Thursday, September20, 2018 L-36.com


Marine Weather and Tides
Elmhurst, IL

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9/17/2018 XTide broke when 1and1 "upgraded" my server. It has been esculated. I am sorry for the problem.

Sunrise 6:36AMSunset 6:53PM Thursday September 20, 2018 4:21 AM CDT (09:21 UTC) Moonrise 4:55PMMoonset 2:05AM Illumination 79% Phase: Waxing Gibbous; Moon at 10 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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LMZ741 Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 315 Am Cdt Thu Sep 20 2018
.small craft advisory in effect from this evening through Saturday morning...
Today..Southeast winds 5 to 10 kt becoming south 10 to 20 kt this afternoon. Chance of showers and Thunderstorms, mainly this morning. Waves 1 to 3 ft building to 2 to 4 ft late in the afternoon.
Tonight..Southwest winds to 30 kt. Gale force gusts to 35 kt possible. Slight chance of showers and Thunderstorms after midnight. Waves 3 to 5 ft.
Friday..West winds around 25 kt becoming 20 to 25 kt in the afternoon. Slight chance of showers and Thunderstorms in the morning. Waves 2 to 4 ft.
Friday night..North winds 15 to 25 kt diminishing to 10 to 20 kt after midnight. Mostly cloudy. Waves 3 to 5 ft building to 4 to 7 ft occasionally to 9 ft after midnight.
LMZ741 Expires:201809201515;;921245 FZUS53 KLOT 200815 NSHLOT NEARSHORE MARINE FORECAST National Weather Service Chicago/Romeoville IL 315 AM CDT Thu Sep 20 2018 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>742-201515-


7 Day Forecast for Marine Location Near Elmhurst, IL
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location: 41.89, -87.94     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 200808
afdlot
area forecast discussion
national weather service chicago romeoville, il
308 am cdt Thu sep 20 2018

Short term
300 am cdt
through Friday...

main forecast concerns revolve around the chances for showers and
thunderstorms both today and tonight, along with the gusty winds
expected to develop over the area by this evening and continue on
Friday.

Convection continues to develop early this morning within a
corridor of enhanced lower-level warm air advection across much
of iowa and into southern wi. While the primary focus has largely
been to our north and west in closer proximate to the nose of the
low-level jet, it appears that some of these storms will push
east-southeast across far northern il over the next few hours.

There is even signs of outflow shifting southeastward out of these
storms now entering far northwestern il. For this reason it
appears likely that there will be storms over the area early this
morning, especially along and north of i-88, though storms could
impact areas as far south as i-80. The main threat from these
storms will be some locally heavy rainfall. These storms should
begin abate across the area by mid to late morning.

The next question is how quickly can the warm front lift north of
the area today, especially given the outflow from the the storms
entering the area acting to reinforce the front south of the
area. Overall, I think the front may end up being several hours
slower than the model guidance suggests. With this in mind, it
appears that the front may not move north of far northeastern il
until sometime this afternoon. I don't necessarily think this
will impact the near record high temperatures much, as once the
warm front does lift north temperatures should warm quickly with
the onset of south- southwesterly winds. Instead what could happen
is that some additional isolated or widely scattered
thunderstorms could try to develop over portions of northeastern
il in the vicinity of the front. Little to no capping is forecast
for this area, so any influence with the surface boundary near the
lake could spark off some activity. Confidence in any storms
occurring over northeast il this afternoon is low, but we will
continue a slight chance for storms through the afternoon.

The warm front will eventually shift north of the area later today
as the parent low pressure quickly shifts northeast from the
plains to the upper midwest. Once this occurs, expect a mild a
windy night across the area tonight. The wind field across the
area will increase significantly by early this evening as pressure
falls (associated with the fast moving surface low moving into
the upper midwest) overspread the upper great lakes. This will
quickly tighten the pressure gradient across much of the region
supporting stronger winds. Winds at 950 mb (about 1000 ft agl)
are progged to increase to around 40 kt (~45 mph) this evening.

