965
FXUS63 KDMX 070351
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1051 PM CDT MON JUL 6 2026
...UPDATED FOR THE 06Z AVIATION DISCUSSION...
KEY MESSAGES
- QUIET, SUMMER-LIKE CONDITIONS EXPECTED TODAY AND TUESDAY.
PATCHY FOG MAY DEVELOP OVERNIGHT INTO TUESDAY MORNING.
- WARMER TEMPERATURES IN THE UPPER 80S AND 90S ON WEDNESDAY,
WITH THUNDERSTORM AND HEAVY RAIN CHANCES RETURNING WEDNESDAY
NIGHT INTO THURSDAY AND POTENTIALLY FRIDAY.
- WARMER AND DRIER CONDITIONS DEVELOP LATE THIS WEEKEND INTO
EARLY NEXT WEEK.
SHORT TERM /THROUGH WEDNESDAY/
ISSUED AT 245 PM CDT MON JUL 6 2026
DRY AND OVERALL PLEASANT CONDITIONS ARE IN PLACE OVER IOWA TODAY
THANKS TO SURFACE HIGH PRESSURE OVERHEAD. WINDS HAVE BEEN CALM
TO LIGHT, WITH CUMULUS CLOUDS SPECKLING THE SKIES AT THE TOP OF
THE MIXED BOUNDARY LAYER. AT THE UPPER LEVELS, RIDGING IS IN
PLACE OVER IOWA AS A SHORTWAVE TROUGH HAS STALLED OUT TO OUR
SOUTH, KEEPING THE GULF MOISTURE STREAM DISRUPTED. FARTHER
NORTH, WEAK ENERGY TOPPING THE BROAD, WESTERN CONUS RIDGE IS
EXPECTED TO PRODUCE THUNDERSTORMS ALONG A SOUTHWEST TO NORTHEAST
ORIENTED BOUNDARY OVER THE DAKOTAS AND MINNESOTA TONIGHT INTO
TUESDAY. THIS ACTIVITY IS EXPECTED TO GENERALLY STAY TO THE
NORTH OF OUR FORECAST AREA, BUT THERE ARE A FEW MODEL SOLUTIONS
THAT BRING THE OUTFLOW FROM THESE STORMS DOWN INTO FAR
NORTHWESTERN IOWA. WITH THE HIGH PRESSURE OVERHEAD, GENERAL
SUBSIDENCE AND DIMINISHING INSTABILITY WILL LIKELY WORK TO
DISSIPATE UPDRAFTS AS THIS OUTFLOW WORKS SOUTHWARD, SO HAVE KEPT
THE FORECAST DRY AT THIS TIME, BUT WILL BE MONITORING FOR ANY
ACTIVITY PERSISTING INTO THE AREA EARLY TUESDAY MORNING.
OUTSIDE OF ANY CONVECTIVE DEBRIS LEAKING INTO NORTHERN IOWA EARLY
TUESDAY MORNING, SKIES WILL GENERALLY REMAIN CLEAR WITH LIGHT WINDS
OVERNIGHT. THIS, COMBINED WITH DEWPOINTS STILL IN THE MID 60S, WILL
FAVOR MORE PATCHY FOG DEVELOPMENT AS TEMPERATURES COOL PRIOR TO
SUNRISE EARLY TUESDAY MORNING. MODEL GUIDANCE IS GENERALLY FAVORING
THE EASTERN PORTIONS OF THE STATE WHERE WINDS WILL BE RELATIVELY
LIGHTER, BUT COULD CERTAINLY SEE SHALLOW FOG IN LOW LYING AREAS
THROUGH MUCH OF CENTRAL IOWA. THE SURFACE HIGH GENERALLY STICKS
AROUND THROUGH TUESDAY, MAINTAINING THE WARM AND DRY CONDITIONS
TOMORROW.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
ISSUED AT 245 PM CDT MON JUL 6 2026
THE UPPER LEVEL WAVE TO OUR SOUTH AND SURFACE HIGH OVERHEAD WILL
BEGIN TO DEPART EASTWARD ON TUESDAY, BRINGING SOUTHERLY RETURN FLOW
BACK UP INTO IOWA TUESDAY NIGHT THROUGH WEDNESDAY. THE RESULT WILL
FIRST BE WARMER TEMPERATURES WITH HIGHS IN THE UPPER 80S TO LOW 90S
ON WEDNESDAY. THE UPPER LEVEL PATTERN WILL BEGIN TO TRANSITION TO
MORE ZONAL FLOW THROUGH THIS SAME PERIOD AND THE BOUNDARY TO OUR
NORTHWEST WILL BEGIN TO SINK SOUTH AND EAST TOWARDS THE STATE. WEAK
ENERGY WORKING THROUGH THE ZONAL FLOW WILL DEVELOP SHOWER AND
THUNDERSTORM CHANCES ALONG SAID BOUNDARY STARTING LATE WEDNESDAY AND
LASTING INTERMITTENTLY OVER IOWA INTO THURSDAY MORNING. PLENTY
OF MOISTURE (2"+ PRECIPITABLE WATER VALUES) AND INSTABILITY
(~1500 TO 2500+ J/KG OF MUCAPE) WILL BE PRESENT OVER IOWA DURING
THIS SAME TIME, ALTHOUGH SHEAR WILL BE MINIMAL (20 TO 30 KTS OF
0-6 KM SHEAR), SUGGESTING UPDRAFTS MAY STRUGGLE TO BECOME
ORGANIZED. LIKEWISE, WHILE THERE DOES APPEAR TO BE WEAK ENERGY
MOVING THROUGH THE ZONAL FLOW, THE FORCING IS UNIMPRESSIVE FOR
MOST OF THE AREA, BARRING SOUTHWEST IOWA WHERE THE LOW LEVEL JET
IS EXPECTED TO NOSE INTO OVERNIGHT. THIS JET COULD PROVIDE SOME
EXTRA LIFT FOR STORMS THROUGH CENTRAL AND SOUTHERN IOWA
WEDNESDAY NIGHT INTO THURSDAY, BUT OTHER AREAS MAY NEED A BIT
MORE JUICE TO KICK THINGS OFF. THEREFORE, THE MAIN CONCERN AT
THIS TIME IS THE POTENTIAL FOR HEAVY RAINFALL FUELED BY THIS LOW
LEVEL JET. SEE HYDRO DISCUSSION BELOW.
