Alert archive / Iowa / Mesoscale Discussions in 2005

Mesoscale Discussion 577

April 17, 200511 counties in Iowa; 5 counties in Minnesota; Lincoln County, Union County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2005, 4:40 PM CDT for 11 counties in Iowa; 5 counties in Minnesota; Lincoln County, Union County, South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 17, 2005, 4:40 PM CDT (21:40 UTC)
Expired: Apr 17, 2005, 6:45 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Clay County, IA, Dickinson County, IA, Emmet County, IA, Kossuth County, IA, Lyon County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Plymouth County, IA, Sioux County, IA, Winnebago County, IA, Faribault County, MN, Jackson County, MN, Martin County, MN, Nobles County, MN, Rock County, MN, Lincoln County, SD, Union County, SD

The radar

The Sioux Falls radar (KFSD), 115 km from the middle of the area, began a volume at 21:42 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

Minneapolis, MN (KMPX), launched 12:00Z, 9.7 hours before the alert went out and 212 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 960 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: -20 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 172140
SWOMCD
SPC MCD 172140 
MNZ000-IAZ000-SDZ000-172345-

MESOSCALE DISCUSSION 0577
NWS STORM PREDICTION CENTER NORMAN OK
0440 PM CDT SUN APR 17 2005

AREAS AFFECTED...SERN SD...FAR SWRN/SCENTRAL MN...FAR NWRN/NCENTRAL
IA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 172140Z - 172345Z

ISOLATED STORMS CAPABLE OF PRODUCING MARGINALLY SVR HAIL/DAMAGING
WINDS WILL BE POSSIBLE OVER THE AREA UNTIL ABOUT 02Z. DUE TO OVERALL
LIMITED SYNOPTIC SCALE LIFT...THE THREAT APPEARS TO BE ISOLATED
ENOUGH THAT A WW IS NOT ANTICIPATED.

LATEST SFC ANALYSIS SHOWS A NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDING FROM NEAR FSD EWD ALONG THE IA/MN BORDER. AIRMASS SOUTH OF
THIS BOUNDARY HAS BECOME MODERATELY UNSTABLE WITH MUCAPES
APPROACHING 2000 J/KG. DESPITE WEAK MID LEVEL FLOW /LESS THAN 20 KTS
 OBSERVED FROM 4-6 KM ON REGIONAL PROFILERS/...RELATIVELY STEEP MID
LEVEL LAPSE RATES FROM 7-7.5 DEG C/KM AND NEARLY DRY ADIABATIC LOW
LEVEL LAPSE RATES WILL FAVOR THE POTENTIAL FOR ISOLATED SVR STORMS. 
DIURNAL DECOUPLING SHOULD AID IN A DIMINISHING ISOLATED SVR THREAT
BEYOND 02Z.

..CROSBIE.. 04/17/2005

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

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

43709348 43809504 43909644 43629685 43389709 42849685
42739617 43109428 43229357

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 17, 1:39 PM CDT	Mesoscale Discussion	SPC	Bennett, Dewey, Haakon, Hughes, Jackson, Jones and 7 more	3 hr

Nearby

Mesoscale Discussions in Iowa, 2005 Mesoscale Discussions in Minnesota, 2005 Mesoscale Discussions in South Dakota, 2005 Every mesoscale discussion in 2005

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.