Saturday, January19, 2019 L-36.com


Marine Weather and Tides
North Riverside, 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 7:12AMSunset 4:51PM Saturday January 19, 2019 9:19 PM CST (03:19 UTC) Moonrise 4:20PMMoonset 6:39AM Illumination 99% Phase: Waxing Gibbous; Moon at 14 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:201901200400;;622506 Fzus53 Klot 200105 Aab Nshlot Nearshore Marine Forecast...updated National Weather Service Chicago/romeoville Il 705 Pm Cst Sat Jan 19 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>742-200400- Winthrop Harbor To Wilmette Harbor- Wilmette Harbor To Northerly Island- Northerly Island To Calumet Harbor- 705 Pm Cst Sat Jan 19 2019
.gale warning in effect until 3 am cst Sunday...
.heavy freezing spray warning in effect through Sunday morning...
.small craft advisory in effect from 3 am cst Sunday through Sunday afternoon...
Tonight..North gales to 35 kt becoming northwest to 30 kt late. Heavy freezing spray. Snow showers. Waves 7 to 10 ft occasionally to 13 ft.
Sunday..Northwest winds to 30 kt. Heavy freezing spray. Chance of snow showers. Waves 5 to 8 ft occasionally to 10 ft subsiding to 4 to 6 ft occasionally to 8 ft in the afternoon.
Sunday night..North winds 15 to 25 kt. Freezing spray. Chance of snow showers. Waves 4 to 6 ft occasionally to 8 ft subsiding to 3 to 5 ft after midnight.
Monday..South winds 10 to 20 kt. Slight chance of snow in the morning. Freezing spray. Waves 2 to 4 ft building to 3 to 5 ft in the afternoon.
LMZ741


7 Day Forecast for Marine Location Near North Riverside, IL
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location: 41.84, -87.82     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 200206
afdlot
area forecast discussion
national weather service chicago romeoville, il
806 pm cst Sat jan 19 2019

Update
806 pm cst
for evening update...

no significant changes to going forecast this evening. Light lake
effect snow showers showing increasing coverage as expected, with
high-res guidance remaining similar in depiction of transition to
a more intense single-band structure late this evening. Going
forecast has this detailed nicely, with headlines structured
appropriately.

Evening surface analysis depicts 996 mb low pressure south of the
ohio river over east central kentucky. Tight surface pressure
gradient extends into the southern great lakes and mid-mississippi
valley regions, producing gusty north-northeast winds and strong
low-level cold advection across the region. While snow associated
with the low pressure system has moved out of the forecast area,
the cold low-level air traversing lake michigan was resulting in
increasingly organized lake effect snow showers into parts of
northeast il and far northwest in early this evening. High-res
model guidance continues to be in very good agreement in depicting
increasing low-level convergent focus developing along the west
shore of the lake later this evening, with a transition from
current loosely organized multi-band snow showers into a stronger
largely single band les plume later tonight. While inversion
heights remain generally in the 6500-7500 ft agl range tonight
into Sunday, all other parameters favor the potential for strong
les with periods of heavy snowfall rates within the single-band
plume. Lake surface to 850 mb delta t's around 20c, large positive
area CAPE below the inversion, and cloud layer temps within the
favored -12c to -18c dendritic growth zone all support strong
convective snow elements. 4km NAM nmm hrrr are all generally
similar in depiction of heavier snow developing into far northeast
il after 9-10 pm this evening, with the best convergent axis
slowly shifting from lake co. Il southeast across cook co. Il
overnight, and eventually into northwest in by early Sunday
morning. Lighter snow showers or flurries will likely persist
farther inland, though the greatest potential for accumulations of
substance appear likely to be limited to the lake-adjacent
counties of lake (il), cook, lake (in) and porter. This is exactly
as indicated in forecast from previous shift, and see no need for
any changes to the details or headlines at this time.

