Marine Weather and Tide Forecast for Delwood, WI

DISCUSSION
Issued at 309 AM CDT Wed Apr 30 2025

Today-Friday: Near Normal Temperatures, Periodic Rain and Thunderstorm Chances:

Ahead of an approaching upper level low from the southern Plains and a shortwave trough dipping down into the Upper Midwest, southwest flow aloft is over the area through the day. This will help mix us out a little and as a result, high temperatures warm into mid to upper 60s. Rain chances increase during the afternoon across northeast Iowa, southeast Iowa, and southwestern Wisconsin as the upper level low shoots off some shortwave impulses into the area.
Initially the lower levels will be drier and may take a couple hours to saturate enough for the rain to reach the surface. Some light rain showers will be possible until enough saturation takes place. A few thunderstorms will also be possible this evening through Thursday evening primarily along and south of I-90 as 100-300 J/kg of MUCAPE moves into the area. There is still some uncertainty in the CAMs as far as coverage of these showers and thunderstorms and where the higher rain totals will be located at.

After Thursday evening, the upper level low moves off to the northeast and we transition to northwest flow aloft as the shortwave trough shifts into our region. This will give the area 20 to 40% chance at some showers for Friday. All precipitation chances are expected to diminish by evening. Overall rain amounts have changed slightly for the forecast area with locations to the north of I-94 receiving 0.1" to 0.25" and locations to the south of I-94 potentially receiving anywhere from 0.25" to 0.4". High temperatures for Thursday and Friday cool slightly compared to today, ranging from the upper 50s to mid 60s.

Saturday-Early Next Week: Warmer Temperatures and Drier?

Once the trough moves off to the east, ridging builds into the area.
While the region remains in northwest flow, temperatures only warm slightly compared to Friday, into the mid to upper 60s, however by Sunday and early next week, southwest flow returns and helps to warm our temperatures into the mid to upper 70s and even near 80 degrees for some locations. Dry conditions are expected for the weekend.
There are some differences in the deterministic models on how early next week pans out. The EC and CMC have an omega block pattern over the central US from Saturday through Wednesday while the GFS brings a shortwave on Monday and shortwave impulses for Tuesday and Wednesday that could increase precipitation chances. Current ensemble guidance does have a low chance for rain to return early next week, however it is roughly 20-30% of all ensemble members. The majority of ensemble members keep us dry through at least the middle of next week.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
Issued at 525 AM CDT Wed Apr 30 2025

VFR conditions throughout the daytime hours will give way to MVFR and eventually IFR cigs overnight. Winds will remain around 8-12 kts during the afternoon before diminishing and switching to the east with sct to bkn high clouds. As a weather system approaches the area, cigs will decrease to MVFR (70-90% chance in the 30.00z HRRR)
and eventually IFR (50-80% chance in the 30.00z HRRR) by 12z.
Additionally, scattered to numerous showers will move into the area with visibility reductions to MVFR and perhaps IFR at times.

ARX WATCHES/WARNINGS/ADVISORIES
WI...None.
MN...None.
IA...None.