018
FXUS63 KABR 242136
AFDABR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
336 PM CST SUN NOV 24 2024
KEY MESSAGES
- LIGHT SNOW EXPECTED THIS EVENING ACROSS CENTRAL/SOUTH CENTRAL
SD INTO NORTHEAST SD AND WEST CENTRAL MINNESOTA. GENERALLY A
TRACE TO 2 INCHES EXPECTED.
- THERE IS A 20 TO 30 PERCENT CHANCE OF LIGHT SNOW WEDNESDAY
MORNING THROUGH THE AFTERNOON OVER PORTIONS OF NORTHEASTERN SD
INTO WEST CENTRAL MN.
- HIGH CONFIDENCE ON MUCH BELOW NORMAL TEMPERATURES BY THE END OF
THE WEEK THROUGH THE WEEKEND, WITH HIGHS IN THE LOWER TEENS TO
20S AND LOWS IN THE SINGLE DIGITS ABOVE ZERO TO THE SINGLE
DIGITS BELOW ZERO.
SHORT TERM /THIS EVENING THROUGH MONDAY NIGHT/
ISSUED AT 335 PM CST SUN NOV 24 2024
WILL BE WATCHING THE BAND OF LIGHT SNOW MOVING/DEVELOPING EASTWARD
ACROSS THE REGION INTO THE EVENING HOURS. MODELS HAVE INCREASED QPF
SLIGHTLY ACROSS THE EASTERN CWA, AND HAVE FOLLOWED SUIT IN THE
FORECAST. RADAR IMAGERY AS OF 3PM CST SHOWS SNOW ACROSS SOUTHWEST
AND SOUTH CENTRAL SD, AND EXPECT THIS TO CONTINUE MOVING/DEVELOPING
EASTWARD INTO THE EVENING HOURS. LATEST FORECAST BRINGS GENERALLY A
TRACE TO 2 INCHES FROM SOUTH CENTRAL SD UP THROUGH NORTHEAST SD INTO
WEST CENTRAL MN. BEST POTENTIAL FOR 1 TO 2 INCHES LOOKS TO SET UP
OVER THE EASTERN CWA INTO WEST CENTRAL MN, WHERE 700MB FRONTOGENESIS
MAY CONTRIBUTE TO SLIGHTLY HEAVIER TOTALS. HREF GRAND ENSEMBLE
PROBABILITY FOR AN INCH+ (ASSUMING 10:1 SNOW RATIOS) SHOWS ABOUT 50-
80% ACROSS THE EASTERN CWA. THE PROBABILITY FOR 2+ INCHES DROPS OFF
QUITE A BIT, BUT IS STILL AROUND 20-40% OVER FAR NORTHEAST SD INTO
WEST CENTRAL MN. ALSO INCREASED POPS FROM THE PREVIOUS FORECAST
ACROSS SOUTH CENTRAL SD INTO THE EASTERN CWA, WHILE ALSO PUSHING
THEM WESTWARD A BIT.
TURNING TO CLOUD COVER, STRATUS CONTINUES TO BLANKET MOST OF THE
CWA, BUT RECENTLY THE FAR NORTHWEST CWA HAS SEEN THE STRATUS DEPART,
AND MODELS CONTINUE TO SHOW A SLOW DEPARTURE OF THE CLOUDS FROM WEST
TO EAST OVERNIGHT INTO MONDAY MORNING. IN FACT, HREF ENSEMBLE MEAN
CLOUD COVER SHOWS MOSTLY SUNNY SKIES ACROSS THE AREA ON MONDAY.
AS FOR TEMPERATURES, LOW-LEVEL COLD AIR ADVECTION RAMPS UP ACROSS
THE CWA OVERNIGHT AS 925MB TEMPS COOL TO -7C TO -10C. OVERNIGHT LOWS
ARE A BIT TRICKY AS BREEZY NORTHWEST WINDS AND CLOUDS HAVE TO BE
BALANCED WITH THE STRENGTHENING COLD AIR ADVECTION. LAV GUIDANCE
SHOWS LOWS MAY NOT BE REACHED UNTIL ABOUT 15Z MONDAY MORNING.
LOOKING AT TEENS FOR MOST AREAS BY THE TIME WE GET TO MONDAY MORNING.
LONG TERM /TUESDAY THROUGH SUNDAY/
ISSUED AT 335 PM CST SUN NOV 24 2024
MAIN CONCERN IN THE LONG TERM WILL BE THE COLDER TEMPERATURES FOR
THE END OF THE WEEK INTO NEXT WEEKEND WHERE OUR FIRST BELOW ZERO
TEMP READINGS OF THE SEASON ARE BECOMING LIKELY! STARTING OUT
TUESDAY MORNING, AN ELONGATED AREA OF HIGH PRESSURE WILL BE OVER THE
NORTHERN PLAINS INTO CANADA, WITH ZONAL WINDS ALOFT. THIS HIGH WILL
BE SHIFTING OUT OF THE AREA AS MODELS AGREE AS A LARGE AREA OF LOW
PRESSURE SETTING UP FROM MT AND SOUTHEASTWARD THROUGH COLORADO
THROUGH THE DAY INTO THE EVENING, WITH A CO LOW FORMING. ALOFT, A
POSITIVE TILTED SHORTWAVE WILL MOVE FROM THE NORTHWEST OVER THE
NORTHERN ROCKIES (NORTHERN STREAM), AS SPLIT FLOW CONTINUES, WITH
ZONAL FLOW OVER THE CENTRAL ROCKIES TO CENTRAL MIDWEST ON THE
DOWNWIND SIDE OF A TROUGH, WITH THE AXIS MOVING IN OVER THE WESTERN
CONUS (WHICH HELPS THE CO LOW FORM). WITH THE CWA ON THE THE
NORTHEAST SIDE OF THIS LARGE AREA OF OF LOW PRESSURE (AND HIGH
MOVING OUT), WE WILL SEE SURFACE TROUGHING THROUGH TUESDAY EVENING
INTO EARLY WEDNESDAY.
