125
FXUS63 KABR 260526 AAC
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1126 PM CST WED DEC 25 2024
KEY MESSAGES
- FOG IS EXPECTED AGAIN TONIGHT INTO THURSDAY MORNING. SOME OF THE
FOG WILL BE LOCALLY DENSE WITH VISIBILITY DROPPING TO A HALF
MILE OR LESS. A DENSE FOG ADVISORY HAS BEEN POSTED FOR PARTS OF
EAST CENTRAL SOUTH DAKOTA THIS EVENING THROUGH THURSDAY MORNING.
- VERY LIGHT PRECIPITATION (20 TO 45% CHANCE FOR MOISTURE) WILL
MOVE INTO EASTERN SD/WESTERN MN LATE FRIDAY. A MIX OF
PRECIPITATION TYPES (RAIN, DRIZZLE AND/OR LIGHT SNOW) ARE ALL
POSSIBLE. IF ROAD SURFACES FAIL TO WARM ABOVE FREEZING, TRAVEL
MAY BE IMPACTED.
- TEMPERATURES WILL RUN AROUND 10 TO 20 DEGREES ABOVE NORMAL FROM
THURSDAY THROUGH SUNDAY.
UPDATE
ISSUED AT 1124 PM CST WED DEC 25 2024
SEE UPDATED AVIATION DISCUSSION BELOW.
UPDATE ISSUED AT 908 PM CST WED DEC 25 2024
NO MAJOR CHANGES TO THE FORECAST THIS EVENING. DENSE FOG IS
CONFINED TO THE SOUTHEASTERN PORTION OF THE CWA, SO NO CHANGES TO
THE CURRENT HEADLINES, OR TO WINDS OR TEMPERATURES.
SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/
ISSUED AT 334 PM CST WED DEC 25 2024
ULTIMATELY GOING TO CONTINUE TO FOLLOW PERSISTENCE IN THIS PERIOD AS
WE'RE NOT EXPECTING A WHOLE LOT OF VARIATION IN CONDITIONS. A
MAJORITY OF OUR FORECAST AREA HAS SEEN AN ABUNDANCE OF LOW LEVEL
MOISTURE(STRATUS/FOG) THE LAST COUPLE OF DAYS AND THIS WILL NOT
CHANGE MUCH TONIGHT THROUGH THURSDAY NIGHT.
A SFC TROUGH OF LOW PRESSURE REMAINS POSITIONED NORTH TO SOUTH
ACROSS THE WESTERN DAKOTAS THIS AFTERNOON. SOUTHERLY LOW LEVEL FLOW
AHEAD OF THIS FEATURE HAS CONTINUED TO MAINTAIN OUR RATHER DAMP
CONDITIONS IN TERMS OF FOGGY CONDITIONS AND/OR STRATUS. SOUTHEAST
WINDS HAVE BEEN GUSTY MOST OF THE DAY, TOPPING OUT BETWEEN 25-35
MPH. THESE WILL BEGIN TO RELAX THIS EVENING BUT REMAIN ELEVATED IN
OUR EASTERN ZONES OVERNIGHT. THE SFC TROUGH WILL SHIFT EAST INTO
CENTRAL PORTIONS OF SOUTH DAKOTA AS A COLD FRONT THIS EVENING AND
THEN BASICALLY WASH OUT BEFORE IT GETS INTO THE JAMES VALLEY.