For this reason it appears likely that wind gusts up around 35 to
possible up to 40 mph will be possible across the area tonight.

Finally as the surface low tracks into western quebec early
Friday morning, an associated cold front will push eastward across
the area. With the approach of this front there will be another
small chance for some widely scattered storms, mainly later
tonight. However, it appears the main threat for storms will
remain north of the area in closer proximity to the better
atmospheric dynamics. In our area, it appears the poor diurnal
timing will result in weakening storms as they shift into il late
tonight. Winds will turn west-northwesterly in the wake of this
cold front, however, and wind speeds will likely remain gusty
through much of the day on Friday.

Kjb

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

surface high pressure builds across the great lakes region Friday
night as the cold front settles into the ohio valley. Cooler, drier
low level air spreads into the forecast area on north-northeasterly
winds. Steep low-level lapse rates develop as the cooler air crosses
still mild lake michigan waters, and forecast soundings suggest a
period of lake-induced stratocu into northeast il Friday night into
Saturday morning, which along with a breezy northeast wind will
likely keep temps from dipping too low close to the lake. Some model
guidance even tries to develop a little lake-effect precip, though
forecast soundings suggest inversion heights around 5000-6000 ft
which would likely limit anything to just sprinkles. Further inland
however, across north central il, where skies remain clear mostly
clear and winds decouple, temps may drop into the low-mid 40s by
sunrise Saturday.

Once lake effect clouds decay Saturday, pleasant weather is in store
for the first weekend of autumn. High pressure will continue to
drift slowly east across the great lakes, providing dry, seasonably
cool weather with onshore lake winds. Daytime highs should range
from the low-mid 60s near the lake, to the upper 60s low 70s farther
inland and south Saturday. Widespread lows in the 40s are expected
Saturday night away from the immediate lakeshore and city, when
light winds and mainly clear skies will provide the strongest
radiational cooling conditions. Moderating low level temps Sunday
should support low-mid 70s away from the lake.

An upper level trough will propagate from the west coast into the
rockies Sunday night, inducing low pressure development across the
plains, and a gradual veering of the low level flow into the midwest
into Monday. Warm moist advection associated with this return flow,
and continued height falls forced by the approaching upper trough,
will lead to the return of shower chances early next week. While the
ecmwf has been developing precip as early as late Sunday night, the
greatest potential for rain and a few thunderstorms appears to be
Monday night into Tuesday, with the arrival of the amplifying upper
trough, and the approach of a cold front. While clouds and precip
may have an impact, temps should warm in the mid-upper 70s in many
areas ahead of the front Monday Tuesday. Cooler weather then returns
behind the front Tuesday night and Wednesday. Presence of the deep
upper trough aloft may support lingering clouds and perhaps a few
showers sprinkles.

Ratzer

Climate
Record high temps could be jeopardy Thursday. Here are the
current records:
chicago 92 (2017)
rockford 92 (1920)

Aviation
For the 06z tafs...

the main concern through the period will be the timing of wind
direction changes, and increasing southerly winds today.

Additionally, we will once again be on the lookout for storms
possibly impacting some of the terminals overnight, and then
possibly again this afternoon.

Winds are likely to remain easterly a bit longer early today as it
appears that the warm front may be slower to move northward across
the area into this afternoon. Therefore, it appears that the area
will remain in an area favorable for low CIGS through at least
around daybreak. Current satellite imagery indicates that the
eastern edge of these ifr CIGS are right near ord. So, the main
chicago area terminals maybe in and out of low CIGS through the
night. Lowering vsby will also be possible at the terminals as dew
point depressions lower.

The other concern is for a round of thunderstorms overnight
towards daybreak. For the most part the focus for storms has
remained north of the area into southern wi. However, current
trends with the thunderstorms in iowa indicate outflow pushing the
storms a bit more to the south. As a result, it appears probable
that a round of thunderstorms will push across far northern il
after 09z. It appears krfd stands the best chance of getting in on
this activity, though I am concerned the ord and dpa could also
see some of this activity move into the area just prior to
daybreak. For now I have added a vcts at both sites to cover this
threat, but I have left it out of mdw and gyy for now. Trends will
need to continue to be watched overnight.

