324  
FXUS63 KDMX 160906  
AFDDMX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DES MOINES IA  
406 AM CDT FRI MAY 16 2025  
   
KEY MESSAGES  
 
- STRONG AND GUSTY WINDS TODAY, WITH A WIND ADVISORY IN EFFECT ACROSS  
MUCH OF NORTHERN AND WESTERN IOWA.  
 
- LIGHT RAIN SHOWERS POSSIBLE (30-60%) MAINLY THIS MORNING TO  
AFTERNOON OVER PORTIONS OF NORTHERN INTO CENTRAL IOWA.  
OTHERWISE, THE FORECAST IS DRY UNTIL AT LEAST SUNDAY.  
 
- MORE ACTIVE WEATHER IS FORECAST SUNDAY INTO EARLY NEXT WEEK.  
SEVERE THUNDERSTORMS AND HEAVY RAIN MAY BE POSSIBLE DURING  
THIS PERIOD, BUT CONFIDENCE IS LOW.  
 
 
   
UPDATE  
 
ISSUED AT 406 AM CDT FRI MAY 16 2025  
 
FAIRLY QUIET CONDITIONS ACROSS IOWA ARE NOTED THIS MORNING, WITH  
WEST/SOUTHWEST WINDS LIGHT OVERALL BUT SOME LIGHT BREEZES HAVE  
INCREASED UP TO 15-20 MPH AT TIMES. SURFACE MAP ANALYSIS DEPICTS THE  
DEEP 982MB LOW PRESSURE SYSTEM CURRENTLY CENTERED OVER WESTERN  
MINNESOTA, WITH A TIGHT PRESSURE GRADIENT ACROSS MUCH OF THE UPPER  
MIDWEST. THIS SYSTEM IS STILL EXPECTED TO GRADUALLY TRACK WESTWARD  
OUT OF THE REGION THROUGH THE DAY, WHICH WILL BRING GUSTY WINDS  
ACROSS MUCH OF THE STATE GENERALLY AFTER SUNRISE AND THROUGH MUCH OF  
THE DAY. LATEST MODEL SOUNDINGS ARE TRENDING HIGHER ON THE POTENTIAL  
GUSTS, WITH VALUES AT THE TOP OF THE MIXED LAYER AROUND 40-45+ MPH  
AND AVERAGE VALUES GENERALLY AROUND 30-35+ MPH. WHILE THESE VALUES  
STILL LARGELY ARE SUGGESTED OVER MUCH OF WESTERN AND NORTHERN IOWA,  
SOUNDINGS AT KDSM AND KCSQ ARE SHOWING SIMILAR VALUES THROUGH THE  
COLUMN. THEREFORE HAVE INCREASED COVERAGE OF THE WIND ADVISORY TO  
INCLUDE POLK, MADISON, ADAMS, UNION, TAYLOR, AND RINGGOLD  
COUNTIES. THE STRONGEST WINDS GENERALLY LOOK TO OCCUR INTO THE  
LATE MORNING THROUGH THE AFTERNOON, DECREASING BY THE EVENING  
BUT STILL REMAINING BREEZY WITH GUSTS UP TO 25-30 MPH ACROSS THE  
STATE. ANOTHER NOTABLE ADDITION WITHIN THE CURRENT FORECAST  
PACKAGE IS THE ADDITION OF SPRINKLES AND LOW POPS TO PARTS OF  
CENTRAL IOWA AROUND SUNRISE UNTIL THE EARLY AFTERNOON TIMEFRAME  
AS A SHORTWAVE EJECTING OUT OF KANSAS QUICKLY PASSES OVERHEAD.  
DRY LOW LEVELS PER SOUNDINGS INDICATE THAT ANY RAIN THAT MAY  
FALL WOULD BE IN THE FORM OF VIRGA, WHICH ALSO MAY ENHANCE GUSTY  
WINDS AT TIMES DURING THE MORNING HOURS, WHICH ALSO PROMPTED  
THE EXPANSION OF THE CURRENT WIND ADVISORY. AS THE  
AFOREMENTIONED LOW PRESSURE SYSTEM TRACKS OUT OF THE REGION  
TODAY, A SLIGHT SOUTHWARD SHIFT IN ITS TRACK HAS ALSO LED TO AN  
EXPANSION OF POPS FURTHER SOUTH THIS AFTERNOON INTO THE EVENING,  
WHICH AGAIN WILL ADD ANOTHER WINDOW OF FURTHER ENHANCEMENT TO  
WIND GUSTS AS ANY RAIN WILL HAVE MUCH DRY AIR TO OVERCOME.  
 
