Alert archive / Illinois / Flash Flood Watches in 2021

Flash Flood Watch 2, NWS Lincoln, IL

May 17, 2021Sangamon County, Illinois

NWS Lincoln, IL issued this flash flood watch at May 17, 2021, 9:22 PM CDT for Sangamon County, Illinois. It was in force for 13 hr.

The area

The counties it named.

The facts

Issued
May 17, 2021, 9:22 PM CDT (02:22 UTC)
Expired
May 18, 2021, 10:19 AM CDT
In force
13 hr
Issued by
NWS Lincoln, IL
Flood severity
None

County Sangamon County, IL

The radar

The Lincoln radar (KILX), 52 km from the middle of the area, began a volume at 02:25 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, 2.4 hours before the alert went out and 100 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-pSkew-T log-p diagram, Lincoln, IL at 00:00Z on 2021-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 00:00Z on 2021-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
5 J/kg
Mixed-layer CIN
-69 J/kg
Mixed-layer LCL
822 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

161 
WGUS63 KILX 180222
FFAILX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Lincoln IL
922 PM CDT Mon May 17 2021

.DAM FLOODGATE RELEASE IMPACTING SUGAR CREEK BELOW SPAULDING DAM IN 
SANGAMON COUNTY.

ILZ051-181030-
/O.NEW.KILX.FF.A.0002.210518T0222Z-210518T2100Z/
/00000.0.DR.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sangamon-
Including the cities of Springfield
922 PM CDT Mon May 17 2021

...FLASH FLOOD WATCH FOR A DAM FLOODGATE RELEASE IN EFFECT THROUGH 
TUESDAY AFTERNOON...

The National Weather Service in Lincoln has issued a

* Flash Flood Watch for a portion of central Illinois, including the 
  following area, Sangamon.

* Through Tuesday afternoon

* At 922 PM CDT, dam operators reported the Spaulding Dam on the 
  Sugar Creek may experience a significant floodgate release during 
  the watch period.

* Some locations that may experience flash flooding include...
  Springfield, Chatham, Auburn, Sherman, Rochester, Riverton, 
  Pawnee, Williamsville, New Berlin, Ashland, Divernon, Illiopolis, 
  Pleasant Plains, Loami, Mechanicsburg, Jerome, Southern View, 
  Leland Grove, Grandview and Spaulding.

$$

Deubelbeiss
2 follow-up statements
233 
WGUS63 KILX 180935
FFAILX

Flood Watch
National Weather Service Lincoln IL
435 AM CDT Tue May 18 2021

.DAM FLOODGATE RELEASE IMPACTING SUGAR CREEK BELOW SPAULDING DAM IN 
SANGAMON COUNTY.

ILZ051-182100-
/O.CON.KILX.FF.A.0002.000000T0000Z-210518T2100Z/
/00000.0.DR.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sangamon-
Including the cities of Springfield
435 AM CDT Tue May 18 2021

...FLASH FLOOD WATCH FOR A DAM FLOODGATE RELEASE REMAINS IN EFFECT 
UNTIL 4 PM CDT THIS AFTERNOON...

The Flash Flood Watch continues for

* A portion of central Illinois, including the following area, 
  Sangamon.

* Until 4 PM CDT this afternoon

At 435 AM CDT, dam operators reported the Spaulding Dam on the Sugar 
Creek may experience a significant floodgate release during the 
watch period.

Some locations that may experience flash flooding include...
locations near Sugar Creek downstream of the Spaulding Dam.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Watch means that conditions may develop that lead to 
Flash Flooding. Flash Flooding is a very dangerous situation. You 
should monitor later forecasts and be prepared to take action should 
Flash Flood Warnings be issued.

&&

$$

Shimon
836 
WGUS63 KILX 181519
FFAILX

Flood Watch
National Weather Service Lincoln IL
1019 AM CDT Tue May 18 2021

ILZ051-181630-
/O.CAN.KILX.FF.A.0002.000000T0000Z-210518T2100Z/
/00000.0.DR.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sangamon-
Including the cities of Springfield
1019 AM CDT Tue May 18 2021

...FLASH FLOOD WATCH FOR A DAM FLOODGATE RELEASE IS CANCELLED...

The Flash Flood Watch for a portion of central Illinois, including 
the following county, Sangamon has been cancelled.

The Flash Flood Watch downstream of the Spaulding Dam is cancelled. 
Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

$$

Roberson

The office that day

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

IssuedProductOfficeCountiesLasted
May 18, 6:19 PM CDTRiver Flood WarningILXFulton, Knox71 hr

Nearby

Flash Flood Watches in Illinois, 2021Every flash flood watch in 2021

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.