Tornado Warning 4, NWS Chicago, IL

278 
WWUS53 KLOT 090129
SVSLOT

Severe Weather Statement
National Weather Service Chicago/Romeoville
829 PM CDT Wed May 8 2019

ILC099-090138-
/O.EXP.KLOT.TO.W.0004.000000T0000Z-190509T0130Z/
La Salle IL-
829 PM CDT Wed May 8 2019

...THE TORNADO WARNING FOR SOUTHWEST LA SALLE COUNTY WILL EXPIRE
AT 830 PM CDT...
                
The storm which prompted the warning has weakened below severe 
limits, and no longer appears capable of producing a tornado at this 
time. Therefore, the warning will be allowed to expire.

LAT...LON 4130 8916 4128 8900 4123 8888 4110 8907
      4110 8916
TIME...MOT...LOC 0128Z 213DEG 46KT 4201 8849 

$$

IZZI

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
637 PM CDT Wed May 8 2019

.SHORT TERM...
256 PM CDT

Through Thursday night...

Focus continues to be on the potential for some severe
thunderstorms this evening as well as heavy rain this evening into
the overnight.

This afternoon: A long-wave mid-level trough currently over the
central and northern Rockies into the Great Plains continues to
induce an elongated surface trough from the TX panhandle NE to a
closed surface low over central IA. A surface warm from associated
with the low extends SE. As of 19Z, analysis of surface obs and the
demarcation of surface-based cumulus on visible satellite indicate
the warm front stretches from near Peoria SE through southern Ford
county to near Danville. With stout easterly winds off the lake
across the northern CWA, a fairly large temp gradient has developed
across the CWA with 19Z temps ranging from 47F in Waukegan to near
80F in Paxton. The presence of the surface cumulus indicate that a
previously decent cap in place is gradually eroding. With all that
said, the lack of any notable forcing this afternoon combined with
decent stability north of the warm front should prevent any
convective initiation through at least late afternoon.

Tonight: The true surface warm front will have likely become
somewhat diffuse by this point, with afternoon clearing/heating
north of it possibly allowing the front to jump northward across
western IL late this afternoon. To complicate matters, the front
will start to become occluded across eastern IA. Forcing for
convective initiation near the Mississippi River early this evening
looks to be tied to a trough currently tracking NE from eastern KS.
Activity along this trough axis should gradually move eastward
through the evening, reaching the Chicago metro by late evening.

Convective mode and strength continue to be difficult to pin down.
At this time, the best chance for strong to locally severe
thunderstorms will likely be confined to near the occlusion triple
point SE along and south of the warm front into central IL early
this evening. Instability is lacking to some degree owing to only a
narrow depth of better lapse rates. However, deep layer shear will
be supportive of organized convection. With linear forcing and shear
vectors nearly parallel to the trough aloft, convective mode should
quickly evolve into a line. However, a few discrete supercells can
not be ruled out. The tornado threat has appeared to diminish
partially due to lessening low-level instability, but a brief spin
up remains possible with any storm interacting with the warm front
across the extreme SW CWA early this evening. Overall, the main
concern for any severe threat remains west of I-39, but particularly
SW of a line from Dixon to southern La Salle county through mid-
evening. A few stronger storms may reach the Chicago metro, with
gusty winds the primary threat. Activity will continue east
overnight while in a weakening trend.

Thursday: CAA will be ongoing across the far west CWA just after
daybreak while showers and possibly embedded convection will be
ongoing across the eastern CWA. Forecast trends have been to end
precip chances across the east earlier than before, thus limiting
any severe storm threat across the far SE CWA during the afternoon.
Decent cloud cover and CAA will also allow temps to hold steady or
even fall during the afternoon.

Thursday night: Another shortwave trough embedded in broader
cyclonic flow aloft will track ENE across the area during this time.
While deep moisture is lacking, there may be sufficient low-level
moisture and cloud depth to generate some isolated very light rain
showers late evening into the overnight. Overall, a large majority
of the area will remain dry through the night.

Kluber

&&

.LONG TERM...
204 PM CDT

Friday through Wednesday...

