Alert archive / Michigan / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 8, NWS Detroit, MI

April 21, 2004Lapeer County, Michigan

NWS Detroit, MI issued this severe thunderstorm warning at Apr 21, 2004, 5:24 PM EDT for Lapeer County, Michigan. It was in force for 66 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Apr 21, 2004, 5:24 PM EDT (21:24 UTC)
Expired: Apr 21, 2004, 6:30 PM EDT
In force: 66 min
Issued by: NWS Detroit, MI
Area: Counties, with a storm outline in the text

County Lapeer County, MI

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Detroit, MI (KDTX), launched 12:00Z, 9.4 hours before the alert went out and 50 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: 4 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 998 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 235 m²/s²
0-3 km storm-relative helicity: 260 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.

785 
WUUS53 KDTX 212124
SVRDTX
MIC087-212230-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
523 PM EDT WED APR 21 2004

THE NATIONAL WEATHER SERVICE IN DETROIT/PONTIAC HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  LAPEER COUNTY IN SOUTHEAST MICHIGAN

* UNTIL 630 PM EDT

* AT 520 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING UP TO ONE INCH IN DIAMETER
  HAIL...AND DAMAGING WINDS UP TO 60 MPH. THIS STORM WAS LOCATED 9
  MILES SOUTHWEST OF NORTH BRANCH...OR ABOUT OVER LAPEER...AND MOVING
  NORTHEAST AT 40 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  NORTH BRANCH BY 533 PM EDT

TAKE COVER IN A SUBSTANTIAL SHELTER UNTIL THE STORM HAS PASSED.

LAT...LON 4316 8340 4300 8326 4311 8299 4331 8319

$$

BGM / BT

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Detroit, MI wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 21, 2:55 PM EDT, 2 hours 29 minutes earlier.

Area forecast discussion, Apr 21, 2:55 PM EDT, 2 hours 29 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
255 PM EDT WED APR 21 2004

.DISCUSSION...

CONVECTION HAS INCREASE IN FAR SOUTHEAST CWA...ON INTO NRN IN/OH
THE PAST FEW HOURS. WILL HAVE TO MONITOR TRENDS TO DECIDE JUST
NOW TO WORD THE LATE AFTN/EARLY EVENING. WILL LIKELY HAVE SCT SHRAS
AND STORMS IN ADVANCE OF COLD FRONT...AND PERHAPS A STORM OR TWO
WITH ACTUAL COLD FROPA AT AND BEYOND 00Z. CELLS HAVE BEHAVED WELL
SO FAR...WITH LITTLE MORE THAN GARDEN VARIETY GUSTY WINDS AND HEAVY
DOWNPOURS. WOULD NOT BE SURPRISED AT ALL TO SEE A FEW WARNINGS FLY
WITH STRONG WIND FIELD IN PLACE...AND AT LEAST MODEST INSTABILITY
DUE TO A FAIR AMOUNT OF SUNSHINE THIS AFTN. BIG MINUS HAS BEEN THE
MEAGER LLVL MOISTURE TO THIS POINT. THIS WILL IMPROVE JUST A BIT...
AS WEDGE OF 60F DWPTS SLIP INTO PARTS OF CWA FROM FAR SW LOWER MI
AND NRN IN.

NO MAIN BIG CHANGES TO THE FORECAST TODAY. BEYOND THIS EVENING...
REALLY ONLY FOCUSING ON A COUPLE OF PRECIP EVENTS...ONE THU NIGHT
INTO FRIDAY MORNING...AND THE OTHER IN THE SATURDAY NIGHT/SUNDAY
TIMEFRAME. ETA NOW SOMEWHAT ON BOARD WITH GFS WITH NORTHERN EXTENT
OF PRECIP FOR THE FIRST WX MAKER. GFS CONTINUES TO HAVE FEEDBACK
PROBLEMS...AND BLOWS UP QPF BOMB WELL NORTH...COVERING ALL OF CWA
BEFORE IT ENDS 18Z FRIDAY. AM MUCH MORE COMFORTABLE WITH THE ETA
DEPICTION...KEEPING FRONT/SFC WAVE BASICALLY SOUTH OF THE AREA...
WITH SRN 1/2 OF CWA ON TARGET FOR THE NRN EDGE OF PRECIP SHIELD
WITH THIS SYSTEM. WILL ADJUST GOING FCST AND EXTEND POPS INTO FRI
AM...AND BRING THEM FURTHER NORTH INTO CWA...SAY TO I-69 OR SO.

