Alert archive / Massachusetts / Mesoscale Discussions in 2012

Mesoscale Discussion 1567

July 24, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Jul 24, 2012, 12:52 PM EDT for 4 states. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Jul 24, 2012, 12:52 PM EDT (16:52 UTC)
Expired: Jul 24, 2012, 2:15 PM EDT
In force: 83 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Barnstable County, MA, Bristol County, MA, Dukes County, MA, Essex County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Cumberland County, ME, Knox County, ME, Lincoln County, ME, Sagadahoc County, ME, York County, ME, Hillsborough County, NH, Rockingham County, NH, Strafford County, NH, Bristol County, RI

The radar

The Boston radar (KBOX), 81 km from the middle of the area, began a volume at 16:55 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.

Severe Thunderstorm Watch 511Jul 24, 1:40 PM EDT

The nearest sounding before it

Chatham, MA (KCHH), launched 12:00Z, 4.9 hours before the alert went out and 119 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: 313 J/kg
Mixed-layer CIN: -144 J/kg
Mixed-layer LCL: 967 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 94 m²/s²
0-3 km storm-relative helicity: 142 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.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 24, 2:29 AM EDT	Mesoscale Discussion	SPC	Androscoggin, Cumberland, Franklin, Kennebec, Oxford, Somerset and 1 more	31 min
Jul 23, 10:29 PM EDT	Mesoscale Discussion	SPC	Berkshire	91 min
Jul 24, 1:38 PM EDT	Severe Thunderstorm Watch	SPC	Barnstable, Bristol, Dukes, Essex, Franklin, Hampden and 7 more	6 hr

Nearby

Mesoscale Discussions in Massachusetts, 2012 Mesoscale Discussions in Maine, 2012 Mesoscale Discussions in New Hampshire, 2012 Every mesoscale discussion in 2012

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.