Alert archive / Illinois / Areal Flood Warnings in 2011

Areal Flood Warning 66, NWS St. Louis, MO

July 7, 2011Fayette County, Marion County, Illinois

NWS St. Louis, MO issued this areal flood warning at Jul 7, 2011, 11:30 PM CDT for Fayette County, Marion County, Illinois. It was in force for 10 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: Jul 7, 2011, 11:30 PM CDT (04:30 UTC)
Expired: Jul 8, 2011, 9:30 AM CDT
In force: 10 hr
Issued by: NWS St. Louis, MO
Area: Storm-based polygon
Flood severity: None

Counties Fayette County, IL, Marion County, IL

The radar

The Evansville,IN radar (KVWX), 125 km from the middle of the area, began a volume at 04:31 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, 4.5 hours before the alert went out and 151 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: 143 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1134 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.7

Open this sounding in Storm Lab

What forecasters said that day

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

NWS St. Louis, MO wrote its last area forecast discussion before this areal flood warning went out at Jul 7, 7:05 PM CDT, 4 hours 25 minutes earlier.

Area forecast discussion, Jul 7, 7:05 PM CDT, 4 hours 25 minutes before

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
705 PM CDT THU JUL 7 2011

.DISCUSSION...
/251 PM CDT THU JUL 7 2011/

CONVECTION WILL CONTINUE TO DEVELOP ACROSS OUR FORECAST AREA TGT
AHEAD OF AN MCV OVER WRN MO...JUST W OF COU AND ANOTHER VORT MAX
DROPPING S-SEWD INTO NERN KS. THIS CONVECTION IS ALONG A WEAK
BOUNDARY EXTENDING FROM NERN KS SE THROUGH CNTRL MO AND E-NE
THROUGH CNTRL IL. IT APPEARS THAT THE MAJORITY OF THE CONVECTION
WILL SHIFT INTO SERN MO SWRN IL LATER THIS EVNG AND OVERNIGHT AS
THE VORT CENTERS AND SFC BOUNDARY SHIFT SLOWLY SEWD. THE LATEST 4
KM NCEP WRF SHIFTS MOST OF THE CONVECTION SE OF OUR FORECAST AREA
BY LATE TGT BUT THIS MAY BE A LITTLE TOO FAST. EXPECT CONVECTION
TO CONTINUE LATE TGT...AT LEAST ACROSS AREAS FROM STL S AND E
WITH A 20-30 KT SWLY LOW LEVEL JET CONTINUING TO BRING LOW LEVEL
WAA AND MOISTURE CONVERGENCE TO THIS AREA WITH A WEAK SFC LOW OVER
SERN MO PROVIDING SFC CONVERGENCE. WITH LOW FLASH FLOOD GUIDANCE
ACROSS THE AREA THERE MAY BE A FLASH FLOOD THREAT TGT UNLESS THE
CONVECTION IS ABLE TO ORGANIZE AND DEVELOP A COLD POOL ALLOWING
FOR A QUICKER...MORE PROGRESSIVE SEWD MOVEMENT. THE CONVECTION
SHOULD SHIFT SE OF OUR FORECAST AREA BY LATE FRI MRNG AS THE
MCV...WEAK SFC LOW AND BOUNDARY SHIFT S-SE OF OUR AREA. THERE
WILL CONTINUE TO BE SHORTWAVES DROPPING SEWD THROUGH THE AREA ON
FRI NE OF THE UPPER LEVEL RIDGE CENTERED OVER THE SWRN US...BUT
IT APPEARS THAT MUCH OF THE LOW LEVEL MOISTURE AND INSTABILITY
ALONG THE SFC BOUNDARY WILL BE SE OF OUR AREA BY THIS TIME.
TEMPERATURES SHOULD BE A LITTLE COOLER ON FRI WITH LOW LEVEL
CLOUDS ACROSS THE AREA DURING THE MRNG...WEAK LOW LEVEL CAA AND
NELY SFC WINDS. TEMPERATURES SHOULD ALSO BE RELATIVELY COOL FRI
NGT WITH A MOSTLY CLEAR SKY AND LIGHT WIND. A WARMING TREND SHOULD
BEGIN ON SAT AS THE UPPER LEVEL RIDGE BEGINS TO SHIFT NEWD INTO
OUR AREA WITH RISING HEIGHTS. SFC WINDS WILL ALSO GRADUALLY VEER
AROUND TO A SELY DIRECTION ON SAT AND TO A SLY DIRECTION ON SUN AS
A WEAK WARM FRONT MOVES NWD THROUGH THE AREA. COULD NOT RULE OUT
SCATTERED CONVECTION ON SUN ALONG AND JUST AHEAD OF THE WARM
FRONT BUT LEFT THE FORECAST DRY FOR NOW. THE MAIN WEATHER CONCERN
WILL BE THE RETURN OF HIGH LEVELS OF HEAT AND HUMIDITY BEGINNING
ON SUN AND CONTINUING INTO THE WORK WEEK. THERE IS SOME
UNCERTAINTY AS TO HOW LONG THIS HOT STRETCH WILL LAST AS THE GFS
MODEL FLATTENS THE UPPER LEVEL RIDGE ALLOWING A FRONT TO SAG SWD
INTO OUR AREA MON NGT AND TUE. THE ECMWF MODEL KEEPS THE FRONT N
OF OUR FORECAST AREA DUE TO A STRONGER MID-UPPER LEVEL RIDGE. KEPT
CHANCE POPS OVER NERN MO AND W CNTRL IL FOR MON THROUGH WED WITH
THE POSSIBILITY OF CONVECTION...MCS ACTIVITY DROPPING SEWD THROUGH
THIS AREA.