Farther west, skies have begin to clear across parts of north
central il, allowing better radiational cooling in those
locations. This has helped the boundary layer to decouple, and
winds to ease with the loss of more frequent gusts. Temps will
slide into the single digits in many areas away from the lake-
effect cloud cover, with lows of zero to 5 above expected over new
snow cover across our western counties where cloud cover will be
minimal. Have lowered temps another degree or so in the rockford,
sterling, rochelle and belvidere areas, but otherwise going
forecast again remains in good shape.

Ratzer

Short term
318 pm cst
through Sunday night...

the first wave of snow associated with the winter storm warning
has ended, though blowing and drifting snow in open areas
continues to be a concern into early this evening. Focus now
shifts to lake effect snow showers, with the high likelihood of at
least temporary heavy rates for tonight and very early Sunday in
northeast illinois and for northwest indiana mainly Sunday. A
winter weather advisory has been issued for this.

The strong upper low to our south is entering the ohio river valley
and will progress northeast and strengthen tonight. The surface
low around 996 mb will deepen several millibars tonight as it
lifts from kentucky to the mid-atlantic. This will keep winds
elevated through early to mid evening area wide and near lake
michigan throughout the night. Regional radar VWP data has sampled
30 kt at the top of the boundary layer and this should remain
steady through that time, so gusts of 30-35 mph look to be
consistent, along with a few gusts to 40 mph especially near the
lake. The reports of blowing and drifting snow have for the most
part not been too bad, or if worse then not that widespread. For
this reason we continue a special weather statement noting areas
of blowing snow into the evening.

Temperatures will drop into the single digits in parts of north
central illinois by midnight with lows in that area of 0 to 5, and
elsewhere upper single digits to lower to mid teens under lake
effect clouds snow showers. With winds easing later tonight, wind
chills Sunday morning will not be to the level of headlines, but
some wind chill readings just into the negative double digits are
favored for parts of northern illinois.

Lake effect snow showers have shown some strengthening signs
upstream in wisconsin, a sign colder low-level air is creeping
southward behind the departing cyclone. As it continues to do so,
more widespread light to moderate snow showers should be seen
developing into northeast illinois early to mid evening. Guidance
continues to indicate a well-defined convergence area and
resultant moderate to heavy lake effect snow band across the
western part of the lake into wisconsin early this evening and
shifting southward into northeast illinois mid-late evening.

Forecast lake effect parameters remain generally similar to what
has been seen over the past 24 hours, though for far northwest
indiana on Sunday morning the magnitude and residence time does
look better.

For this lake effect band, it is not a question of whether the
snow will be heavy, it is more so how long the residence time of
the band in any one place will be. That tends to be a very
challenging characteristic to determine greater than 12 hours in
advance. The lake effect parameters that are solid are the low-
level lapse rates and the convective cloud depths collocated with
the dendritic growth zone of -12c to -18c. This likely will make
up for the overall shallower cloud depths of 4-5 kft. The
inversion heights equilibrium levels are lower and not what we
typically see for concerns of a six plus inch event. So that
battle of parameters continues. But given consistent high-
resolution model trends and applying lake effect banded snow
conceptual model points toward heavy snow (1+ inch per hour)
likely underneath that band. So a quick several inches along with
very low visibility, both from falling snow and some blowing
snow, is enough to warrant an advisory. Have different start and
end times around the lake to account for the expected migration of
the band. In indiana the time window has lower confidence hence
why it is longer, but some of the higher impacts are likely in the
morning into early afternoon.

For total snowfall with lake effect the residence time is the key
factor, so messaging 2 to 6 inches with the higher end a bit more
favored in northwest indiana. Given the strong advection of the
lake effect parameters, lake effect snow is likely all the way
inland to the southern CWA border of ford and iroquois counties!
the snow should not be that heavy that far inland, but some
accumulation including possibly over an inch is possible in parts
of eastern dupage, will, kankakee, newton, and jasper counties.

Some lake effect snow showers are likely to shift back westward
and possibly back into illinois Sunday evening overnight, but
parameters should be weakening as the wind field diminishes.

