Tuesday, May21, 2019 L-36.com


Marine Weather and Tides
Chicago, IL

Version 3.4
What's New / NOTES
10/6/2018 Colors of tide XTide graphs changed to emphasize that they were upgraded. See next note. Comments welcome.
10/4/2018 I have fixed XTide and updated the harmonic files. There were some name changes so you might have to click EDIT to find the new station name.

Sunrise 5:23AMSunset 8:10PM Tuesday May 21, 2019 2:07 PM CDT (19:07 UTC) Moonrise 11:06PMMoonset 7:40AM Illumination 92% Phase: Waning Gibbous; Moon at 17 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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LMZ742 Expires:201905212115;;223463 Fzus53 Klot 211359 Nshlot Nearshore Marine Forecast National Weather Service Chicago/romeoville Il 859 Am Cdt Tue May 21 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>743-212115- Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor-calumet Harbor To Gary- 859 Am Cdt Tue May 21 2019
.small craft advisory in effect from 4 pm cdt this afternoon through Wednesday evening...
Rest of today..East winds to 30 kt. Rain showers likely. Waves 2 to 4 ft building to 3 to 5 ft late.
Tonight..East winds to 30 kt becoming southeast in the evening then diminishing to 15 to 25 kt overnight. Showers likely and a slight chance of Thunderstorms in the evening, then showers with Thunderstorms likely after midnight. Waves 5 to 8 ft occasionally to 10 ft.
Wednesday..South winds 20 to 25 kt. Slight chance of showers in the morning. Waves 4 to 7 ft occasionally to 9 ft subsiding to 2 to 4 ft in the afternoon.
Wednesday night..Southwest winds 15 to 20 kt. Slight chance of showers after midnight. Waves 2 to 4 ft subsiding to 1 to 3 ft after midnight.
LMZ742


7 Day Forecast for Marine Location Near Chicago, IL
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location: 41.85, -87.6     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 211811
afdlot
area forecast discussion
national weather service chicago romeoville, il
111 pm cdt Tue may 21 2019

Short term
359 am cdt
through Wednesday...

overnight an 11,000 ft cloud deck has been overperforming a bit in
terms of rainfall production, though overperforming in this case
means a couple hundredths of measurable rainfall at the surface.

More widespread shower activity is expected to move into the area
during the morning, followed by a break this afternoon and then a
round of showers and thunderstorms tonight.

Today's predawn activity was supported by moisture convergence
focused around the 700mb level, which explains the high bases, along
with some shortwave energy riding up the west side of an upper ridge
positioned over the area. Stronger shortwaves appear poised to move
across the area during the morning as the upper ridge axis drifts
east, while moisture convergence also becomes more pronounced at
lower levels. There appears to be a brief period this afternoon
where the upper shortwave energy lifts north of the area and the low
level moisture convergence becomes less focused. This would support
a break in the rainfall activity until the next round arrives this
evening.

Showers and thunderstorms tonight will be rooted along a warm front
and accompanied by increasing temperatures and dewpoints in a non-
diurnal trend, especially after midnight. This warm front extends
east from the low pressure center which is consolidating over the
southern plains and lifting north over the next 2-3 days, reaching
the lake superior area by Thursday morning. After the front lifts
north tonight, height rises aloft and pressure rises at the surface
will bring an end to the precipitation by mid to late morning
Wednesday.

Some of the storms tonight could produce locally heavy rain, but
the system overall appears to be progressive enough to avoid
widespread flooding issues.

Lenning

Long term
359 am cdt
Wednesday night through Monday...

as the occluding plains low continues its trek north, models show
the trailing cold front getting somewhat sheared out and left
behind, but eventually do have it drifting south through the area
on Thursday, turning winds northwest and pushing the better
boundary layer moisture farther south. For now, to mark the
progress of the boundary, will plan to carry chance pops in the
northwest early Thursday, across the south half of the forecast
area during the morning, and across our southeast in the
afternoon.

The slightly drier air Thursday night will be short-lived, as the
cold front stalls to our south and then gets pulled back north as a
warm front ahead of the next low pressure system lifting through the
plains on Friday. Shower and thunderstorm chances likely will be a
bit higher on Friday, especially in the west and northwest part of
the forecast area.

Confidence of course begins to decrease heading into the holiday
weekend, but models are in reasonable agreement in pushing the next
stalling out cold front through the area early on Saturday as the
plains low moves from minnesota across the northern great lakes and
into eastern canada. This would be accompanied by yet higher shower
and thunderstorm chances Friday night into Saturday.

By late in the weekend and into early next week the continued
evolution of this frontal boundary will help drive local
thunderstorm chances, but confidence is too low to say with
certainty which periods will be most favored. Early indications
would have the activity focused across the southern portion of the
forecast area with the boundary stalled to our south.

Lenning

Aviation
For the 18z tafs...

several concerns this period including...

light rain with MVFR CIGS possible this afternoon.

Strong gusty east winds this afternoon into tonight.

Thunderstorms late this evening into early Wednesday morning.

Gusty south winds Wednesday.

In general, the initial forecast trends look good. The main
adjustment has been to add the tempo MVFR cig vis with the ongoing
warm advection wing of showers lifting north through NRN il in.

