610  
FXUS63 KDMX 152341  
AFDDMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DES MOINES IA  
641 PM CDT SUN SEP 15 2024  
 
...UPDATED FOR THE 00Z AVIATION DISCUSSION...  
   
KEY MESSAGES  
 
- A FEW SHOWERS AND ISOLATED THUNDERSTORMS MAINLY SOUTH AND EAST  
INTO EARLY THIS EVENING.  
 
- MAINLY DRY WITH ABOVE NORMAL TEMPERATURES THIS WEEK.  
 
- PATTERN CHANGE EXPECT LATE THIS WEEK AND INTO NEXT WEEKEND.  
 
 
   
DISCUSSION  
 
ISSUED AT 236 PM CDT SUN SEP 15 2024  
 
ANOTHER DAY AND LITTLE CHANGE IN THE OVERALL GOING FORECAST OUTSIDE  
OF THE TYPICAL DELAYED PROGRESS BY THE MID TO LATE PORTION OF THE  
WEEK. WIDESPREAD CUMULUS DEVELOPMENT HAS OCCURRED THIS AFTERNOON AS  
TEMPERATURES IN THE LOW TO MID 80S ARE NEAR CONVECTIVE TEMPERATURES.  
PROXIMITY SOUNDINGS SHOW SOME WEAK CAPPING IS HOLDING JUST ABOVE THE  
CUMULUS BASE LEVEL AND IS HELPING HOLD CONVECTIVE POTENTIAL IN  
CHECK. A FRAGMENT OF ENERGY FROM FRANCINE REMNANTS IS LIFTING INTO  
SOUTHEAST IOWA THIS AFTERNOON AND EVENING, THE OVERALL KINEMATIC  
FORCING IS LOW BUT THERE IS SOME CONVECTIVE BUBBLING GOING ON OVER  
THAT PORTION OF THE STATE. A FEW WEAK SHOWERS AND THUNDERSTORMS WILL  
REMAIN POSSIBLE ACROSS THAT AREA INTO EARLY THIS EVENING.  
 
AS MENTIONED, LITTLE HAS CHANGED GOING FORWARD. THE PSEUDO REX BLOCK  
IS UNDERGOING A TRANSITION AS A NON-TROPICAL LOW MOVES OVER THE  
CAROLINAS TONIGHT AND THIS LOW WILL EVENTUALLY ABSORB THE REMNANTS  
OF FRANCINE DURING THE DAY MONDAY. THIS WILL LEAD TO A FURTHER  
DEEPENING UPPER LOW THAT WILL MOVE VERY SLOWLY OVER THE EASTERN  
CONUS MUCH OF THIS WEEK. OUT WEST, ANOTHER DEEPENING UPPER LOW IS  
DIVING SOUTH OVER OREGON AND NORTHERN CALIFORNIA THIS AFTERNOON.  
THAT SYSTEM WILL EVENTUALLY EJECT NORTHEAST WHILE ANOTHER DEEP UPPER  
LOW DIVES SOUTH ALONG WITH WEST COAST. EVENTUALLY THE OTHER SYSTEM  
WILL MOVE EAST TOWARDS THE END OF THE WEEK. WHAT DOES THIS ALL MEAN  
FOR IOWA. FOR THE MOST PART, WEAK HIGH PRESSURE RIDGING WILL REMAIN  
INTACT ACROSS MUCH OF THE AREA THIS WEEK WITH ABOVE NORMAL  
TEMPERATURES AND GENERALLY DRY CONDITIONS. WILL NOTE THAT THE  
OVERALL TRENDS WITH THIS ENTIRE SETUP IS A BIT FURTHER WEST AND  
DELAYED MEANING LESS PRECIPITATION CHANCES MID-WEEK.  
 
THE FIRST SYSTEM LIFTING NORTHEAST WILL BRING SOME MODEST KINEMATIC  
FORCING INTO FAR WESTERN IOWA BUT AS NOTED, THE SHIFT A BIT WEST  
WILL DIMINISH THE AREAL COVERAGE FOR PRECIPITATION CHANCES INTO  
CENTRAL IOWA. THIS SHIFT INCLUDES THAT GULF MOISTURE STREAM NORTH  
WHICH IS TRENDING MORE INTO EASTERN NEBRASKA AS OPPOSED TO WESTERN  
IOWA. MUCH OF CENTRAL AND EASTERN IOWA LIKELY WILL REMAIN DRY  
THROUGH THE WORK WEEK BEFORE THE STRONGER SYSTEM FINALLY BREAKS THE  
PATTERN STALEMATE OVER IOWA. THIS SHOULD BRING COOLER FALL LIKE  
TEMPERATURES SOMETIME NEXT WEEKEND AND GREATER PRECIPITATION  
CHANCES.  
 
 
   
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/  
 
ISSUED AT 641 PM CDT SUN SEP 15 2024  
 
VFR CONDITIONS CAN BE EXPECTED INTO THE OVERNIGHT HOURS WITH  
VARIED MID AND HIGH CLOUDS DRIFTING ACROSS THE STATE. THERE IS  
SOME MINOR POTENTIAL FOR FOG DEVELOPMENT AGAIN TONIGHT, BUT  
CONFIDENCE IS INSUFFICIENT TO MENTION AT THE MOMENT. CONFIDENCE  
IN VFR IS HIGH AGAIN BY MONDAY MIDDAY AND AFTERNOON HOWEVER WITH  
SOME DIURNAL CUMULUS AGAIN POSSIBLE AND PERSISTENT PATCHY HIGH  
CLOUDINESS.  
 
 
   
DMX WATCHES/WARNINGS/ADVISORIES  
NONE.  
 
 
 
 
 
DISCUSSION...DONAVON  
AVIATION...SMALL  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab IA Page
Main Text Page