Marine Weather and Tide Forecast for Boscobel, WI

DISCUSSION
Issued at 245 AM CDT Fri May 16 2025

TODAY-TONIGHT: Windy. Scattered to areas of showers.

The upper level closed low is edging into western MN early this morning, shifting over northern WI this evening. Lobes of shortwave energy will rotat
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
Issued at 631 PM CDT Thu May 15 2025

Strong subsidence and steep 1000-700 mb lapse rates will continue to mix strong southwest winds to the surface. Sustained winds will range from 25 to 35 knots with gusts to 50 knots. These winds have been picking up dust from recently plowed farm fields and lowering visibilities to 2 miles or less at times.

As diurnal mixing occurs on Friday, the sustained southwest winds will range from 20 to 30 knots and gust from 30 to 45 knots during the late morning and afternoon.e around the low while short term guidance also favors streaking a weak ripple from the southern plains to across southern WI by the afternoon. Add in favorable low level lapse rates and ample saturation and scattered to areas of showers will be the result. The instability axis is shifting east so not anticipating much/if any thunder threat.

Currently across SD, just west of the sfc low center, winds are gusting in the upper 30s/lower 40s mph. That low shifts over northern WI this evening, but is progged to undergo some weakening as it does. Low level winds become unidirectional across the forecast area this morning, promoting deep mixing upwards of 9 kft at times. RAP/HRRR suggest winds at the top of the mix layer could flirt with the upper 50s/60 kts, but only briefly. Generally, both bring upper 30s to near 40 kts to the sfc via momentum transfer, topping gusts out in the lower 40s mph. Flirting with wind advisory criteria, but mostly below. However, if the EC is to be believed, the wind prone areas west of the Mississippi River will be gusting well into the 50s mph (almost 10% of its members reach 60 at KRST).
EFIs for wind gusts continue 0.8 to 0.9 today with SoT of 1. The EPS has been running "hot" when it comes to winds and doesn't have a lot of support from the other short/medium range guidance. The GEFS, for instance, has only 20% of its members reaching 45 mph at KRST.
Latest HRRR suggests approx 40-80% for 40 mph gusts for much of the forecast area, but only spotty 10-20% to exceed 45.

Tossing a lot of numbers, percentages out there...presenting a muddy picture. Sensible outcomes say it's going to be windy eitherway. For now, per coordination with surrounding offices, will hold of an advisory. Will keep a close eye on evolution/sfc observations through the day, adjusting forecast and potential headline needs if warranted.

- WEEKEND: cooler, lingering showers Saturday. Sunday dry, sunny with much lighter winds.

The upper level closed low will be across Mich Sat morning, exiting over the eastern Great Lakes by Sat evening. Cyclonic flow, lingering bits of shortwave energy, potentially a westward hanging sfc trough along with favorable low level lapse rates will continue a smattering of showers Sat - mostly across WI. These should all exit east by the evening. A shortwave ridge a loft moves in for Sunday, bringing the weekend to a dry, less windy, mostly sunny and seasonable close.

- START OF NEW WORK WEEK: periods of showers

GEFS and EPS have been favoring bringing a longwave trough from off the west coast this weekend, moving it over the mid mississippi river valley by Tue morning. Bits of shortwave energy will pinwheel around the trough. Fairly messy setup as there will be a few shortwaves at play that could merge/stay solo/or come together well east of the local area. While these details aren't clear, a branch of the low level jet looks to funnel moisture north then westward, feeding the upper level forcing. Sensible outcomes, sans clarity in some of the finer details, is for areas of rain to spread across the forecast area as early as Mon morning, with periods of rain potentially lingering into Wed. The EPS and GEFS are a bit quicker with bringing in the rain chances compared to previous runs and there has been some shift southward in the GEFS. For now, will let the model blend detail the rain chances - which are still looking likely for a large portion of the forecast area. The current track of the trough would hold much/if not all of the instability pool well south, limiting the threat for thunder.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
Issued at 1212 AM CDT Fri May 16 2025

Main forecast concern will be increased winds through Friday. At 16.06Z TAF issuance a temporary reprieve in winds seen from Nebraska to west-central Wisconsin affecting most of the local forecast area.
As a result have added low level wind shear to both TAF sites for the next couple hours while surface winds are expected to abstain from gusts.

This frontal boundary shifts southeast through the forecast area today increasing winds concurrent with daytime mixing.
Subsequent accompanying precipitation also shifts southeast through the afternoon into the evening. Limited thunder chances primarily overnight into early Saturday morning. Little to no visibility restrictions expected but eventual MVFR ceilings potentially lowering to IFR towards the end of the 16.06Z TAF period.

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