Sunday, December17, 2017 L-36.com


Marine Weather and Tides
Winthrop Harbor, IL

Version 3.4
What's New / NOTES
6/25/2017 - NOAA is having a major issue that impact the 7 day forecast load times. Many users are reporting problems. The issue has been reported.
5/23/2017 - Worked with NOAA again to speed up the 7 day forecast load times. Thanks to them for being responsive.
5/19/2016 - There were issues with the 3 day airport observation history. I switched to another data source. Let me know if you see any issues with the data feeds.

Sunrise 7:14AMSunset 4:21PM Sunday December 17, 2017 7:44 AM CST (13:44 UTC) Moonrise 7:26AMMoonset 5:18PM Illumination 1% Phase: Waning Crescent; Moon at 29 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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LMZ646 Wind Point Wi To Winthrop Harbor Il- 705 Am Cst Sun Dec 17 2017
Today..East wind 10 to 15 knots easing to 5 to 10 knots early in the afternoon, then backing northeast late in the afternoon. Patchy fog through the day. Waves 2 to 4 feet subsiding to 1 to 3 feet late in the afternoon.
Tonight..West wind 5 to 10 knots. Patchy fog through the night. Waves around 1 foot.
Monday..West wind 5 to 10 knots becoming southwest 10 to 15 knots with gusts to around 20 knots in the late morning and early afternoon, then rising to 15 to 20 knots with gusts to around 25 knots late in the afternoon. Mostly cloudy. Waves around 1 foot.
Monday night..Southwest wind 15 to 20 knots becoming 10 to 20 knots late in the evening, then becoming southwest 10 to 20 knots after midnight veering west 15 to 20 knots early in the morning. Gusts up to 30 knots. Partly cloudy through around midnight then becoming mostly cloudy. Waves 2 to 4 feet subsiding to 1 to 2 feet early in the morning. Wave heights are for ice free areas.
LMZ646 Expires:201712171700;;027118 FZUS53 KMKX 171305 NSHMKX Nearshore Marine Forecast National Weather Service Milwaukee/Sullivan WI 705 AM CST Sun Dec 17 2017 For waters within five nautical miles of shore on Lake Michigan LMZ646-171700-

7 Day Forecast for Marine Location Near Winthrop Harbor village, IL
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location: 42.47, -87.82     debug


Area Discussion for - Chicago, IL
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Fxus63 klot 171143
afdlot
area forecast discussion
national weather service chicago romeoville, il
543 am cst Sun dec 17 2017

Short term
212 am cst
through Monday...

primary forecast challenges in the short term period of the
forecast revolve around stratus, fog, and drizzle potential and
the subsequent impacts on temperatures.

Have been monitoring a large bank of stratus over wi bleeding into
far northern il using goes-16 nighttime microphysics rgb, which
beautifully showed the stratus expanding south with 1 minute
resolution in meso-sector 2. Unfortunately, the leading edge
became obscured by high cloudiness around 0700 utc, so flying a
bit blind this morning with respect to how far south the stratus
is making it. In terms of the public sky cover forecast, the
stratus location is somewhat irrelevant, since anywhere not
blanketed by stratus will still be ovc thanks to mid-high level
cloudiness streaming northeast ahead of southern stream
disturbance. Primary impact of stratus today will be to keep temps
from rising much at all and have lowered high temps northern cwa
as it would appear stratus could linger much of the day far
northern cwa.

Regarding the southern stream shortwave, guidance continue to show
this wave rapidly dampening today as it encounters confluent convergent
flow aloft. Big question is how quickly the precip will dissipate
as it lifts north. The trend in model guidance has been strongly
toward a rapid dissipation of precip with many models now showing
little if any precip making it into our CWA today. Have trended
pops lower today, though generally keep pops higher than guidance
supports in deference to previous forecast and to be in better
collaboration with neighboring offices. Any precip that falls
should be light and in the form of liquid.

Tonight, what's left of the weak front over the CWA will lift
north as a warm front with slightly higher low level moisture
advecting northeast into the area. Strong signal in available
guidance for development of widespread stratus deck this evening,
with some drizzle likely along with at least some threat for fog
development. Warm air advection and ovc skies should result in
nearly steady temps all night and have gone well above guidance
for low temps and suspect that low temp forecast for tonight is
still too cold over northern cwa. It's unclear how dense the fog
will become tonight, since with 4" soil temps in mid-upper 30s
and some wind it is not a particularly favorable set-up for
stratus building down to widespread dense fog. Still some guidance
suggests that could happen, so maintained a mention of patchy fog
tonight, but suspect that will be fairly widespread light fog vs
dense fog.

