Alert archive / Indiana / Flash Flood Warnings in 2020

Flash Flood Warning 10, NWS Chicago, IL

May 23, 2020Porter County, Indiana

NWS Chicago, IL issued this flash flood warning at May 23, 2020, 8:06 PM CDT for Porter County, Indiana. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 23, 2020, 8:06 PM CDT (01:06 UTC)
Expired: May 24, 2020, 12:00 AM CDT
In force: 4 hr
Issued by: NWS Chicago, IL
Area: Storm-based polygon
Flood severity: None

County Porter County, IN

The radar

The Chicago radar (KLOT), 85 km from the middle of the area, began a volume at 01:10 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.1 hours before the alert went out and 198 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 778 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 1426 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 122 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Chicago, IL wrote its last area forecast discussion before this flash flood warning went out at May 23, 6:37 PM CDT, 1 hour 29 minutes earlier.

Area forecast discussion, May 23, 6:37 PM CDT, 1 hour 29 minutes before

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Hazardous weather outlook, May 23, 5:09 PM CDT, 2 hours 57 minutes before

Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
509 PM CDT Sat May 23 2020

ILZ003>006-008-010>013-019>021-023-032-033-039-103>108-INZ001-002-
010-011-019-242215-
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage-
La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford-
Northern Cook-Central Cook-Southern Cook-Northern Will-
Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton-
509 PM CDT Sat May 23 2020 /609 PM EDT Sat May 23 2020/

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

.DAY ONE...Tonight.

Weather hazards expected...

  Significant Thunderstorm Risk...with an associated:
     Elevated Tornado risk.
     Elevated hail risk...up to golf ball size.
     Elevated damaging wind risk...up to 70 mph.
  Limited Flooding Risk.

DISCUSSION...

Scattered strong to severe thunderstorms will continue across
the area through early this evening. These are likely to move out
of northern Illinois by 8 to 9 p.m. and northwest Indiana by
10 p.m., though scattered storms may linger in eastern Illinois
and northwest Indiana into early overnight.

The primary severe threat are tornadoes, large hail, and damaging
winds. Given the wet conditions of late and elevated river levels,
very heavy downpours from thunderstorms will be capable of
producing isolated to instances of flash flooding, along with
renewed river and stream rises. After the primary severe and
flooding threat ends, the potential exists for thunderstorms to
focus east of I-57 into the early overnight, which could prolong
the flooding risk for those areas, especially in northwest
Indiana.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Sunday and Monday...
  Limited Thunderstorm Risk.
Tuesday and Wednesday...
  Significant Thunderstorm Risk.
Thursday...
  Elevated Thunderstorm Risk.
Friday...
  Limited Thunderstorm Risk.

DISCUSSION:

There will be daily scattered thunderstorm chances amidst very
warm and humid conditions Sunday through Tuesday, with possibly
higher coverage of thunderstorms by mid week. Any thunderstorms
will be capable of producing heavy downpours and possibly an
isolated flooding risk. Thunderstorm chances may be limited to
areas south of I-80 or south of there by Thursday and especially
Friday.

.SPOTTER INFORMATION STATEMENT...

  Spotters will continue to be needed through early evening.

GENERAL STORM MOTION OF THE DAY:

  Moving toward the east northeast at 30 to 35 mph.

LMZ740>745-242215-
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-
509 PM CDT Sat May 23 2020

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...

  Significant Thunderstorm Risk...with an associated:
     Limited Waterspout Risk.
     Elevated hail risk...up to ping pong ball size.
     Limited thunderstorm wind gust risk...up to 40 kt.
  Elevated Fog Risk.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Sunday...
  Limited Thunderstorm Risk.
  Elevated Fog Risk.
Monday...
  Limited Thunderstorm Risk.
Tuesday...
  Elevated Thunderstorm Risk.
Wednesday...
  Significant Thunderstorm Risk.
Thursday and Friday...
  Limited Thunderstorm Risk.

MTF

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In the hours before

Local storm report, May 23, 6:03 PM CDT, 2 hours 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
603 PM CDT SAT MAY 23 2020

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

0320 PM     TSTM WND DMG     1 NNW ROCKDALE          41.52N 88.12W
05/23/2020                   WILL               IL   BROADCAST MEDIA

            NEAR LARKIN AND JEFFERSON. WIDESPREAD TREE
            DAMAGE, INCLUDING SOME HEALTHY TREES A FOOT
            OR TWO IN DIAMETER, BLOCKING MULTIPLE
            STREETS. BETWEEN 3:15 AND 3:25 PM CDT.

&&

Local storm report, May 23, 6:05 PM CDT, 2 hours 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
605 PM CDT SAT MAY 23 2020

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

0602 PM     HEAVY RAIN       3 N AROMA PARK          41.12N 87.80W
05/23/2020  E1.22 INCH       KANKAKEE           IL   COCORAHS

            FLOODING HAS NEVER BEEN THIS BAD. WATER HAS
            ERODED A STREAM THROUGH THE FIELD AND IT IS
            FLOWING HEAVILY.

&&

C

Local storm report, May 23, 6:13 PM CDT, 1 hour 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO IL
613 PM CDT SAT MAY 23 2020

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

0612 PM     HEAVY RAIN       CHESTERTON              41.61N 87.06W
05/23/2020  E1.60 INCH       PORTER             IN   PUBLIC

            RAIN FELL BETWEEN 5:15 AND 6:00 PM.

&&

C

Local storm report, May 23, 6:20 PM CDT, 1 hour 46 minutes before

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Local storm report, May 23, 6:44 PM CDT, 1 hour 22 minutes before

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Local storm report, May 23, 6:47 PM CDT, 1 hour 19 minutes before

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The office that day

Everything else NWS Chicago, IL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 23, 7:02 PM CDT	Special Marine Warning	LOT		118 min
May 23, 7:37 PM CDT	Areal Flood Advisory	LOT	Cook, Lake	3 hr
May 23, 9:20 PM CDT	River Flood Advisory	LOT	Boone	64 hr
May 23, 9:20 PM CDT	River Flood Advisory	LOT	Winnebago	3 days
May 23, 9:20 PM CDT	River Flood Advisory	LOT	Ogle	4 days
May 23, 11:57 PM CDT	River Flood Advisory	LOT	Cook	7 hr
May 24, 12:38 AM CDT	River Flood Advisory	LOT	Cook	16 hr
May 24, 12:42 AM CDT	River Flood Warning	LOT	Kane, Kendall	3 days
May 24, 12:43 AM CDT	River Flood Advisory	LOT	LaSalle	3 days
May 24, 8:43 AM CDT	River Flood Warning	LOT	LaSalle	25 hr
May 24, 8:57 AM CDT	River Flood Advisory	LOT	Grundy	25 hr
May 24, 9:01 AM CDT	River Flood Advisory	LOT	Winnebago	21 hr
May 24, 9:17 AM CDT	River Flood Advisory	LOT	Winnebago	16 hr
May 24, 3:52 PM CDT	River Flood Advisory	LOT	Kankakee	13 hr
May 23, 7:33 PM CDT	Severe Thunderstorm Warning	LOT	Lake, Porter	72 min
May 23, 7:42 PM CDT	River Flood Warning	LOT	Lake	10 hr
May 23, 7:54 PM CDT	Areal Flood Advisory	LOT	Lake, Porter	3 hr
May 24, 8:41 AM CDT	River Flood Warning	LOT	Lake, Newton	4 days
May 24, 3:52 PM CDT	River Flood Advisory	LOT	Jasper, Porter	17 hr

Nearby

Flash Flood Warnings in Indiana, 2020 Every flash flood warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.