Alert archive / Iowa / Mesoscale Discussions in 2016

Mesoscale Discussion 1513

August 10, 201622 counties in Iowa; Jackson County, Minnesota

The Storm Prediction Center issued this mesoscale discussion at Aug 10, 2016, 3:52 PM CDT for 22 counties in Iowa; Jackson County, Minnesota. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
Aug 10, 2016, 3:52 PM CDT (20:52 UTC)
Expired
Aug 10, 2016, 5:45 PM CDT
In force
113 min
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 23 counties

Boone County, IA, Buena Vista County, IA, Calhoun County, IA, Carroll County, IA, Clay County, IA, Dallas County, IA, Dickinson County, IA, Emmet County, IA, Greene County, IA, Guthrie County, IA, Hamilton County, IA, Humboldt County, IA, Kossuth County, IA, Madison County, IA, Palo Alto County, IA, Pocahontas County, IA, Polk County, IA, Sac County, IA, Story County, IA, Warren County, IA, Webster County, IA, Wright County, IA, Jackson County, MN

The radar

The Des Moines radar (KDMX), 82 km from the middle of the area, began a volume at 20:54 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

Omaha, NE (KOAX), launched 12:00Z, 8.9 hours before the alert went out and 205 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, Omaha, NE at 12:00Z on 2016-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2010 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, Omaha, NE at 12:00Z on 2016-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 121 square meters per square second.1939Sfc1 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
2010 J/kg
Mixed-layer CIN
-74 J/kg
Mixed-layer LCL
1074 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

008 
ACUS11 KWNS 102052
SWOMCD
SPC MCD 102052 
IAZ000-MNZ000-102245-

MESOSCALE DISCUSSION 1513
NWS STORM PREDICTION CENTER NORMAN OK
0352 PM CDT WED AUG 10 2016

AREAS AFFECTED...PORTIONS OF CNTRL/WRN IA...FAR SRN MN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 102052Z - 102245Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A FEW STRONG TSTMS CAPABLE OF GUSTY WINDS MAY OCCUR
THROUGH THE LATE AFTERNOON HOURS...THOUGH WW ISSUANCE IS NOT
ANTICIPATED.

DISCUSSION...TSTMS CONTINUE DEVELOPING WITH THE VERY MOIST AIR MASS
CHARACTERIZED BY MIDDLE/UPPER 70S SFC DEWPOINTS ACROSS PARTS OF
CNTRL IA...WITH ADDITIONAL CONVECTIVE TOWERS EXTENDING NWD INTO
S-CNTRL MN. OBSERVATIONAL DATA SUGGEST THAT SFC CONVERGENCE IS VERY
WEAK...WITH ONLY POCKETS OF SUBTLE CONFLUENCE NOTED ACROSS THE
REGION. REGARDLESS...WITH AROUND 2500-4000 J/KG OF MLCAPE...AND
AROUND 20-25 KT OF EFFECTIVE SHEAR...SOME CONDITIONAL POTENTIAL FOR
AN ISOLATED CONVECTIVE ELEMENT OR TWO CAPABLE OF PRODUCING STRONG
WIND GUSTS MAY EXIST THROUGH LATE AFTERNOON...ESPECIALLY IF
CONVECTION WERE TO BECOME ROOTED NEAR THE SFC.  AN ISOLATED DMGG
WIND GUST CANNOT BE RULED OUT. A 53-KT WIND GUST WAS RECENTLY
REPORTED AT THE DES MOINES IA ASOS IN ASSOCIATION WITH A TSTM.
HOWEVER...GIVEN THE LACK OF LARGE-SCALE ASCENT...DEARTH OF SFC
CONVERGENCE...MODEST NATURE OF DEEP SHEAR...A SUSTAINED/ORGANIZED
SVR RISK IS UNLIKELY.

..COHEN/DARROW.. 08/10/2016

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

ATTN...WFO...MPX...DMX...FSD...

LAT...LON   41229405 41849495 43109554 43759516 43669459 43039392
            41849310 41319330 41229405

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 9, 10:19 PM CDTSevere Thunderstorm WatchSPCBig Stone, Chippewa, Clay, Douglas, Grant, Lac qui Parle and 8 more8 hr
Aug 10, 1:05 AM CDTMesoscale DiscussionSPCBig Stone, Lac qui Parle, Swift, Traverse55 min
Aug 10, 3:30 AM CDTMesoscale DiscussionSPCAnoka, Benton, Big Stone, Chisago, Douglas, Grant and 20 more60 min
Aug 10, 4:02 AM CDTSevere Thunderstorm WatchSPCAitkin, Benton, Cass, Chisago, Crow Wing, Isanti and 7 more4 hr
Aug 10, 11:19 AM CDTMesoscale DiscussionSPCBecker, Clay, Otter Tail, Wilkin2 hr
Aug 10, 1:15 PM CDTSevere Thunderstorm WatchSPCBecker, Big Stone, Clay, Douglas, Grant, Lac qui Parle and 8 more7 hr
Aug 10, 3:45 PM CDTMesoscale DiscussionSPCBecker, Big Stone, Cass, Chippewa, Clay, Crow Wing and 14 more2 hr
Aug 10, 4:04 PM CDTMesoscale DiscussionSPCAnoka, Benton, Carver, Chisago, Hennepin, Isanti and 13 more26 min
Aug 10, 4:20 PM CDTSevere Thunderstorm WatchSPCAitkin, Anoka, Benton, Carlton, Carver, Cass and 17 more5 hr
Aug 10, 6:54 PM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Carlton, Cass, Chisago and 15 more66 min

Nearby

Mesoscale Discussions in Iowa, 2016Mesoscale Discussions in Minnesota, 2016Every mesoscale discussion in 2016

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.