Thursday, July18, 2019 L-36.com


Marine Weather and Tides
Gurnee, IL

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Sunrise 5:29AMSunset 8:26PM Thursday July 18, 2019 3:42 AM CDT (08:42 UTC) Moonrise 9:49PMMoonset 7:00AM Illumination 98% Phase: Waning Gibbous; Moon at 16 days in cycle
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.
Marine Forecasts
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LMZ740 Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 314 Am Cdt Thu Jul 18 2019
Today..South winds 10 to 15 kt becoming southeast 10 to 20 kt in the late morning, then becoming southwest late in the afternoon. Occasional gusts to 25 kt. Showers and Thunderstorms likely through the day. Waves 1 ft or less building to 2 to 3 ft this morning.
Tonight..Southwest winds 10 to 20 kt. Slight chance of showers and Thunderstorms through the night. Waves 1 to 3 ft.
Friday..Southwest winds 15 to 20 kt. Mostly Sunny. Waves 1 to 3 ft.
Friday night..Southwest winds 10 to 20 kt. Slight chance of showers and Thunderstorms through the night. Waves 1 to 3 ft.
LMZ740 Expires:201907181530;;241317 FZUS53 KLOT 180814 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 314 AM CDT Thu Jul 18 2019 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. LMZ740>742-181530-


7 Day Forecast for Marine Location Near Gurnee, IL
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location: 42.38, -87.94     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 180748
afdlot
area forecast discussion
national weather service chicago romeoville, il
248 am cdt Thu jul 18 2019

Short term
244 am cdt
through Friday...

for today...

quite the challenging forecast today as a currently-developing
convective complex near the iowa minnesota border has the potential
to disrupt the gradient flow (and thus the high temperature and
dewpoint forecasts) today, in addition to bringing a potential for
strong to severe weather to parts of the area.

Strong low-level warm advection, forced by a robust 40-50 kt llj,
has been interacting with the northeastern periphery of a very steep
mid-level lapse rate plume this evening. The result has been the
development of an area of elevated thunderstorms near the
iowa minnesota border which continues to grow upscale. Should cold
pool amalgamation occur--and latest visual indications point to it--
we should begin to see a more southeastward movement (and possibly
even more southerly after daybreak) to this activity through the
rest of the early-morning hours as an instability axis pivots
eastward. Objective analyses reveal a local minimum in the mucape
field across northwest illinois--likely due to yesterday's forward-
propagating mcs. Veering and strengthening 850 mb winds should,
however, push a reservoir of high theta-e air eastward into the
state over the next few hours. Plenty of spread exists in the hi-res
guidance at this time, but latest thinking has this area of storms
making a run at our region. Best guess at is stands right now is
activity (or additional elevated convection ahead of this main
complex) getting close to our northwest counties by 5-6 am, towards
the i-80 corridor during the 7-9 am timeframe, and possibly
continuing through most of our CWA through 11 am-1 pm (sans perhaps
our far southern row of counties).

The other issue revolves around the potential for additional
elevated convection to bubble over the next several hours across
southwest minnesota, possibly associated with a subtle shortwave and
associated local enhancement to 700 mb warm advection. This has been
indicated by a few hi-res cams, but no clear signal one way or
another exists in the guidance. Should this activity develop into a
second complex, precipitation chances could linger notably longer
across our CWA into the afternoon hours than currently advertised
and further act to disrupt our high temperature forecast.

Forecast soundings show effective inflow layers will likely be
rooted above 925-850 mb, making it unlikely that surface-based
parcels will be able to join in on the convective inflow. In
addition, mid-level flow should weaken some through the early-
morning which would allow outflow to sneak out quickly ahead of this
complex. This casts some doubt as to the severity of whatever
potential complex bears down on the area. Thinking now is that this
complex will be in a weakening trend through the morning hours, but
diurnal gains in instability might allow for some rejuvenation to
occur early this afternoon. We'll continue to advertise a risk for
some 50-60 mph wind gusts this morning and afternoon.

A convective complex(es) would greatly disrupt the background flow
today as an associated cold pool oozes into the region. While some
late-day modification to the airmass is possible, it's looking like
a period of southeasterly winds behind morning convection may keep
dewpoints in the upper 60s and temperatures cooler than previously
forecast. Some guidance even supports the development of a lake
breeze due to the disrupted low-level wind fields.

