711  
FXUS63 KABR 211748 AAC  
AFDABR  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE ABERDEEN SD  
1248 PM CDT THU MAY 21 2026  
   
KEY MESSAGES  
 
- THERE IS A 50-80 PERCENT CHANCE OF 1/2 INCH OR MORE RAINFALL  
OCCURRING FRIDAY INTO FRIDAY NIGHT.  
 
- TURNING MUCH WARMER SUNDAY THROUGH NEXT WEEK, AROUND 10 TO 20  
DEGREES ABOVE NORMAL, WITH HIGHS IN THE 80S TO NEAR 90.  
 
 
   
UPDATE  
 
ISSUED AT 1245 PM CDT THU MAY 21 2026  
 
SEE BELOW FOR AN AVIATION FORECAST DISCUSSION FOR THE 18Z TAFS.  
 
UPDATE ISSUED AT 824 AM CDT THU MAY 21 2026  
 
SO FAR, JUST A FEW POCKETS OF SPRINKLES ACTIVITY THIS MORNING.  
LOW LEVEL MOISTURE RETURN FLOW REALLY STARTS RAMPING UP LATER  
THIS EVENING. NO CHANGES PLANNED, AT THIS TIME, TO THE TODAY  
PERIOD FORECAST.  
 
UPDATE ISSUED AT 615 AM CDT THU MAY 21 2026  
 
UPDATE FOR 12Z AVIATION DISCUSSION  
 
 
   
DISCUSSION  
 
ISSUED AT 205 AM CDT THU MAY 21 2026  
 
WEAK MID LEVEL WARM ADVECTION AND SUBTLE SHORTWAVE RESPONSIBLE FOR  
LIGHT SHOWERS AND SPRINKLES THIS AM, WHICH WILL LIFT NORTHEAST.  
OTHERWISE WE MAINTAIN A GRADIENT WITH WINDS OUT OF THE SOUTH  
GUSTING TO 20 TO 35 MPH.  
 
AS FOR THE WAVE FRIDAY, TIMING IS LATE TONIGHT WEST RIVER WITH SOME  
CONVECTIVE NATURE BUT REALLY JUST SKINNY CAPE IN MODEST SHEAR, WHICH  
WEAKENS WITH LOSS OF DAYTIME HEATING. SOME OF THAT MIGHT LEAK INTO  
THE MISSOURI VALLEY BEFORE DISSIPATING. AFTER 06Z A MORE  
CONSOLIDATED (24 HOURS AGO IT WAS 2) NEGATIVELY TILTED WAVE LIFTS UP  
ACROSS THE AREA. CAMS TAKE MOST OF THE DAY FRIDAY TO LIFT THIS  
SYSTEM UP ACROSS THE CWA AND IT MAY TAKE THE NORTHEAST UNTIL EARLY  
SATURDAY BEFORE EVERYTHING HAS LIFTED NORTH. THE 25TH PERCENTILE IS  
AROUND 1/4 INCH WEST RIVER TO 1/2 INCH IN THE NORTHEAST WHILE THE  
75TH IS CLOSER TO 1 INCH SO STILL A BIT OF RANGE. JUST SOME SKINNY  
OR SHALLOW CAPE DEPENDING ON MODEL AND LOCATION, SO OVERALL  
ASSESSMENT IS MAINLY JUST RAIN/SHOWERS WITH LITTLE THUNDER.  
 
THEREAFTER, THERE IS A SECONDARY WAVE ALOFT 12Z SATURDAY OVERHEAD.  
THIS, AND DAYTIME HEATING MAY LEAD TO ADDITIONAL LIGHT SHOWER  
ACTIVITY. NBM IS DRY AT THIS TIME, SOMETHING TO WATCH.  
 
WE HAVE BRIEF ZONAL FLOW OVERHEAD/UPSTREAM FOR SUNDAY/EARLY MONDAY,  
WITH FLOW BECOMING SOUTHWESTERLY ALOFT AS A TROUGH DEEPENS ACROSS  
THE PACIFIC NORTHWEST. THIS INCREASING HEIGHTS AND TEMPERATURES ALOFT  
TRANSLATES TO WARMER CONDITIONS FOR SUNDAY - THURSDAY. 700MB  
TEMPERATURES INCREASE TO +6 TO +10C, ABOUT A STANDARD DEVIATION  
ABOVE CLIMO. HIGH TEMPERATURES THAT TIMEFRAME STILL 10 TO 20F ABOVE  
CLIMO.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/  
 
ISSUED AT 1245 PM CDT THU MAY 21 2026  
 
TERMINALS KABR,KATY,KPIR,KMBG  
 
VFR CONDITIONS WILL CONTINUE THROUGH ROUGHLY 06Z TONIGHT. THEN,  
BETWEEN 06Z AND 15Z, SUB-VFR CIGS (AND EVENTUALLY VSBYS IN RAIN)  
WILL OVERSPREAD THE WHOLE REGION, WORKING SOUTHWEST TO  
NORTHEAST. EXPECT PREVAILING RAINFALL CONDITIONS TO ESTABLISH AT  
KPIR BY 09Z AND PERSIST THROUGH THE END OF THE TAF VALID PERIOD.  
KMBG, KABR AND KATY WILL BEGIN TO EXPERIENCE LIGHT RAIN,  
GENERALLY, AT OR AFTER 12Z FRIDAY.  
 
 
   
ABR WATCHES/WARNINGS/ADVISORIES  
 
SD...NONE.  
MN...NONE.  
 
 
 
 
 
UPDATE...10  
DISCUSSION...10  
AVIATION...10  
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