Chicago Weather Forecast (O'Hare Official) 5:17 pm CDT Sep 28, 2017 with Forecast Discussion


Tonight: Isolated showers after 1am. Partly cloudy, with a low around 54. West southwest wind 5 to 10 mph. Chance of precipitation is 20%.

Friday: Mostly sunny, with a high near 69. Northwest wind 10 to 15 mph becoming north northeast in the afternoon. Winds could gust as high as 20 mph.

Friday Night: Partly cloudy, with a low around 51. North northeast wind 5 to 10 mph.

Saturday: Sunny, with a high near 65. East wind 5 to 10 mph.

Saturday Night: Mostly clear, with a low around 49. South southeast wind around 5 mph.

Sunday: Mostly sunny, with a high near 70.

Sunday Night: Mostly cloudy, with a low around 56.

Monday: Partly sunny, with a high near 81.

Monday Night: Partly cloudy, with a low around 62.

Tuesday: Mostly sunny, with a high near 85.

Tuesday Night: Partly cloudy, with a low around 63.

Wednesday: Mostly sunny, with a high near 84.

Wednesday Night: Mostly cloudy, with a low around 60.

Thursday: Partly sunny, with a high near 77.


Amf Ohare IL
 41.98°N 87.9°W

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AREA FORECAST DISCUSSION
National Weather Service Chicago/Romeoville, IL
GO Current Forecast Discussion

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233 PM CDT Thu Sep 28 2017

.SHORT TERM... 217 PM CDT

Through Friday...

We will have another cold front push through the area from the northwest overnight, driven by potent clipper-like upper level shortwave. The stronger portion of this wave will pass over Lake Michigan. Moisture is weaker on the southwest flanks of the system. Low-mid level lapse rates are modest with the front, and there appears enough forcing for at least some isolated showers with the front, though forecast soundings are capped above these steeper lapse rates which would preclude a thunder threat. These we may see a bit more coverage of precipitation falling then isolated, but have kept pops low as accumulating precip will be harder to come by.

Behind the front a secondary surge of slightly cooler air then our earlier in the week front will move in accompanied by a somewhat stiff NNW wind, with gusts of 20-25 mph certainly plausible. Winds will shift to NNE closer to the lake. Expect highs only in mid 60s north to the lower 70s south with at least some scattered cumulus clouds. With the cold air aloft over the lake and a more focused northerly wind, expect lake effect clouds to extend into northwest Indiana and possibly a bit farther east. While equilibrium levels do increase, they do remain below levels that would support thunder over the lake and near lake areas. Also, moisture is still fairly lacking, so any lake effect showers do look to be fairly isolated.

KMD

&&

.LONG TERM... 232 PM CDT

Friday night through Thursday...

The main weather story for the extended period will be the likely return to at least a few days of much above normal temperatures early next week. The chances for any meaningful precipitation also appears to be low through much of the period.

The period will start out rather chilly on Saturday morning with a stout 1030 MB surface high over the western Great Lakes region. Lows Friday night are likely to drop into the lower to middle 40s inland from Lake Michigan. This surface high will gradually shift towards the eastern Great Lakes during the day Saturday. However, high temperatures during the afternoon will likely remain cool in the 60s to near 70. The high shifts over New England by Sunday, and as it does so, expect the low-level flow should turn southerly again. As a result, a warming trend will commence. While the warmest weather is expected early next week, temperatures on Sunday will likely still warm into the 70s, making for a rather nice day.

An anomalous 500 MB ridge (590 +DAM) will began building across much of the eastern half of the country on Monday, as a trough sets up over the west. This larger scale pattern will help set u Pdeep south-southwesterly flow across our area on Monday, and this will likely result in breezy southerly winds Monday along with a quick jump in temperatures. Highs on Monday are likely to be into the lower 80s for most. However, by Tuesday expect highs into the middle to possibly upper 80s as 850 and 925 MB temperatures warm to around 15-16C and 22C, respectively. These values are near record values for the first week of October, so another record high temperature is certainly not out of the question, especially considering how dry conditions are across the area. The record highs on Tuesday are 91 degrees at Chicago and 90 at Rockford, so temperatures near these values are certainly possible (but not currently forecast) next Tuesday.

Uncertainty begins to increase for the later half of the week as there are some disagreements amongst the forecast guidance with the handing of the upper pattern across the country. This will have large consequences on the timing of any cold frontal passages during the mid to late week period. As a result, there are questions as to how long this very warm weather will last. Overall, though it would appear that the amplitude of the larger scale pattern across the country would tend to favor a slower east to west progression of storm systems. Therefore, its possible that the very warm and dry conditions extend into the later portion of the week.

KJB

&&

.AVIATION... For the 18Z TAFs...

