Alert archive / Michigan / Mesoscale Discussions in 2007
Mesoscale Discussion 1521
The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2007, 4:03 PM EDT for 31 counties in Michigan. It was in force for 117 min.
The area
The outline as issued.
The facts
- Issued
- Jul 18, 2007, 4:03 PM EDT (20:03 UTC)
- Expired
- Jul 18, 2007, 6:00 PM EDT
- In force
- 117 min
- Issued by
- the Storm Prediction Center
All 31 counties
Arenac County, MI, Bay County, MI, Clare County, MI, Clinton County, MI, Genesee County, MI, Gladwin County, MI, Gratiot County, MI, Huron County, MI, Ingham County, MI, Ionia County, MI, Isabella County, MI, Kent County, MI, Lake County, MI, Lapeer County, MI, Livingston County, MI, Macomb County, MI, Mecosta County, MI, Midland County, MI, Missaukee County, MI, Montcalm County, MI, Newaygo County, MI, Oakland County, MI, Ogemaw County, MI, Osceola County, MI, Roscommon County, MI, Saginaw County, MI, Saint Clair County, MI, Shiawassee County, MI, Tuscola County, MI, Wayne County, MI, Wexford County, MI
The radar
The Detroit radar (KDTX), 110 km from the middle of the area, began a volume at 20:05 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Detroit, MI (KDTX), launched 12:00Z, 8.1 hours before the alert went out and 111 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
- 317 J/kg
- Mixed-layer CIN
- -17 J/kg
- Mixed-layer LCL
- 717 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 66 m²/s²
- 0-3 km storm-relative helicity
- 75 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 182003 SWOMCD SPC MCD 182003 MIZ000-182200- MESOSCALE DISCUSSION 1521 NWS STORM PREDICTION CENTER NORMAN OK 0303 PM CDT WED JUL 18 2007 AREAS AFFECTED...MI CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 182003Z - 182200Z STORMS ARE EXPECTED TO INCREASE ACROSS PARTS OF LOWER MI THROUGH THE LATE AFTERNOON AND INTO THE EVENING. ENVIRONMENT CURRENTLY APPEARS SUPPORTIVE FOR A FEW SEVERE EVENTS WITH LARGE HAIL AND HIGH WINDS POSSIBLE. A WATCH MAY BE NEEDED OVER THE AREA IN THE NEXT 1-2 HOURS. STORMS ARE INCREASING ALONG WEAK QUASI-STATIONARY BOUNDARY BISECTING LOWER MI THIS AFTERNOON. AIR MASS NEAR THE BOUNDARY HAS BECOME QUITE UNSTABLE WITH LATEST MLCAPE AROUND 1500 J/KG. ACTIVITY MAY BE INCREASING IN PART FROM STRENGTHENING LARGE SCALE ASCENT ASSOCIATED WITH AN MID/UPPER LEVEL IMPULSE MOVING SEWD FROM MN/WI. IF THIS IS THE CASE...ADDITIONAL DEVELOPMENT IS LIKELY INTO THE EVENING AS THE STRONGER FORCING DEVELOPS ACROSS THE REGION. SHEAR AND INSTABILITY ARE SUFFICIENT TO SUPPORT SUPERCELL STORMS STRUCTURE WITH ATTENDANT THREATS OF LARGE HAIL AND POSSIBLY DAMAGING WINDS. THE CORRIDOR ACROSS CNTRL MI WILL CONTINUE TO BE EVALUATED OVER THE NEXT HOUR WITH A WATCH POSSIBLE IF STORMS CONTINUE TO INTENSIFY. ..CARBIN.. 07/18/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...APX...GRR... 43048576 43888622 44608586 44538430 43928278 43318272 42688254 42178309
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 1:17 PM EDT | Mesoscale Discussion | SPC | Menominee | 118 min |
| Jul 18, 4:39 PM EDT | Severe Thunderstorm Watch | SPC | Arenac, Bay, Clare, Clinton, Genesee, Gladwin and 24 more | 5 hr |
| Jul 18, 6:46 PM EDT | Mesoscale Discussion | SPC | Alcona, Alpena, Arenac, Barry, Bay, Clare and 42 more | 119 min |
| Jul 18, 7:38 PM EDT | Mesoscale Discussion | SPC | Allegan, Berrien, Branch, Calhoun, Cass, Hillsdale and 6 more | 97 min |
Nearby
Mesoscale Discussions in Michigan, 2007Every mesoscale discussion in 2007
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.