The area looks dry across the area for Friday and much of Saturday
as a surface ridge of high pressure dominates across the western
Great Lakes Region. Temperatures for inland areas will likely top
out in the upper 50s to low 60s Friday, and a couple of degrees
warmer on Saturday. However, onshore flow both days will likely
keep temperatures in the 50s along the lakeshore.

The next chance for showers will come late Saturday night and into
Sunday. During this period model/ensemble guidance indicates that a
mid-level shortwave will dig southward across the Upper Midwest
and western Great Lakes Region. This does not appear to be a big
rain event for the area, however, as the main shower and
thunderstorm activity may remain to our southeast in association
with another disturbance shifting over the southern CONUS ahead of
the Upper Midwest disturbance. Therefore, at this time will are
only carrying some low chances for showers and possibly a
thunderstorm for the area on Sunday as the upper system moves
overhead.

Later in the extended temperatures look to moderate back well
into the 60s on Monday, and possibly back into the 70s for Tuesday
of next week. While most of the period will be dry across the
area, there will be some occasional chances for shower and
thunderstorm activity over the area, especially late Tuesday into
Wednesday, when another disturbance may shift over the area. At
this time, however, chances for precipitation late in the period
remains at, or under 50 percent.

KJB

&&

.AVIATION...
For the 00Z TAFs...

637 PM...Forecast concerns include...

Scattered thunderstorms this evening.
Wind shift from southeast to southwest overnight.
Mvfr...possible ifr...cigs Thursday morning.
Showers through Thursday morning.

A line of thunderstorms extends from northwest IL south to west
central IL early this evening. This line is expected to slowly
lift north/northeast through the evening with a slow weakening
trend possible. Even if thunder activity begins to diminish...
brief heavy rain along with mvfr cigs/vis will be possible with
the strongest cells. Scattered showers will continue overnight
slowly ending from west to east. Additional showers and maybe a
few thunderstorms will be possible Thursday morning...after
daybreak...with the best chances mainly southeast of the
terminals.

A warm front is slowly lifting north across northern IL with winds
becoming more south/southeast behind this front. Eventually winds
will shift to the southwest overnight and there may be a wind
shift to westerly with the line of showers/storms as they move
through. Winds will turn more westerly by midday Thursday and then
to the northwest toward Thursday evening.

Mvfr cigs are expected to develop tonight and persist through late
Thursday morning. These cigs may dip into ifr toward sunrise but
confidence is low. Mvfr cigs may also redevelop or persist into
Thursday afternoon/evening with low confidence here too. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...IL nearshore waters until 4 AM Thursday.

&&

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Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
338 PM CDT Wed May 8 2019

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
092045-
Winnebago-Boone-McHenry-Lake-Ogle-Lee-De Kalb-Kane-DuPage-Cook-
La Salle-Kendall-Grundy-Will-Kankakee-Livingston-Iroquois-Ford-
Porter-Newton-Jasper-Benton-
338 PM CDT Wed May 8 2019 /438 PM EDT Wed May 8 2019/

This Hazardous Weather Outlook is for portions of North Central
Illinois...Northeast Illinois and Northwest Indiana.

.DAY ONE...Tonight.

Weather hazards expected...

  Elevated Thunderstorm Risk...with an associated:
     Limited hail risk...up to quarter size.
     Limited damaging wind risk...up to 60 mph.
  Limited Flooding Risk.

DISCUSSION...

An area of showers and thunderstorms developing near
the Mississippi River late this afternoon will move eastward
across northern Illinois through the evening hours. Some storms
could become strong with the main threat from strong gusty winds. The
highest threat will be confined to the southwest half of the forecast
area. The threat for strong storms will decrease through the
evening hours, but gusty winds will remain possible as
activity spreads eastward towards I-57.

While widespread heavy rainfall is not anticipated, thunderstorms
could produce locally heavier amounts which could lead to some
renewed river rises and additional flooding through the end of the
week.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday...
  Limited Thunderstorm Risk.
Tuesday...
  Limited Thunderstorm Risk.

.SPOTTER INFORMATION STATEMENT...

Spotters may be needed late this evening west of I-39 and south
of I-88.