SOUTHWEST LOW LEVEL FLOW BEHIND THIS BOUNDARY SHOULD BE ENOUGH TO
KEEP FOG AND LOW VISIBILITIES FROM DEVELOPING IN PARTS OF CENTRAL
SOUTH DAKOTA. ZONES FARTHER EAST WON'T BE SO LUCKY. SOME FOG
CURRENTLY LINGERS(WATERTOWN AREA) AND THIS WILL ONLY CONTINUE AND
EXPAND AND BECOME MORE THICK WITH TIME AFTER SUNSET. SOME POCKETS OF
DENSE FOG WILL BE POSSIBLE TONIGHT, ESPECIALLY IN THE SOUTHEAST
CORNER OF THE CWA. HREF PROBS FOR SEEING VISIBILITY REACH A HALF
MILE OR LESS RANGE FROM 40-70 PERCENT IN THAT WATERTOWN AND BIG
SIOUX VALLEY AREA. IT ALSO SHOWS ANOTHER AREA OF LOWER VISIBILITY
PROBS ENTERING OUR WESTERN ZONES, PERHAPS ASSOCIATED WITH THAT COLD
FRONT. HOWEVER, OTHER HI-RES GUIDANCE ISN'T PICKING UP ON THIS. SOME
FOG CONTINUES ACROSS THE LEOLA HILLS AREA SOUTHWARD INTO EDMUNDS
COUNTY. HI-RES GUIDANCE USED TO FORECAST VISIBILITIES INDICATES THIS
AREA WILL CONTINUE TO SEE FOG INTO TONIGHT, BUT PERHAPS NOT AS DENSE
AS OUR SOUTHEAST FORECAST AREA. WENT WITH ANOTHER DENSE FOG ADVISORY
FOR TONIGHT INTO TOMORROW MORNING FOR OUR SOUTHEAST CORNER(CLARK,
CODINGTON, HAMLIN AND DEUEL COUNTIES). EVENING AND OVERNIGHT SHIFTS
WILL HAVE TO MONITOR ANY EXPANSION OF THE DENSE FOG AND MODIFY THE
HEADLINE ACCORDINGLY.
AS MENTIONED, FOG WILL CONTINUE THROUGH THURSDAY MORNING BEFORE
VISIBILITIES BEGIN TO IMPROVE BY MIDDAY. HREF ENSEMBLE MEAN CLOUD
COVER INDICATED THE MISSOURI VALLEY SHOULD SEE SOME SUNNY SKIES OR
AT LEAST SOME SUNNY BREAKS IN ANY CLOUD COVER DURING THE DAY. NBM
AGREED AND KEEPS MOST OF THAT SUNSHINE WEST OF THE JAMES VALLEY.
MUCH LIKE TODAY, OUR EASTERN ZONES COULD HOLD ONTO SOME FOG THROUGH
THE AFTERNOON OR THE BREAK IN THE FOG ACTION WILL BE BRIEF. GUIDANCE
POINTS TO ANOTHER OVERNIGHT THURSDAY NIGHT/EARLY FRIDAY MORNING OF
ANOTHER ROUND OF DENSE FOG FOR THE EASTERN HALF OF THE FORECAST
AREA. HREF PROBABILITIES OF SEEING VISIBILITY A HALF MILE OR LOWER
AT THAT TIME RUNS HIGH AT THIS POINT WITHIN A RANGE OF 50-80
PERCENT. TEMPERATURES THROUGH THIS PERIOD WILL CONTINUE TO FEATURE
UNSEASONABLY MILD READINGS BOTH OVERNIGHT AND DURING THE DAY. EXPECT
OVERNIGHT LOWS IN THE 20S TO AROUND 30 THE NEXT COUPLE NIGHT. THOSE
VALUES ARE A BIT WARMER THAN SOME NORMAL HIGHS FOR LATE DECEMBER.
LIKEWISE, DAYTIME HIGHS IN THE 30S AND 40S IS ROUGHLY 10-15 DEGREES
ABOVE NORMAL.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 334 PM CST WED DEC 25 2024
THE UPPER PATTERN FEATURES WEAK FLOW ALOFT, HOWEVER A PAIR OF WEAK
SHORTWAVES EMBEDDED WITHIN THIS FLOW TRAVERSE THE REGION FRIDAY.