Otherwise Sunday will see the coldest high temperatures of the
winter to this point, with a cold air mass giving a glancing blow
to the region. Highs look to be in the lower to middle single
digits. Lows Sunday night are primed to drop hard with potential
clearing inland, although high clouds in the west and lake effect
clouds near the lake could alter that. If not, lows to 5 below
zero or colder are certainly possible in outlying areas.

Mtf

Long term
352 pm cst
Monday through Saturday...

for the long term forecast period, winter will be firmly entrenched
across the region. The long-wave upper level pattern will
transition from a quickly progressive, high amplitude pattern at the
beginning of the period to lower amplitude, slowly progressive, with
a broad upper trough over the entire CONUS by mid-week.

Monday will start out the long term period cold and dry, with max
temps only reaching into the teens. Upper ridging is then expected
to build across the region Monday night and then, the pattern will
continue to amplify into Tuesday as a southern stream shortwave
lifts out of the southern rockies and into the central plains.

Temperatures should reflect a brief warming trend, with highs back
into the lower to middle 30s as broad swly upper flow and deep warm
advection sets up in advance of the deepening trough to the west.

While the global models start out the period relatively consistent,
they begin to quickly diverge in how they handle the southern stream
shortwave in both timing and intensity. While the models all
generally advertise a closed upper low associated with the srn
stream system, they all then evolve into a positively tilted open
wave.

The cold arctic high that is currently centered over manitoba
canada, near lake winnipeg, and is expected to gradually slide
southeast across the great lakes and ohio valley by Monday morning
and then continue to progress to the east coast as the sfc low
associated with the southern stream system lifts into the central
plains while quickly deepening. However, as is frequently the case,
the models are exhibiting differences in the timing and intensity of
the system.

However, there are signals that there may be a significant mixed
pcpn situation with warmer, moist air aloft overspreads a cold sfc
layer. Currently, will continue to carry the categorical pops for
Tuesday afternoon and evening, ramping up quickly Tuesday morning
and then quickly ending from west to east late Tuesday into into
Wednesday morning. Words of caution... Mixed freezing frozen liquid
pcpn details are difficult to pin down in the short term and are
very uncertain this far out in the forecast period. So, with this
caveat, current thinking is that morning snow will transition to a
freezing rain sleet snow mix and then transition to mostly rain late
in the day before changing back over to snow Tuesday night into
early Wednesday. Also, small deviations in the track of the system
could have significant impact on the sensible weather features. A
shift to a more sly ely track to the system would favor a greater
chance for more snow than freezing pcpn rain. A more nly westerly
track would suggest a greater chance for more mixed pcpn rain. There
is also some concern that the associated warm front may not get far
enough north to spread warm, above freezing, surface air across the
local area and that the warm front could be suppressed south by the
cold air associated with arctic high as it slides from manitoba to
the ERN conus. This would set up conditions favorable to an
extended freezing frozen pcpn mix of sleet freezing rain snow for
Tuesday into Tuesday evening. Readers are advised to follow
forecast updates as details regarding this system are likely to
chance over the next few days.

Following the passage of this system, the longer range guidance is
in generally good agreement on a significant cooling trend with
temperatures for the end of the week into the weekend. Sub-zero
lows are possible for next weekend wind chill reading approaching 20
below zero.

Aviation
For the 00z tafs...

546 pm... Primary forecast concern is lake effect snow late this
evening into Sunday morning. Additional concerns are blowing snow
and winds this evening.

Lake effect snow showers are developing spreading across southeast
wi with flurries light snow showers across northeast il. The lake
effect snow showers will continue to increase in intensity across
northeast il this evening... Likely forming a band by late evening.

Timing is still on track in the 04z-08z period for ord and 07z-11z
at mdw. The duration is likely to be less than 4 hours but not
confident to narrow the time window just yet. If the lake effect
does form into a single band... Visibilities 1 2sm or less are
likely though the lowest vis may be east of ord as it begins to
organize overnight. The band is expected to move into northwest in
by 12z and duration at gyy is uncertain. The models move this band
back west Sunday afternoon... Possibly to the il lakeshore by 00z
as its weakening. Added prob mention to gyy for the end of the
period but confidence for how far west this band may move is low.

