406  
FXUS63 KABR 181748 AAB  
AFDABR  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE ABERDEEN SD  
1248 PM CDT MON MAY 18 2026  
   
KEY MESSAGES  
 
- LIGHT RAIN SHOWERS MID DAY TODAY THROUGH THIS EVENING. RAINFALL  
RANGES FROM A TENTH TO A QUARTER INCH.  
 
- COLDER AIR FOR THE FIRST HALF OF THE WORK WEEK. LOWS TUESDAY  
MORNING CLOSE TO FREEZING, BUT WITH CLOUDS AND A STIFF  
NORTHWEST BREEZE TEMPERATURES SHOULD STAY ABOVE 32. MUCH  
BETTER SETUP FOR WIDESPREAD FROST/FREEZE CONDITIONS WEDNESDAY  
MORNING WITH CLEAR SKIES AND LIGHT WINDS.  
 
 
   
UPDATE  
 
ISSUED AT 1236 PM CDT MON MAY 18 2026  
 
AVIATION DISCUSSION UPDATED BELOW FOR THE 18Z TAFS.  
 
 
   
DISCUSSION  
 
ISSUED AT 128 AM CDT MON MAY 18 2026  
 
NEXT WAVE COMING UP FROM THE SOUTHWEST BRINGS IN MOISTURE MID-DAY  
TODAY THROUGH THE EARLY OVERNIGHT. STILL MAINLY LIGHT RAIN/SHOWERS.  
QPF IS JUST A TENTH OR TWO.  
 
FOR TUESDAY MORNING, WE ARE FACED WITH THE PROSPECT OF COLD  
ADVECTION ENHANCED WINDS, SHALLOW CLOUD COVER AND NBM GUIDANCE  
PROPOSING TEMPERATURES DOWN TO THE FREEZING MARK. CLEARLY NOT A  
SETUP FOR FROST, BUT WITH 925MB TEMPERATURES AROUND +1 TO +2C  
BETWEEN DETERMINISTIC MODELS, WHICH IS IN ALIGNMENT WITH THE  
HREF MEAN THAT SHOULD PUT TEMPERATURES INTO THE LOW/MID 30S.  
THAT SAID, THE NSSL WRF, NAM NEST AND HRRR HAVE 925 TEMPS DOWN  
TO 0C FOR VARIOUS PARTS OF THE CWA. LATEST NBM IS A LITTLE  
WARMER FOR LOWS, AND NOW HAS JUST ABOUT EVERYONE AT 33F AND  
WARMER. NO HEADLINES/FROST MENTION FOR TUESDAY MORNING BUT IT  
WILL GET QUITE CLOSE TO THE FREEZING MARK. FROST CADDISHNESS  
NEGATED BY THESE WINDS AND CLOUDS HOWEVER.  
 
MUCH MORE IMPACTFUL DROP IN TEMPERATURES WILL BE NOTED FOR WEDNESDAY  
MORNING. DURING THE DAY TUESDAY, DAYTIME DRIVEN CUMULUS EVIDENT IN  
NAM BUFKIT PROFILES. WHILE THIS IS SHALLOW (~5KFT), CANT RULE OUT  
LIGHT RAIN SHOWERS/SPRINKLES. REGARDLESS, CLOUD COVER DURING  
THE DAY WILL LIMIT HEATING. LOSS OF DAYTIME DRIVEN CONVECTION  
WITH TEMPERATURES ONLY INTO THE 50S AND DEWPOINTS IN THE LOW/MID  
30S AND SURFACE HIGH PRESSURE OVERHEAD WILL LEAVE US WITH A  
GOOD SETUP FOR FROST. 25TH RANGE ACROSS THE CWA IS 29-32 WHILE  
THE UPPER RANGE IS 32-35. KEEPING FROST MENTION AT THIS TIME BUT  
STILL TOO EARLY FOR ANY HEADLINES.  
 
THE UPPER PATTERN FEATURES THE CURRENT UPPER TROUGH DEPARTURE, WITH  
A SECOND TROUGH OVER THE INTERMOUNTAIN WEST. THAT PUTS US UNDER A  
RIDGE FOR WEDNESDAY - EARLY THURSDAY. THERE'S A NEGATIVE TILT TROUGH  
PASSAGE FOR FRIDAY. ASIDE FROM THE PRECIPITATION ASSOCIATED WITH THIS  
WAVE/SURFACE LOW, THERE IS A WIDE RANGE IN TEMPERATURES WITH A 10  
DEGREE SPREAD IN THE 25TH/75TH FOR HIGHS SO A LOW CONFIDENCE  
FORECAST TO CLOSE OUT THE WORK WEEK. AFTER THAT ITS ZONAL FLOW  
ACROSS THE NORTHWESTERN CONUS INTO THE NORTHERN PLAINS.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/  
 
ISSUED AT 1236 PM CDT MON MAY 18 2026  
 
TERMINALS KABR,KATY,KPIR,KMBG  
 
AREAS OF -SHRA WILL MOVE NORTHEAST INTO AND THROUGH THE REGION  
THIS AFTERNOON AND EVENING. VSBY MAY DROP TO MVFR IN  
PRECIPITATION. CIGS WILL GENERALLY BE MVFR, ALTHOUGH FORECAST IS  
FOR IFR AT TIMES IN AREAS OF PRECIPITATION AND OVERALL LOWER  
CLOUD COVER POTENTIAL DURING THE EVENING HOURS.  
 
 
   
ABR WATCHES/WARNINGS/ADVISORIES  
 
SD...NONE.  
MN...NONE.  
 
 
 
 
 
UPDATE...TMT  
DISCUSSION...07  
AVIATION...TMT  
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