AS THIS UPPER WAVE MOVES SOUTHEAST OVER THE NORTHERN PLAINS, CLUSTERS
1 AND 2 (MAJORITY EC) IS WAY MORE AGGRESSIVE ON CHANCES OF SNOW FOR
THE AREA THAN GEFS/GEPS CLUSTERS FROM THIS SHORTWAVE WHICH MAKES
SENSE GIVING EC WAS SHOWING A DEEPER WAVE ALOFT AND SLOWER COMPARED
TO THE OTHER MODELS. THIS IS SEEN IN THE EC METEOGRAMS WHICH HAVE
PEAK CHANCES OF SNOW TOPPING OUT AT 40-50% AT THE ASOS SITES. LATEST
NBM KEEPS THIS CHANCE RANGING FROM 15-30% OVER PORTIONS OF NORTH
CENTRAL TO NORTHEASTERN SD/WESTERN MN WEDNESDAY MORNING THROUGH THE
AFTERNOON WITH THE HIGHEST CHANCES OCCURRING ALONG THE ND/SD BORDER.
PROBABILITY OF 24 HR SNOW> 0.5", ENDING THURSDAY MORNING, IS 5-10%
GEFS AND 20-30% EC. OF NOTE, EC ALSO TRIES TO BRING THIS CO LOW A
BIT NORTHWARD THAN GEFS AND IF THIS PANS OUT, EXPECT AN INCREASE IN
POPS OVER THE SOUTHERN CWA.
WITH NORTHWEST FLOW BEHIND THE FIRST WAVE, ANOTHER SHORTWAVE WILL
PUSH SOUTHEAST OVER THE NORTHERN PLAINS/CANADA WEDNESDAY EVENING
INTO THURSDAY WITH STRONG NORTHWEST FLOW BEHIND IT THURSDAY NIGHT
INTO FRIDAY ON THE BACKSIDE OF IT (50-60KTS). AT THE SURFACE, ITS
LOW WILL TRACK SOUTHEAST OUT OF NORTHWESTERN CANADA AND OVER
~MANITOBA/ONTARIO BORDER BY 12Z THURSDAY (MODEL DEPENDING) AS ITS
MAINLY DRY ARCTIC COLD FRONT IS FORECASTED TO SWEEP ACROSS THE CWA
DURING THIS TIME WITH THE CWA BEHIND THE COLD FRONT BY THURSDAY
MORNING. A STRONG ARCTIC HIGH WILL FILTER IN BEHIND IT AND REMAINS
THE DOMINANT WEATHER FEATURE. WITHIN THIS NORTHWEST FLOW SEVERAL
EMBEDDED SHORTWAVES ARE POSSIBLE BRINGING A 15-20% CHANCE OF POPS
SATURDAY, HOWEVER, CONFIDENCE REMAINS LOW TO DUE MODEL VARIABILITY
THIS FAR OUT.
COLD TEMPS WILL STICK AROUND TUESDAY AND WEDNESDAY WITH HIGHS IN THE
20S TO AROUND 30 WHICH IS ABOUT 5-10 DEGREES BELOW AVERAGE. LOWS
WILL RANGE IN THE SINGLE DIGITS TO AROUND 11 WHICH IS ABOUT 3-7
DEGREES BELOW AVERAGE. WE GET THAT FIRST TASTE OF ARCTIC AIR FOR THE
END OF THE WEEK AS OVERALL HIGHS ARE ONLY FORECASTED FROM 10-11
DEGREES TO 20S ACROSS THE CWA AND LOWS DOWN TO THE LOWER SINGLE
DIGITS TO BELOW ZERO. HIGHS WILL BE ABOUT 10-20 DEGREES BELOW
AVERAGE AND LOWS ABOUT 10-15 DEGREES BELOW AVERAGE! LATEST NBM
PROBABILITY OF LOW TEMPS BELOW ZERO FRIDAY MORNING TO MONDAY MORNING
RANGE FROM 20-75% WITH THE HIGHEST CHANCES OVER THE JAMES RIVER
VALLEY.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1138 AM CST SUN NOV 24 2024
TERMINALS KABR,KATY,KPIR,KMBG
MVFR/IFR CIGS WILL CONTINUE ACROSS THE REGION THIS AFTERNOON INTO
THE OVERNIGHT HOURS. ALTHOUGH, FORECAST IS FOR GRADUAL DEPARTURE
OF THESE LOW CLOUDS FROM WEST TO EAST BEGINNING LATE THIS
AFTERNOON THROUGH EARLY MONDAY MORNING. ALSO, AN AREA OF -SN IS
EXPECTED TO MOVE EASTWARD ACROSS THE REGION LATER THIS AFTERNOON
THROUGH THE EVENING HOURS, WITH MVFR/IFR VSBY POSSIBLE.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
SHORT TERM...TMT
LONG TERM...MMM
AVIATION...TMT
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