With the possibly for a slower northward moving warm front, it is
possible that some additional isolated to widely scattered storms
could develop in the vicinity of the chicago area terminals this
afternoon. However, confidence is very low at this time on if this
will occur, so I have left the mention out of the TAF at this
time.

Otherwise, expect winds to turn southerly and begin to increase by
late this afternoon early this evening as the warm front finally
shifts north of the area. It appears that winds will gust up to 30
kt at times tonight from the south-southwest.

Kjb

Marine
307 am cdt
the main concern for the near shore waters will be the increasing
southerly winds later today and especially this evening. A rather
potent and fast moving area of low pressure will shift
northeastward from the plains to the upper midwest today. As this
occurs, a warm front will north over the lake later today. In the
wake of this front, expect strong southerly winds to develop and
continue tonight. It appears that wind speeds will easily reach 30
kt and we cant rule out some gale force gusts. The winds will then
turn west northwesterly early Friday following a cold front, then
turn northerly late Friday into Friday evening as a strong area of
high pressure builds into the midwest. Wind speeds will remain up
in the 25 to 30 kt range Friday before gradually abating into
Saturday.

Given this rather active period of strong winds and high waves, we
have issued a small craft advisory for the southern lake michigan
near shore waters from early this evening through Saturday
morning.

Kjb

Lot watches warnings advisories
Il... None.

In... None.

Lm... None.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FSTI2 17 mi82 min SE 1.9 69°F
CNII2 18 mi22 min WSW 1.9 G 4.1 70°F 67°F
CHII2 - Chicago, IL 20 mi32 min SSW 4.1 G 5.1 71°F 70°F
JAKI2 21 mi82 min SW 4.1 G 8 71°F
45174 23 mi22 min ESE 3.9 G 5.8 70°F 70°F2 ft70°F
CMTI2 - 9087044 - Calumet, IL 24 mi40 min 70°F 1013.7 hPa68°F
WHRI2 - Waukegan Harbor, IL 33 mi42 min NNE 8 G 9.9 69°F
45186 34 mi22 min NNE 3.9 70°F 70°F1 ft
45187 42 mi22 min 70°F 70°F1 ft
BHRI3 - Burns Harbor, IN 45 mi42 min SSE 6 G 11 72°F 1014.9 hPa
KNSW3 - Kenosha, WI 49 mi22 min NNE 14 G 16 69°F 1014.6 hPa (-1.0)

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago-O'Hare International Airport, IL7 mi31 minN 09.00 miOvercast67°F64°F93%1013.7 hPa
Chicago, Chicago Midway Airport, IL12 mi29 minNNW 37.00 miMostly Cloudy69°F66°F90%1013.5 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL15 mi30 minN 07.00 miFair67°F64°F91%1014 hPa
Chicago / West Chicago, Dupage Airport, IL17 mi30 minN 03.00 miFog/Mist66°F63°F90%1013.8 hPa
Lewis University Airport, IL21 mi47 minNE 32.00 miFog/Mist65°F64°F99%1014.9 hPa

Wind History from ORD (wind in knots)
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Last 24hrNE9NE9E7E7E7E5E5NE9NE10NE10NE12NE9N11NE10E9E5NE7NE9NE8NE5NE3CalmN5Calm
1 day agoNE10NE9NE6N13N3NW5NW4N7N10N11N12CalmSE6CalmNE12NE13SE8NE10NE4NE7N7NE9NE8NE8
2 days agoCalmCalm3SW3W43CalmN6NW3NW4NW7NW7NW6E5E6SE4S4CalmCalmCalmCalmNW4SW4NE8

Tide / Current Tables for
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Weather Map and Satellite Images
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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 (5,6,7,8)
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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.