NOTE: Some of the data on this page has not been verified and should be used with that in mind. It may and occasionally will, be wrong. The tide reports are by xtide and are NOT FOR NAVIGATION. Privacy and Cookie policy

LMZ744 Expires:202310030915;;399099 Fzus53 Klot 030207 Nshlot
nearshore marine forecast national weather service chicago/romeoville il 907 pm cdt Mon oct 2 2023
for waters within five nautical miles of shore on lake michigan
waves are provided as a range of significant wave heights, which is the average of the highest 1/3 of the waves, along with the average height of the highest 10 percent of the waves which will occasionally be encountered.
lmz742>745-030915- northerly island to calumet harbor il- calumet harbor il to gary in-gary to burns harbor in- burns harbor to michigan city in- 907 pm cdt Mon oct 2 2023
Rest of tonight..East winds 5 to 10 kt becoming south. Clear. Waves around 1 ft.
Tuesday..South winds 5 to 10 kt increasing to 10 to 15 kt and becoming southeast late. Sunny. Waves around 1 ft.
Tuesday night..South winds 10 to 15 kt. Partly cloudy in the evening, then becoming mostly cloudy. Waves around 1 ft.
Wednesday..South winds 10 to 15 kt becoming southwest 15 to 20 kt. Slight chance of showers in the afternoon. Waves 1 to 3 ft.

LMZ700
No data

FXUS63 KLOT 022321 AFDLOT

Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 621 PM CDT Mon Oct 2 2023

SHORT TERM
Issued at 1232 PM CDT Mon Oct 2 2023

Through Tuesday night...

Key messages...

* Continued unseasonably warm temperatures, slightly below records for early October

Mostly sunny skies and highs topping out in the mid 80s (except for the immediate lakeshore in northeast IL) today will give way to another seasonally mild evening with clear skies.

The upper ridge that is centered over the area will slowly drift east tomorrow. This will allow south-southwesterly winds to pick up, likely keeping any lake cooling confined right at the immediate shoreline. 925 mb temperatures on Tuesday again will be at the 90th percentile climo but a tad below maximums. Forecasted highs today solidly in the mid to even some localized upper 80s reflect that as these values are a tad below record highs for early October, which still hold in the lower 90s. Of note, the last date of a record high in the 90s in Chicago is October 6th.

KMD

LONG TERM
Issued at 135 PM CDT Mon Oct 2 2023

Wednesday through Monday...

Key Messages:

* Showers and a few thunderstorms Wednesday PM into Thursday as a cold front slowly moves across the region

* Turning much cooler to close out the work week and into the weekend with spotty showers possible Friday

Wednesday will be our transition day as the expansive upper ridge will become centered over the east coast, while the long wave trough makes it slow eastward jog closer to our region. The long wave will take on a positive tilt closer to our latitude, and thus main surface low will pass well to the north of the region, where the strongest large scale forcing will reside. A cold front will extend south of the low. Persistent mid-level height falls, strengthening isentropic upglide, frontal convergence, along with some upper jet support will cause showers to uptick in coverage, particularly later in the afternoon and evening into overnight from west to east.

Initially shower coverage maybe a bit limited and focused across our northwestern counties, as the upper level flow is parallel to the advancing cold front, but eventually with persistent southwest flow increasing moisture (PWATs above 1.5") expect an uptick in coverage later Wednesday night into Thursday, with the highest coverage from Chicago southeastward, where some heavier downpours would be favored. Instability never peaks above 500 J/Kg across the area and mid level lapse rates are only marginal for more than isolated to widely scattered thunderstorms. The lead cold front will shift into the area Thursday and will allow for clearing from northwest to southeast in the afternoon.

The more formidable push of cold air will arrive on Friday. The upper jet will dig on the back side of the cold upper low centered over Lake Superior. The first autumn cold fronts coming after a warm spell often have a decent surge of winds with them, and this front will be no exception. Probabilities of exceeding 25 mph gusts on the tune of 60-80 percent for the region, and this will add bite to the forecasted highs in the upper 50s to lower 60s. A few spotty steep low-mid-level lapse rate driven showers will be possible on Friday-Friday evening, though the much drier air mass should help limit coverage, and this is consistent with only 20-30 pct of GFS/EC ensembles members having any measurable QPF (and most under 0.1" of QPF).

The theme of the weekend will be seasonally cool and breezy. Current NBM forecasted high temperatures for Saturday and Sunday keep all of NE Illinois and NW Indiana in the 50s. Some light lake effect rain showers will be featured close to the shore. NBM offers some low end chances into Chicago (10-20%), but they will be favored east and southeast into NW Indiana and into lower Michigan.

KMD

AVIATION
For the 00Z TAFs...

Our stretch of quiet weather at the terminals will continue through this TAF period with high pressure firmly overhead. A lake breeze continues to move through the Chicago terminals at this hour which will turn winds southeasterly at ORD, MDW, and GYY for tonight. While speeds should generally be light around 5 kts, I cannot completely rule out a brief period of winds brushing 8 to 10 kts as the boundary moves through. Otherwise, light south- southeast winds tonight will become southwesterly Tuesday morning with speeds increasing to around 10 kts by mid-morning. A few gusts in the upper teens to around 20 kts will also be possible Tuesday afternoon especially for areas near RFD. Lastly, mostly clear skies are expected through the period but some BKN cirrus do look to move in towards the end of the TAF period.

Yack

LOT WATCHES/WARNINGS/ADVISORIES
IL...None.
IN...None.
LM...None.

toggle option: (graph/table)

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Northern Indiana, IN,