Alert archive / Massachusetts / Severe Thunderstorm Watches in 2020
Severe Thunderstorm Watch 261
The Storm Prediction Center issued this severe thunderstorm watch at Jun 6, 2020, 12:23 PM EDT for 5 states. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 6, 2020, 12:23 PM EDT (16:23 UTC)
- Expired
- Jun 6, 2020, 8:00 PM EDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 32 counties
Capitol Planning Region, CT, Northeastern Connecticut Planning Region, CT, Bristol County, MA, Essex County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Androscoggin County, ME, Cumberland County, ME, Kennebec County, ME, Knox County, ME, Lincoln County, ME, Oxford County, ME, Sagadahoc County, ME, York County, ME, Belknap County, NH, Carroll County, NH, Cheshire County, NH, Coos County, NH, Grafton County, NH, Hillsborough County, NH, Merrimack County, NH, Rockingham County, NH, Strafford County, NH, Sullivan County, NH, Kent County, RI, Providence County, RI
The radar
The Portland,ME radar (KGYX), 51 km from the middle of the area, began a volume at 16:22 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
- 5%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 6, 12:34 PM EDT | Severe Thunderstorm Warning | GYX | Androscoggin, Cumberland, Oxford | 41 min |
| Jun 6, 12:38 PM EDT | Severe Thunderstorm Warning | GYX | Carroll, Grafton | 36 min |
| Jun 6, 12:58 PM EDT | Severe Thunderstorm Warning | GYX | Androscoggin, Cumberland, Sagadahoc | 32 min |
| Jun 6, 1:04 PM EDT | Severe Thunderstorm Warning | GYX | York | 26 min |
| Jun 6, 1:15 PM EDT | Severe Thunderstorm Warning | GYX | Androscoggin, Cumberland, Kennebec, Lincoln, Sagadahoc | 45 min |
| Jun 6, 2:06 PM EDT | Severe Thunderstorm Warning | GYX | Belknap, Merrimack, Sullivan | 39 min |
| Jun 6, 2:15 PM EDT | Severe Thunderstorm Warning | BOX | Franklin, Hampden, Hampshire, Worcester | 60 min |
| Jun 6, 2:24 PM EDT | Severe Thunderstorm Warning | GYX | York | 37 min |
| Jun 6, 2:39 PM EDT | Severe Thunderstorm Warning | BOX | Northeastern Connecticut Planning Region | 66 min |
| Jun 6, 2:51 PM EDT | Severe Thunderstorm Warning | BOX | Northeastern Connecticut Planning Region | 54 min |
| Jun 6, 2:52 PM EDT | Severe Thunderstorm Warning | GYX | York | 38 min |
| Jun 6, 3:14 PM EDT | Severe Thunderstorm Warning | GYX | York | 26 min |
| Jun 6, 3:29 PM EDT | Severe Thunderstorm Warning | BOX | Bristol, Middlesex, Norfolk, Plymouth, Suffolk | 61 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
Gray, ME (KGYX), launched 12:00Z, 4.4 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.
- Mixed-layer CAPE
- 662 J/kg
- Mixed-layer CIN
- -66 J/kg
- Mixed-layer LCL
- 1024 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 43 m²/s²
- 0-3 km storm-relative helicity
- 117 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.8
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 6, 2:20 PM EDT | Mesoscale Discussion | SPC | 85 min | |
| Jun 6, 10:46 AM EDT | Mesoscale Discussion | SPC | Androscoggin, Cumberland, Kennebec, Knox, Lincoln, Oxford and 3 more | 119 min |
Nearby
Severe Thunderstorm Watches in Massachusetts, 2020Severe Thunderstorm Watches in New Hampshire, 2020Severe Thunderstorm Watches in Maine, 2020Every severe thunderstorm watch in 2020
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.