Monday's forecast is tricky thanks to the lingering stratus and
fog from Sunday night. Most guidance suggests that this stratus
will quickly clear out Monday, however given the time of year and
the expectation that it will be quite thick, it seems likely that
most of the area should stay socked in all day. Best chance of
clearing would be western CWA later in the afternoon, but even
that would likely be too little, too late for high temps Monday.

Given the expectation of stratus have lowered high temps from the
blended model guidance, however if stratus lingers as expected
then high temps Monday would likely be even cooler than what i've
got in for highs Monday.

- izzi

Long term
318 am cst
Monday night through Saturday...

the main focus is the stronger storm system expected to impact the
midwest and great lakes Thursday and Friday. As we've been
advertising, the above normal temperature regime will persist
much if not all of the work week. This will occur as the mid and
upper pattern across north america reshuffles, resulting in mainly
positive mid-level height anomalies. A dry cold front trough
passage will occur Monday night into Tuesday. Steady to gusty
southwest winds ahead of the front Monday night will keep lows
above normal highs for mid december.

Guidance has backed off on the strength of the height falls and
caa with this front, which will play a role in high temperatures
Tuesday. Assuming any lingering clouds clear out, mixing should be
fairly deep as a drier air mass moves in behind the front with
breezy west-northwest winds. Given well above normal thermal
profiles now expected behind the front, the drier air and deeper
mixing should enable temps to warm into the upper 40s to lower 50s
and wouldn't be surprised at mid 50s readings especially south.

Again, the one fly in the ointment could be cloud cover which is
always tricky with such a low Sun angle, but currently have decent
confidence in them clearing.

Tuesday night into Wednesday could very well be the coolest
portion of the work week and even it will be above normal. A broad
surface ridge axis will stretch across the region, so mostly clear
skies and diminishing winds will support lows in the 20s area
wide, followed by a pleasant Wednesday with highs in the mid 30s
to lower 40s under increasing mid and high clouds.

Turning to later in the work week, significant re-amplification
of anomalous poleward ridging up to and north of alaska will set
the stage for the likelihood of the return of a colder pattern
christmas weekend. The late week storm system continues to be
highly uncertain with respect to its magnitude, track and
evolution from the plains toward the midwest and great lakes as it
affects the region Thursday and Friday and heralds the return of
the colder pattern. A swath of accumulating snow will be likely
with this system to the north of this path. It is quite early yet
to be mentioning trends in any meaningful sense given
predictability issues this far out, but a majority of the guidance
and ensemble members currently favor keeping the snow swath mostly
north and west of the cwa.

Adding some more detail, the mid upper pattern will be complex
with this setup, with none of the major players being sampled by
the RAOB network for the next few days. Thus expect continued
model ensemble variability until everything gets sorted out. This
is important to note, because while much of the latest guidance
exhibited a decided shift to a warmer outcome for the cwa, we're
still in the time range where significant shifts are possible if
not likely.

It appears that some energy in the western trough will dive into
the southwest CONUS and could get even cut off or take on a
negative tilt, slowing the overall progression of the system.

Thus, there was also a slowing trend noted in the 00z guidance
suite. Where the surface low ejects northeast from in the plains
will ultimately dictate its track and impacts to the CWA later
Thursday through Friday, with again the majority of the 00z
guidance favoring a warmer rainier outcome due to downstream mid-
level heights over our area being pumped higher. In fact, the
warmest models, namely the 00z operational ECMWF (and a
substantial majority of its ensemble members), support a surface
low track that would surge unseasonable warmth and moisture into
parts of the area Friday and a non-zero thunder threat. On the
other end of the spectrum, the 00z GFS and some of its ensembles
still kept open possibility of a change to snow for parts of
northern half of cwa.

Taking the previous few paragraphs into account, have trended
grids to more rain mention Thursday night and Friday, but still
feature a rain snow mix for the northwest half of the CWA given
the inherent uncertainty lower confidence in this time range. This
includes bumping up temperatures from previous forecast. As the
much colder air arrives behind the cold front later Friday into
Saturday, may need to monitor for a short-wave riding along the
front for any snow possibly getting back into parts of the cwa.

