050  
FXUS63 KDMX 251152  
AFDDMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DES MOINES IA  
652 AM CDT SAT JUN 25 2016  
   
..UPDATED FOR 12Z AVIATION DISCUSSION
 
 
   
SHORT TERM
 
/TODAY/  
ISSUED AT 346 AM CDT SAT JUN 25 2016  
 
ONGOING PRECIP WITH ISO THUNDER ACROSS THE SW PORTION OF THE DMX CWA  
AS A WAVE OF THETA-E PUSHES NORTHWESTWARD. ALIGNED WELL WITH THIS  
BOUNDARY IS THE NOSE OF A 35KT LLJ. APPEARS TO BE SUFFICIENT  
ISENTROPIC UPGLIDE WITH THIS SETUP TO KEEP PRECIP FIRING THROUGH AT  
LEAST THE 12Z-14Z TIMEFRAME.  
 
AFOREMENTIONED BOUNDARY TIED IN WITH A DEEP, NEGATIVELY TILTED LOW  
PRESSURE SYSTEM WHICH WILL BE PROPAGATING ACROSS MANITOBA. LLJ  
CONTINUES TO BE WELL-ALIGNED WITH THIS LOW ALL THE WAY UP INTO  
CANADA, WHICH WILL HELP ABUNDANT MOISTURE SURGE INTO IA AS THE GULF  
WILL BE OPEN. CWA WILL BE UNCAPPED DURING THE DAYTIME HOURS, BUT  
LACK OF ANY FOCUSING MECHANISM WILL PRECLUDE THUNDERSTORM  
DEVELOPMENT.  
 
MAIN SHOW ARRIVES LATE AFTERNOON/EARLY EVENING AS AN ATTENDANT  
BOUNDARY WILL DRAPE DOWN ALL THE WAY THROUGH WESTERN IOWA INTO  
NEBRASKA. TIMING OF THE BOUNDARY IMPORTANT WITH PEAK HEATING, AS  
THIS WILL BE THE TARGET AREA FOR INITIATION. MODELS COMING INTO  
AGREEMENT WITH THIS AREA BEING IN WESTERN IA, CLIPPING THE DMX CWA  
ROUGHLY WEST OF I-35 AND NORTH OF I-80 BY 00Z SUN. SEVERE THREAT  
CERTAINLY EXISTS WITH SUFFICIENT CAPE/INSTABILITY. 0-6KM BULK SHEAR  
VALUES OF 20 TO 25 KTS NOT THE GREATEST, HOWEVER, SUFFICIENT. STRONG  
WAA WITH 12Z 850MB TEMPS IN THE 19C TO 22C RANGE WILL MAKE FOR  
ANOTHER HOT DAY IN THE MID 80S TO LOW 90S ACROSS CENTRAL IOWA.  
   
LONG TERM
 
/TONIGHT THROUGH FRIDAY/  
ISSUED AT 346 AM CDT SAT JUN 25 2016  
 
MAIN FOCUS THROUGHOUT THE MID/LONG RANGE WILL BE ON THUNDERSTORM  
CHANCES TONIGHT. AN UPPER LEVEL LOW WILL CONTINUE TO PUSH EAST  
THROUGH THE SOUTHERN CANADIAN PRAIRIE PROVINCES TODAY INTO TONIGHT,  
WITH AN ASSOCIATED AREA OF SFC LOW PRESSURE CURRENTLY SITUATED  
ACROSS THE DAKOTAS INTO NE/KS. THE AREA OF LOW PRESSURE WILL SLIDE  
ESE THROUGH THE DAY INTO TONIGHT PUSHING INTO THE GREAT LAKES REGION  
BY EARLY MONDAY. THE SFC TROUGH AXIS AND WEAK COOL FRONT WILL DROP  
THROUGH THE CWA TONIGHT, WITH THUNDERSTORM DEVELOPMENT EXPECTED  
ALONG AND AHEAD OF THE BOUNDARY. CAPE VALUES CLIMB TO AROUND 2-3K  
J/KG BY THIS AFTERNOON, HOWEVER DEEP LAYER SHEAR WILL BE QUITE WEAK.  
THIS WILL LIMIT THE SEVERE POTENTIAL SOME, AND ALLOW FOR MORE OF A  
WIND/HAIL THREAT. STORM MOTIONS TO BE SLOWER AS WELL AND SOMEWHAT  
PARALLEL TO THE BOUNDARY. GIVEN THE HIGHER FREEZING LEVELS AROUND  
14KFT, THE SLOWER STORM MOTION AND HIGH PWATS APPROACHING 2 INCHES,  
THERE WILL BE A THREAT OF HEAVY RAIN AS WELL. FFG IS LOWEST IN THE  
NORTHEAST WHERE HEAVIER RAINFALL AMOUNTS HAVE FELL IN THE PAST 1-2  
WEEKS, BUT STILL PUSHING 2-2.5 INCHES FOR 6 HOURS. THEREFORE WILL  
NOT ISSUE ANY FF HEADLINES FOR NOW, AS CROPS REALLY GETTING GOING AS  
WELL WHICH ALSO HELPS SOAK UP HEAVIER RAINFALL WITH LESS RUNOFF INTO  
AREA CREEKS AND STREAMS. EXPECT A LINE OF STORMS TO MOVE THROUGH THE  
CWA THROUGHOUT THE EVENING/OVERNIGHT HOURS WITH MAINLY DRY  
CONDITIONS INTO SUNDAY AS AN AREA OF HIGH PRESSURE BUILDS INTO THE  
STATE.  
 
NORTHWEST UPPER LEVEL FLOW PATTERN THEN IN PLACE INTO NEXT WEEK,  
WITH ANOTHER COLD FRONT TO DROP THROUGH THE STATE MONDAY INTO MONDAY  
NIGHT. A LARGE AREA OF COOL CANADIAN HIGH PRESSURE TO BUILD INTO THE  
STATE TOWARD MID-WEEK, WITH H85 TEMPS DROPPING TO AROUND +10C. THIS  
SHOULD BRING IN A FEW DAYS OF COOLER, MORE SEASONAL TEMPERATURES. A  
SERIES OF WEAK SHORTWAVES THEN TOP THE WESTERN US UPPER RIDGE BY THE  
END OF THE WEEK INTO NEXT WEEKEND, AND DROP SOUTHEASTWARD THROUGH  
THE CWA. THIS COULD BRING A FEW SCATTERED CHANCES FOR SHOWERS AND  
THUNDERSTORMS TO END THE UPCOMING WEEK. TEMPERATURES WILL ALSO  
REBOUND SOME BACK INTO THE MID 80S BY NEXT WEEKEND.  
 

 
   
AVIATION
 
/FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING/  
ISSUED AT 647 AM CDT SAT JUN 25 2016  
 
CONFIDENCE INCREASING FOR OCCURRENCE OF TSRA DURING THE LATE  
AFTERNOON TO EVENING HOURS. WILL HAVE TO FINE TUNE TIMING OF  
ARRIVAL, TIMING OF DEPARTURE, AND HOW LOW VSBYS WILL BECOME DURING  
PERIODS OF HEAVIER RAIN. 18Z TAFS SHOULD HAVE MORE SPECIFICS. MAY  
NEED TO LOWER TO AT LEAST IFR AS VSBYS COULD REACH 2 SM OR LESS.  
CONDITIONS EXPEXCTED TO BE IN VFR AGAIN TOWARDS THE END OF THIS  
TAF PERIOD.  
 

 
   
DMX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...KOTENBERG  
LONG TERM...BEERENDS  
AVIATION...KOTENBERG  
 
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