470
FXUS63 KDMX 201941
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
241 PM CDT TUE MAY 20 2025
KEY MESSAGES
- GENERALLY COOL OVER THE NEXT WEEK WITH VERY LOW CHANCES FOR
SEVERE WEATHER THROUGH MOST OF THE PERIOD.
- VERY COOL NORTH WITH HIGHS IN THE 40S AND A FEW SHOWERS ON
WEDNESDAY.
- NEXT MAIN CHANCE FOR PRECIPITATION ARRIVES THIS WEEKEND.
DISCUSSION
ISSUED AT 236 PM CDT TUE MAY 20 2025
LARGE AREA OF SURFACE LOW PRESSURE IS CENTERED OVER IOWA WITH A
PRONOUNCED INVERTED TROUGH EXTENDING NORTHWEST THROUGH THE DAKOTAS. A
SECONDARY VORTICITY LOBE IS ROTATING AROUND THE SOUTHERN PERIPHERY
OF THE UPPER LEVEL LOW. THAT SHORT WAVE IS MOVING ACROSS KANSAS AND
MISSOURI EARLY THIS AFTERNOON AND THIS SYSTEM IS HELPING FIRE A
SHOWERS AND STORMS OVER PARTS OF SOUTHEAST IOWA/NORTHEAST MISSOURI
AND INTO ILLINOIS. OTHER SHOWERS ARE OVER CENTRAL AND NORTH CENTRAL
IOWA. AS THIS SURFACE LOW MOVES EAST INTO TONIGHT AND WEDNESDAY, THE
INVERTED TROUGH WILL BE DRAGGED EAST, WHICH IN ITS CURRENTLY
ORIENTATION, WILL ALSO RESULT IN IT MOVING NORTH AND EAST ACROSS THE
STATE.
THE NEXT SEVERAL DAYS WEATHER WILL HAVE THE UPPER LOW TO THE NORTH
TO SHEAR OUT AND EVENTUALLY HAVE THE HUDSON BAY UPPER LOW TAKE OVER
AND SETTLE SOUTH INTO THE GREAT LAKES REGION BY THURSDAY. FOR
WEDNESDAY, WITH THE SURFACE INVERTED TROUGH NEARBY, IOWA WILL HAVE
MOSTLY CLOUDY AND VERY COOL TEMPERATURES OVER NORTHERN IOWA AND MORE
SUN AND WARMER ACROSS THE SOUTH. BY THURSDAY, THE UPPER LOW
EVOLUTION WILL LEAD TO COOL CYCLONIC FLOW OVER IOWA. A FEW PERIODS
OF LIGHT RAIN IS POSSIBLE OVER NORTHERN IOWA THROUGH WEDNESDAY NIGHT
AND A FEW SPRINKLES COULD OCCUR INTO THURSDAY. ANOTHER UPPER LEVEL
PATTERN TRANSITION WILL OCCUR LATE IN THE WEEK WITH A MORE MODIFIED
ZONAL FLOW OCCURRING THOUGH OVERALL IOWA WILL BE ON THE COOLER SIDE
OF THIS PATTERN. MOISTURE OVERRUNNING THIS COOLER AIR IS EXPECTED
THIS WEEKEND AND THAT MAY BRING THE NEXT CHANCE FOR PRECIPITATION TO
IOWA WITH THE GREATEST CHANCES OVER SOUTHERN IOWA. THESE
PRECIPITATION CHANCES MAY LINGER INTO NEXT MONDAY. TEMPERATURES FOR
LATE WEEK AND INTO EARLY NEXT WEEK WILL BE SEASONABLY COOL WITH
HIGHS IN THE 60S TO LOW 70S. MORE SIGNIFICANT WARMING SHOULD ARRIVE
BY MID NEXT WEEK WITH AN UPPER LEVEL RIDGE MOVING INTO THE
REGION.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1231 PM CDT TUE MAY 20 2025
WIDESPREAD IFR TO LOCAL LIFR CIGS ARE OVER MUCH OF CENTRAL AND
NORTHERN IOWA EARLY THIS AFTERNOON. SOME BREAKS OF VFR OCCURRING
AT KOTM AND THAT COULD POTENTIAL GET INTO KDSM FOR A BRIEF
PERIOD THIS AFTERNOON. OTHERWISE PERIODS WITH SHOWERS TODAY THAT
WILL DIMINISH OVERNIGHT. CIGS WILL GRADUALLY IMPROVE LATE
TONIGHT INTO WED MORNING. THE WIND IS VARIABLE WIND DIRECTIONS
TO START WITH LOW PRESSURE OVER IOWA. THE WIND WILL TURN
WEST/NORTHWEST DURING THE PERIOD AND BECOME GUSTY BY WED
MORNING.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...DONAVON
AVIATION...DONAVON
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