454  
FXUS63 KDMX 171117  
AFDDMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DES MOINES IA  
617 AM CDT WED OCT 17 2018  
   
SHORT TERM
 
/TODAY THROUGH TONIGHT/  
ISSUED AT 342 AM CDT WED OCT 17 2018  
 
HIGH PRESSURE SITUATED OVER THE NORTHERN ROCKIES AND PLAINS STATES  
WILL CONTINUE TO BUILD INTO IOWA TODAY BECOMING CENTERED OVER THE  
STATE BY LATE AFTERNOON AND THEN PUSH JUST TO THE SOUTH TONIGHT.  
THIS WILL ALLOW FOR DRY AND SUNNY CONDITIONS ACROSS THE AREA TODAY.  
COOLER AIR IN INITIALLY IN PLACE TODAY WITH H85 TEMPS NEAR 0C, WITH  
WAA EXPECTED THROUGH THE DAY AS LOW/MID LEVEL WINDS SHIFT AROUND TO  
THE WEST TO SOUTHWEST THROUGH THE PERIOD. EXPECT HIGHS TO BE COOLER  
TOPPING OUT INTO THE 50S WITH LOWS BACK INTO THE 30S TONIGHT. SFC  
WINDS TO BE OUT OF THE NORTHWEST TODAY AND A LITTLE GUSTY, THEN  
DIMINISH TOWARD AFTERNOON AND START TO SHIFT AROUND TO THE SOUTH  
TONIGHT.  
   
LONG TERM
 
/THURSDAY THROUGH TUESDAY/  
ISSUED AT 342 AM CDT WED OCT 17 2018  
 
THURSDAY AND THURSDAY NIGHT WAS ARE AHEAD OF AN UPPER TROUGH AND  
SOUNDINGS SHOW A WELL MIXED FAIRLY DEEP SOUTHWEST FLOW OVER IOWA  
AHEAD OF THIS FEATURE. AT THE SURFACE, IOWA WILL BE WEDGED IN  
BETWEEN A LOW OVER CANADA THAT WILL ATTEMPT TO DROP A COLD FRONT  
INTO THE STATE AND HIGH PRESSURE OVER THE EAST CENTRAL CONUS. THE  
FLOW AROUND THIS HIGH WILL LIKELY COUNTER ANY EFFECTS OF THE COLD  
FRONT SO BOTH THURSDAY AND FRIDAY LOOK RELATIVELY WARM WITH HIGHS IN  
THE 60S. THURSDAY NIGHT THROUGH FRIDAY MORNING, THERE IS SPARSE BUT  
SUFFICIENT MOISTURE AND A FAIR AMOUNT OF FORCING WITH THE UPPER  
TROUGH TO KICK OFF SOME SPRINKLES OR LIGHT SHOWERS. REALLY NO  
CHANGE IN THIS PERIOD FROM THE PREVIOUS COUPLE OF FORECAST PACKAGES  
BUT WE ARE NOT REALLY LOOKING AT MUCH IMPACT.  
 
FRIDAY NIGHT AND SATURDAY THE UPPER TROUGH DEEPENS OVER THE GREAT  
LAKES WHILE ACROSS THE WEST, HIGH PRESSURE BUILDS OVER THE ROCKIES.  
THIS WILL PUT IOWA IN A DEEP NORTHWEST FLOW AND THIS WILL BE FELT AS  
TEMPERATURES WILL FALL BACK INTO THE 40S TO MID 50S FAR SOUTH. AT  
THE SURFACE, WE WILL BE UNDER HIGH PRESSURE. NOT REALLY SEEING MUCH  
IN THE WAY OF CLOUD COVER, DESPITE STRONG COLD ADVECTION, BUT IF  
SOUNDINGS ARE NOT PICKING UP MOISTURE THAT MAY BE AROUND, THEN WE  
COULD SEE MORE CLOUD COVER THAN WE CURRENTLY HAVE IN THE GRIDS.  
 
LATE SUNDAY THROUGH MONDAY, THE UPPER RIDGE SHIFTS MORE INTO THE  
PLAINS WHILE THE SURFACE HIGH SHIFTS ONCE AGAIN TO THE EASTERN U.S.  
BRINGING WARMER TEMPS BACK INTO IOWA. HIGHS WILL CLIMB BACK INTO  
THE MID 50S TO AROUND 60.  
 
MONDAY NIGHT AND TUESDAY, ANOTHER COLD HIGH WILL DROP A FRONT  
THROUGH THE REGION AND WHILE WE ARE NOT EXPECTING PRECIP WITH THIS,  
WE WILL ONCE AGAIN SEE SLIGHTLY COOLER HIGHS FOR TUESDAY/WEDNESDAY  
WITH READINGS MAINLY IN THE LOWER TO MID 50S...EXCEPT FOR THE SOUTH  
WHERE THERE WILL BE A FEW UPPER 50S. AS FOR OVERNIGHT LOWS...WE  
WILL MAINLY SEE LOWS TO MID 30S NORTH WITH UPPER 30S TO LOWER 40S  
SOUTH. SATURDAY NIGHT LOOKS TO BE THE COLDEST NIGHT WITH LOWS IN  
THE 20S. SINCE IOWA HAS SEEN A WIDESPREAD FREEZE, NO HEADLINES ARE  
ANTICIPATED FOR SATURDAY NIGHT.  
 

 
   
AVIATION
 
/FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING/  
ISSUED AT 617 AM CDT WED OCT 17 2018  
 
VFR CONDITIONS THROUGH THE FORECAST PERIOD. NORTHWEST WINDS TODAY  
TO BECOME LIGHT AND VARIABLE THIS EVENING AND SHIFT AROUND TO THE  
SOUTH TO SOUTHWEST LATE TONIGHT INTO THURSDAY.  
 

 
   
DMX WATCHES/WARNINGS/ADVISORIES
 
NONE.  
 

 
 

 
 
SHORT TERM...BEERENDS  
LONG TERM...FAB  
AVIATION...BEERENDS  
 
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