MOISTURE CREEPS UP ACROSS MOST OF EAST RIVER, WITH NAM BUFKIT
PROFILES FROM KMBG TO KATY INDICATING A DEEP SATURATED LAYER, WITH
INTERMITTENT SATURATION IN THE DENDRITIC GROWTH ZONE, AND A LOW
LEVEL INVERSION THAT IS FAIRLY CLOSE TO 0C. NBM PROBABILITIES OF P-
TYPE ARE CLOSER TO FREEZING RAIN FROM 12-15Z AND THEN TRANSITION TO
PRIMARILY RAIN BETWEEN 21-00Z. AGAIN, QPF IS LIGHT WITH RELATIVELY
LITTLE ASCENT THROUGH THE PROFILE (5 MICROBARS OR LESS). NBM
PROBABILITY OF EXCEEDING 0.01" IS 20% OR LESS. THE LAST WRINKLE IS
TO FIGURE OUT WHAT WILL ROAD SURFACE TEMPERATURES EVEN BE BY THIS
POINT? THUS, CONFIDENCE IS LOW AS TO THE AMOUNT AND TYPE OF
PRECIPITATION, BUT THE GENERAL ASSESSMENT IS THAT IT WILL BE ONE OF
THESE EXTREMELY LIGHT (IE TRACE TO A HUNDREDTH OR TWO) MIXED
PRECIPITATION EVENTS (DRIZZLE SPRINKLES BACK AND FORTH WITH VERY
LIGHT SNOW) THAT COULD POTENTIALLY HAVE AN IMPACT ON TRAVEL IN THE
FORM OF SLICK ROADS IF ROAD TEMPERATURES REMAIN BELOW FREEZING.
WESTERLY LOW LEVEL FLOW SATURDAY AND SUNDAY WILL HELP TO VERY VERY
SLOWLY PUSH THIS LOW LEVEL MOISTURE EASTWARDS AND ALLOW FOR A BETTER
MIXING ENVIRONMENT TO HELP US REALIZE THE MILDER TEMPERATURES ALOFT.
SATURDAY WE WILL BE IN A GAP BETWEEN THESE WEAK SHORTWAVES FOR MORE
SUN THAN CLOUDS, HOWEVER SUNDAY WILL SEE PLENTY OF MID AND HIGH
CLOUDS TO POTENTIALLY NEGATIVELY IMPACT DAYTIME HEATING.
THE NEXT FORECAST ISSUE WILL BE A COLORADO LOW THAT MAKES A RAPID
WEST TO EAST PROGRESSION ACROSS THE ROCKIES INTO THE
SOUTHERN/CENTRAL PLAINS MONDAY. THE MAIN QUESTION HERE IS WHAT WILL
BE THE NORTHERN EXTENT OF THE PRECIPITATION AND P-TYPE, WHICH
CURRENTLY RESIDES SOMEWHERE BETWEEN THE SOUTHERN HALF OF SOUTH
DAKOTA TO JUST ABOUT AT THE STATE LINE (NEBRASKA-SOUTH DAKOTA)
ACCORDING TO DETERMINISTIC GUIDANCE. THERE ARE ONLY A FEW EC
ENSEMBLE MEMBERS THAT WOULD BRING MOISTURE INTO PIERRE, WHILE ABOUT
HALF OF THE GEFS AND CANADIAN MEMBERS DO LIKEWISE. SO FOR NOW, WILL
STICK WITH NBM WHICH IS ON THE INCREASE.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1124 PM CST WED DEC 25 2024
TERMINALS KABR,KATY,KPIR,KMBG
VFR CONDITIONS WILL PREVAIL OVERNIGHT AND THROUGH THE DAY
THURSDAY ACROSS CENTRAL SOUTH DAKOTA, INCLUDING KPIR AND KMBG. THE
CENTRAL PART OF THE REGION, INCLUDING KABR, WILL SEE IFR/MVFR
CIGS AND VFR VSBYS THROUGH THE TAF PERIOD. THE EASTERN PART OF THE
REGION, INCLUDING KATY, WILL SEE IFR CIGS AND VSBYS FALL TO LIFR/IFR
VSBYS IN FOG LATE TONIGHT THROUGH MIDDAY THURSDAY. THE VSBYS WILL
THEN IMPROVE TO MVFR LEVELS, BUT IFR CIGS WILL REMAIN THROUGH THE
AFTERNOON HOURS.
ABR WATCHES/WARNINGS/ADVISORIES
SD...DENSE FOG ADVISORY UNTIL NOON CST THURSDAY FOR SDZ019-020-022-
023.
MN...NONE.
UPDATE...PARKIN
SHORT TERM...VIPOND
LONG TERM...CONNELLY
AVIATION...PARKIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page