Alert archive / Massachusetts / Special Weather Statements in 2021

Special Weather Statement, NWS Boston/Norton, MA

July 21, 2021Barnstable County, Massachusetts

NWS Boston/Norton, MA issued this special weather statement at Jul 21, 2021, 9:53 PM EDT for Barnstable County, Massachusetts. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 21, 2021, 9:53 PM EDT (01:53 UTC)
Expired
Jul 21, 2021, 10:30 PM EDT
In force
37 min
Issued by
NWS Boston/Norton, MA

County Barnstable County, MA

The radar

The Boston radar (KBOX), 83 km from the middle of the area, began a volume at 01:53 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 nearest sounding before it

Gray, ME (KGYX), launched 00:00Z, 1.9 hours before the alert went out and 206 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 00:00Z on 2021-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 445 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 00:00Z on 2021-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 square meters per square second.193958Sfc1 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
445 J/kg
Mixed-layer CIN
-27 J/kg
Mixed-layer LCL
843 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
42 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

As transmitted.

095 
WWUS81 KBOX 220153
SPSBOX

Special Weather Statement
National Weather Service Boston/Norton MA
953 PM EDT Wed Jul 21 2021
 
MAZ022-220230-
Barnstable MA-
953 PM EDT Wed Jul 21 2021

...STRONG THUNDERSTORM NEAR PROVINCETOWN...

At 952 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles northwest of Provincetown, moving east at 25 mph.

Pea size hail and winds in excess of 30 mph will accompany this
storm.

Locations impacted include...
Provincetown and Truro. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get indoors when this storm approaches. Winds may be strong enough to
produce minor damage, such as a few downed branches.

Frequent lightning was occurring. Lightning can strike far away from
the storm. Go inside a building or vehicle. Wait at least 30 minutes
until after the storm has passed to resume outdoor activities.

&&

LAT...LON 4200 7008 4203 7009 4206 7013 4206 7017
      4204 7019 4202 7018 4203 7020 4207 7024
      4208 7022 4207 7012 4203 7005 4199 7001
TIME...MOT...LOC 0152Z 275DEG 22KT 4215 7037 

$$

Chai

The office that day

Everything else NWS Boston/Norton, MA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 8:20 PM EDTSpecial Weather StatementBOXNorfolk40 min
Jul 21, 8:27 PM EDTSpecial Marine WarningBOX63 min
Jul 21, 8:30 PM EDTSevere Thunderstorm WarningBOXNorfolk, Plymouth, Suffolk30 min
Jul 21, 8:42 PM EDTSpecial Marine WarningBOX63 min
Jul 21, 8:46 PM EDTSpecial Weather StatementBOXPlymouth44 min
Jul 21, 9:29 PM EDTSpecial Weather StatementBOXPlymouth46 min
Jul 21, 9:51 PM EDTSpecial Marine WarningBOX54 min

Nearby

Special Weather Statements in Massachusetts, 2021Every special weather statement in 2021

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.