As a result of all of this, have nudged highs downwards for today,
most notably for locales north and east of a harvard to joliet to
valparaiso line where potential cooling effects from lingering
outflow would be most pronounced. The latest grids will reflect heat
indices rising above 105 degrees south of i-80 after 1 pm, and into
the 99-106 degree range for a brief period late this afternoon as
mid 70s dewpoints return and possibly remaining just in the upper
90s at the immediate lakeshore.

We will not be making any temporal or spatial changes to the ongoing
heat headlines for consistency-of-messaging purposes, but note that
high heat index values may only occur for a brief period late this
afternoon with "cooler" conditions at the lakeshore. However, we
continue to have relatively high confidence that the heat will build
Friday and Saturday.

For tonight...

it's looking like another region of warm advection could spark
additional elevated thunderstorms across southern wisconsin this
evening and overnight within a steep lapse rate plume. Have thrown
in some chance pops across our northern counties as a result as
activity may attempt to build southwestward into the low-level jet.

Have also nudged lows down a bit north and east of i-88 i-39 where
outflow effects could locally cool things a bit. Still looking warm
and uncomfortable south of i-88 and in the heart of chicago as
dewpoints in the mid-upper 70s return with lows either side of 80
degrees.

For Friday...

we'll continue to advertise a dry forecast on Friday but may also
have to keep an eye on possible morning convection across western
michigan which could build southwestward along the lake. Assuming
things remain dry and un-muddled from convective debris cloud cover,
temperatures still look set to rise into the upper 90s. Dewpoints in
the mid to possibly upper 70s would support peak heat indices in the
107-115 degree range. Wet bulb globe temperatures of 90-92 degrees
will support a potential for very high heat stress.

Carlaw

Long term
244 am cdt
Friday night through Wednesday...

main focus at the start of the period will be with the likely
continued dangerous heat on Saturday as well as increasing
thunderstorm chances Saturday afternoon into Saturday night.

Dry conditions expected at the start of the period, however,
pattern will remain active to our north and northwest. Surface
trough and front expected to be in place across the upper midwest,
with the LLJ once again ramping up across the region. At this
time, it is appearing that this focus should be well enough to the
north to keep the CWA dry Friday night into early Saturday
morning. However, some guidance bringing this focus slightly
further to the south. If this scenario were to occur, would be a
little concerned for some thunderstorms to dive more to the south
into the higher instability. With this still a possibility, have
left slight chance pops for thunder Friday night mainly across the
northern half of the cwa.

Expect much of the day Saturday to be dry, with sunny to partly
cloudy skies initially in place. With a similar air mass still in
place, will see temps once again rise well into the 90s with mid
to upper 90s still forecast for Saturday. Guidance varying to the
extent of the dewpoints in place on Saturday but think low to mid
70s dewpoints are likely. Am a little concerned that there could
be more mid 70s and even mid to upper 70s dewpoints, with some
moisture pooling possibly occurring ahead of approaching front to
the north. With the current forecast highs and dewpoints, expect
dangerous heat indices of 105 to 110. Some locations, south of
i-80, will likely exceed 110 and get into the 110-113 range. These
conditions would continue to support the current excessive heat
warning in place. For the tier of counties along the il in border,
its possible that another heat advisory would be needed. However,
confidence with high temps on Saturday does lower some further to
the north. This is due to the previously mentioned front, that
will likely aid in thunderstorm development in the afternoon and
the evening. Saturday night into Sunday appearing to be active
with these thunderstorms, some of which could be strong to severe.

Front expected to push through the area on Sunday with cooler
temps expected. Some lingering showers and storms will be possible
Sunday morning, but chances will lower Sunday afternoon into the
evening.

Rodriguez

Aviation
For the 06z tafs...

main forecast concerns challenges for the TAF period will be with
thunderstorm potential early this morning across all of the
sites. Monitoring area of storms currently developing across
northern ia, as this will likely be the storms that impact the
area later this morning. Expect this area of storms to further
develop into a complex of storms, and then begin tracking east
southeast towards the terminals over the next several hours.

Timing in the tafs still looks good, and did not make any changes
to the forecast at this time. The arrival of these storms still
looks to bring a gusty wind shift to the north northwest, and it's
quite possible that the speeds gusts could be more than currently
forecast. After these storms depart by mid to late morning, a
period of easterly southeasterly winds will be likely before
turning back towards a south southwest direction. Southwest
winds gusts andVFR conditions then likely for the remainder of
the period.

