919
FXUS63 KDMX 280338
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1038 PM CDT WED MAY 27 2026
...UPDATED FOR THE 06Z AVIATION DISCUSSION...
KEY MESSAGES
- AROUND 15% CHANCE FOR ISOLATED AND SHORT LIVED SHOWERS AND
STORMS IN THE NORTHERN PART OF THE STATE THIS AFTERNOON
- OVERALL DRY PATTERN INTO THE WEEKEND, WITH CONSISTENT HIGHS IN
THE MID 80S.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 225 PM CDT WED MAY 27 2026
AN ANOMALOUSLY MUNDANE WEATHER PATTERN CONTINUES ACROSS THE STATE
TODAY AS A PERSISTENT OMEGA BLOCK CENTERS OVER IOWA. ASIDE FROM
THE TYPICAL OMEGA BLOCK PATTERN (LONGWAVES IN THE WEST AND
EAST, RIDGE IN THE CENTRAL US), A SHORTWAVE EMBEDDED IN THE SUB-
TROPICAL JET OVER TEXAS IS VISIBLE ON WATER VAPOR IMAGERY. FOR
IOWA SPECIFICALLY, CLEAR SKIES ARE PUTTING TEMPERATURES ON TRACK
FOR THE UPPER 80S LATER THIS AFTERNOON. MOISTURE IS MIXED OUT
FOR THE MOST PART, EXCEPT FOR NORTHERN IOWA WHERE ABOUT 1000
J/KG OF SBCAPE IS IN PLACE. THIS COMBINED WITH VERY WEAK SHEAR
MAY ALLOW FOR A FEW ISOLATED AND SHORT LIVED THUNDERSTORMS IN
THE NORTHERN PART OF THE STATE OVER THE NEXT FEW HOURS. DRY LOW
LEVELS WILL LIKELY KEEP QPF LOW FROM THESE STORMS.
THROUGH THE OVERNIGHT AND THURSDAY MORNING, THE TEXAS SHORTWAVE WILL
ATTEMPT TO PIVOT AROUND THE LONGWAVE TOWARDS IOWA, BUT WILL BE
SHUNTED TO THE SOUTH AND WEST BY THE 500MB RIDGE ACROSS THE NORTH-
CENTRAL US. THE MOISTURE AXIS BEING DRAGGED ALONG WITH THE SHORTWAVE
WILL LIKELY REMAIN JUST WEST OF THE CWA THURSDAY INTO THE WEEKEND.
AT THE SAME TIME, HIGH PRESSURE OVER THE GREAT LAKES WILL
STRENGTHEN. SUBSIDENT SURFACE FLOW OUT OF THE EAST AND OFF OF THE
GREAT LAKES WILL BRING IN COOLER, DRIER AIR THROUGH THE DAY
THURSDAY. STILL, THE 850MB HIGH WILL BE CENTERED OVER IOWA, AND WARM
850 TEMPS WILL STILL BE IN PLACE. THOSE TWO THINGS CONSIDERED, HIGHS
THURSDAY MAY BE WARM BUT ARE EXPECTED TO BE SLIGHTLY COOLER THAN
TODAY IN THE LOW TO MID 80S.
LONG TERM /SATURDAY THROUGH TUESDAY/
ISSUED AT 225 PM CDT WED MAY 27 2026
REMARKABLY SIMILAR MID-80S HIGHS ARE EXPECTED THROUGH THE END OF THE
PERIOD, THOUGH CONFIDENCE DECREASES AFTER MONDAY. THE MOISTURE AXIS
MENTIONED ABOVE WILL LIKELY REMAIN WEST OF OUR AREA UNTIL SUNDAY AND
KEEP PRECIP CHANCES LOW, THOUGH SOME LIGHT SHOWER CHANCES EXIST
FRIDAY/SATURDAY IN SOUTHWEST IOWA DEPENDING ON UPSTREAM MIXING AND
CONVECTIVE EVOLUTION. ON SUNDAY, A SHORTWAVE EMBEDDED WITHIN THE
WESTERN LONGWAVE WILL PIVOT ACROSS THE HIGH PLAINS. IT IS LIKELY
THIS WILL BE TOO FAR WEST TO CREATE ANY MEANINGFUL SHEAR, BUT MAY BE
ENOUGH TO BRING THE MOISTURE AXIS FURTHER INTO IOWA. GEFS SBCAPE
PROBABILITIES INCREASE SIGNIFICANTLY SUNDAY AND BEYOND, AND MORE QPF
OUTLIERS SHOW UP IN THE NBM MEMBERS SUNDAY NIGHT AND AFTERWARDS
(THOUGH AN OVERALL DRY PATTERN WILL LIKELY STILL DOMINATE).
ENSEMBLES SUGGEST THE OMEGA BLOCK PATTERN WILL BEGIN TO BREAK DOWN
EARLY NEXT WEEK, AND THE EXACT EVOLUTION OF HOW THE RIDGE BREAKS
DOWN AND THE LONGWAVE FINALLY EJECTS WILL DETERMINE WHETHER OUR
HAZARDS FOR NEXT WEEK ARE GARDEN VARIETY SINGLE CELL THUNDERSTORMS
OR STRONGER, MORE ORGANIZED STORMS.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1036 PM CDT WED MAY 27 2026
VFR CONDITIONS WILL PERSIST THROUGH THE PERIOD. SCATTERED CIRRUS
OVERNIGHT MAY BECOME BKN AT TIMES ON THURSDAY. LIGHT WIND
OVERNIGHT THE BECOMING EAST/SOUTHEAST AROUND 10 KTS BY MID TO
LATE MORNING.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...DE BRUIN
LONG TERM...DE BRUIN
AVIATION...DONAVON
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