Alert archive / Missouri / Mesoscale Discussions in 2017

Mesoscale Discussion 1713

October 14, 201716 counties in Illinois; 9 counties in Iowa; 37 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Oct 14, 2017, 3:35 PM CDT for 16 counties in Illinois; 9 counties in Iowa; 37 counties in Missouri. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Oct 14, 2017, 3:35 PM CDT (20:35 UTC)
Expired
Oct 14, 2017, 6:00 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 62 counties

Appanoose County, IA, Davis County, IA, Decatur County, IA, Des Moines County, IA, Henry County, IA, Jefferson County, IA, Lee County, IA, Van Buren County, IA, Wayne County, IA, Adams County, IL, Brown County, IL, Cass County, IL, Fulton County, IL, Hancock County, IL, Henderson County, IL, Knox County, IL, Logan County, IL, Mason County, IL, McDonough County, IL, Menard County, IL, Peoria County, IL, Pike County, IL, Schuyler County, IL, Tazewell County, IL, Warren County, IL, Adair County, MO, Andrew County, MO, Buchanan County, MO, Caldwell County, MO, Carroll County, MO, Chariton County, MO, Clark County, MO, Clay County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Howard County, MO, Jackson County, MO, Johnson County, MO, Knox County, MO, Lafayette County, MO, Lewis County, MO, Linn County, MO, Livingston County, MO, Macon County, MO, Marion County, MO, Mercer County, MO, Monroe County, MO, Platte County, MO, Putnam County, MO, Ralls County, MO, Randolph County, MO, Ray County, MO, Saline County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO, Sullivan County, MO, Worth County, MO

The radar

The Pleasant Hill radar (KEAX), 192 km from the middle of the area, began a volume at 20:35 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 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 12:00Z, 8.6 hours before the alert went out and 257 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 12:00Z on 2017-10-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2017-10-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
594 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
160 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

The text

As transmitted.

079 
ACUS11 KWNS 142035
SWOMCD
SPC MCD 142035 
ILZ000-MOZ000-IAZ000-KSZ000-142300-

Mesoscale Discussion 1713
NWS Storm Prediction Center Norman OK
0335 PM CDT Sat Oct 14 2017

Areas affected...northern/central Missouri...far southern Iowa...and
west-central Illinois

Concerning...Severe potential...Watch possible 

Valid 142035Z - 142300Z

Probability of Watch Issuance...40 percent

SUMMARY...The discussion area is being monitored for increasing
severe potential over the next 2-3 hours, which may necessitate a WW
issuance.

DISCUSSION...A complex surface pattern currently exists across the
discussion area.  Both a warm front and differential heating zone
are separating a moderately unstable airmass (nearly 2000 J/kg
MLCAPE) over central Missouri from rain-cooled air to the north. 
Isolated convection was located along and just north of these
boundaries, although weak mid-level lapse rates and a lack of
forcing for ascent aloft has resulted in sub-severe convection so
far this afternoon.

Continued surface heating and convergence along the front may be
enough to encourage isolated surface-based development that will
pose a risk for wind/hail and perhaps a tornado over the next 2-3
hours, especially near the differential heating zone.  While this
initial activity may be too isolated to necessitate a WW, increasing
convective activity upstream in eastern Kansas may further organize
and pose a severe risk initially in northwestern Missouri -
spreading eastward across the discussion area over time.  A WW
issuance is possible for this activity, and convective trends will
continue to be monitored.

..Cook/Hart.. 10/14/2017

...Please see www.spc.noaa.gov for graphic product...

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

LAT...LON   39179469 39529485 39969492 40309475 40649434 40899337
            41019232 41079107 41059008 40908949 40508907 40068921
            39808985 39559096 39419160 38929279 38699373 38659437
            38719446 39179469

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 14, 5:09 PM CDTTornado WatchSPCAdams, Brown, Bureau, Ford, Fulton, Grundy and 24 more8 hr
Oct 14, 6:01 PM CDTMesoscale DiscussionSPCBrown, Cass, Cook, DeWitt, DuPage, Ford and 21 more89 min
Oct 14, 4:21 AM CDTMesoscale DiscussionSPCAdair, Adams, Cass, Clarke, Fremont, Madison and 8 more84 min
Oct 14, 2:40 PM CDTMesoscale DiscussionSPCPlatte3 hr
Oct 14, 4:45 PM CDTSevere Thunderstorm WatchSPCVernon5 hr
Oct 14, 6:23 PM CDTMesoscale DiscussionSPCAudrain, Bates, Benton, Boone, Callaway, Cole and 14 more97 min

Nearby

Mesoscale Discussions in Missouri, 2017Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Iowa, 2017Every mesoscale discussion 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.