698
FXUS63 KFSD 192336
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
536 PM CST TUE NOV 19 2024
KEY MESSAGES
- STRONG NORTHWESTERLY WINDS CONTINUE INTO WEDNESDAY WITH WIND
GUSTS BETWEEN 35 TO 50 MPH POSSIBLE OVERNIGHT. DAYTIME GUSTS
OF 45 TO 60 MPH EXPECTED WEST OF I-29, 45-50 MPH ALONG I-29,
AND 40-45 MPH EAST OF I-29. WIND HEADLINES IN EFFECT FOR AREAS
ALONG AND WEST OF I-29.
- A NARROW CORRIDOR OF 2 TO 4 INCHES OF SNOWFALL IS EXPECTED
WEST OF I-29 BETWEEN THE JAMES AND BIG SIOUX RIVER VALLEY. DUE
TO THE SNOWFALL AMOUNTS AND STRONG WINDS, WINTER WEATHER
ADVISORY HAS BEEN ISSUED.
- LIGHT SNOW REMAINS EXPECTED NEAR AND NORTH OF I-90 LATE
OVERNIGHT INTO WEDNESDAY AFTERNOON. WHILE AMOUNTS LOOK TO
REMAIN BELOW AN INCH, REGARDLESS OF AMOUNTS THE STRONG WINDS
COMBINED WITH FALLING/BLOWING SNOW WILL LEAD TO DIFFICULT
TRAVEL CONDITIONS.
- COLD WIND CHILLS IN THE SINGLE DIGITS TO TEENS ARE LIKELY
TUESDAY NIGHT INTO THURSDAY MORNING.
DISCUSSION
ISSUED AT 253 PM CST TUE NOV 19 2024
AFTERNOON SATELLITE IMAGERY SHOWS A STRATUS DECK REMAINS LINGERING
OVER THE AREA FROM HURON TO SIOUX FALLS TO STORM LAKE AND
NORTHWARDS, WITH CLEAR SKIES SOUTH OF THE AFOREMENTIONED LINE.
SURFACE OBSERVATIONS SHOW BREEZY WIND GUSTS CONTINUING WITH GUSTS
GENERALLY 35 TO 45 MPH, ALBEIT WEAKENING A TOUCH EARLIER THAN
EXPECTED, WITH AFTERNOON TEMPERATURES IN THE LOWER TO UPPER 40S. AS
THE SURFACE LOW PRESSURE CONTINUES TO MOVE NORTHWARDS, EXPECT WIND
GUSTS TO CONTINUE DECREASING AS THE SURFACE PRESSURE GRADIENT (SPG)
ALSO DECREASES, THOUGH WINDS REMAINING BREEZY OVERNIGHT WITH GUSTS
IN THE 20S AND 30S.
THROUGHOUT THE OVERNIGHT HOURS, A STRONG UPPER LEVEL LOW MOVING EAST
ALONG THE SOUTHERN CANADIAN BORDER WILL INTERACT WITH THE SURFACE
LOW OFF TO OUR NORTH. AT THE SAME TIME A STRONG HIGH PRESSURE SYSTEM
DIVES SOUTH INTO TEXAS, AGAIN INCREASING THE SPG ACROSS THE REGION
LEADING TO ANOTHER BREEZY DAY FOR WEDNESDAY. LOOKING ALOFT, ENSEMBLE
SITUATIONAL AWARENESS TABLES REVEAL THAT WIND SPEEDS AT 850MB ARE
ABOVE THE 90TH PERCENTILE OF CLIMATOLOGY FOR THE ENTIRE AREA,
INCREASING FURTHER INTO THE 97.5TH PERCENTILE FOR AREAS WELL WEST OF
I-29. SO AS THE INVERSION MIXES OUT, EXPECT THE 40 TO 55 KNOT WINDS
AT THE TOP OF THE MIXED LAYER TO CREATE WIND GUSTS OF 45 TO 60 MPH
THROUGHOUT THE MORNING HOURS ALONG AND WEST OF I-29. THROUGHOUT THE
AFTERNOON HOURS, THE 850MB WINDS WEAKEN WHICH WILL ALLOW FOR A
GRADUAL DECREASE IN WIND SPEEDS INTO THE EVENING HOURS.