BEYOND TODAY, NO MAJOR CHANGES TO NOTE WITH THIS FORECAST PACKAGE,  
AS DRY WEATHER AND SLIGHTLY COOLER TEMPERATURES IN THE 60S TO LOW  
70S ARE EXPECTED INTO THE WEEKEND. ACTIVE WEATHER LOOKS TO RETURN  
SUNDAY AS A LOW PRESSURE SYSTEM LIFTING NORTHEAST OUT OF THE DESERT  
SOUTHWEST TRACKS INTO THE CENTRAL PLAINS, WITH AN ACTIVE PATTERN  
CONTINUING THROUGH EARLY NEXT WEEK. MODEL MEMBERS ARE STILL VARIED  
ON THE OVERALL TRACK AND MAGNITUDE OF ACTIVITY WITH THESE SYSTEMS,  
BUT THE SIGNAL REMAINS FOR AT LEAST SOME RETURNING STORM CHANCES AND  
MORE APPRECIABLE RAINFALL AMOUNTS. CLOSE MONITORING WILL REMAIN WITH  
MORE DETAILS EXPECTED OVER THE NEXT FEW DAYS.  
 
 
   
DISCUSSION  
 
ISSUED AT 218 PM CDT THU MAY 15 2025  
 
TODAY'S WEATHER HAS UNFOLDED LARGELY AS FORECAST, WITH A LARGE  
CYCLONE STACKING AND DEEPENING OVER THE DAKOTAS AND MOVING  
QUICKLY NORTH NORTHEASTWARD TOWARD THE NORTH DAKOTA/MINNESOTA  
BORDER. A DRYLINE TRAILING FROM THE SYSTEM IS SPARKING STRONG  
THUNDERSTORMS OVER MINNESOTA, BUT THE BOUNDARY HAS ALREADY MOVED  
NORTHEAST OF OUR FORECAST AREA. AN AREA OF SCATTERED LIGHT  
SHOWERS IS MOVING ACROSS NORTHWESTERN IOWA AND MAY JUST CLIP  
AREAS AROUND ESTHERVILLE THIS AFTERNOON, BUT WITH NO IMPACT AND  
OTHER THAN THIS THE FORECAST IS DRY THROUGH TONIGHT AND INTO  
FRIDAY MORNING. HOWEVER, WITH A TIGHTENING PRESSURE GRADIENT AND  
DEEP MIXING WE ARE SEEING STRONG AND GUSTY WINDS SPREADING  
ACROSS OUR AREA AND THESE WILL CONTINUE UNTIL SUNSET WHEN THEY  
SHOULD DIMINISH SOMEWHAT AS MIXING DECREASES. THE CURRENT  
ADVISORY REMAINS IN EFFECT, AND WHILE A COUPLE OF REPORTING  
SITES OUTSIDE THE ADVISORY HAVE OCCASIONALLY REACHED CRITERIA,  
IT HAS NOT BEEN CONSISTENT OR WIDESPREAD ENOUGH TO WARRANT  
EXPANSION.  
 