Aviation concerns are generally low. First on the docket is the inland progression of the lake breeze, and then a cold front that will shift southeast through the area tonight. Winds have shifted to NE right along the lakefront. Hi res guidance brings these NE winds to MDW in the afternoon, and we have already seen it occasionally at MDW. Confidence on how long the NW wind will mix in is only medium, and therefore expect some variability through at least 19z. ORD will keep the westerly winds today.

Some isolated/scattered showers are possible along a line from RFD-ORD-VPZ after midnight with the cold front. Coverage should be somewhat low, best chances along the WI border and over the lake. These will quickly shift southeast of the area before daybreak. Visibility restrictions would be short lived if any, and conditions should largely remain VFR. Behind the front winds will shift to a NNW and become gusty in the morning, likely taking on a NNE component by midday Friday, so expect winds at ORD/MDW to flo Pcloser to the N through the morning then specifically outlined in the TAF. Lake effect showers in IN should be spotty.

KMD

&&

.MARINE... 232 PM CDT

Breezy west-southwesterly flow on the lake this afternoon will turn northerly tonight as a cold front drops down the lake. Expect northerly winds to increase up around 30 kt late tonight, and continue on Friday as a stout surface high begins to build in across the Upper Midwest. These strong winds will set up dangerous conditions for small craft along the southern Lake Michgian near shores, where waves are likely to top 6 feet on Friday. There will also be a decent chance for lake effect showers with waterspouts tonight into Friday, especially over eastern sections of the lake as favorable thermodyamics set up over the lake. A surface high is then forecast to shift over the lake on Saturday, which should result in lighter and more variable winds, followed by breezy southerly winds late Sunday into early next week.

KJB

&&

.LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None.

MORE BELOW
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Arlingtoncardinal.com/radar
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Arlingtoncardinal.com/usforecastchart
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Arlingtoncardinal.com/uvindex
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Arlingtoncardinal.com/sun
Chicagoland Sunrise, Sunset and Solar Information for Chicago area

Arlingtoncardinal.com/moon
Chicagoland Moonrise, Moonset and Lunar Phase information for Chicago area

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Chicago record high temperatures

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Chicago extreme records

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allergy.chgowx.com
Chicago allergy weather

arthritis.chgowx.com
Chicago arthritis weather

respiratory.chgowx.com
Chicago respiratory weather

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 BEACH HAZARDS … 

LAKESHORE HAZARD MESSAGE NATIONAL WEATHER SERVICE CHICAGO IL 325 PM CDT THU SEP 28 2017

ILZ006-014-290430- /O.NEW.KLOT.BH.S.0022.170929T1800Z-170930T1200Z/ LAKE IL-COOK- 325 PM CDT THU SEP 28 2017

...BEACH HAZARDS STATEMENT IN EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY MORNING...

THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A BEACH HAZARDS STATEMENT...WHICH IS IN EFFECT FROM FRIDAY AFTERNOON THROUGH SATURDAY MORNING.

* LOCATION...ILLINOIS LAKE MICHIGAN BEACHES.

* HIGH WAVE ACTION AND DANGEROUS SWIMMING CONDITIONS EXPECTED.

* FORECAST WAVE HEIGHTS...4 TO 7 FEET.

* STRONG RIP CURRENTS AND STRUCTURAL CURRENTS EXPECTED.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

LIFE THREATENING WAVES AND CURRENTS ARE EXPECTED AT THE BEACHES. PEOPLE VISITING THE BEACHES SHOULD STAY OUT OF THE WATER.

RIP CURRENTS ARE POWERFUL CHANNELS OF WATER FLOWING QUICKLY AWAY FROM SHORE, WHICH OCCUR MOST OFTEN AT LOW SPOTS OR BREAKS IN SANDBARS. RIP CURRENTS CAN SWEEP YOU INTO DEEPER WATER.

STRUCTURAL CURRENTS FORM ALONG PIERS WHERE LONGSHORE CURRENTS AND WAVE ACTION FLOW INTO THE STRUCTURE. STRUCTURAL CURRENTS CAN SWEEP YOU INTO DEEPER WATER ALONG THE PIER STRUCTURE.

EXPOSED BEACHES ARE MORE LIKELY TO EXPERIENCE THE MOST SIGNIFICANT WAVE AND CURRENT IMPACTS. IMPACTS AT BEACHES WITH PROTECTIVE BREAKWALLS OR JETTIES WILL BE SUBJECT TO THE ORIENTATION OF STRUCTURES AS WELL AS WIND AND WAVE DIRECTION.

FOR INFORMATION ON SWIM ADVISORIES OR BANS AT CHICAGO BEACHES VISIT: WWW.CPDBEACHES.COM.