Alert archive / Michigan / Severe Thunderstorm Watches in 1999

Severe Thunderstorm Watch 607

July 29, 199922 counties in Michigan

The Storm Prediction Center issued this severe thunderstorm watch at Jul 29, 1999, 8:00 AM EDT for 22 counties in Michigan. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Jul 29, 1999, 8:00 AM EDT (12:00 UTC)
Expired
Jul 29, 1999, 12:00 PM EDT
In force
4 hr
Issued by
the Storm Prediction Center
All 22 counties

Alpena County, MI, Antrim County, MI, Arenac County, MI, Charlevoix County, MI, Cheboygan County, MI, Clare County, MI, Crawford County, MI, Emmet County, MI, Gladwin County, MI, Grand Traverse County, MI, Iosco County, MI, Kalkaska County, MI, Lake County, MI, Missaukee County, MI, Montmorency County, MI, Ogemaw County, MI, Osceola 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), 16 km from the middle of the area, began a volume at 12:01 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

Alpena, MI (KAPX), launched 12:00Z, 0.0 hours before the alert went out and 198 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 1999-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Alpena, MI at 12:00Z on 1999-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 123 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1638 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
123 m²/s²
0-3 km storm-relative helicity
212 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.

276 
WWUS9 KMKC 291130
SEL7  
MKC WW 291130
MIZ000-LMZ000-LHZ000-291600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 607
STORM PREDICTION CENTER NORMAN OK
730 AM EDT THU JUL 29 1999

THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH
FOR PORTIONS OF

   NORTHERN LOWER MICHIGAN                           
   EASTERN LAKE MICHIGAN                      
   WESTERN LAKE HURON                         

EFFECTIVE THIS THURSDAY MORNING FROM 800 AM UNTIL NOON EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 65 STATUTE MILES
EITHER SIDE OF A LINE FROM 25 MILES WEST NORTHWEST OF TRAVERSE CITY
MICHIGAN TO 10 MILES NORTH NORTHEAST OF OSCODA MICHIGAN.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

OTHER WATCH INFORMATION...  CONTINUE...WW 605...WW 606...

DISCUSSION...STRONG LOW LEVEL WARM ADVECTION AND SHORTWAVE TROUGH
MOVING THROUGH NRN WI WILL RESULT IN A LINE OF SEVERE THUNDERSTORMS
TO MOVE RAPIDLY EAST-SOUTHEASTWARD ACROSS NRN LOWER MICHIGAN. LARGE
HAIL WILL BE THE MAIN THREAT...BUT DESPITE THE RELATIVELY COOL
STABLE BOUNDARY LAYER...DAMAGING WINDS ARE ALSO POSSIBLE GIVEN THE
STRONG FORCING AND STRONG WINDS ALOFT.   

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550.  MEAN STORM
MOTION VECTOR 29045.

...IMY

454,0855 453,0830 433,0833 435,0861

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 29, 6:00 AM EDTSevere Thunderstorm WatchSPCAlger, Baraga, Delta, Dickinson, Iron, Marquette and 1 more5 hr

Nearby

Severe Thunderstorm Watches in Michigan, 1999Every severe thunderstorm watch in 1999

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.