195
FXUS63 KABR 020207 AAB
AFDABR
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
907 PM CDT THU MAY 1 2025
KEY MESSAGES
- SCATTERED SHOWERS (20-50% COVERAGE, HIGHEST CENTRAL SD) WILL
CONTINUE INTO THE EVENING HOURS. ADDITIONAL RAINFALL AMOUNTS
GENERALLY LESS THAN 0.25IN.
- DRY WITH A WARMUP EXPECTED THIS WEEKEND INTO NEXT WEEK, WITH
HIGH TEMPERATURES IN THE 70S AND LOW TEMPERATURES IN THE 40S.
THESE TEMPERATURES ARE 10 TO 15 DEGREES ABOVE NORMAL.
UPDATE
ISSUED AT 859 PM CDT THU MAY 1 2025
MADE SOME ADJUSTMENTS TO RAINFALL CHANCES BASED ON CURRENT RADAR
TRENDS, WHICH NOW SHOW THE EASTERN CWA DRY, BUT SCATTERED SHOWERS
CONTINUING ACROSS CENTRAL SD. BASED ON UPSTREAM ACTIVITY ACROSS
WESTERN/CENTRAL ND, MAY HAVE TO EXTEND CHANCES FURTHER INTO THE
NIGHTTIME HOURS. WATER VAPOR IMAGERY SHOWING A VORT MAX SLIDING
SOUTH ACROSS ND, SO SHOWERS MAY BE ABLE TO PERSIST A BIT LONGER
THAN THE DIURNAL ENDING AFTER SUNSET. ALSO WATCHING AN AREA OF
SHOWERS SLIDING SOUTH ACROSS THE CENTRAL RED RIVER VALLEY. IF
THESE WERE TO PERSIST, RAINFALL CHANCES MAY NEED TO BE ADDED BACK
INTO PORTIONS OF THE EASTERN CWA OVER THE NEXT FEW HOURS. ALSO
FINE-TUNED SKY COVER GRIDS BASED ON SATELLITE TRENDS AND
EXPECTATIONS.
SHORT TERM /THIS EVENING THROUGH FRIDAY NIGHT/
ISSUED AT 246 PM CDT THU MAY 1 2025
CURRENT WATER VAPOR IMAGERY INDICATES A POSITIVE TILTED EMBEDDED
SHORTWAVE (AXIS OVER WESTERN DAKOTAS/MT) WITHIN NORTHWEST FLOW OF A
LARGER TROUGH POSITIONED OVER THE NORTHERN PLAINS AND UPPER
MIDWEST. AT THE SURFACE WE ARE SANDWICHED BETWEEN A LOW TO OUR
EAST IN MN, A LOW TO OUR NORTH IN MANITOBA (ASSOCIATED WITH THIS
EMBEDDED WAVE), AND A HIGH TO OUR WEST. WITH WEAK INSTABILITY AND
DAYTIME HEATING/MIXING, ALONG WITH UPPER LEVEL SUPPORT ON THE PVA
SIDE OF SHORTWAVE, SATELLITE IMAGERY INDICATES CUMULUS CLOUDS
PUSHING FROM THE NORTHWEST TO THE SOUTHEAST OVER THE AREA. A FEW OF
THEM ARE VERTICALLY RISING ENOUGH TO PRODUCE POPCORN SHOWERS AND A
FEW LIGHTNING STRIKES, HOWEVER, CAMS ARE STRUGGLING TO SHOW THIS
COVERAGE DUE TO THE WEAK INSTABILITY.
HREF INDICATES THIS EMBEDDED SHORTWAVE WILL TRACK SOUTHEAST OVER THE
NORTHERN PLAINS THROUGH TONIGHT INTO FRIDAY MORNING ALONG WITH ITS
SURFACE LOW. MODELS INDICATE THE CENTER OF THIS LOW WILL BE OVER
ND/MN BORDER BY 00Z FRIDAY, WITH THE COLD FRONT DRAPING HORIZONTALLY
FROM IT THROUGH ND INTO MT. THROUGH THE OVERNIGHT, THE CENTER OF THE
LOW WILL TRACK EAST/SOUTHEAST THROUGH MN AND OVER NORTHERN WI BY 12Z
FRIDAY. ITS COLD FRONT WILL PUSH SOUTHEAST THROUGH THE CWA AND EXIT
THE AREA BY THE LATE MORNING OR SO. HIGH PRESSURE BUILDS TO OUR
NORTH BEHIND THE FRONT AND SINKING OVER THE AREA FRIDAY EVENING AND
JUST TO OUR SOUTHWEST BY SATURDAY MORNING. BEHIND THE EXITING
SHORTWAVE, A HIGHLY AMPLIFIED RIDGE WILL CONTINUE TO PUSH EASTWARD,
WITH THE NORTHERN PLAINS ON THE RIGHT SIDE OF THIS RIDGE (SOUTHERLY
FLOW) BY 12Z SATURDAY.