OVERNIGHT TONIGHT, WHILE SURFACE WINDS DIMINISH SOMEWHAT, SOME  
SHORT-RANGE MODELS ARE TRACKING A VERY SUBTLE SHORTWAVE IMPULSE  
MOVING OVER CENTRAL IOWA AND PRODUCING SPOTTY LIGHT QPF.  
HOWEVER, FORECAST SOUNDINGS ARE QUITE DRY AND MOST SOLUTIONS  
REMAIN DRY, SO HAVE MAINTAINED POPS BELOW 10% ACCORDINGLY. ON  
FRIDAY THE STACKED AND SLOWLY FILLING LOW WILL DRIFT EASTWARD  
ACROSS NORTHERN MINNESOTA, WITH AN EXPANDING SHIELD OF STRATUS  
AND SHOWERS ADVANCING AROUND ITS SOUTHERN FLANK AND INTO OUR  
AREA FROM THE NORTHWEST. HAVE MAINTAINED POPS IN THAT AREA,  
DIMINISHING FROM LIKELIES (60-70% CHANCE OF RAIN) IN OUR  
NORTHWESTERN CORNER TO LOWER CHANCES (20-30%) NEAR THE HIGHWAY  
30 CORRIDOR AND JUST SPRINKLES SOUTH OF THAT. IN ANY EVENT, NO  
SIGNIFICANT RAINFALL OR THUNDER IS ANTICIPATED WITH THIS  
PRECIPITATION. OF GREATER CONSEQUENCE IS ANOTHER SURGE OF STRONG  
AND GUSTY WINDS DURING THE DAY, THIS TIME FROM THE WEST  
NORTHWEST. WHILE FORECAST SOUNDINGS INDICATE NOTABLY SHALLOWER  
AND LESS EFFICIENT MIXING BENEATH THE LOW CLOUD DECK, STRONGER  
WINDS JUST OFF THE DECK AND MODERATE COLD AIR ADVECTION WILL AID  
IN MOMENTUM TRANSPORT AND WE SHOULD SEE ADVISORY LEVEL WINDS  
ONCE AGAIN, PERHAPS EVEN OVER A SLIGHTLY LARGER AREA THAN TODAY.  
IN LIGHT OF THIS, AND WITH WINDS EXPECTED TO REACH CRITERIA IN  
OUR NORTHWESTERN COUNTIES JUST AFTER SUNRISE, HAVE ELECTED TO GO  
AHEAD AND ISSUE ANOTHER WIND ADVISORY NOW FOR FRIDAY,  
ENCOMPASSING THE SAME AREA AS TODAY'S ADVISORY PLUS SEVERAL MORE  
OF OUR SOUTHWESTERN COUNTIES. THIS MAY NEED TO BE EXPANDED OR  
TIME-ADJUSTED A BIT TONIGHT AS MORE DATA COMES IN.  
 
ON FRIDAY NIGHT, AS THE LARGE STORM SYSTEM MOVES AWAY OVER THE  
GREAT LAKES, WINDS SHOULD GRADUALLY DIMINISH AND CLOUDS AND ANY  
LINGERING SPRINKLES WILL MOVE OUT. THIS WILL GIVE WAY TO A BRIEF  
SPELL OF QUIET AND RELATIVELY COOL WEATHER AS A SURFACE HIGH  
PRESSURE RIDGE SLIDES ACROSS THE UPPER MIDWEST AROUND SATURDAY  
AND INTO SUNDAY. HIGH TEMPERATURES SATURDAY AFTERNOON WILL ONLY  
RANGE IN THE 60S TO LOWER 70S SOUTH, AND LOWS SUNDAY MORNING ARE  
FORECAST IN THE UPPER 30S NORTHEAST TO UPPER 40S SOUTH; A  
NOTABLE CHANGE FROM OUR LONG RECENT SPELL OF UNSEASONABLE  
WARMTH.  
 