Winds will remain northerly this evening with gusts into the mid
upper 20kt range. Blowing and low drifting snow is expected to
continue and as more fluffy lake effect snow falls... Blowing snow
may continue with gusts finally diminishing by sunrise though
speeds will remain 10-15kts Sunday as directions turn more to the
north northwest. Cms

Lot watches warnings advisories
Il... Winter weather advisory... Ilz014 until 9 am Sunday.

Lakeshore flood advisory... Ilz006-ilz014 until 9 am Sunday.

Winter weather advisory... Ilz006 until 4 am Sunday.

In... Lakeshore flood advisory... Inz001 until 9 am Sunday.

Winter weather advisory... Inz001-inz002... Midnight Sunday to 4
pm Sunday.

Lm... Gale warning... Nearshore waters until 3
am Sunday.

Heavy freezing spray warning... Lmz740-lmz741-lmz742-lmz743-
gary to michigan city in until 10 am Sunday.

Small craft advisory... Lmz740-lmz741-lmz742-lmz743-lmz744-
lmz745... 3 am Sunday to 3 pm Sunday.

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Weather Reporting Stations
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Stations Dist Age Wind Air TempWater Temp WavesPressureDewPt
FSTI2 13 mi140 min N 34 26°F
JAKI2 14 mi140 min NNE 19 G 34 28°F
CMTI2 - 9087044 - Calumet, IL 17 mi32 min N 21 G 29 25°F 1015.7 hPa19°F
WHRI2 - Waukegan Harbor, IL 36 mi40 min NNW 16 G 25 15°F
BHRI3 - Burns Harbor, IN 38 mi40 min NNE 16 G 19 25°F 1014.9 hPa

Wind History for Calumet Harbor, IL
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Last
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E14
NE16
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G23
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NE17
G24
NE18
G22
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G23
NE22
G29
NE21
G27
NE18
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NE16
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NE20
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G25
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NE22
G30
N19
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W4
G8
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G11
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W3
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W4
G8
NW6
NW2
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G10
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G8
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G10
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G12
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G15
NE14
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G21
2 days
ago
NE10
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G12
NE7
G11
E9
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NE8
E7
E7
E4
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E3
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E2
SE3
NE3
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SE1
--
W6
G9
W5
G9

Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago, Chicago Midway Airport, IL5 mi27 minNNW 18 G 265.00 miLight Snow Fog/Mist and Breezy23°F17°F78%1018.2 hPa
Chicago, Chicago-O'Hare International Airport, IL11 mi29 minN 22 G 282.50 miLight Snow Fog/Mist and Breezy16°F12°F84%1018.6 hPa
Chicago / Wheeling, Pal-Waukee Airport, IL19 mi28 minNNW 16 G 291.50 miLight Snow17°F8°F68%1019.7 hPa
Lewis University Airport, IL22 mi25 minN 20 G 267.00 miLight Snow and Breezy20°F14°F82%1017.3 hPa
Chicago / West Chicago, Dupage Airport, IL24 mi28 minN 18 G 353.00 miBlowing Snow and Breezy16°F9°F74%1019.1 hPa

Wind History from MDW (wind in knots)
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Last 24hrE13E13
G22
E14E15
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G23
E17
G26
E18
G28
NE15
G24
NE17NE17
G28
NE21
G28
NE16NE19
G26
NE17NE22
G29
NE22
G32
NE23
G33
N20
G29
N19
G31
N16
G28
N21
G28
N17
G23
N18
G26
1 day agoNW8NW7W7NW6W7NW9NW6NW7N6W5W5N8N4N5NE5N8NE10NE13NE10E13E17E15E14
G23
E14
2 days agoE10E7E6E8E6E7E6E5E7E3E5NE3CalmCalmCalmCalmW3W4NW6NW7W8NW8W7NW6

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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 (22,6,7,8)
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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.