Latest radar trends suggest that the main area of elevated warm
advection forcing will lift north of the terminals within the next
hour or 2. There may be a chance for a few isolated showers for
the remainder of the afternoon and into early evening, but the
stronger forcing will move north of the terminals. Guidance still
suggests strong, gusty east winds through the afternoon and into
early evening. May be a bit early introducing 30kt gusts at
issuance time, but confidence is relatively high that stronger
winds should mix down to the surface this afternoon.

Have ended the initial gustiness by early evening as a strong
inversion under the elevated warm advection sets up. This
inversion should limit mixing, but with 45-50kt winds just above
the inversion should set up a period with the potential for llws.

A line of showers and thunderstorms is expected to move across the
region late this evening and into the early morning hours. The
high res models are in relatively good agreement on the timing and
speed of the line of storms, so confidence is high enough to
introduce the tempo group. Most of the TS should be along the
leading edge of the pcpn shield, with some more isold TS in the
trailing pcpn shield, but have tried to highlight the most likely
timing in the tempo group, though the total residence time of ts
at the terminals could be shorter than the tempo duration as the
line is expected to move very quickly across the region.

Following the passage of the line of tsra shra, winds should trend
to southerly. The pressure gradient across the region will
strengthen through the morning as low pressure deepens rapidly
while lifting newd through the upper missouri valley. Southerly
winds should strengthen through the morning, with gusts to 30 kt
expected. The timing of the stronger gusts may be later than the
15z timing indicated in the 18z update, but have introduced the
stronger gusts with the favored timing of gusts beginning though
it is likely that the strongest gusts could be later in the
morning or early afternoon.

Lot watches warnings advisories
Il... Beach hazards statement... Ilz006-ilz014... 4 pm Tuesday to 10 am
Wednesday.

In... Beach hazards statement... Inz001... 4 pm Tuesday to 4 am
Wednesday.

Lm... Small craft advisory... Lmz740-lmz741-lmz742-lmz743... 4 pm
Tuesday to 7 pm Wednesday.

Small craft advisory... Lmz744-lmz745... 4 pm Tuesday to 4 am
Wednesday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
CNII2 1 mi23 min ENE 16 G 17 48°F 44°F
CHII2 - Chicago, IL 5 mi38 min E 19 G 21 48°F 47°F
JAKI2 5 mi128 min E 13 G 19 49°F
CMTI2 - 9087044 - Calumet, IL 9 mi50 min ENE 9.9 G 14 50°F 1019.6 hPa48°F
FSTI2 9 mi128 min E 23 47°F
45174 20 mi28 min ENE 12 G 14 45°F 2 ft1021.1 hPa45°F
BHRI3 - Burns Harbor, IN 28 mi60 min E 6 G 9.9 51°F 1020.7 hPa
45170 34 mi28 min E 14 G 18 51°F 52°F2 ft43°F
45186 37 mi28 min E 7.8 G 12 45°F 47°F1 ft
MCYI3 - Michigan City, IN 37 mi38 min E 14 G 16 51°F 42°F
WHRI2 - Waukegan Harbor, IL 37 mi88 min E 9.9 G 12 44°F
45187 45 mi28 min E 7.8 G 12 44°F 46°F1 ft

Wind History for Calumet Harbor, IL
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N8
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G11
NE7
G11
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N5
N6
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G9
N6
NW2
N5
G8
N8
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N4
G7
NE12
G15
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G11
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E8
G14
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NE9
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SW13
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G11
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W3
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G11
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G11
W5
G10
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N9
G13
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N5
G8
W13
G19
--
S7
SE10
G14
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G14
N3
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NW1
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G9
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G16
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G18
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G18
S15
G24
S12
G18
S12
G20
S11
G19
S16
G23

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL9 mi75 minE 1010.00 miOvercast50°F46°F86%1020.2 hPa
Chicago, Chicago-O'Hare International Airport, IL18 mi77 minE 1410.00 miOvercast48°F45°F89%1020 hPa
Gary Regional Airport, IN19 mi83 minSE 910.00 miOvercast52°F46°F82%1020.3 hPa
Lansing Municipal Airport, IL22 mi73 minE 710.00 miOvercast51°F46°F84%1020.3 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL24 mi76 minE 8 G 1610.00 miOvercast49°F44°F83%1021 hPa

Wind History from MDW (wind in knots)
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Last 24hrE8E8E9NE7NE11NE10NE8CalmW3N5NE9E4NE13E8E8E10SE9SE13E11
G19
E8E10E12E10E15
G22
1 day agoW25
G37
W16
G28
W15
G25
W17
G27
W13
G24
W16
G23
W19
G26
W22
G33
W11W14
G23
NW16
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W10W15
G22
W10W12NW12
G19
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G21
NW13NW11N14
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NW12N9N3N4
2 days agoW9
G24
SE7S11
G19
S12
G22
W5N4NE3E4NE3NE8NE7N5NE5E3S8S10S13
G20
S14S14
G27
SW14
G27
S14
G25
SW16
G25
SW16
G27
W21
G33

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    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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Other links: Northern Pacific     Contential US     Full GOES-East
Wind Forecast for Chicago, IL (15,3,4,5)
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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.