Alert archive / Maine / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 355

June 19, 201710 counties in Maine; 10 counties in New Hampshire; 10 counties in Vermont

The Storm Prediction Center issued this severe thunderstorm watch at Jun 19, 2017, 12:24 PM EDT for 10 counties in Maine; 10 counties in New Hampshire; 10 counties in Vermont. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Jun 19, 2017, 12:24 PM EDT (16:24 UTC)
Expired
Jun 19, 2017, 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 30 counties

Androscoggin County, ME, Aroostook County, ME, Cumberland County, ME, Franklin County, ME, Kennebec County, ME, Oxford County, ME, Penobscot County, ME, Piscataquis County, ME, Somerset 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, Addison County, VT, Caledonia County, VT, Chittenden County, VT, Essex County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Rutland County, VT, Washington County, VT, Windsor County, VT

The radar

The Portland,ME radar (KGYX), 171 km from the middle of the area, began a volume at 16:23 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
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
50%
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
70%

Warnings issued inside it

18 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jun 19, 1:00 PM EDTSevere Thunderstorm WarningGYXBelknap, Carroll, Merrimack, Strafford60 min
Jun 19, 1:33 PM EDTSevere Thunderstorm WarningGYXSomerset57 min
Jun 19, 2:04 PM EDTSevere Thunderstorm WarningCARPiscataquis41 min
Jun 19, 2:39 PM EDTFlash Flood WarningGYXCheshire, Sullivan6 hr
Jun 19, 3:30 PM EDTFlash Flood WarningGYXGrafton, Hillsborough, Merrimack, Sullivan3 hr
Jun 19, 3:32 PM EDTFlash Flood WarningGYXSomerset3 hr
Jun 19, 3:37 PM EDTSevere Thunderstorm WarningGYXBelknap, Carroll68 min
Jun 19, 3:40 PM EDTFlash Flood WarningCARPiscataquis7 hr
Jun 19, 3:44 PM EDTSevere Thunderstorm WarningGYXBelknap, Grafton, Merrimack, Sullivan46 min
Jun 19, 3:52 PM EDTFlash Flood WarningGYXBelknap, Carroll, Grafton, Hillsborough, Merrimack3 hr
Jun 19, 4:02 PM EDTFlash Flood WarningBTVEssex3 hr
Jun 19, 4:29 PM EDTSevere Thunderstorm WarningGYXOxford, York46 min
Jun 19, 4:57 PM EDTSevere Thunderstorm WarningGYXCheshire, Sullivan48 min
Jun 19, 5:02 PM EDTFlash Flood WarningGYXFranklin, Oxford, Somerset3 hr
Jun 19, 5:03 PM EDTSevere Thunderstorm WarningGYXAndroscoggin, Cumberland, Oxford31 min
Jun 19, 5:41 PM EDTSevere Thunderstorm WarningGYXHillsborough, Merrimack64 min
Jun 19, 6:39 PM EDTSevere Thunderstorm WarningGYXBelknap, Carroll, Strafford36 min
Jun 19, 6:50 PM EDTFlash Flood WarningCARAroostook4 hr

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 171 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-pSkew-T log-p diagram, Gray, ME at 12:00Z on 2017-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 178 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Gray, ME at 12:00Z on 2017-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
178 J/kg
Mixed-layer CIN
-166 J/kg
Mixed-layer LCL
886 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 19, 10:45 AM EDTMesoscale DiscussionSPCAndroscoggin, Franklin, Kennebec, Oxford, Piscataquis, Somerset3 hr
Jun 19, 2:58 PM EDTMesoscale DiscussionSPCFranklin, Oxford, Piscataquis, Somerset2 hr
Jun 19, 11:13 AM EDTSevere Thunderstorm WatchSPCAlbany, Bronx, Columbia, Delaware, Dutchess, Fulton and 21 more9 hr
Jun 19, 2:21 PM EDTMesoscale DiscussionSPCBronx, Kings, New York, Queens, Richmond, Rockland114 min

Nearby

Severe Thunderstorm Watches in Maine, 2017Severe Thunderstorm Watches in New Hampshire, 2017Severe Thunderstorm Watches in Vermont, 2017Every severe thunderstorm watch in 2017

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.