Alert archive / Michigan / Mesoscale Discussions in 2007
Mesoscale Discussion 1421
The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2007, 6:12 PM EDT for 28 counties in Michigan. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- Jul 8, 2007, 6:12 PM EDT (22:12 UTC)
- Expired
- Jul 8, 2007, 7:15 PM EDT
- In force
- 63 min
- Issued by
- the Storm Prediction Center
All 28 counties
Alcona County, MI, Alpena County, MI, Antrim County, MI, Arenac 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, Kalkaska County, MI, Lake County, MI, Leelanau County, MI, Mackinac County, MI, Manistee 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), 42 km from the middle of the area, began a volume at 22:12 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
Alpena, MI (KAPX), launched 12:00Z, 10.2 hours before the alert went out and 190 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
- 2108 J/kg
- Mixed-layer CIN
- -83 J/kg
- Mixed-layer LCL
- 956 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 95 m²/s²
- 0-3 km storm-relative helicity
- 89 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.1
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 082212 SWOMCD SPC MCD 082212 MIZ000-082315- MESOSCALE DISCUSSION 1421 NWS STORM PREDICTION CENTER NORMAN OK 0512 PM CDT SUN JUL 08 2007 AREAS AFFECTED...NRN LOWER AND ERN UPPER MI CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY VALID 082212Z - 082315Z DOWNSTREAM OF WW 492...AIR MASS REMAINS QUITE UNSTABLE ACROSS NRN LOWER MI WITH STRONG DEEP-LAYER SHEAR. ONGOING CLUSTERS OF STRONG TO SEVERE TSTMS OVER NRN WI/CNTRL UPPER MI WILL LIKELY CONTINUE EWD THROUGH THE EVENING...NECESSITATING A SEVERE TSTM ISSUANCE BY 23Z. AS OF 2205Z...RADAR/SATELLITE IMAGERY DEPICTED SEVERAL CLUSTERS/BANDS OF STRONG TO OCCASIONALLY SEVERE TSTMS ALONG A SLOW-MOVING COLD FRONT FROM E-CNTRL MN E/NEWD THROUGH CNTRL UPPER MI. WITH 40 TO 50 KTS OF MID-LEVEL WLY FLOW....THESE TSTMS SHOULD CONTINUE EWD ACROSS UPPER MI AND EVENTUALLY INTO NRN LOWER MI TOWARDS 02Z. ALTHOUGH CONVECTION FROM EARLIER TODAY AND ONSHORE FLOW FROM LKS MI AND HURON HAVE STABILIZED THE SURFACE LAYER ACROSS ERN UPPER MI...A THREAT FOR ELEVATED SUPERCELLS WILL LIKELY EXIST GIVEN THE STRONG DEEP-LAYER SHEAR. FARTHER S ACROSS NRN LOWER MI...NEARLY CLOUD FREE HEATING HAS RESULTED IN A VERY UNSTABLE AIR MASS WITH MLCAPES OF 2500 TO 3500 J/KG AWAY FROM THE IMMEDIATE COASTLINE /PER LATEST RUC OBJECTIVE ANALYSIS/. ALTHOUGH DIURNAL COOLING WILL RESULT IN SOME STABILIZATION...THE THREAT FOR LARGE HAIL AND DAMAGING WINDS SHOULD STILL BE MAINTAINED GIVEN THE ORGANIZED NATURE OF THE CONVECTION OVER NRN WI. ..GRAMS.. 07/08/2007 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...DTX...APX...GRR...MQT... 46728469 45688322 44578270 43788394 43878577 44278652 45418632 46488543
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 8, 4:14 AM EDT | Mesoscale Discussion | SPC | Alger, Baraga, Delta, Dickinson, Gogebic, Houghton and 6 more | 2 hr |
| Jul 8, 4:37 AM EDT | Severe Thunderstorm Watch | SPC | Alger, Antrim, Baraga, Benzie, Charlevoix, Cheboygan and 21 more | 6 hr |
| Jul 8, 7:48 AM EDT | Mesoscale Discussion | SPC | Alger, Benzie, Charlevoix, Cheboygan, Chippewa, Delta and 8 more | 87 min |
| Jul 8, 2:05 PM EDT | Mesoscale Discussion | SPC | Baraga, Dickinson, Gogebic, Iron, Marquette | 55 min |
| Jul 8, 2:28 PM EDT | Severe Thunderstorm Watch | SPC | Alger, Baraga, Delta, Dickinson, Gogebic, Houghton and 6 more | 8 hr |
| Jul 8, 3:21 PM EDT | Mesoscale Discussion | SPC | Alcona, Alpena, Antrim, Arenac, Charlevoix, Cheboygan and 17 more | 84 min |
| Jul 8, 5:00 PM EDT | Mesoscale Discussion | SPC | Alger, Delta, Dickinson, Iron, Menominee, Schoolcraft | 60 min |
| Jul 8, 6:23 PM EDT | Severe Thunderstorm Watch | SPC | Alcona, Alpena, Antrim, Arenac, Benzie, Charlevoix and 19 more | 4 hr |
| Jul 8, 7:40 PM EDT | Mesoscale Discussion | SPC | Alger, Delta, Dickinson, Luce, Mackinac, Menominee and 1 more | 65 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.