Alert archive / Michigan / Tornado Watches in 2015
Tornado Watch 48
The Storm Prediction Center issued this tornado watch at Apr 9, 2015, 7:11 PM EDT for 7 counties in Michigan. It was in force for 98 min.
The area
The outline as issued.
The facts
- Issued
- Apr 9, 2015, 7:11 PM EDT (23:11 UTC)
- Expired
- Apr 9, 2015, 8:49 PM EDT
- In force
- 98 min
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
Counties Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Washtenaw County, MI, Wayne County, MI
The radar
The Detroit radar (KDTX), 40 km from the middle of the area, began a volume at 23:14 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 50%
Warnings issued inside it
1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 7:50 PM EDT | Severe Thunderstorm Warning | DTX | Washtenaw, Wayne | 38 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
Detroit, MI (KDTX), launched 12:00Z, 11.2 hours before the alert went out and 44 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 734 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 39 m²/s²
- 0-3 km storm-relative helicity
- 179 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
600 WWUS20 KWNS 092308 SEL8 SPC WW 092308 MIZ000-LEZ000-100300- URGENT - IMMEDIATE BROADCAST REQUESTED TORNADO WATCH NUMBER 48 NWS STORM PREDICTION CENTER NORMAN OK 710 PM EDT THU APR 9 2015 THE NWS STORM PREDICTION CENTER HAS ISSUED A * TORNADO WATCH FOR PORTIONS OF SOUTHEAST LOWER MICHIGAN LAKE ERIE * EFFECTIVE THIS THURSDAY EVENING FROM 710 PM UNTIL 1100 PM EDT. * PRIMARY THREATS INCLUDE... A COUPLE TORNADOES POSSIBLE ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 40 STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES WEST OF ANN ARBOR MICHIGAN TO 20 MILES SOUTH OF MOUNT CLEMENS MICHIGAN. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... 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. && OTHER WATCH INFORMATION...CONTINUE...WW 39...WW 40...WW 41...WW 42...WW 43...WW 44...WW 45...WW 46...WW 47... DISCUSSION...SEVERAL SMALL SUPERCELL STORMS HAVE FORMED ALONG THE WARM FRONT OVER LOWER MI. STRONG LOW LEVEL VERTICAL SHEAR AND MARGINAL INSTABILITY WILL POSE A RISK OF HAIL...DAMAGING WINDS...OR PERHAPS A TORNADO OR TWO FROM THESE STORMS THIS EVENING. AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM MOTION VECTOR 27035. ...HART
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 9, 6:20 PM EDT | Mesoscale Discussion | SPC | Allegan, Barry, Branch, Calhoun, Cass, Eaton and 10 more | 85 min |
Nearby
Tornado Watches in Michigan, 2015Every tornado watch in 2015
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.