736
FXUS63 KFSD 012350
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
650 PM CDT SAT APR 1 2023
SHORT TERM
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 250 PM CDT SAT APR 1 2023
KEY MESSAGES
1. MOSTLY QUIET THROUGH THE WEEKEND WITH TEMPERATURES BELOW NORMAL,
WARMEST SOUTH OF I-90 BY SUNDAY.
2. NEXT STRONG STORM SYSTEM STILL LOOKS TO ARRIVE TUESDAY INTO EARLY
WEDNESDAY. UNCERTAINTY REMAINS BUT IMPACTFUL SNOW TO THE NORTH AND
WEST AND SEVERE WEATHER TO THE SOUTH AND EAST LOOK PLAUSIBLE ONCE
AGAIN WITH WIND FOR ALL.
TONIGHT: NEXT STRONG PUSH OF WAA IN THE 850:700 MB LAYER ARRIVES
OVERNIGHT AND WILL RESULT IN AN INCREASE IN MID LEVEL CLOUD COVER. A
FEW HIGH-RES MODELS TRY TO DEVELOP WEAK RADAR RETURNS OVERNIGHT BUT
A DRY SUB-CLOUD LAYER SHOULD PRECLUDE ANY SURFACE IMPACT. STRONGER
FLOW AT AND ABOVE THE INVERSION MAY RESULT IN OCCASIONAL GUST ABOVE
25-30 MPH WITH THE HIGHER ELEVATIONS OF THE BUFFALO RIDGE LIKELY
STANDING THE BEST CHANCE OF ANY OF THIS STRONGER MOMENTUM SURFACING.
SUNDAY: LOW LEVEL FLOW TURNS BACK OUT OF THE WEST TO WNW FOR SUNDAY
WITH A FAIRLY NOTABLE NORTH TO SOUTH THERMAL GRADIENT ACROSS THE
COVERAGE AREA. AREAS ALONG THE HWY 20 CORRIDOR MAY VERY WELL PUSH
INTO THE 60S WITH THE HWY 14 CORRIDOR STUCK IN THE LOWER TO MID 40S
WITH A MORE STUBBORN SNOWPACK. WINDS MAY REMAIN ON THE BREEZIER
SIDE, PERHAPS PUSHING NEAR ELEVATED FIRE CONCERNS ACROSS PORTIONS OF
NW IA.
SUNDAY NIGHT: MAIN FEATURE OF NOTE IS SOME MIDLEVEL FRONTAL FORCING
LAID OUT ACROSS THE MO RIVER INTO NW IA. MOISTURE IN THE LOWER
LEVELS STILL A BIT NEBULOUS BUT COULD BE ENOUGH FOR A NARROW
CORRIDOR OF LIGHT PRECIPITATION.
LONG TERM
(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 250 PM CDT SAT APR 1 2023
LONG TERM 12Z MONDAY MORNING - 12Z SUNDAY
MONDAY WILL BE SLIGHTLY COOLER THAN SUNDAY DUE TO NORTHWESTERLY
WINDS AND SOME CAA. INCREASING CLOUDS DURING THE DAY AS MOISTURE
BUILDS INTO THE LOW AND MID LEVELS AHEAD OF THE ARRIVAL OF THE NEXT
WAVE. SOME WEAK FRONTOGENESIS MAY RESULT IN LIGHT RAIN/MIXED
PRECIPITATION SHOWERS ALONG HIGHWAY 20 IN THE AFTERNOON TO EVENING.
WINDS BECOME NORTHEASTERLY AS THE LOW PRESSURE ALONG THE CANADIAN
BORDER MOVES OFF TO THE EAST. HIGHS WILL BE IN THE 30S AND 40S WITH
A FEW 50S ALONG THE HIGHWAY 20 CORRIDOR.
THE TUESDAY/WEDNESDAY STORM CONTINUES TO SHOW HIGH AGREEMENT ACROSS
THE MODELS. THERE REMAINS UNCERTAINTY IN THE TYPE OF PRECIPITATION
FOR THE SOUTHERN PORTION OF THE CWA. ECMWF HAS TRENDED VERY SLIGHTLY
COLDER THIS RUN THAN THE PREVIOUS, WHILE THE GFS HAS TRENDED
SLIGHTLY WARMER THAN THE PREVIOUS RUN. BUFKIT SOUNDINGS INDICATE IN
A ROUGH LINE FROM YANKTON TO WINDOM PRECIPITATION COULD START AS
RAIN BEFORE TRANSITIONING TO SNOW AS THE LOW PROGRESSES TO THE
NORTHEAST AND BRINGS DOWN COLDER AIR BEHIND IT. REGARDLESS, AS YOU
MOVE NORTH THE RISK OF SNOW AND HIGHER SNOW AMOUNTS INCREASES. GFS
AND ECMWF AGREE THAT THE HIGHEST PRECIPITATION AMOUNTS LOOK TO FALL
IN A ROUGH LINE FROM SOUTHWESTERN SD NORTHEASTWARD TOWARD
NORTHEASTERN SD AND WEST CENTRAL MN. SPC DAY 3 STORM TOTAL QPF
RANGES FROM AROUND 0.1 AND INCREASES TOWARD CENTRAL SD TO AROUND
1.25 INCHES. AS A RESULT WE ARE LOOKING AT SOME IMPACTFUL SNOWFALL
THROUGH MOST OF THE REGION. ANOTHER CONCERN WILL BE THE STRONG WINDS
THAT ACCOMPANY THIS SYSTEM. SUSTAINED WINDS OF 25 TO 35 MPH WITH
GUSTS 40+ MPH. BLOWING AND DRIFTING SNOW WITH REDUCED
VISIBILITIES IS LIKELY, EVEN IN AREAS WITH LOWER SNOW TOTALS.
PRECIPITATION MOVES OUT BY THURSDAY AFTERNOON. WINDS BECOME
SOUTHERLY AND REMAIN ON THE BREEZY SIDE BUT DECREASE THROUGH THE
DAY. TEMPERATURES WILL BE ON THE COOL SIDE, IN THE UPPER 20S AND
30S. FRIDAY AND SATURDAY WILL BE IN THE 30S AND 40S WITH A FEW 50S
SATURDAY IN NORTHWESTERN IA!
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 633 PM CDT SAT APR 1 2023
INCREASING WINDS, BOTH SURFACE AND ALOFT, WILL BE THE PRIMARY
AVIATION CONCERN THIS FORECAST PERIOD. SOUTH TO SOUTHEAST LOW
LEVEL FLOW WILL INCREASE THIS EVENING, AS SURFACE RIDGE CONTINUES
TO SLIDE OFF TO THE EAST. SURFACE WIND GUSTS GENERALLY 20-25KT ARE
EXPECTED, WITH A SOUTH-SOUTHWESTERLY LOW LEVEL JET 40-50KT ABOVE
A SURFACE-BASED INVERSION LEADING TO LOW LEVEL WIND SHEAR FROM 03Z
THIS EVENING THROUGH ABOUT 14-16Z SUNDAY.
WINDS BOTH SURFACE AND ALOFT WILL GRADUALLY BECOME WESTERLY
THROUGH SUNDAY MORNING, AND THOUGH LOW LEVEL WIND SHEAR WILL
DIMINISH, WESTERLY GUSTS TO AROUND 25KT ARE EXPECTED THROUGH THE
END OF THIS TAF PERIOD.
VFR CONDITIONS WILL PREVAIL, WITH OCCASIONAL MID-LEVEL CLOUDS AT
OR ABOVE 8KFT AGL.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
SHORT TERM...KALIN
LONG TERM...AJP
AVIATION...JH
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