Thursday, January17, 2019 L-36.com


Marine Weather and Tides
Lincolnwood, 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 7:13AMSunset 4:48PM Thursday January 17, 2019 3:00 AM CST (09:00 UTC) Moonrise 2:33PMMoonset 4:22AM Illumination 86% Phase: Waxing Gibbous; Moon at 11 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 Expires:201901171015;;471231 Fzus53 Klot 170315 Nshlot Nearshore Marine Forecast National Weather Service Chicago/romeoville Il 915 Pm Cst Wed Jan 16 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>742-171015- Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 915 Pm Cst Wed Jan 16 2019
Rest of tonight..Northeast winds 10 to 15 kt becoming east. Slight chance of snow toward morning. Waves 2 to 4 ft.
Thursday..Southeast winds around 10 kt becoming west in the afternoon. Chance of snow. Snow may mix with rain as it tapers off in the afternoon. Waves 2 to 4 ft subsiding to 1 to 3 ft.
Thursday night..Northwest winds 10 to 15 kt. Mostly cloudy. Waves 1 to 3 ft.
Friday..North winds 10 to 15 kt. Slight chance of snow in the afternoon. Waves 1 to 3 ft.
LMZ741


7 Day Forecast for Marine Location Near Lincolnwood, IL
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location: 41.95, -87.63     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 170503
afdlot
area forecast discussion
national weather service chicago romeoville, il
1103 pm cst Wed jan 16 2019

Update
814 pm cst
for evening update...

made a few changes to the going forecast tonight into Thursday,
most notably to add a brief period of freezing rain snow mix at
onset late tonight south of i-80, and to tighten up the gradient
between higher pops to the south on Thursday and lower pops
farther north.

Early evening surface analysis depicts an elongated area of high
pressure stretching from the canadian prairie provinces southeast
to the great lakes. Farther southwest, low pressure was developing
across the texas panhandle, in response to short wave energy
tracking out of the southern rockies. This low is forecast to
propagate east-northeastward into far southern il by midday
Thursday, before merging with weaker low pressure over the eastern
lakes Thursday night. Southerly return flow downstream of the
short wave was already evident in upper air analysis this evening,
with development of light patchy precip noted from the plains
into the lower missouri valley, and model guidance supports precip
developing into northern il in after midnight tonight. Ilx 00z
sounding depicts shallow moist layer from near the surface to just
below 850 mb, with dry mid-levels above that. Mid-levels are
progged to moisten from the top-down by Thursday morning, though
there is some concern that patchy light freezing drizzle may
develop from the shallow moist layer south of i-80 before ice
nucleation can be developed via a feeder-seeder method from mid
levels. Mid-level saturation should eventually allow for precip to
turn over to all snow by morning. Light snow then appears to be
focused mainly along south of a peru il to gary in line during the
day Thursday, with mainly only very light snow farther north. As
mentioned above, have sharpened up the gradient in pops along that
axis, with accumulation mainly south of that line. Amounts are
expected to range from a tenth or two along the i-80 corridor, to
1-2 inches across the far southern tier of WFO lot CWA counties.

Snow will likely taper off in the afternoon, and may mix with some
light rain or drizzle as it does, though with temps a little
above freezing by that time.

Updated digital text forecasts and sps available.

Ratzer

Short term
233 pm cst
through Thursday night...

main concern for the short term forecast period will focus on the
onset time and areal extent of the next round of snow, currently
expected for late tonight and through Thursday.