THE PATTERN REMAINS ACTIVE THROUGH THE END OF THE WEEK, WITH ANOTHER
SHORTWAVE SLATED TO MOVE THROUGH THE MIDWEST FRIDAY, ALBEIT WITH
MORE UNCERTAINTY ON EXACT TRACK AND EVOLUTION. HOWEVER, BY THIS
WEEKEND MODELS SHOW GOOD CONSENSUS OF A BROAD UPPER LEVEL RIDGE
SPANNING MUCH OF THE WESTERN AND CENTRAL US. THIS REGIME WOULD LEND
ITSELF TO WARMER TEMPERATURES AND DRIER CONDITIONS FOR IOWA LATE
THIS WEEKEND AND INTO EARLY NEXT WEEK.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1046 PM CDT MON JUL 6 2026
TRENDED MORE AGGRESSIVE FOR FOG THIS ISSUANCE AS CLOUD COVER
WILL BE DELAYED IN REACHING MOST TAF SITES. CONFIDENCE HAS
INCREASED IN RIVER VALLEY FOG AT KFOD DUE TO LESS CLOUDS AND
HAVE REFLECTED TRANSIENT LIFR CONDITIONS TYPICALLY SEEN THERE.
KDSM WILL HAVE A SHORT WINDOW OF MVFR VSBYS FROM FOG. HIGHEST
CONFIDENCE IN FOG WILL BE AT KALO AND KOTM WITH IFR VSBYS
POSSIBLE WITHIN 2 HOURS OF SUNRISE.
HYDROLOGY
ISSUED AT 245 PM CDT MON JUL 6 2026
RIVERS AND STREAMS IN CENTRAL IOWA CONTINUE TO SEE INCREASED
FLOW AS WATER FROM THE HEAVY RAINS LATE LAST WEEK AND THIS
WEEKEND CONTINUES TO ROUTE THROUGH THE SYSTEM. TWO RIVERS IN
CENTRAL IOWA MAINTAIN FLOOD WARNINGS AT THIS TIME. THE FIRST IS
THE SOUTH SKUNK RIVER NEAR COLFAX (CFXI4) WHICH IS ACTIVELY
CRESTING AT MODERATE FLOOD STAGE AND EXPECTED TO FALL BELOW
FLOOD STAGE TOMORROW. THIS PORTION OF THE SOUTH SKUNK RIVER
FLOWS INTO THE OSKALOOSA (OOAI4) AREA, BUT THIS POINT SHOULD
REMAIN BELOW IT'S MINOR FLOOD STAGE. THE IOWA RIVER NEAR TAMA
(TMAI4) ALSO MAINTAINS A FLOOD WARNING AS IT CONTINUES TO
SLOWLY RISE, WITH AN EXPECTED TO CREST AT OR JUST BELOW MINOR
FLOOD STAGE TODAY. OTHER RIVERS WITHIN THE DES MOINES AND CEDAR
RIVER BASINS ARE ALSO AT INCREASED LEVELS AS WATER WORKS IT'S
WAY DOWN STREAM, ALBEIT ALL BELOW FLOOD STAGE AND CONTINUING TO
RECEDE.
ADDITIONAL RAINFALL LATER THIS WEEK, ESPECIALLY WEDNESDAY EVENING
THROUGH FRIDAY, COULD LEAD TO SLOWER IMPROVEMENT AND/OR ADDITIONAL
RISES ON AREA RIVERS, DEPENDING ON WHAT BASINS THIS RAIN AFFECTS.
THE EXACT CORRIDOR OF THE HEAVIEST RAIN IS STILL UNCERTAIN, BUT WILL
BE MONITORING CLOSELY THROUGH THE COMING DAYS.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...DODSON
LONG TERM...DODSON
AVIATION...JIMENEZ
HYDROLOGY...DODSON
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page