711  
FXUS63 KDMX 010029  
AFDDMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DES MOINES IA  
729 PM CDT WED SEP 30 2020  
   
SHORT TERM
 
/TONIGHT THROUGH THURSDAY NIGHT/  
ISSUED AT 313 PM CDT WED SEP 30 2020  
 
CONFIDENCE: MEDIUM  
 
MAIN FORECAST CONCERN WILL BE WIND INTO THE EARLY EVENING, THEN  
TEMPERATURES AND FROST POTENTIAL FOR THURSDAY NIGHT. LOW OVER  
MICHIGAN CONTINUES TO FORCE ADDITIONAL BOUNDARIES SOUTH THROUGH THE  
REGION. OVERNIGHT BOUNDARY A BIT MORE ACTIVE WITH EARLY SHOWERS THAT  
HAVE MOVED EAST. A SECONDARY BOUNDARY IS ENTERING SOUTHERN MN AT  
1745Z AND WILL MOVE SOUTH TONIGHT INTO THURSDAY. THIS WILL ALSO  
BRING SOME ADDITIONAL SHOWERS TO THE NORTH THIS EVENING AND TO  
NORTHEAST IOWA AFTER 12Z THURSDAY THROUGH THE MORNING HOURS.  
CYCLONIC FLOW ALOFT WILL SETTLE INTO THE REGION TOMORROW AND AGAIN  
IN THE AFTERNOON THERE IS A SMALL RISK OF SOME SHOWERS MAINLY EAST  
OF I35. HAVE INCLUDED AN AREA OF SLIGHT CHANCE IN THE FORECAST NOW,  
AND THE OVERNIGHT SHIFT WILL NEED TO EVALUATE THE COVERAGE FOR  
POSSIBLE EXTENSION WESTWARD. TONIGHT OVERNIGHT LOWS WILL DROP TO  
THE LOWER TO MID 40S WITH AFTERNOON HIGHS THURSDAY CAPPED TO THE  
LOWER 50S NORTH AND IN THE MID TO UPPER 50S OVER THE CENTRAL AND  
SOUTH. SOME QUESTIONS REMAIN FOR THURSDAY NIGHT INTO FRIDAY WITH  
REGARD TO CLOUDS AND TEMPS. THERE REMAINS A SPLIT IN GUIDANCE AS TO  
THE ARRIVAL TIME OF THE CLOUDS FRIDAY. THE EURO AND SOME OF THE  
HIRES GUIDANCE SUGGEST AN EARLIER ARRIVAL, SIMILAR TO YESTERDAY AFT  
06Z TO 12Z WHILE THE GFS KEEPS THE THICKER CLOUDS TO OUR WEST AND  
GENERALLY CLEAR THROUGH 12Z. OVERNIGHT MINS HAVE BEEN ADJUSTED A  
COUPLE OF DEGREES UPWARD THIS PACKAGE, DUE TO INCREASE IN CLOUDS AND  
GUIDANCE WHICH IS ALSO WARMER. LOWS THURSDAY NIGHT WILL FALL TO  
AROUND 32 IN THE NORTHWEST TO THE UPPER 30S SOUTH. THIS WILL STILL  
GIVE WAY TO FROST OVER A GOOD SHARE OF THE FORECAST AREA, THOUGH A  
HARD FREEZE IS NOT ANTICIPATED AT THIS TIME.  
   
LONG TERM
 
/FRIDAY THROUGH WEDNESDAY/  
ISSUED AT 313 PM CDT WED SEP 30 2020  
 
CONFIDENCE: MEDIUM  
 
FRIDAY TEMPERATURES WILL RECOVER THE TO THE 50S WITH CLOUDS  
CONTINUING ACROSS THE REGION. HIGHS WILL REACH THE LOWER 50S  
NORTHEAST TO THE MID TO UPPER 50S SOUTHWEST. THE NEXT SYSTEM WILL BE  
ARRIVING FRIDAY NIGHT WITH SHOWERS SPREADING OVER THE REGION. THERE  
IS PRETTY HIGH CONFIDENCE IN THE COVERAGE AND TIMING OF  
PRECIPITATION WHICH SHOULD CONTINUE THROUGH SATURDAY NIGHT. THOUGH  
RAINFALL AMOUNTS ARE EXPECTED TO BE UNDER A HALF INCH FOR THE EVENT,  
LIGHT SHOWERS WILL BE AROUND FOR ABOUT 24 TO 36 HOURS. TODAY THE  
GFS IS SHOWING A WEAKER SOLUTION WHILE THE EURO IS SLIGHTLY MORE  
DEVELOPED WITH THE LOW CROSSING JUST SOUTH OF THE STATE. LOWS OVER  
THE WEEKEND MAY NEED A SLIGHT ADJUSTMENT IF CLOUD COVERAGE REMAINS  
THICK ENOUGH. CURRENTLY THE MID 30S OVER THE NORTH MAY BE TOO LOW  
FOR SATURDAY AND SUNDAY MORNING. ONCE THE SYSTEM TRACKS EAST OF THE  
REGION BY MIDDAY SUNDAY, CLOUDS WILL BE ON THE DECREASE THROUGH  
SUNSET. MONDAY MORNING MAY BE ANOTHER PERIOD OF POTENTIAL FROST AS A  
RIDGE OF HIGH PRESSURE BUILDS INTO IOWA. A QUICK TRANSITION TO A  
SOUTHWEST FLOW BY AFTERNOON WITH DECENT MIXING WILL BRING WARM AND  
BREEZY CONDITIONS BACK TO THE AREA WITH AFTERNOON HIGHS WELL INTO  
THE 60S. THE WARMING TREND WILL CONTINUE INTO WEDNESDAY AS HIGHS ARE  
MAINTAINED IN THE 70S BOTH DAYS. OVERNIGHT MINS WILL MODERATE TO  
THE 40S TO AROUND 50 WITH NO PRECIPITATION EXPECTED DURING THE  
PERIOD.  
 

 
   
AVIATION
 
/FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING/  
ISSUED AT 725 PM CDT WED SEP 30 2020  
 
VFR CONDITIONS WITH LIGHTER WINDS EXPECTED THIS EVENING AND  
OVERNIGHT. NORTHERN SITES (KMCW AND KALO) WILL LIKELY DROP INTO  
MVFR CEILINGS WITH ANOTHER BOUNDARY APPROACHING THURSDAY MORNING  
THAT COULD ALSO BRING SOME VCSH TO BOTH SITES THROUGH MIDDAY.  
INCREASED MIXING AFTER SUNRISE WILL INCREASE WINDS AT ALL SITES  
FOR MOST OF THURSDAY WITH NW WINDS GUSTING TO NEAR 25 KTS.  
 

 
   
DMX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...REV  
LONG TERM...REV  
AVIATION...KCM  
 
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