Alert archive / Michigan / Severe Thunderstorm Watches in 2002

Severe Thunderstorm Watch 519

July 21, 200221 counties in Michigan

The Storm Prediction Center issued this severe thunderstorm watch at Jul 21, 2002, 7:25 PM EDT for 21 counties in Michigan. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jul 21, 2002, 7:25 PM EDT (23:25 UTC)
Expired
Jul 22, 2002, 12:00 AM EDT
In force
5 hr
Issued by
the Storm Prediction Center
All 21 counties

Alpena County, MI, Antrim County, MI, Benzie County, MI, Charlevoix County, MI, Cheboygan County, MI, Chippewa County, MI, Crawford County, MI, Emmet County, MI, Grand Traverse County, MI, Kalkaska County, MI, Leelanau County, MI, Mackinac County, MI, Manistee County, MI, Missaukee County, MI, Montmorency County, MI, Ogemaw County, MI, Oscoda County, MI, Otsego County, MI, Presque Isle County, MI, Roscommon County, MI, Wexford County, MI

The radar

The NCL Michigan radar (KAPX), 40 km from the middle of the area, began a volume at 23:26 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.

Warnings issued inside it

3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jul 21, 7:39 PM EDTSevere Thunderstorm WarningAPXMackinac51 min
Jul 21, 8:03 PM EDTSevere Thunderstorm WarningAPXChippewa57 min
Jul 21, 8:30 PM EDTSevere Thunderstorm WarningAPXMackinac60 min

The nearest sounding before it

Alpena, MI (KAPX), launched 12:00Z, 11.4 hours before the alert went out and 215 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, Alpena, MI at 12:00Z on 2002-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2407 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, Alpena, MI at 12:00Z on 2002-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 307 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
2407 J/kg
Mixed-layer CIN
-69 J/kg
Mixed-layer LCL
821 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
307 m²/s²
0-3 km storm-relative helicity
327 m²/s²
Significant tornado parameter
0.0
Supercell composite
9.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 3:55 PM EDTSevere Thunderstorm WatchSPCGogebic, Iron6 hr
Jul 21, 5:25 PM EDTSevere Thunderstorm WatchSPCDelta, Dickinson, Luce, Menominee, Schoolcraft6 hr

Nearby

Severe Thunderstorm Watches in Michigan, 2002Every severe thunderstorm watch in 2002

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.