IN ADDITION, CHANCES FOR LIGHT SNOWFALL MOVE INTO THE AREA DURING
THE LATE OVERNIGHT HOURS AND STICK AROUND THROUGHOUT THE MAJORITY OF
DAYTIME HOURS. MODEL AGREEMENT CONTINUED TO RISE OVER THE PAST
COUPLE MODEL RUNS SHOWING THE PROGRESSION OF WRAP-AROUND MOISTURE
MAKING ITS WAY AROUND THE LOW AND BACK DOWN INTO THE REGION. WHILE
THIS WON'T RESULT IN MUCH ACCUMULATING SNOW, UP TO AN INCH OF SNOW
IS EXPECTED FOR AREAS ALONG AND NORTH OF THE I-90 CORRIDOR. HOWEVER,
CONFIDENCE CONTINUES TO RISE IN A NARROW CORRIDOR OF HIGHER SNOWFALL
TOTALS WEST OF I-29, ON THE WESTERN SIDE OF THE COTEAU ACROSS
KINGSBURY/MINER/LAKE COUNTIES. WHILE I DO THINK THE SNOWFALL
PROBABILITIES ARE A TOUCH HIGH CONSIDERING THE WINDS THAT WILL BE
ACCOMPANYING THE SNOW, THE HREF 24 HOUR PROBABILITY MATCHED MEAN FOR
SNOWFALL IS JUST SHY OF 6 INCHES IN THE NORTHERN FOURTH OF KINGSBURY
AND BEADLE COUNTY, AND SHOWING 90% CHANCE FOR 4 INCHES AGAIN JUST
NORTH OF KINGSBURY COUNTY. DUE TO THE COMBINATION OF FALLING/
ACCUMULATING SNOW WITH THE STRONG WINDS MAKING DIFFICULT TRAVEL, DID
ISSUE A SMALL WINTER WEATHER ADVISORY FOR THOSE THREE COUNTIES, BUT
WILL REMAIN SANS WINTER HEADLINES FOR THE REST OF THE AREA DUE TO
THE LACK OF ACCUMULATING SNOW. HOWEVER, THERE IS POTENTIAL THAT THE
LIGHT SNOWFALL WITH THE STRONG WINDS MAY REQUIRE THE EXPANSION OF
THE WINTER WEATHER ADVISORY. EITHER WAY, EXERCISE CAUTION
TRAVELING ON WEDNESDAY AS THE COMBINATION OF FALLING SNOW AND
STRONG WINDS WILL LEAD TO PERIODS OF DIFFICULT TRAVEL.
SURFACE HIGH PRESSURE COMES SLIDING DOWN THURSDAY INTO FRIDAY,
KEEPING THE COOLER TEMPERATURES AROUND A BIT LONGER WITH AFTERNOON
HIGHS IN THE 30S AND LOWER 40S INTO THE WEEKEND. DRY CONDITIONS ARE
EXPECTED THURSDAY INTO THE BEGINNING OF NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 526 PM CST TUE NOV 19 2024
LOWER END VFR STRATUS CONTINUES THROUGH THE EVENING HOURS
ALONG/NORTH OF I-90, WITH INCREASING HIGH CLOUDS MOVING INTO THE
US HWY 20 CORRIDOR. MVFR STRATUS BEGINS TO MOVE IN ALONG WITH
SNOW CHANCES FROM NORTH TO SOUTH AFTER 20.08Z AND CONTINUING FOR
AREAS ALONG/NORTH OF I-90 INTO WEDNESDAY EVENING. GREATEST
ACCUMULATIONS EXPECTED NORTH OF I-90 BETWEEN KHON AND KBKX.
STRONG WINDS COULD LEAD TO VISIBILITY RESTRICTIONS BOTH IN
FALLING SNOW AND WITH BLOWING SNOW POTENTIAL.
BREEZY NORTHWESTERLY WINDS TAPER OF SOMEWHAT TONIGHT, STILL
GUSTING 20 TO 30 KNOTS. HAVE INCLUDED LLWS FOR KSUX THROUGH THE
EARLY PART OF THE OVERNIGHT, AS GUSTS ARE LESS LIKELY THERE
OVERNIGHT. WINDS INCREASE AFTER ABOUT 20.09Z AND CONTINUE
STRENGTHENING DURING THE DAY. BY 20.18Z, GUSTS 40 TO 50 KNOTS
FOR AREAS WEST ALONG/WEST OF THE JAMES RIVER, 30-45 KNOTS FOR
THE I-29 CORRIDOR, AND 30-40 KNOTS EAST OF I-29. WINDS AND GUSTS
REMAIN STRONG BUT BEGIN TO DECREASE AFTER SUNSET WEDNESDAY.
FSD WATCHES/WARNINGS/ADVISORIES
SD...WIND ADVISORY UNTIL 6 PM CST WEDNESDAY FOR SDZ038>040-052>056-
058>062-064>071.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST
WEDNESDAY FOR SDZ039-054-055.
HIGH WIND WARNING UNTIL 6 PM CST WEDNESDAY FOR SDZ050-057-063.
MN...WIND ADVISORY UNTIL 6 PM CST WEDNESDAY FOR MNZ071-097.
IA...NONE.
NE...WIND ADVISORY UNTIL 6 PM CST WEDNESDAY FOR NEZ013-014.
DISCUSSION...APT
AVIATION...SG
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