE OF THE SHOWERS.
NORTHWEST WINDS WILL RESTRENGTHEN FOR THE AFTERNOON HOURS WITH GUSTS
AGAIN UP TO 30-40 KNOTS. THE SCATTERED SHOWERS AND STRONG NORTHWEST
WINDS WILL FINISH OUT THE TAF PERIOD.
FIRE WEATHER
ISSUED AT 224 PM CDT SUN APR 13 2025
LOWER DEWPOINTS A BIT SLOWER TO ADVECT EAST AND MIX DOWN THIS
AFTERNOON, DELAYING THE LOWEST RELATIVE HUMIDITY VALUES SLIGHTLY.
THAT SAID, WITH WINDS REMAINING WELL ABOVE RED FLAG CRITERIA INTO
THE EVENING, SEE NO REASON TO MODIFY CURRENT RED FLAG WARNING AS
RELATIVE HUMIDITY VALUE BOTTOM OUT THIS EVENING.
A SLIGHTLY MORE UNCERTAIN FIRE WEATHER FORECAST IS IN PLACE FOR
MONDAY. STRONG SUSTAINED WINDS BETWEEN 20 AND 30 MPH WITH
OCCASIONAL GUSTS UP TO 45 MPH MAY BE AGAIN POSSIBLE MONDAY AND
MONDAY AFTERNOON. MORE UNCERTAIN HOWEVER IS WHAT WILL HAPPEN
WITH DEW POINTS IN THE AFTERNOON, ESPECIALLY ALONG THE MISSOURI
RIVER. CURRENTLY PROJECTED RELATIVE HUMIDITY VALUES BOTTOM AT 25
TO 30%, WITH POTENTIAL FOR GUSTS IN THE AFTERNOON AROUND 40 TO
45 MPH. ADDITIONALLY, THE DEVELOPMENT OF SCATTERED TO NUMEROUS
SHOWERS IN THE AFTERNOON MAY LIMIT FIRE DANGER SLIGHTLY, THOUGH
LIGHTNING COULD PROVIDE FIRE STARTS. DO NOT FEEL CONFIDENT
ENOUGH TO ISSUE A RED FLAG WARNING AT THIS TIME, BUT WILL ISSUE
A FIRE WEATHER WATCH TO ADVERTISE THE POTENTIAL ALONG THE EDGE
OF CRITICAL LEVELS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY
EVENING FOR SDZ050-063-068>071.
RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR SDZ050-
063>071.
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR SDZ038-
052>055-057>062.
WIND ADVISORY UNTIL 4 AM CDT MONDAY FOR SDZ038-050-052-053-
057>060-063>065-068.
MN...NONE.
IA...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY
EVENING FOR IAZ031.
NE...FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY
EVENING FOR NEZ013-014.
RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR NEZ013-014.
DISCUSSION...DUX
AVIATION...MEYERS
FIRE WEATHER...DUX
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