Alert archive / Kentucky / Mesoscale Discussions in 2011

Mesoscale Discussion 521

April 22, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2011, 5:27 PM CDT for 4 states. It was in force for 33 min.

The area

The outline as issued.

The facts

Issued
Apr 22, 2011, 5:27 PM CDT (22:27 UTC)
Expired
Apr 22, 2011, 6:00 PM CDT
In force
33 min
Issued by
the Storm Prediction Center
All 100 counties

Clinton County, IL, Edwards County, IL, Franklin County, IL, Gallatin County, IL, Hamilton County, IL, Hardin County, IL, Jackson County, IL, Jefferson County, IL, Johnson County, IL, Marion County, IL, Massac County, IL, Monroe County, IL, Perry County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Saint Clair County, IL, Saline County, IL, Union County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Clark County, IN, Crawford County, IN, Dubois County, IN, Floyd County, IN, Gibson County, IN, Harrison County, IN, Perry County, IN, Pike County, IN, Posey County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Adair County, KY, Anderson County, KY, Bath County, KY, Bourbon County, KY, Boyle County, KY, Breckinridge County, KY, Bullitt County, KY, Butler County, KY, Caldwell County, KY, Casey County, KY, Clark County, KY, Crittenden County, KY, Daviess County, KY, Edmonson County, KY, Estill County, KY, Fayette County, KY, Franklin County, KY, Garrard County, KY, Grayson County, KY, Green County, KY, Hancock County, KY, Hardin County, KY, Harrison County, KY, Hart County, KY, Henderson County, KY, Henry County, KY, Hopkins County, KY, Jackson County, KY, Jefferson County, KY, Jessamine County, KY, Larue County, KY, Lee County, KY, Lincoln County, KY, Livingston County, KY, Lyon County, KY, Madison County, KY, Marion County, KY, McLean County, KY, Meade County, KY, Menifee County, KY, Mercer County, KY, Montgomery County, KY, Muhlenberg County, KY, Nelson County, KY, Nicholas County, KY, Ohio County, KY, Oldham County, KY, Owen County, KY, Powell County, KY, Rockcastle County, KY, Scott County, KY, Shelby County, KY, Spencer County, KY, Taylor County, KY, Union County, KY, Warren County, KY, Washington County, KY, Webster County, KY, Wolfe County, KY, Woodford County, KY, Cape Girardeau County, MO, Perry County, MO, Saint Francois County, MO, Sainte Genevieve County, MO

The radar

The Louisville radar (KLVX), 63 km from the middle of the area, began a volume at 22:26 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 10.5 hours before the alert went out and 195 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, Nashville Metro, TN at 12:00Z on 2011-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 71 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, Nashville Metro, TN at 12:00Z on 2011-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 230 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
71 J/kg
Mixed-layer CIN
-117 J/kg
Mixed-layer LCL
784 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
230 m²/s²
0-3 km storm-relative helicity
237 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

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

202 
ACUS11 KWNS 222227
SWOMCD
SPC MCD 222227 
KYZ000-INZ000-ILZ000-MOZ000-222300-

MESOSCALE DISCUSSION 0521
NWS STORM PREDICTION CENTER NORMAN OK
0527 PM CDT FRI APR 22 2011

AREAS AFFECTED...LOWER OH RIVER VALLEY...PORTIONS OF WRN/CNTRL
KY...SRN IL AND FAR ERN MO

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON 

VALID 222227Z - 222300Z

LATEST RADAR TRENDS SHOW QLCS PROGRESSING EWD ACROSS CNTRL/NRN
KY...WITH INCREASING DEVELOPMENT ALONG THE SRN FLANK WITH A FEW OF
THE STRONGER CORES CAPABLE OF PRODUCING HAIL AND STRONG WINDS. THIS
LINE IS MOVING OFF THE LLJ AND MAXIMUM INSTABILITY AXES...THOUGH AN
ISOLATED THREAT FOR DMGG WINDS AND HAIL MAY PERSIST FARTHER EWD.
ISOLATED THUNDERSTORM DEVELOPMENT HAS ALSO OCCURRED WITHIN THE WARM
SECTOR ACROSS SWRN AND S-CNTRL KY.

FARTHER W...CONCERN IS INCREASING ALONG AND TO THE S OF A WARM FRONT
DRAPED ACROSS SRN IL EXTENDING INTO NRN KY. CLOUD COVER HAS CLEARED
ACROSS MUCH OF THE WARM SECTOR TO ALLOW TEMPERATURES TO HEAT INTO
THE UPPER 70S. ADDITIONALLY...LOW-LEVEL SHEAR IS MODERATELY STRONG
WITHIN THIS ENVIRONMENT...WITH 0-1 KM BULK SHEAR RANGING FROM 20-30
KTS. AS CONVECTION OVER CNTRL MO/SRN IL INCREASES INTO THIS
EVENING...A THREAT FOR DMGG WINDS...LARGE HAIL...AND TORNADOES IS
EXPECTED TO DEVELOP.

A TORNADO WATCH WILL BE NEEDED SOON FOR THIS REGION...REPLACING
PORTIONS OF SVR WW 178...WHICH IS SET TO EXPIRE AT 2300Z.

..ROGERS.. 04/22/2011

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

ATTN...WFO...JKL...ILN...LMK...IND...PAH...ILX...LSX...

LAT...LON   37048534 36928752 37208932 37479027 37889060 38349043
            38788970 38608812 38488670 38588571 38608505 38478410
            38298349 37828332 37328379 37208426 37048534

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 22, 10:09 AM CDTMesoscale DiscussionSPCAlexander, Bond, Calhoun, Clinton, Franklin, Greene and 14 more66 min
Apr 22, 1:14 PM CDTMesoscale DiscussionSPCCrawford, Edwards, Jasper, Lawrence, Richland, Wabash61 min
Apr 22, 1:31 PM CDTSevere Thunderstorm WatchSPCEdwards, Franklin, Gallatin, Hamilton, Jefferson, Saline and 4 more4 hr
Apr 22, 3:34 PM CDTTornado WatchSPCCalhoun, Greene, Jersey, Macoupin, Madison, Monroe and 2 more6 hr
Apr 22, 5:21 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Macoupin114 min
Apr 22, 5:49 PM CDTTornado WatchSPCAlexander, Bond, Clay, Clinton, Crawford, Edwards and 26 more7 hr
Apr 22, 3:48 PM CDTMesoscale DiscussionSPCClark, Jefferson, Ohio, Switzerland87 min
Apr 21, 11:27 PM CDTMesoscale DiscussionSPCBarton, Bates, Buchanan, Cass, Clay, Jackson and 3 more3 hr
Apr 22, 2:48 AM CDTSevere Thunderstorm WatchSPCAndrew, Bates, Buchanan, Cass, Clay, Clinton and 4 more4 hr
Apr 22, 5:18 AM CDTMesoscale DiscussionSPCBuchanan, Caldwell, Cass, Clay, Clinton, Jackson and 2 more87 min
Apr 22, 10:44 AM CDTMesoscale DiscussionSPCBarry, Bollinger, Carter, Christian, Crawford, Dent and 19 more61 min
Apr 22, 1:04 PM CDTMesoscale DiscussionSPCBarry, Barton, Benton, Callaway, Camden, Cedar and 40 more116 min
Apr 22, 1:23 PM CDTMesoscale DiscussionSPCMcDonald, Newton97 min

Nearby

Mesoscale Discussions in Kentucky, 2011Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Indiana, 2011Every mesoscale discussion 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.