658
FXUS63 KABR 241813 AAC
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1213 PM CST TUE DEC 24 2024
KEY MESSAGES
- FOG, SOME OF WHICH IS DENSE, WILL PERSIST THROUGH THIS MORNING
BEFORE ANY IMPROVEMENT IS EXPECTED. VISIBILITY OF A QUARTER MILE OR
LESS CAN BE EXPECTED AT TIMES THIS MORNING AND THEN AGAIN TONIGHT.
- THERE IS AROUND A 25% CHANCE OF LIGHT RAIN FORECAST FRIDAY INTO
EARLY SATURDAY OVER PARTS OF NORTHEASTERN SD AND WESTERN MN.
- TEMPERATURES WILL RUN AROUND 5 TO 15 DEGREES ABOVE NORMAL THROUGH
NEXT SUNDAY.
UPDATE
ISSUED AT 1204 PM CST TUE DEC 24 2024
SEE THE UPDATED AVIATION DISCUSSION BELOW FOR THE 18Z TAFS.
THE DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE AT NOON. FOG WILL
CONTINUE FOR SOME AREAS INTO THE AFTERNOON, BUT OVERALL WIDESPREAD
DENSE FOG HAS LIFTED.
UPDATE ISSUED AT 1022 AM CST TUE DEC 24 2024
TRACKING LOW CLOUDS AND FOGGY CONDITIONS ACROSS A GOOD PORTION OF
THE FORECAST AREA THIS MORNING. THE EXCEPTIONS BEING WEST RIVER
ZONES AND PARTS OF THE PRAIRIE COTEAU AND GLACIAL LAKES REGION
WHERE THE SUN HAS MADE AN APPEARANCE. WE'LL CONTINUE TO FOLLOW
TRENDS THE REMAINDER OF THE MORNING WHEN IT COMES TO THIS FOG AS
IT PERTAINS TO THE CURRENT DENSE FOG ADVISORY. MAY NEED TO TRIM
OFF SECTIONS OR LET IT EXPIRE ON TIME WHILE OTHER AREAS, PERHAPS
IN PARTS OF THE JAMES AND BIG SIOUX VALLEYS WILL NEED AN EXTENSION
OF THE ADVISORY INTO THE AFTERNOON. OTHERWISE, NO OTHER CHANGES
TO OTHER PARTS OF THE FORECAST ARE ANTICIPATED FOR THE REMAINDER
OF TODAY.
SHORT TERM /TODAY THROUGH TUESDAY/
ISSUED AT 159 AM CST TUE DEC 24 2024
QUARTER TO HALF MILE VISIBILITIES IN FOG PERSIST OVER MOST OF THE
FORECAST AREA EARLY THIS MORNING. THERE IS SOME CLEARING ON THE
HIGHER ELEVATIONS OF THE COTEAU. EXPECT VERY LITTLE IMPROVEMENT
UNTIL AFTERNOON AS FOG SHRINKS TOWARD THE JAMES VALLEY. SOME MODEL
GUIDANCE HAS BROWN AND SPINK COUNTIES REMAINING BELOW 1 MILE VSBY
UNTIL CHRISTMAS AFTERNOON.
THERE'S NOT MUCH AT A SYNOPTIC LEVEL THAT WOULD ARGUE WITH THIS
PERSISTENT LOW VSBY SOLUTION. UPPER RIDGING BRIEFLY GETS SHUTTLED
OUT THIS AFTERNOON IN A SHORTWAVE TROUGH OVER THE PLAINS. RIDGING
MOVES RIGHT BACK IN BEHIND IT TONIGHT. LOW LEVEL SOUTHERLY FLOW WILL
CONTINUE TO REPLENISH THE LLM. THEREFORE, EXPECT THE FOG TO EXPAND
AGAIN TONIGHT EVEN IN AREAS THAT CLEAR OUT THIS AFTERNOON. SOUTHERLY
WINDS INCREASE BY WEDNESDAY AFTERNOON WHICH IS EXPECTED TO HELP MIX
OUT MORE OF THE REGION AND BREAK UP ANY FOG. GENERALLY, DRY
CONDITIONS ARE EXPECTED WITH DRIER AIR IN PLACE AT THE MID LEVELS.
HOWEVER, THERE COULD BE PATCHY AREAS OF FLURRIES OR ACCRETING
FREEZING FOG THAT COULD MAKE ROADS SLIPPERY THROUGH CHRISTMAS
MORNING.
