Alert archive / Illinois / Mesoscale Discussions in 2009

Mesoscale Discussion 607

April 27, 200913 counties in Illinois

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2009, 5:34 PM CDT for 13 counties in Illinois. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2009, 5:34 PM CDT (22:34 UTC)
Expired
Apr 27, 2009, 6:30 PM CDT
In force
56 min
Issued by
the Storm Prediction Center

Counties Brown County, IL, Cass County, IL, Fulton County, IL, Greene County, IL, Logan County, IL, Mason County, IL, Menard County, IL, Morgan County, IL, Pike County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Tazewell County, IL

The radar

The Lincoln radar (KILX), 61 km from the middle of the area, began a volume at 22:35 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 12:00Z, 10.6 hours before the alert went out and 123 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 12:00Z on 2009-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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 12:00Z on 2009-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 274 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
1 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
1111 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
274 m²/s²
0-3 km storm-relative helicity
325 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
ACUS11 KWNS 272234
SWOMCD
SPC MCD 272234 
ILZ000-MOZ000-272330-

MESOSCALE DISCUSSION 0607
NWS STORM PREDICTION CENTER NORMAN OK
0534 PM CDT MON APR 27 2009

AREAS AFFECTED...WRN AND CNTRL IL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 272234Z - 272330Z

AN ISOLATED DAMAGING WIND THREAT EXISTS DURING THE NEXT HR OR TWO
OVER WRN AND CNTRL IL...BUT A WW DOES NOT APPEAR NECESSARY.

A BOW ECHO IS MOVING ENE AT AROUND 25 KT INTO W CNTRL IL...AND MAY
POSE AN ISOLATED THREAT OF DAMAGING WIND GUSTS DURING THE NEXT HR OR
TWO. RUC FORECAST SOUNDINGS AHEAD OF THE BOW INDICATE VERY MOIST
LOW/MID LVL LAPSE RATES EXIST ACROSS THE REGION...WITH LITTLE
ADDITIONAL DESTABILIZATION LIKELY DUE TO WIDESPREAD CLOUD COVER. AS
A RESULT...BOTH MOST UNSTABLE AND MIXED LAYER CAPE VALUES WILL
REMAIN QUITE LOW...WHICH SHOULD PRECLUDE A MORE ROBUST SVR WEATHER
THREAT DESPITE GENERALLY FAVORABLE WIND PROFILES.

..GARNER.. 04/27/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ILX...LSX...DVN...

LAT...LON   40659011 40778945 40408885 39718931 39289022 39289104
            39969090 40439048 40659011

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 27, 5:08 PM CDTMesoscale DiscussionSPCAlexander, Jackson, Johnson, Pulaski, Union, Williamson97 min

Nearby

Mesoscale Discussions in Illinois, 2009Every mesoscale discussion in 2009

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.