Rodriguez

Lot watches warnings advisories
Il... Excessive heat warning... Ilz008-ilz010-ilz011-ilz012-ilz013-
ilz014-ilz019-ilz020-ilz021-ilz022-ilz023-ilz032-ilz033-
ilz039... Noon Thursday to 7 pm Saturday.

Heat advisory... Ilz003-ilz004-ilz005-ilz006... Noon Thursday to
11 pm Friday.

In... Excessive heat warning... Inz001-inz002-inz010-inz011-
inz019... Noon Thursday to 7 pm Saturday.

Lm... None.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
45186 8 mi42 min SSW 1.9 G 3.9 71°F 71°F
45187 11 mi42 min S 3.9 G 3.9 73°F 71°F
KNSW3 - Kenosha, WI 16 mi42 min S 8 G 8.9 73°F 1011.2 hPa (-1.0)
45174 23 mi52 min SSE 5.8 G 5.8 1 ft1008.8 hPa
FSTI2 32 mi102 min S 8.9 78°F
OKSI2 36 mi102 min Calm G 1.9 82°F
45177 38 mi162 min 71°F
CHII2 - Chicago, IL 38 mi52 min S 8 G 8 78°F 76°F
CNII2 40 mi27 min S 4.1 G 4.1 77°F 72°F
JAKI2 46 mi102 min SSW 1.9 G 4.1 79°F
MLWW3 - Milwaukee, WI 46 mi52 min S 4.1 G 4.1 71°F

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago/Waukegan Regional Airport, IL5 mi47 minN 010.00 miOvercast75°F70°F84%1009.6 hPa
Kenosha, Kenosha Regional Airport, WI15 mi49 minS 410.00 miOvercast76°F73°F91%1010.7 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL19 mi50 minN 010.00 miOvercast76°F70°F82%1011.1 hPa

Wind History from UGN (wind in knots)
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Last 24hrW3CalmNW33NW6NW4CalmNE6E7E9SE9SE8SE9S6SW8S5SE3SE4CalmCalmS4SE3CalmCalm
1 day agoS4SW4S11S11SW6SW6SW633E5E66SE5SE6SE4SE7SE6CalmCalmCalmCalmCalmCalmSW3
2 days agoSW4SW5SW7SW6SW9SW12
G18
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SW9SW7SW5SW3CalmSW6

Tide / Current Tables for
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Tide / Current Tables for
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Weather Map and Satellite Images
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GOES Local Image of Midwest    EDIT
NOTE: East coast views moved to GEOS-16. They are experimental and not well supported by NOAA so they may not be correct so be warned. This change required redoing a large amount of the GOES code. If the image you are expecting is not showing, please let me know. You may need to use the EDIT function to update your location.
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Wind Forecast for Chicago, IL (4,6,7,8)
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Ground Weather Radar Station Chicago, IL
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Disclaimer:
The information on this web site has not been checked for accuracy. It is for entertainment purposes only and should be independently verified before using for any other reason. There are five sources. 1) Documents and manuals from a variety of sources. These have not been checked for accuracy and in many cases have not even been read by anyone associated with L-36.com. I have no idea of they are useful or accurate, I leave that to the reader. 2) Articles others have written and submitted. If you have questions on these, please contact the author. 3) Articles that represent my personal opinions. These are intended to promote thought and for entertainment. These are not intended to be fact, they are my opinions. 4) Small programs that generate result presented on a web page. Like any computer program, these may and in some cases do have errors. Almost all of these also make simplifying assumptions so they are not totally accurate even if there are no errors. Please verify all results. 5) Weather information is from numerious of sources and is presented automatically. It is not checked for accuracy either by anyone at L-36.com or by the source which is typically the US Government. See the NOAA web site for their disclaimer. Finally, tide and current data on this site is from 2007 and 2008 data bases, which may contain even older data. Changes in harbors due to building or dredging change tides and currents and for that reason many of the locations presented are no longer supported by newer data bases. For example, there is very little tidal current data in newer data bases so current data is likely wrong to some extent. This data is NOT FOR NAVIGATION. See the XTide disclaimer for details. In addition, tide and current are influenced by storms, river flow, and other factors beyond the ability of any predictive program.