Finally, confidence is fairly high in below normal temperatures to
start christmas weekend, but low confidence in the magnitude of it.

As we've seen this month, the overall lack of snow cover has
modified the cold air masses that have visited the area. A shot of
even colder air is possible christmas eve into christmas day.

Castro

Aviation
For the 12z tafs...

flying a bit blind early this morning with respect to the
location of the leading edge of the ifr stratus with mid-high
clouds obscuring it on satellite imagery. The ifr stratus had been
building steadily southward and reached pwk before 09z, however
after talking to observer at ord, is still not visible on the
northern horizon. Given the light northeast flow and earlier
presence of some ifr stratus downtown, opted to leave ifr CIGS in
ord for a time this morning based on the assumption that it is
still inching south. By later this morning, boundary layer flow
should begin to turn light southerly and have ord going back to
vfr. This is very low confidence forecast and when if ifr arrives
it could linger longer, but given uncertainty whether it will even
arrive, opted to not change timing of its departure.

Low level moisture should increase again tonight and any where
that isn't socked in with stratus is expected to see stratus
develop during the mid-late evening hours. Potential exists for
vlifr lifr stratus and fog, but for now just trended CIGS down
further from the previous forecast but not taking conditions as
low as they could potentially get. Could also see some drizzle
develop later tonight and have added a prob30 for this potential
and added lower CIGS vsby in that prob30 to open the door to
potentially lower conditions tonight.

- izzi

Marine
212 am cst
only real marine concern through the middle of next week is with
powerful low pressure tracking across central canada bringing a
period of strong, potentially gale force, winds Monday night ahead
of a cold front. Forecast guidance has been slowly backing off on
the magnitude of the winds with this event and it now looks like
the best shot of gales is over the northern portions of the lake
with the southwest winds Monday night. Behind the front Tuesday
afternoon into Tuesday evening, it is looking more like 30kt
winds south with the best chance for prevailing lower end gales
over the central and northern portion of the lake. Thus have
trended the forecast winds down slightly. Still looks like the
next system will impact the region late in the week, but the
forecast track is still highly uncertain and will play a big role
in eventual wind speeds direction.

- izzi

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
KNSW3 - Kenosha, WI 8 mi45 min ENE 11 G 13 34°F 1019 hPa (-0.3)
WHRI2 - Waukegan Harbor, IL 8 mi65 min NE 11 G 12 35°F
FSTI2 35 mi105 min NE 11 37°F
OKSI2 40 mi105 min E 1.9 38°F
MLWW3 - Milwaukee, WI 40 mi35 min E 12 G 14 33°F
CHII2 - Chicago, IL 40 mi25 min ENE 8 G 8.9 39°F 36°F
CNII2 44 mi30 min NNE 4.1 G 8 36°F 34°F
JAKI2 49 mi105 min SSE 2.9 36°F

Wind History for Calumet Harbor, IL
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W7
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Airport Reports
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AirportDistAgeWind ktVisibilitySky/WeatherTempDewPtHumidityPressure
Chicago/Waukegan Regional Airport, IL4 mi50 minENE 63.00 miFog/Mist34°F32°F92%1019.5 hPa
Kenosha, Kenosha Regional Airport, WI10 mi52 minENE 95.00 miFog/Mist35°F30°F85%1019.3 hPa
Racine, Batten International Airport, WI20 mi52 minE 75.00 miFog/Mist34°F30°F89%1020.1 hPa

Wind History from UGN (wind in knots)
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Last 24hrW3SW5543S5SW4E5E4E3NE3N3N4N4CalmNE5NE7NE7NE8E5NE6NE7NE6NE6
1 day agoW8
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W86SW7SW85SW4SW7SW7SW7SW8SW12
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2 days agoNW7NW8N8NW6NW7NW7NW7NW5NW4CalmCalmSW33SW3CalmSW6SW4SW7SW7SW7SW7W5W9
G15
W12

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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Weather Map
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IR Satellite Image from GEOS
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GOES Local Image of GreatLakes    EDIT
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Wind Forecast for Chicago, IL (8,2,3,4)
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Ground Weather Radar Station Milwaukee, WI
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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.