GKS
&&

.AVIATION...
/705 PM CDT THU JUL 7 2011/
MCV MOVING THROUGH FORECAST AREA WITH SHOWERS AND THUNDERSTORMS
DEVELOPING...MAINLY ALONG AND SOUTH OF I-70. MOST OF THIS ACTIVITY
SHOULD MOVE OUT OF TAF SITES BY 0030Z...SO JUST KEPT VCSH MENTION AT
KCOU AND KUIN THROUGH 03Z AND SHOWERS WITH VCTS AT KSUS/KSTL THROUGH
ABOUT 04Z. THEN MODELS ALL OVER THE PLACE WITH NAM SUGGESTING IFR
CONDITIONS...BUT PREFER GFS WITH MVFR FOG DEVELOPING LATER
TONIGHT...THEN DIMINISHING BY MID MORNING ON FRIDAY. AS FOR
WINDS...TO REMAIN LIGHT AND VARIABLE...THEN PICKUP FROM THE
NORTHEAST WITH SOME DIURNAL CU.

SPECIFICS FOR KSTL...MCV MOVING THROUGH METRO AREA WITH SHOWERS
AND THUNDERSTORMS DEVELOPING...MAINLY ALONG AND SOUTH OF I-70. MOST
OF THIS ACTIVITY SHOULD MOVE OUT OF KSTL BY 0030Z...SO JUST KEPT
SHOWERS WITH VCTS AT KSTL THROUGH 04Z. THEN MODELS ALL OVER THE
PLACE WITH NAM SUGGESTING IFR CONDITIONS...BUT PREFER GFS WITH MVFR
FOG DEVELOPING LATER TONIGHT...THEN DIMINISHING BY 14Z ON FRIDAY. AS
FOR WINDS...TO REMAIN LIGHT AND VARIABLE...THEN PICKUP FROM THE
NORTHEAST WITH SOME DIURNAL CU.

BYRD
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

WFO LSX

Hazardous weather outlook, Jul 7, 10:49 PM CDT, 41 minutes before

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In the hours before

Local storm report, Jul 7, 7:50 PM CDT, 3 hours 40 minutes before

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Local storm report, Jul 7, 7:54 PM CDT, 3 hours 36 minutes before

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Local storm report, Jul 7, 8:04 PM CDT, 3 hours 26 minutes before

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Local storm report, Jul 7, 9:03 PM CDT, 2 hours 27 minutes before

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Local storm report, Jul 7, 10:21 PM CDT, 1 hour 9 minutes before

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Local storm report, Jul 7, 10:47 PM CDT, 43 minutes before

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The office that day

Everything else NWS St. Louis, MO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 7, 7:07 PM CDT	Tornado Warning	LSX	Sainte Genevieve	23 min
Jul 7, 7:51 PM CDT	Flash Flood Warning	LSX	Sainte Genevieve	6 hr
Jul 8, 12:03 AM CDT	Areal Flood Warning	LSX	Saint Louis	9 hr
Jul 8, 3:17 PM CDT	Heat Advisory	LSX	Audrain, Boone, Callaway, Cole, Crawford, Franklin and 23 more	4 days
Jul 7, 7:14 PM CDT	Flash Flood Warning	LSX	Bond, Fayette, Macoupin, Madison, Montgomery	6 hr
Jul 7, 7:48 PM CDT	Severe Thunderstorm Warning	LSX	Randolph	42 min
Jul 8, 10:19 AM CDT	River Flood Warning	LSX	Fayette	10 hr

Nearby

Areal Flood Warnings in Illinois, 2011 Every areal flood warning in 2011

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.