CAMS CONTINUE TO INDICATE ISOLATED TO SCATTERED SHOWERS AND WEAK
THUNDERSTORMS (20-65%) THIS EVENING INTO EARLY TONIGHT MAINLY OVER
CENTRAL SD (40-65%) WITH CHANCES LOWERING THE FURTHER EAST YOU GO
FROM HERE. CAPE LOOKS TO REMAIN UNDER 1000 J/KG WITH MID LEVEL LAPSE
RATES BETWEEN 6.5-7.5C, HIGHEST OVER NORTH CENTRAL SD. NO SEVERE
WEATHER IS ANTICIPATED, HOWEVER, BRIEF LOCALIZED HEAVY DOWNPOURS AND
WIND GUSTS UP TO 50 MPH (DCAPE 200-500 J/KG) MAY ACCOMPANY ANY
STRONGER CELLS. THIS ACTIVITY SHOULD EXIT THE FAR SOUTHERN CWA BY 08-
10Z OR SO WITH DRY WEATHER THROUGH THE REST OF THE SHORT TERM AS THE
HIGH MOVES IN.
LOWS TONIGHT WILL RANGE IN THE UPPER 30S TO THE LOWER 40S WITH
COOLER TEMPS FOR FRIDAY, WITH THE INCOMING HIGH, WITH HIGHS IN THE
UPPER 50S TO THE LOWER 60S.
LONG TERM /SATURDAY THROUGH THURSDAY/
ISSUED AT 246 PM CDT THU MAY 1 2025
WHEN THE PERIOD OPENS, AN UPPER RIDGE WEST/TROF EAST PATTERN IS IN
PROGRESS OVER THE CONUS, WITH THIS CWA IN NORTHWEST FLOW ALOFT.
STILL SEEING THE PATTERN EVOLVE INTO AN OMEGA BLOCK PATTERN (UPPER
CLOSED LOW/RIDGE/UPPER CLOSED LOW) ON SUNDAY, WITH UPPER RIDGING
OVER THE CWA. SAME PATTERN IN PLACE ON MONDAY, EXCEPT THE UPPER
RIDGE IS MORE PINCHED OR BEING PINCHED BY THE TWO UPPER LOW
CIRCULATIONS. THIS IS ALL GOING ON CUT-OFF FROM OR SPLIT-OFF FROM A
MORE GENERAL PROGRESSIVE UPPER STEERING PATTERN WELL OFF TO THE
NORTH IN CANADA. WITHIN THIS PATTERN, AN ADDITIONAL UPPER RIDGE
BEGINS BUILDING OVER THE WESTERN AND CENTRAL CONUS TUESDAY INTO
WEDNESDAY, ALL THE WHILE THE SOUTHWESTERN CUT-OFF LOW IS FORECAST TO
BEGIN MEANDERING OFF TO THE EAST. NOT AN IDEAL SET UP FOR HAVING
POPS IN THE FORECAST; SLOW/BLOCKY PATTERN WITH LIMITED UPPER LEVEL
SHORTWAVE/FAVORABLE JET POSITIONING SUPPORT. IT DOES LOOK LIKE A
FAIRLY WARM (STAGNANT) PATTERN, THOUGH, FOR MOST OF THE PERIOD, WITH
GUIDANCE SUGGESTING THE CWA WILL SETTLE INTO A MULTI-DAY PERIOD OF
HIGHS MAINLY IN THE 70S AND LOWS IN THE 40S BETWEEN SATURDAY AND
THURSDAY.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 638 PM CDT THU MAY 1 2025
TERMINALS KABR,KATY,KPIR,KMBG
VFR CONDITIONS ARE LARGELY EXPECTED THROUGH THE EVENING HOURS.
ONLY EXCEPTION MAY BE BRIEF MVFR VSBY IN ANY HEAVIER SHRA THAT MAY
AFFECT A TAF SITE THIS EVENING. BEST CHANCE FOR THIS WOULD BE
ACROSS KPIR/KMBG. MVFR CIGS ARE ALSO FORECAST TO DEVELOP OVER THE
REGION PRIOR TO SUNRISE FRIDAY AND MAY PERSIST INTO THE MID
MORNING. CONFIDENCE ISN'T OVERLY HIGH IN REGARDS TO AREAL
COVERAGE, BUT HAVE INCLUDED TEMPO MENTION FOR THIS.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
UPDATE...TMT
SHORT TERM...MMM
LONG TERM...10
AVIATION...TMT
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