For the remainder of this afternoon and into this evening, skies
were able to partially clear as some drier air was drawn across the
region in nely flow. Locations near lake michigan have remained
under broken lake effect cloud cover while the portions of the cwa
south of i-80 remained under dense mid and high cloud. High
pressure is parked over the upper great lakes with a warm front
extending from developing low pressure over the south high plains
through the lower ohio valley. The warm front is expected to lift
slowly north through SRN cntrl il as the sfc low tracks through the
southern plains to SRN missouri by tomorrow morning. In the mid-
levels, 2 shortwaves are forecast approach the region. A southern
stream wave will is expected to track through cntrl il, while a
northern stream shortwave drops through the upper
missouri mississippi valley and SRN wi. Each of these waves will
have a role in the snowfall expected across the area. The models
are in relatively good agreement on the evolution of these waves,
with the SRN stream wave a little faster, but weaker that the
northern stream wave. The models do not exhibit any phasing of the
2 waves, so there should not be any significant sfc development and
the bulk of the forcing will be from the mid levels. The SRN stream
shortwave will initiate snow over the far swrn portions of the cwa
by arnd midnight tonight and then spread north and east overnight
and into the morning hours tomorrow. The northern stream shortwave
should reach nwrn il swrn wi by arnd daybreak tomorrow and quickly
track east, across southern lake michigan in the afternoon. Snow
associated with this wave should reach the rockford area shortly
after daybreak and then quickly spread east. While all of the cwa
should receive some snowfall, limited moisture availability and only
indirect forcing should limit total snowfall amounts as the
strongest mid-level forcing with the northern stream wave will be
more forcing north of the wisconsin border and the forcing with the
southern stream wave will be more focused over central illinois.

Forecast thermal profiles suggest that p-type will generally be all
snow, but some rain could mix in with the snow over the SRN portions
of the CWA as sfc temps rise to 34-35 f over srn ERN portions of the
cwa, as the pcpn is ending from west to east, tomorrow afternoon.

Latest thoughts are that arnd 1-2 inches total accumulation is
likely south of the illinois kankakee rivers and up to an inch north
of the rivers to along the i-80 corridor. Snow totals should
diminish farther to the north, with a dusting to, perhaps, a half an
inch north of i-80, including the rockford and chicago metro
areas.

Long term
236 pm cst
Thursday night through Wednesday...

impactful winter storm still slated to impact the region late
Friday into Saturday with lake effect snow potentially lingering
into Saturday night into Sunday.

Synoptically, we're looking at an active split flow regime likely
to persist through the long term period. First system in the long
term period will begin to impact things late Friday through
Saturday. As is often the case, guidance continues to struggle
with the interaction between the strong southern stream shortwave
and digging northern stream trough. General trend in the models
over the past 24 hours has been for a delay in the phasing of the
these two wave, with any meaningful interaction looking delayed
until after this wave is past our area.

Given these complexities, still some room for model solutions to
change over the next day or so, but it does seem that we may be
honing in a solution. As it looks now, lead shortwave should
result in backing low mid level flow over the region later Friday
which should result in strengthening low-mid level frontogenetic
(f-gen) circulation. NAM and fv3-gfs both depict this scenario
well and depict this narrow f-gen driven band of precip over our
northern cwa. Worth noting that it probably isn't wise to key in
on a precise location of a narrow f-gen band this far out, but
rather take note that one seems likely to develop in the area.

Vertical cross sections through this model depicted f-gen band
do raise some concern that snow intensity could get rather
intense. Deep and moderately respectably strong ascent, including
through the dendritic growth zone, suggest that we could see
respectable totals under this band, particularly if it remains
quasi-stationary for 6-9 hours as NAM and fv3-gfs suggest it
could.

As the f-gen band translates eastward, look for more widespread
snow to envelop the remainder of the CWA overnight Friday into
Saturday morning. Snow should end from northwest to southeast
over most of the CWA Saturday, though far southern CWA could see
accumulating snow linger into the late afternoon Saturday. As it
looks now, we could see a couple of snow maximum over the cwa, one
associated with the initial f-gen band, probably over our northern
cwa and then a second MAX over far southern CWA associated with
the northern flank of the deformation band from the system which
now looks to pass pretty well south of our cwa.

Inherent uncertainties in pinpointing an f-gen driven band of snow
this far out, make detailed snowfall forecast totals difficult.

General snowfall totals across the CWA look to be in the 2-5"
range, but depending on how well organized and transient the
f-gen band ends up being, we could see totals reach or possibly
even exceed 6 inches in with that feature Friday night. Could also
see totals nearing 6 inches far southern CWA closer to the defo
bands with the cyclone passing south of the area.