FOG AND STRATUS WILL MODERATE THE MUCH WARMER AIR ALOFT. WITH MORE
BREAKS IN THE CLOUDS EXPECTED ON WEDNESDAY, FINALLY HAVE HIGHS
POPPING ABOVE FREEZING. FOR TODAY, THOUGH, KEPT HIGHS IN THE 20S -
MORE IN LINE WITH HI-RES MODELS - FOR AREAS FROM THE JAMES VALLEY
EAST.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ISSUED AT 159 AM CST TUE DEC 24 2024
THURSDAY, A SHORTWAVE RIDGE WILL BE SET UP OVER THE FORECAST AREA
ALLOWING FOR WARM AIR TO STAY IN THE REGION. 850MB TEMPERATURES OF
+5C WILL BE CLOSE TO THE 90TH PERCENTILE, AND SURFACE TEMPERATURES
COULD BE UP TO 10-15 DEGREES ABOVE NORMAL THROUGH SUNDAY.
THE ONE THING THAT COULD STAND IN THE WAY OF THIS WARMUP IS
CONTINUING FOG OVER THE AREA. MODEL GUIDANCE SUGGESTS AN ABUNDANCE
OF LOW-LEVEL MOISTURE THROUGH AT LEAST THE END OF THE WEEK AND
POTENTIALLY INTO THE WEEKEND. NBM PROBABILITIES OF VISIBILITIES LESS
THAN 5 MILES HOLDS AT AROUND 20-30% OVER NORTHEASTERN SOUTH DAKOTA
UNTIL FRIDAY MORNING (AT WHICH POINT IT IS NO LONGER CALCULATED).
SOUTHERLY WINDS UNDER 10 KNOTS THROUGH THIS PERIOD WILL BE UNLIKELY
TO HELP LIFT THE CLOUD DECK/FOG OUT OF THE AREA, SO IT IS ENTIRELY
POSSIBLE THAT AT LEAST SOME OF THE FORECAST AREA WILL HAVE
RESTRICTED VISIBILITIES THROUGH FRIDAY.
THE NEXT CHANCES FOR PRECIPITATION COME FRIDAY INTO SATURDAY AS A
SURFACE LOW TRACKS NORTHEASTWARD FROM THE SOUTHERN PLAINS.
PROBABILITIES OF MEASURABLE PRECIPITATION MAX OUT AT AROUND 25% OVER
THE EASTERNMOST PART OF THE AREA ACCORDING TO NBM GUIDANCE, AND THE
SYSTEM COULD EASILY TRACK EASTWARD AND MISS THE FORECAST AREA
ENTIRELY AS WELL. IF WE DO SEE PRECIPITATION OUT OF THIS, EXPECT A
LOW IMPACT EVENT. ADDITIONAL CHANCES FOR PRECIPITATION COME FROM A
SHORTWAVE TROUGH SUPPORTING A BAND OF LIGHT PRECIPITATION SETTING UP
SOMEWHERE OVER THE FORECAST AREA DURING THE DAY SATURDAY.
BEYOND SUNDAY, ZONAL FLOW/SLIGHT RIDGING OVER THE WESTERN CONUS IS
SET TO RETURN, WHICH WILL HELP BRING TEMPERATURES BACK DOWN TO
NORMAL FOR LATE DECEMBER. THE NEXT BIG SYSTEM MAY MOVE IN ON MONDAY
AND BRING SNOW TO PARTS OF THE FORECAST AREA.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1204 PM CST TUE DEC 24 2024
TERMINALS KABR,KATY,KPIR,KMBG
LOW STRATUS AND FOG WILL PERSIST INTO THE AFTERNOON, ESPECIALLY AT
KABR/KATY TERMINALS. IFR/LIFR CIGS AND MVFR/IFR VSBYS CAN BE
EXPECTED AT THESE TAF SITES THROUGH THE AFTERNOON HOURS. ANY
IMPROVEMENTS COULD BE BRIEF AS LIFR CIGS/VSBYS WILL RETURN TONIGHT
INTO WEDNESDAY MORNING. FARTHER WEST, AT KPIR/KMBG WILL SEE
IMPROVEMENTS THROUGH THE AFTERNOON. VFR CONDITIONS ARE EXPECTED TO
HANG ON OVERNIGHT THROUGH WEDNESDAY MORNING.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
UPDATE...VIPOND
SHORT TERM...WISE
LONG TERM...BC
AVIATION...VIPOND
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