BY SUNDAY MORNING THE NEXT STORM SYSTEM WILL BE TAKING SHAPE AS  
A 500 MB TROUGH DIGS DOWN OVER THE WESTERN U.S. AND ROCKIES. A  
REINFORCING VORTICITY MAXIMUM WILL MOVE FROM AROUND SEATTLE DOWN  
INTO THE LARGER TROUGH DURING THE DAY ON SUNDAY, AND THE ENTIRE  
SYSTEM WILL THEN MOVE EASTWARD TOWARD THE MIDWEST AND IOWA IN  
THE EARLY PART OF NEXT WEEK. HOWEVER, THE INTERACTION BETWEEN  
THE TWO VORTICITY MAXIMA WOBBLING AROUND THE LARGER CYCLONIC  
FLOW IS NOT BEING WELL-RESOLVED BY THE LONG RANGE MODELS,  
RESULTING IN DIFFERENCES BETWEEN SOLUTIONS THAT COULD HAVE  
SIGNIFICANT IMPLICATIONS FOR HAZARDOUS WEATHER POTENTIAL IN OUR  
SERVICE AREA. IT IS LIKELY THAT AN INITIAL SURGE OF THETA-E AND  
MOISTURE ADVECTION, ALONG THE INFLECTION ZONE WHERE 500 MB FLOW  
TURNS TO SOUTHWESTERLY IN ADVANCE OF THE APPROACHING SYSTEM,  
WILL PRODUCE A SWATH OF RAIN MOVING ACROSS IOWA FROM SOUTHWEST  
TO NORTHEAST ON SUNDAY NIGHT OR MONDAY. HOWEVER, POTENTIAL FOR  
HEAVY RAIN OR SEVERE WEATHER IS UNCLEAR AT THIS TIME, AS IS THE  
TIMING OF THIS PROGRESSION. AFTER THAT CONFIDENCE STEADILY  
DECREASES AS THE LARGE, DISCOMBOBULATED TROUGH APPROACHES. LONG  
RANGE MODELS HAVE BEEN TRENDING SLOWLY BUT STEADILY SOUTHWARD  
WITH HEAVY RAIN AND THUNDERSTORM CHANCES SINCE YESTERDAY, BUT  
STILL KEEP THESE OVER OR JUST SOUTH OF SOUTHERN IOWA AND HAVE  
MAINTAINED HIGH (70-80%) POPS MONDAY NIGHT AND TUESDAY FOR NOW,  
TAPERING OFF THEREAFTER AS THE LARGE SYSTEM MOVES AWAY TO THE  
EAST. DESPITE THE MAINTENANCE OF HIGH POPS IN A DESIRE FOR  
FORECAST CONSISTENCY, OVERALL CONFIDENCE IN THE EVOLUTION OF  
THIS SYSTEM HAS FADED, AND WILL NEED TO WAIT FOR BETTER  
RESOLUTION OF THIS SCENARIO BEFORE ADDITIONAL DETAILS CAN BE  
SUSSED OUT. NEVERTHELESS, CERTAINLY THE POTENTIAL FOR SEVERE  
THUNDERSTORMS AND/OR HEAVY RAIN REMAINS FOR OUR AREA EARLY NEXT  
WEEK, AND SHOULD BE MONITORED OVER THE NEXT SEVERAL DAYS.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/  
 
ISSUED AT 1248 AM CDT FRI MAY 16 2025  
 
CLOUDS ARE EXPECTED TO GRADUALLY SINK SOUTH ACROSS THE STATE  
THROUGH TODAY, WHICH WILL GRADUALLY LEAD TO LOW CEILINGS LATE  
MORNING TO AFTERNOON ACROSS THE NORTHERN TERMINALS AND INTO  
CENTRAL IOWA BY THIS EVENING. THE LOW POTENTIAL REMAINS FOR RAIN  
SHOWERS MAINLY ACROSS THE NORTHERN TERMINALS AS THE SYSTEM  
PASSES THROUGH, THOUGH CONFIDENCE IS NOT HIGH ENOUGH TO GO  
BEYOND PROB30 MENTIONS SO HAVE REMAINED WITH WHAT THE PREVIOUS  
FORECAST HAD FOR MENTIONS AND WILL CONTINUE TO MONITOR. WINDS  
WILL BE QUITE GUSTY, WITH VALUES UP TO 35+ KNOTS FOR MUCH OF THE  
AREA LATE THIS MORNING AND THROUGH THE AFTERNOON.  
 
 
   
DMX WATCHES/WARNINGS/ADVISORIES  
 
WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR IAZ004>007-  
015>017-023>026-033>037-044>048-057>060-070>072-081-082-092-  
093.  
 
 
 
 
 
UPDATE...BURY  
DISCUSSION...LEE  
AVIATION...BURY  
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