784
FXUS63 KDMX 240016
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
ISSUED BY NATIONAL WEATHER SERVICE DULUTH MN
716 PM CDT WED APR 23 2025
...UPDATED FOR THE 00Z AVIATION DISCUSSION...
KEY MESSAGES
- A MARGINAL RISK FOR SEVERE WIND AND HAIL AS STORMS REDEVELOP
THIS EVENING ACROSS CENTRAL AND SOUTHERN IOWA.
- MORE WIDESPREAD RAIN ON THURSDAY WITH OVER AN INCH EXPECTED
AND SOME MORE ISOLATED LOCATIONS SEEING OVER AN INCH.
DISCUSSION
ISSUED AT 326 PM CDT WED APR 23 2025
MORNING SHOWERS & THUNDERSTORMS HAVE DISSIPATED AND LEFT BEHIND
PARTLY CLOUDY SKIES FOR MUCH OF IOWA. MODEST INSTABILITY REMAINS IN
PLACE AND OUR QUASI-STATIONARY BOUNDARY WILL GRADUALLY LIFT NORTH
OVER THE NEXT 24 HOURS. ADDITIONAL THUNDERSTORM & SHOWER DEVELOPMENT
WILL BEGIN THIS EVENING INTO THURSDAY. SPC'S SWO DAY 1 MAINTAINS A
MARGINAL RISK (1 OUT OF 5) FOR A FEW STRONG TO SEVERE STORMS THAT
MAY BE CAPABLE OF PRODUCING ISOLATED GUSTY WINDS & LARGE HAIL,
SIMILAR TO WHAT WE SAW YESTERDAY EVENING. FORECAST SOUNDINGS WOULD
INDICATE OUR MUCAPE DROPS OFF AFTER 03Z TONIGHT & ANY SEVERE WEATHER
THREAT LIKELY TAPERS OFF TOO.
THURSDAY & FRIDAY CONTINUE THE THEME OVER THE PAST FEW DAYS WITH A
RATHER GLOOMY OUTLOOK THAT FEATURES ADDITIONAL RAIN & STORM CHANCES.
THE CULPRIT SHORTWAVE TROUGH WILL EJECT OUT OF THE PLAINS ON
THURSDAY. THIS WILL PROMPT THE SFC LOW OVER THE WESTERN OK TO MOVE
NORTHEAST TOWARDS THE GREAT LAKES REGION THURSDAY AFTERNOON. AN
SUBTLE INCREASE IN MOISTURE WILL OCCUR AHEAD OF THIS LEADING TO PWAT
VALUES 1.0-1.2" THURSDAY PM. THE SFC LOW WILL STRUGGLE AS A SFC HIGH
PRESSURE DROPS INTO THE NORTHERN PLAINS AND ACTS TO SUPPRESS OUR SFC
LOW. ENOUGH FORCING WILL BE PRESENT TO BRING A MORE ORGANIZED ROUND
OF SHOWERS & THUNDERSTORMS THURSDAY AFTERNOON INTO EARLY FRIDAY.
PRECIPITATION AMOUNTS OVER THE NEXT 48 HOURS OF AN INCH OR MORE SEEM
LIKELY FOR MUCH OF IOWA. SEVERE WEATHER POTENTIAL THURSDAY AND
THURSDAY NIGHT WILL BE VERY LOW AS THIS BECOMES A STRATIFORM-DRIVEN
RAIN EVENT VS A CONVECTIVE RAIN EVENT. PRECIPITATION WILL EXIT AS
THE SFC LOW SHIFTS INTO THE SOUTHERN GREAT LAKES ON FRIDAY AND WILL
LEAVE BEHIND DRIER WEATHER & SEASONABLE TEMPERATURES FOR FRIDAY &
SATURDAY.
SUNDAY & MONDAY WILL SEE THE SFC HIGH PRESSURE MOVE EAST INTO THE
EASTERN CONUS. THIS WILL ALLOW FOR SOUTHERLY RETURN FLOW SET UP OVER
IOWA AND BEGIN TO USHER IN MOISTURE & WARMER TEMPERATURES. THIS WILL
LEAD TO MORE SHOWER AND STORM CHANCES RETURNING SUNDAY INTO MONDAY.
OUR PATTERN REMAINS FAIRLY ACTIVE INTO NEXT WEEK, WITH SPC
MAINTAINING A DAY 6 15% RISK (SLIGHT RISK) FOR SEVERE WEATHER MONDAY
INTO TUESDAY AS A WOUND UP LOW PRESSURE LIFTS INTO THE AREA. MORE ON
THIS SYSTEM WILL BE PROVIDED IN THE COMING DAYS.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 707 PM CDT WED APR 23 2025
A DIFFUSE NEARLY STATIONARY FRONT STRETCHED SOUTHWEST TO
NORTHEAST FROM NEAR OMA TO NEAR ALO TO NEAR PDC AS OF 00Z.
SHOWERS AND THUNDERSTORMS DEVELOPED THIS AFTERNOON AND WILL
PERSIST THROUGH TONIGHT. HAIL OF HALF-INCH TO 1.5 INCH DIAMETER
IS POSSIBLE AT THE SURFACE AND ALOFT WITH THE STRONGEST STORMS.
EXPECT MVFR CIGS WITH STORMS. VISIBILITY MAY BRIEFLY FALL TO IFR
OR LIFR WITH STORMS. RAIN AND STORM ARE EXPECTED TO TAPER OFF
AFTER SUNRISE THURSDAY MORNING. ANOTHER ROUND OF RAIN AND STORMS
IS FORECAST LATE THURSDAY MORNING THROUGH THE EVENING.
HYDROLOGY
ISSUED AT 326 PM CDT WED APR 23 2025
WIDESPREAD RAINFALL EXPECTED ACROSS CENTRAL IOWA (80-90%)
THURSDAY CONTINUES TO SIGNAL AN INCREASING POTENTIAL FOR
ADDITIONAL RAINFALL TOTALS AROUND AN INCH, WITH AN ISOLATED
HIGHER AMOUNT NEAR 1.5’’ ACROSS CENTRAL AND NORTHERN IOWA. RIVER
RESPONSES PER HEFS GUIDANCE SUGGESTS THAT A RISE ABOVE ACTION
STAGE IS LIKELY (70-90%) AT SHELL ROCK AND CEDAR RIVERS THURSDAY
INTO FRIDAY. THOUGH THE LIKELIHOOD FOR ADDITIONAL SITES TO SEE
RIVER FLOW EXCEEDANCE IS ON THE LOWER END (<=30) AT THE IOWA
RIVER, DES MOINES RIVER, AND RACCOON RIVER, RISES AT AND ABOVE
THE ACTION STAGE THRESHOLD IF HIGHER RAINFALL AMOUNTS WERE TO
OCCUR. CLOSE MONITORING WILL CONTINUE TO WATCH FOR THIS
POTENTIAL.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...BPH
AVIATION...HUYCK
HYDROLOGY...BURY
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