Alert archive / Michigan / Tornado Watches in 2003
Tornado Watch 878
The Storm Prediction Center issued this tornado watch at Aug 21, 2003, 1:30 PM EDT for 37 counties in Michigan. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 21, 2003, 1:30 PM EDT (17:30 UTC)
- Expired
- Aug 21, 2003, 7:00 PM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
All 37 counties
Alcona County, MI, Alpena County, MI, Antrim County, MI, Arenac County, MI, Bay County, MI, Benzie County, MI, Charlevoix County, MI, Cheboygan County, MI, Chippewa County, MI, Clare County, MI, Crawford County, MI, Emmet County, MI, Gladwin County, MI, Grand Traverse County, MI, Iosco County, MI, Isabella County, MI, Kalkaska County, MI, Lake County, MI, Leelanau County, MI, Luce County, MI, Mackinac County, MI, Manistee County, MI, Mason County, MI, Mecosta County, MI, Midland County, MI, Missaukee County, MI, Montmorency County, MI, Newaygo County, MI, Oceana County, MI, Ogemaw County, MI, Osceola County, MI, Oscoda County, MI, Otsego County, MI, Presque Isle County, MI, Roscommon County, MI, Schoolcraft County, MI, Wexford County, MI
Warnings issued inside it
13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 2:13 PM EDT | Severe Thunderstorm Warning | MQT | Luce, Schoolcraft | 62 min |
| Aug 21, 2:48 PM EDT | Severe Thunderstorm Warning | APX | Chippewa | 57 min |
| Aug 21, 3:03 PM EDT | Severe Thunderstorm Warning | APX | Montmorency, Presque Isle | 57 min |
| Aug 21, 3:15 PM EDT | Severe Thunderstorm Warning | MQT | Luce | 25 min |
| Aug 21, 3:46 PM EDT | Severe Thunderstorm Warning | APX | Chippewa | 44 min |
| Aug 21, 3:48 PM EDT | Severe Thunderstorm Warning | APX | Oscoda | 57 min |
| Aug 21, 4:09 PM EDT | Severe Thunderstorm Warning | APX | Roscommon | 36 min |
| Aug 21, 4:15 PM EDT | Severe Thunderstorm Warning | APX | Alpena, Presque Isle | 60 min |
| Aug 21, 4:34 PM EDT | Tornado Warning | APX | Alpena | 41 min |
| Aug 21, 4:40 PM EDT | Severe Thunderstorm Warning | APX | Ogemaw | 65 min |
| Aug 21, 4:49 PM EDT | Severe Thunderstorm Warning | APX | Alcona | 71 min |
| Aug 21, 6:00 PM EDT | Severe Thunderstorm Warning | APX | Iosco | 30 min |
| Aug 21, 6:27 PM EDT | Severe Thunderstorm Warning | APX | Iosco | 33 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Green Bay/Straub, WI (KGRB), launched 12:00Z, 5.5 hours before the alert went out and 234 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.
- Mixed-layer CAPE
- 1787 J/kg
- Mixed-layer CIN
- -178 J/kg
- Mixed-layer LCL
- 1082 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 297 m²/s²
- 0-3 km storm-relative helicity
- 304 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.4
The text
As transmitted, in the capitals the NWS used until 2016.
086
WWUS20 KWNS 211736
SEL8
SPC WW 211730
MIZ000-LMZ000-LSZ000-LHZ000-212300-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 878
NWS STORM PREDICTION CENTER NORMAN OK
130 PM EDT THU AUG 21 2003
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
EASTERN UPPER AND NORTHERN/CENTRAL LOWER MICHIGAN
LAKE MICHIGAN
LAKE SUPERIOR
LAKE HURON
EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 130 PM UNTIL
700 PM EDT.
TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE TORNADO WATCH AREA IS ALONG AND 85 STATUTE MILES EAST AND WEST
OF A LINE FROM 35 MILES NORTH OF SAULT STE MARIE MICHIGAN TO 55
MILES WEST OF SAGINAW MICHIGAN.
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.
DISCUSSION...THUNDERSTORMS EXPECTED TO INTENSIFY ALONG PREFRONTAL
TROUGH NOW APPROACHING WRN LWR MI...AND ALONG COLD FRONT CROSSING
THE CNTRL U.P ...AS POTENT UPPER IMPULSE NOW OVER NRN WI CONTINUES
EWD. WHILE DEEP WIND PROFILES ARE LARGELY UNIDIRECTIONAL...LENGTH
OF HODOGRAPHS /50+ KT FLOW AOA 3 KM ON GRB VWP/...DEGREE OF
INSTABILITY /100 MB MLCAPE TO 2000 J/KG/ AND CELLULAR NATURE OF
EXISTING STORMS SUGGEST POSSIBILITY OF TORNADOES IN ADDITION TO
SUPERCELLS/BOWING SEGMENTS WITH HIGH WIND.
AVIATION...TORNADOES AND 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 27035.
...CORFIDI
465,0823 432,0832 432,0865 465,0860SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 8:22 PM EDT | Mesoscale Discussion | SPC | Gogebic, Iron, Ontonagon | 113 min |
| Aug 21, 5:29 AM EDT | Mesoscale Discussion | SPC | Antrim, Arenac, Barry, Bay, Calhoun, Cheboygan and 26 more | 3 hr |
| Aug 21, 1:07 PM EDT | Mesoscale Discussion | SPC | Alger, Antrim, Benzie, Charlevoix, Cheboygan, Chippewa and 34 more | 113 min |
| Aug 21, 3:49 PM EDT | Mesoscale Discussion | SPC | Alcona, Alpena, Antrim, Arenac, Bay, Benzie and 31 more | 86 min |
| Aug 21, 6:20 PM EDT | Mesoscale Discussion | SPC | Alcona, Alpena, Antrim, Arenac, Bay, Benzie and 31 more | 55 min |
Nearby
Tornado Watches in Michigan, 2003Every tornado watch in 2003
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.