Marine Weather and Tide Forecast for Beach Park, IL

DISCUSSION
Issued at 309 PM CDT Thu May 15 2025

Late This Evening Through Friday Night:

The threat for severe thunderstorms will come to an end from west-to-east this evening as a cold front/dry line shifts eastward across the area. A much drier airmass will move in across the area in the wake of this feature tonight, and this will set up a rather quiet night across the area.

This very dry airmass will persist across the area into Friday and will act to foster deep diurnal mixing of the boundary layer as temperatures warm into the mid to upper 80s. With mixing heights expected to top 6,000 ft AGL into a layer characterized by 40-45 kt of flow, increasingly gusty surface winds are expected across the area late Friday morning and afternoon. We also would not be surprised to see some surface gusts reach these magnitudes, which would be right around wind advisory criteria (45 mph). If this occurs, it looks to be the most favored across my northern IL counties. Given the expectation of these very windy, dry and warm conditions a Fire Weather Watch was issued for my northern IL counties. See the fire weather discussion below for more on this.

The other concern from these strong gusty winds on Friday is the potential for blowing dust, particularly in areas of north central and northwestern IN that misses out of storms this evening. Very dry soils and recent farm field work will make for favorable conditions for dust to be picked up and blown in the wide open areas of northern IL. At this point no headline is planned for this, but a wind advisory and/or a blowing dust advisory could be needed for parts of northern IL west of the Fox Valley.

Later Friday afternoon we should see a better northward return of low-level moisture (low 60s dew points) across eastern IL into northwestern IN in advance of another approaching cold front. At this time it appears the best low-level moisture return will be mainly along and east of I-55 late in the afternoon and evening. This thus appears to be the best potential area for scattered late day and early evening thunderstorm development. The SPC highlights this general area in a level 2 of 5 severe risk. Conversely, the activity looks to remain more isolated farther to the northwest of I-55.
Regardless, any storms that develop will be capable of producing damaging wind gusts given the inverted-V type soundings with strong low-to-mid level lapse rates. Instances of very large hail would also be plausible, particularly with any supercells.
Expect the storm threat to come to an end by mid to late Friday evening following the passage of this second cold front.

KJB

Saturday through Thursday:

A strong, slow-moving Hudson Bay high will gradually shift eastward this weekend into early next week as western CONUS troughing settles toward the central Great Plains. Breezy conditions with seasonable temps in the upper 60s to low 70s are expected Saturday. A backdoor cold front crossing the area from the northeast early Sunday will result in high temps ranging from the mid 50s near the lake to the mid 70s well inland.

The trough will then slowly cross the Ohio River Valley and bring a a period of unsettled with with period of showers and some storms amid cooler conditions late Monday through midweek.

Kluber

AVIATION /06Z TAFS THROUGH 12Z SATURDAY/
Issued at 1230 AM CDT Fri May 16 2025

The key aviation weather messages are:

- Increasingly gusty south-southwesterly winds Friday morning and afternoon. Some potential for non-thunderstorm winds to gust 40+ knots for a brief period during the mid to late afternoon.

- Chance for thunderstorms during the late afternoon and early evening. Any storms that develop could produce wind gusts in excess of 50 knots.

- Winds shifting to the WSW Friday evening and will remain gusty, with some potential for 30+ knot gusts through the overnight.

VFR conditions with southwesterly winds will prevail tonight.
Winds will increase steadily through Friday morning and into the afternoon and will become south-southwesterly. During peak heating, there is some potential for intermittent gusts of 40+ knots at times (roughly during the 20-23z timeframe), although confidence in persistent gusts this high was not high enough to introduce higher gusts at this time.

Thunderstorms appear likely to develop late in the afternoon, although confidence in them directly impacting the terminals still remains a bit unclear, with the greatest coverage currently depicted just south. Made no significant alterations to the inherited PROB30 groups, but consideration for upgrades to TEMPOs will be needed in future TAF updates if model trends continue. Any storms that develop will have very high cloud bases (near 10 kft) and will be capable of producing severe wind gusts/microbursts.

Winds will shift out of the WSW Friday evening. Another "pop" of strong winds is possible late in the evening and overnight, and there is a signal that gusts could be a bit higher than the current TAFs indicate. MVFR cigs may eventually develop, but these look to hold off until the very end of the extended ORD/MDW TAF window or just beyond.

Carlaw

MARINE
Issued at 309 PM CDT Thu May 15 2025

Key Messages:

- Severe thunderstorms possible late afternoon into early evening - Gale Warning in effect Friday afternoon/evening for IL nearshore to Gary, IN

Thunderstorms appear poised to develop just west of if Lake Michigan late this afternoon into the evening. Any storm may produce gale to storm force winds and damaging hail. A brief period of southwesterly gale force winds cannot be ruled out behind the storms, as well. A small craft advisory is in effect this afternoon into the evening.

Finally, a period of southwesterly gale force winds are expected Friday afternoon, particularly northwest of Gary, Indiana. A Gale Warning has been issued to account for this.

Team LOT

FIRE WEATHER
Issued at 1138 AM CDT Thu May 15 2025

We have issued a Fire Weather Watch for our northern IL counties for Friday.

A much drier airmass is expected to shift over the area in the wake of a cold frontal passage later this afternoon. The dry airmass will remain in place across most of northern IL through most of Friday afternoon, before some better moisture recovery occurs late in the day across parts of east central IL and northwestern IN. As temperatures warm into the mid to upper 80s by early Friday afternoon, very low RH's in the 20 to 25 percent range are expected, particularly across northern IL. These very dry conditions are likely to combine with strong and gusty south winds (gusting up to 45 mph), thus creating a period of critical fire weather conditions.

A period of showers and thunderstorms are expected across parts of northeastern IL and northwestern IN late this afternoon into the early evening. Rainfall from these storms could help mitigate the degree of the fire weather threat to some extent for Friday, but areas that receive little to no rainfall will be primed for rapid wildfire spread on Friday as dry and windy conditions develop during the mid to late morning hours.

Very late in the day on Friday (after 4 or 5 pm), some better low-level moisture return is anticipated from the south in advance of another approaching cold front. At this time, it appears this better moisture return (near 60 degree dewpoints)
will occur generally along and east of the I-55 corridor. This may thus result in quickly improving conditions for these areas late in the afternoon, though this moisture may foster some very gusty late afternoon and evening storms. Farther northwest of I-55, continued dry and windy weather through the afternoon will likely continue the threat of wild fire spread through around sunset before abating winds and improving RH's end the threat.

KJB

LOT WATCHES/WARNINGS/ADVISORIES
IL...Fire Weather Watch from 10 AM CDT this morning through this evening for ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039.

IN...None.
LM...Small Craft Advisory until 1 AM CDT early this morning for the IL and IN nearshore waters.

Gale Warning from noon today to 10 PM CDT this evening for Winthrop Harbor IL to Gary IN.