In addition, we could turn on the lake effect machine later
Saturday and particularly Sunday as coldest air moves in. Lake-
850mb delta-t values should look to approach 20c, suggesting
fairly strong lake induced instability. The big negative factor in
the models at this point is the low inversion heights, only
peaking between 5500-6500 ft. While inversion heights aren't
forecast to be overly impressive, the magnitude of the instability
could augment the less than stellar inversion heights and still
result in a respectable lake effect snow showers and
accumulations. This could particularly be the case Sunday as
gradient eases some allowing for a pronounced land breeze
convergence zone to develop and potentially lead to a more
organized les band.

The heart of the arctic air will arrive Sunday with daytime
temperatures potentially holding in the single digits many areas
away from the lake. Sfc ridge axis looks to move across the area
Sunday evening and could allow for a quick temps free fall during
the evening over the fresh snow pack (assuming skies have cleared
out). If skies clear, the favorable cold spots could see temps
reach the double digits below zero, with much milder conditions
near and downwind of the lake, including chicago. Temps could
level off or even begin to rise later Sunday night depending on
how fast the ridge moves east, though strong radiational
cooling decoupling could end up preventing much in the way of a
meaningful rise.

Finally, worth mentioning medium range models bring another
potentially interesting system across the area the middle of next
week. As we saw with this first system, there is a lot of time for
things to change, so at this point probably just worth mentioning
another system to watch later Tuesday Wednesday. Too much
uncertainty at this distance to talk about precip type and
amounts, just something to watch in coming days.

- izzi

Aviation
For the 06z tafs...

primary forecast concern remains the potential for light snow
Thursday.

A weak storm system will move across central il and central in
overnight through Thursday afternoon. Light precipitation is
expected to spread north to near i-80 by morning with very light
snow or flurries possible at the terminals Thursday morning
through mid Thursday afternoon. Its possible this light snow or
flurries may not lower prevailing visibility much and there may be
dry hours. Best chance for any MVFR vis will be at gyy. If any
precipitation does occur at the terminals and it lingers into the
afternoon... It may change to light rain or sprinkles if temps warm
enough. For areas south of the terminals and before sunrise...

there is a chance for light freezing drizzle before a transition
to light snow.

MVFR CIGS have scattered across parts of northeast il and
northwest in late this evening but are expected to fill back in
and become prevailing in the next few hours. CIGS will then lower
toward ifr by sunrise and will likely reach ifr by late morning or
early afternoon but confidence is low. CIGS may remain near 1kft
along north of a rfd dpa ord line with MVFR CIGS persisting into
Thursday night.

Easterly winds to 10kts overnight will slowly diminish by morning
with a period of light and variable or calm possible midday on
Thursday then winds will shift west northwest by late afternoon
with speeds generally under 10kts expected into Thursday night.

Cms

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 2 mi121 min E 11 30°F
CNII2 7 mi16 min E 8 G 9.9 29°F 22°F
JAKI2 12 mi121 min E 6 G 8.9 31°F
CMTI2 - 9087044 - Calumet, IL 16 mi31 min E 7 G 8.9 29°F 1022.1 hPa23°F
WHRI2 - Waukegan Harbor, IL 30 mi81 min E 7 G 8.9 30°F
BHRI3 - Burns Harbor, IN 33 mi56 min E 5.1 G 6 28°F 1023.4 hPa
KNSW3 - Kenosha, WI 45 mi61 min ESE 9.9 G 12 30°F 1023.4 hPa (-1.3)

Wind History for Calumet Harbor, IL
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL13 mi68 minE 610.00 miOvercast30°F23°F75%1024.1 hPa
Chicago, Chicago-O'Hare International Airport, IL14 mi70 minENE 610.00 miOvercast29°F21°F72%1023.4 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL18 mi69 minE 310.00 miOvercast30°F19°F66%1024.3 hPa

Wind History from MDW (wind in knots)
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Last 24hrNW5NW6NW5NW6N11N10N7N53N8NE9E10E11NE13NE7NE9E10NE10E10E7E6E8E6E7
1 day agoW9W10W10W8SW9SW9SW10SW11W13
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2 days agoNW6NW5NW5NW6NW7NW6NW8W5SW5W8W11SW10SW10W10SW12SW10W12W11
G18
W10W10W11W6W10W9

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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 (4,6,7,8)
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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.