GENERAL STORM MOTION OF THE DAY:

 Moving toward the northeast at 40 to 50 mph.

LMZ740>745-092045-
Winthrop Harbor to Wilmette Harbor IL-
Wilmette Harbor to Northerly Island IL-
Northerly Island to Calumet Harbor IL-
Calumet Harbor IL to Gary IN-Gary to Burns Harbor IN-
Burns Harbor to Michigan City IN-
338 PM CDT Wed May 8 2019

This Hazardous Weather Outlook is for portions of the Illinois
nearshore waters of Lake Michigan and the Indiana nearshore
waters of Lake Michigan.

.DAY ONE...Tonight.

Weather hazards expected...

  Hazardous conditions for small craft.
  Elevated Thunderstorm Risk.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Thursday...
  Limited Thunderstorm Risk.
Tuesday...
  Limited Thunderstorm Risk.

KJB

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Special Weather Statement
National Weather Service Chicago/Romeoville
724 PM CDT Wed May 8 2019

ILZ010-011-019-090100-
De Kalb IL-La Salle IL-Lee IL-
724 PM CDT Wed May 8 2019

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN LA SALLE...EASTERN
LEE AND SOUTHWESTERN DE KALB COUNTIES UNTIL 800 PM CDT...

At 724 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles west of Paw Paw to near Mendota to near
Varna. Movement was northeast at 60 mph.

Wind gusts up to 50 mph will be possible with these storms.

Strong thunderstorms will be near...
  Mendota around 730 PM CDT.
  Earlville and Paw Paw around 735 PM CDT.
  Peru and Oglesby around 740 PM CDT.
  Shabbona, La Salle, Utica and North Utica around 745 PM CDT.

Other locations impacted by these storms include Compton, Leonore,
Troy Grove, West Brooklyn, Lee, Lostant, Cedar Point and Steward.

Including the following interstates...
 I-39 between mile markers 41 and 95.
 I-80 between mile markers 74 and 85.
 I-88 between mile markers 83 and 85.

This includes...  Illinois Valley Community College, Matthiessen
State Park, Starved Rock State Park, and Tri-County Fairgrounds.

LAT...LON 4189 8900 4189 8894 4193 8894 4186 8881
      4115 8898 4110 8905 4110 8916 4132 8917
      4146 8912 4168 8921
TIME...MOT...LOC 0024Z 213DEG 54KT 4168 8914 4153 8907 4108 8922

IZZI

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
750 PM CDT WED MAY 8 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0735 PM     TSTM WND GST     PERU AIRPORT            41.35N 89.15W
05/08/2019  M46 MPH          LA SALLE           IL   AWOS

0735 PM     TSTM WND GST     ROCHELLE AIRPORT        41.89N 89.08W
05/08/2019  M43 MPH          OGLE               IL   AWOS

&&

Special Weather Statement
National Weather Service Chicago/Romeoville
753 PM CDT Wed May 8 2019

ILZ011-019-090130-
De Kalb IL-La Salle IL-
753 PM CDT Wed May 8 2019

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN LA SALLE AND DE KALB
COUNTIES UNTIL 830 PM CDT...

At 753 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Kirkland to near Waterman to 6 miles west of
Serena. Movement was northeast at 50 to 60 mph.

Wind gusts up to 50 mph will be possible with these storms.

Strong thunderstorms will be near...
  Kirkland and Kingston around 800 PM CDT.
  Genoa and Hinckley around 805 PM CDT.
  DeKalb around 810 PM CDT.
  Sandwich, Cortland, Somonauk and Maple Park around 815 PM CDT.
  Sycamore around 820 PM CDT.

Other locations impacted by these storms include Millington.

Including the following interstates...
 I-80 between mile markers 87 and 91.
 I-88 between mile markers 85 and 101.

This includes...  Northern Illinois University, Sandwich Fairgrounds,
and Buffalo Rock State Park.

LAT...LON 4213 8859 4207 8859 4206 8860 4158 8860
      4147 8865 4132 8892 4167 8887 4202 8894
      4210 8894 4215 8871
TIME...MOT...LOC 0053Z 220DEG 42KT 4209 8888 4173 8881 4145 8885

IZZI