Alert archive / Illinois / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 194, NWS Paducah, KY

September 4, 20174 counties in Illinois

NWS Paducah, KY issued this severe thunderstorm warning at Sep 4, 2017, 10:06 PM CDT for 4 counties in Illinois. It was in force for 21 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 4, 2017, 10:06 PM CDT (03:06 UTC)
Expired
Sep 4, 2017, 10:27 PM CDT
In force
21 min
Issued by
NWS Paducah, KY
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Franklin County, IL, Hamilton County, IL, Saline County, IL, Williamson County, IL

The radar

The Paducah radar (KPAH), 91 km from the middle of the area, began a volume at 03:07 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, 3.1 hours before the alert went out and 252 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 2017-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1325 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 00:00Z on 2017-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 square meters per square second.19395878Sfc1 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
1325 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
909 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
132 m²/s²
Significant tornado parameter
-0.1
Supercell composite
-1.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Paducah, KY wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 4, 6:36 PM CDT, 3 hours 30 minutes earlier.

Area forecast discussion, Sep 4, 6:36 PM CDT, 3 hours 30 minutes before
Area Forecast Discussion
National Weather Service Paducah KY
636 PM CDT Mon Sep 4 2017

.UPDATE...
Issued at 636 PM CDT Mon Sep 4 2017

The AVIATION section has been updated for the 00Z TAF issuance.

&&

.SHORT TERM...(Tonight through Wednesday night)
Issued at 250 PM CDT Mon Sep 4 2017

A fairly strong cold front will move toward the area this evening
and then cross the region overnight. Scattered thunderstorms will
accompany the front with much cooler air to follow as we head
through the short term period. There remains a slight risk of
severe thunderstorms for tonight, mainly along and north of the
I-64 corridor. There is some offset of upper level wind dynamics
and the surface cold front (better dynamics lag frontal
convergence and instability) and we will be losing a good chunk of
instability between 9 PM and midnight.

Best guess for timing remains an onset of thunderstorms this
evening with a 7-10 pm start time looking reasonable for the I-64
corridor of our region then progressing southward through the late
evening and overnight. By tomorrow morning, showers/thunderstorms
will be limited to mainly the quarter of the forecast area,
ending across all of the region during the afternoon.

A large 500 mb trough will pivot SE across the FA through mid
week with surface high pressure building south into our region
from Canada. The much advertised unseasonable cool pattern ushered
in by northerly winds will ensue with max temps only in the mid
to upper 70s Tuesday and the lower 70s on Wednesday with lows
likely reaching the upper 40s in many locations Wednesday night.

.LONG TERM...(Thursday through Monday)
Issued at 250 PM CDT Mon Sep 4 2017

High forecast confidence still remains in place for a dry period
from this Thursday through next Monday across the WFO PAH forecast
area. Below normal temperatures (10-15 degrees) below normal are
expected through the extended period.

Regionally blended model guidance continues to be on the warmer end
of the forecast temperature solutions. Again, weighted temperatures
toward the EKD MOS, as well as the ECMWF/NAM-WRF guidance suite.
temperatures. Given the drier air mass, diurnal temperature ranges
will likely be within a 20 to 28 degree range.

No precipitation expected through extended period. Although the
ECMWF has been running about 5-10 decameters too low in 500 mb
heights recently, it still remain much closer in height fields
versus most of the numerical guidance suite. The ECMWF along with
the RAP model guidance were the closest to the raw upper air
observations at 12z and 18z Monday. Only the UKMET (which has
historically been the case) is more accurate with height fields and
low/high pressure centers in a global sense. Sensitivity of model
fields at 500 mb versus observations is a good benchmark for model
reliability.

Will be interested to see how collaborated NHC/WPC forecasts handle
Irma's track later this week. There still remains some varied
solutions from the Canadian, GFS, and ECMWF for the next several
days. Depending on the final track of Irma, could see some
interaction with the synoptic scale features near the WFO PAH
forecast area around the middle of September.

&&

.AVIATION...
Issued at 636 PM CDT Mon Sep 4 2017

A broken line of thunderstorms has developed along the cold front
from just north of KSTL to near KDEC in central Illinois. There is
a strong signal in the latest short term guidance that a portion
of this will be progressive, pushing eastward through KEVV and
KOWB after 04Z, while the western portions will develop more
slowly southward for awhile this evening and then mostly
dissipate around 06Z. Left the VCSH at all sites except KPAH where
it may remain dry. An outflow or enhanced frontal passage can be
expected at KEVV and KOWB 04Z-07Z. VFR conditions are forecast,
but lower conditions can be expected if a bonafide thunderstorm
reaches any of the sites tonight. A few northwesterly gusts into
the teens will be possible throughout the area Tuesday.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

UPDATE...DRS
SHORT TERM...GM
LONG TERM...Smith
AVIATION...DRS
Hazardous weather outlook, Sep 4, 3:10 PM CDT, 6 hours 56 minutes before
Hazardous Weather Outlook
National Weather Service Paducah KY
310 PM CDT Mon Sep 4 2017

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-050845-
Jefferson-Wayne IL-Edwards-Wabash-Perry IL-Franklin-Hamilton-
White-Jackson-Williamson-Saline-Gallatin-Union-Johnson-Pope-
Hardin-Alexander-Pulaski-Massac-Gibson-Pike-Posey-Vanderburgh-
Warrick-Spencer-Fulton-Hickman-Carlisle-Ballard-McCracken-Graves-
Livingston-Marshall-Calloway-Crittenden-Lyon-Trigg-Caldwell-
Union KY-Webster-Hopkins-Christian-Henderson-Daviess-McLean-
Muhlenberg-Todd-Perry MO-Bollinger-Cape Girardeau-Wayne MO-Carter-
Ripley-Butler-Stoddard-Scott-Mississippi-New Madrid-
310 PM CDT Mon Sep 4 2017

This Hazardous Weather Outlook is for portions of southern
Illinois, southwest Indiana, western Kentucky, and southeast
Missouri.

.DAY ONE...Today and Tonight

Scatterd thunderstorms will be likely tonight. There is a slight
risk of isoalted severe thunderstorms along and north of the I 64
corridor. Gusty and potentially damaging winds, frequent lightning
and locally heavy rain may accompany the stronger storms.

Minor flooding is forecast on parts of the Green River. See the
latest river flood warning products for details.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be requested tonight.

In the hours before

Special weather statement, Sep 4, 9:27 PM CDT, 39 minutes before
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<body>
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    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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The office that day

Everything else NWS Paducah, KY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 5, 5:30 AM CDTSevere Thunderstorm WarningPAHBallard, McCracken35 min
Sep 5, 5:59 AM CDTSevere Thunderstorm WarningPAHMcCracken20 min
Sep 5, 6:26 AM CDTSpecial Weather StatementPAHBallard, Crittenden, Livingston, McCracken49 min
Sep 5, 9:20 AM CDTSpecial Weather StatementPAHChristian, Todd, Trigg40 min
Sep 4, 9:27 PM CDTSpecial Weather StatementPAHHamilton48 min
Sep 4, 10:02 PM CDTSpecial Weather StatementPAHFranklin43 min
Sep 4, 10:47 PM CDTSpecial Weather StatementPAHWilliamson43 min
Sep 5, 4:06 AM CDTSpecial Weather StatementPAHHamilton, White24 min
Sep 5, 4:48 AM CDTSpecial Weather StatementPAHAlexander27 min
Sep 5, 5:12 AM CDTSevere Thunderstorm WarningPAHAlexander, Pulaski33 min

Nearby

Severe Thunderstorm Warnings in Illinois, 2017Every severe thunderstorm warning in 2017

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.