WEEKEND SYSTEM...THE REMNANTS OF STRONG UPPER STORM NOW DROPPING
SOUTHEAST OUT OF THE PAC NW...SEEMS LIKE A PRETTY GOOD BET AS WELL.
IN THIS CASE...HOWEVER...THE DETAILS ARE FAR MORE ELUSIVE...OR HAVE
BEEN OVER THE PAST SEVERAL DAYS ANYWAY. SEEMS MODELS HAVE NARROWED
THEIR SEARCH TO EITHER SAT NIGHT OR SUN (OR BOTH) FOR THE MOST PART.
WILL KEEP THE ONGOING CHC OF SHRAS/TSRAS IN PLACE. SUPPORT IS SEEN
PRETTY MUCH ACROSS THE BOARD FOR THIS SYS...WHICH LIFTS NORTHEAST
INTO THE WRN LAKES AS A FAIRLY POTENT SHORTWAVE.

SEASONABLY COOL TEMPERATURES APPEAR TO BE THE RULE FOR MUCH OF THE
NEXT WEEK...AS COLD FRONT THAT PASSES THRU THIS EVENING WILL HAVE
TROUBLE RETURNING NORTH THRU CWA AS IT MORE OR LESS STALLS IN THE
OH/TN VALLEY AREA. WITH A PREDOMINANT EAST FLOW...INFLUENCE OF THE
COLD LAKE WATERS WILL ALSO BE MAXIMIZED...ESP THU-SAT. PRETTY GOOD
COLD SHOT THEN TAKES OVER EARLY NEXT WEEK. BY IN LARGE...ONLY MADE
SMALL ADJUSTMENTS OF 1 OR 2 DEGREES.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

GURNEY

EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT
HTTP://WWW.CRH.NOAA.GOV/DTX  (ALL LOWER CASE)

Hazardous weather outlook, Apr 21, 1:37 PM EDT, 3 hours 47 minutes before

HAZARDOUS WEATHER OUTLOOK FOR SOUTHEAST MICHIGAN
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
137 PM EDT WED APR 21 2004

MIZ047>049-053>055-060>063-068>070-075-076-082-083-221100-
BAY-GENESEE-HURON-LAPEER-LENAWEE-LIVINGSTON-MACOMB-MIDLAND-MONROE-
OAKLAND-SAGINAW-SANILAC-SHIAWASSEE-ST. CLAIR-TUSCOLA-WASHTENAW-WAYNE-
137 PM EDT WED APR 21 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST MICHIGAN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON. SOME OF THESE
STORMS MAY BE SEVERE...CAPABLE OF PRODUCING WIND GUSTS TO 70 MPH
AND HAIL TO ONE INCH IN DIAMETER. THUNDERSTORM MOVEMENT WILL BE TO
THE EAST AT 40 MPH.

A COLD FRONT OVER WISCONSIN AND ILLINOIS WILL MOVE INTO LOWER
MICHIGAN LATE THIS AFTERNOON. THIS FRONT WILL INTERACT WITH AN
UNSTABLE AIRMASS OVER SOUTHEAST MICHIGAN...LEADING TO SCATTERED
THUNDERSTORMS AND THE POTENTIAL FOR SEVERE WEATHER. THE BEST CHANCE
FOR THUNDERSTORMS IS BETWEEN 1 PM AND 5 PM FROM METRO DETROIT TO
THE SAGINAW VALLEY...AND BETWEEN 3 PM AND 7 PM ACROSS THE THUMB.

.DAY TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A CHANCE OF THUNDERSTORMS SATURDAY NIGHT THROUGH SUNDAY AS
AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES
REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND INTO THE
EVENING.

BRAVENDER

In the hours before

Local storm report, Apr 21, 4:50 PM EDT, 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
450 PM EDT WED APR 21 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

0415 PM     HAIL             2 NW CHELSEA            42.33N 84.05W
04/21/2004  0.75 INCH        WASHTENAW          MI   EMERGENCY MNGR

&&

BRAVENDER

The office that day

Everything else NWS Detroit, MI issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 21, 12:04 AM EDT	Severe Thunderstorm Warning	DTX	Lenawee	41 min
Apr 21, 12:22 AM EDT	Severe Thunderstorm Warning	DTX	Washtenaw	38 min
Apr 21, 4:08 PM EDT	Severe Thunderstorm Warning	DTX	Livingston	52 min
Apr 21, 4:19 PM EDT	Severe Thunderstorm Warning	DTX	Washtenaw	56 min
Apr 21, 4:40 PM EDT	Severe Thunderstorm Warning	DTX	Genesee	65 min

Nearby

Severe Thunderstorm Warnings in Michigan, 2004 Every severe thunderstorm warning in 2004

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.