Alert archive / Missouri / Mesoscale Discussions in 2015

Mesoscale Discussion 1813

September 17, 20157 counties in Iowa; Atchison County, Doniphan County, Kansas; 16 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Sep 17, 2015, 10:12 PM CDT for 7 counties in Iowa; Atchison County, Doniphan County, Kansas; 16 counties in Missouri. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued
Sep 17, 2015, 10:12 PM CDT (03:12 UTC)
Expired
Sep 17, 2015, 11:15 PM CDT
In force
63 min
Issued by
the Storm Prediction Center
All 25 counties

Appanoose County, IA, Clarke County, IA, Decatur County, IA, Lucas County, IA, Monroe County, IA, Ringgold County, IA, Wayne County, IA, Atchison County, KS, Doniphan County, KS, Andrew County, MO, Buchanan County, MO, Caldwell County, MO, Clay County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Grundy County, MO, Harrison County, MO, Livingston County, MO, Mercer County, MO, Platte County, MO, Putnam County, MO, Sullivan County, MO, Worth County, MO

The radar

The Pleasant Hill radar (KEAX), 125 km from the middle of the area, began a volume at 03:12 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

Topeka, KS (KFOE), launched 00:00Z, 3.2 hours before the alert went out and 166 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, Topeka, KS at 00:00Z on 2015-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2776 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, Topeka, KS at 00:00Z on 2015-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 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
2776 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
1441 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
193 m²/s²
Significant tornado parameter
1.3
Supercell composite
12.1

Open this sounding in Storm Lab

The text

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

196 
ACUS11 KWNS 180313
SWOMCD
SPC MCD 180312 
IAZ000-MOZ000-KSZ000-180415-

MESOSCALE DISCUSSION 1813
NWS STORM PREDICTION CENTER NORMAN OK
1012 PM CDT THU SEP 17 2015

AREAS AFFECTED...NERN KS / NWRN AND NRN MO / S-CNTRL IA

CONCERNING...SEVERE THUNDERSTORM WATCH 511...

VALID 180312Z - 180415Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 511
CONTINUES.

SUMMARY...DISCRETE STORMS WITH INTERMITTENT SUPERCELL
CHARACTERISTICS WILL LIKELY CONTINUE TO BE CAPABLE OF ISOLD LARGE
HAIL AND PERHAPS DMGG WINDS.

DISCUSSION...RADAR IMAGERY SHOWS DISCRETE STORMS OVER THE LOWER MO
VALLEY WITH THE ACTIVITY INVOF A COLD FRONT MOVING SEWD OVER THE
REGION.  A SWLY 40 KT LLJ PER KTWX AND KEAX VAD DATA WILL CONTINUE
PROVIDING STRONG LOW-LEVEL MOISTURE TRANSPORT INTO THE STORM INFLOW
REGION.  DESPITE A COOLING BOUNDARY LAYER...SURFACE DEWPOINTS IN THE
LOWER 70S ARE AIDING IN A FEED OF NEAR-SURFACE PARCELS.  A VEERING
AND STRENGTHENING WIND PROFILE WITH HEIGHT UP THROUGH THE MID
TROPOSPHERE WILL SUPPORT UPDRAFT ROTATION WITH THE STRONGER
UPDRAFTS.  UNTIL STORMS INGEST INCREASINGLY ELEVATED PARCELS...STORM
INTENSITY WILL PROBABLY BE MAINTAINED AND A LARGE HAIL AND DMGG WIND
RISK WILL SLOWLY MOVE EWD ACROSS S-CNTRL IA INTO NWRN AND N-CNTRL MO
OVER THE NEXT FEW HOURS.

..SMITH.. 09/18/2015

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

ATTN...WFO...DMX...EAX...TOP...

LAT...LON   39459557 41079391 41039268 40329255 39679348 39239423
            39189501 39459557

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 7:54 PM CDTMesoscale DiscussionSPCDes Moines, Henry, Jefferson, Lee, Louisa, Van Buren66 min
Sep 18, 9:25 AM CDTMesoscale DiscussionSPCAdams, Cass, Fremont, Mills, Montgomery, Page and 4 more65 min
Sep 18, 5:20 PM CDTMesoscale DiscussionSPCDavis, Des Moines, Henry, Lee, Van Buren2 hr
Sep 18, 3:07 PM CDTMesoscale DiscussionSPCHarper, Sumner2 hr

Nearby

Mesoscale Discussions in Missouri, 2015Mesoscale Discussions in Iowa, 2015Mesoscale Discussions in Kansas, 2015Every mesoscale discussion in 2015

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.