Alert archive / Illinois / Mesoscale Discussions in 2014

Mesoscale Discussion 1349

July 12, 201419 counties in Illinois; 19 counties in Iowa; 11 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Jul 12, 2014, 7:09 PM CDT for 19 counties in Illinois; 19 counties in Iowa; 11 counties in Missouri. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued
Jul 12, 2014, 7:09 PM CDT (00:09 UTC)
Expired
Jul 12, 2014, 8:45 PM CDT
In force
96 min
Issued by
the Storm Prediction Center
All 49 counties

Appanoose County, IA, Cedar County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Mahaska County, IA, Monroe County, IA, Muscatine County, IA, Scott County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Wayne County, IA, Bureau County, IL, Fulton County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Marshall County, IL, McDonough County, IL, Mercer County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Woodford County, IL, Adair County, MO, Clark County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Knox County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO

The radar

The Quad Cities radar (KDVN), 91 km from the middle of the area, began a volume at 00:11 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

Davenport, (KDVN), launched 00:00Z, 0.2 hours before the alert went out and 97 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, Davenport, at 00:00Z on 2014-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2609 joules per kilogram.LCLEL10008507005003002001001 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, Davenport, at 00:00Z on 2014-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 129 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
2609 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
916 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
129 m²/s²
0-3 km storm-relative helicity
199 m²/s²
Significant tornado parameter
2.0
Supercell composite
13.9

Open this sounding in Storm Lab

The text

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

122 
ACUS11 KWNS 130010
SWOMCD
SPC MCD 130009 
ILZ000-IAZ000-MOZ000-130145-

MESOSCALE DISCUSSION 1349
NWS STORM PREDICTION CENTER NORMAN OK
0709 PM CDT SAT JUL 12 2014

AREAS AFFECTED...SE IA...FAR N MO...N IL

CONCERNING...TORNADO WATCH 411...

VALID 130009Z - 130145Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 411 CONTINUES.

SUMMARY...DEVELOPING COLD POOL WITH EMBEDDED SUPERCELL STRUCTURES
SHOULD RESULT IN AN INCREASE DAMAGING WIND RISK THROUGH 03Z.
MARGINALLY SEVERE HAIL AND A TORNADO OR TWO WILL REMAIN
POSSIBLE...WITH DOWNSTREAM WW ISSUANCE STILL LIKELY INTO N IL BY
LATE EVENING.

DISCUSSION...SUPERCELL HAS REMAIN PERSISTENT ALONG THE SW IA/NW MO
BORDER AREA...RIGHT-TURNING OVER WORTH INTO HARRISON COUNTY MO.
FARTHER NE...AMALGAMATING CELLS INTO MONROE AND WAPELLO COUNTY IA
HAVE SHOWN INCREASINGLY STRONG OUTBOUND VELOCITIES PER DMX RADAR.
00Z DVN RAOB SAMPLED MLCAPE AROUND 2500 J/KG WITH MEAN MIXING RATIOS
NEAR 18 G/KG. WITH STRONG 0-3 KM SHEAR AIDED BY 700 MB WLYS TO NEAR
40 KT...LEWP/BOWING STRUCTURES SHOULD FORM AS THE COLD POOL
CONTINUES TO DEEPEN. THIS SHOULD RESULT IN AN INCREASING RISK FOR
DAMAGING WINDS TOWARDS/ACROSS THE MS RIVER INTO LATE EVENING. 

RELATIVELY WEAK CONVERGENCE HAS LIKELY LIMITED MORE ROBUST DISCRETE
CONVECTION FARTHER E INTO IL IN THE NEAR-TERM. BUT AS THE LLJ
STRENGTHENS THIS EVENING...ADDITIONAL CELLS MAY YET DEVELOP OUT
AHEAD OF THE IA/MO MCS.

..GRAMS.. 07/13/2014

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

ATTN...WFO...LOT...ILX...LSX...DVN...DMX...EAX...

LAT...LON   41729192 41899069 41928938 41818882 41588851 41198848
            40708883 40319021 40119172 39949437 40249456 40479442
            40889366 41189301 41729192

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 12, 9:09 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 23 more66 min
Jul 12, 9:51 PM CDTTornado WatchSPCBoone, Cook, DeKalb, DuPage, Ford, Fulton and 21 more3 hr
Jul 12, 11:44 PM CDTMesoscale DiscussionSPCGrundy, Kendall, LaSalle, Will31 min
Jul 13, 12:41 PM CDTMesoscale DiscussionSPCClay, Clinton, Crawford, Edwards, Franklin, Gallatin and 23 more94 min

Nearby

Mesoscale Discussions in Illinois, 2014Mesoscale Discussions in Iowa, 2014Mesoscale Discussions in Missouri, 2014Every mesoscale discussion in 2014

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.