Alert archive / Massachusetts / Tornado Warnings in 2021

Tornado Warning 16, NWS Boston/Norton, MA

November 12, 2021Nantucket County, Massachusetts

NWS Boston/Norton, MA issued this tornado warning at Nov 12, 2021, 5:52 PM EST for Nantucket County, Massachusetts. It was in force for 11 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: Nov 12, 2021, 5:52 PM EST (22:52 UTC)
Expired: Nov 12, 2021, 6:03 PM EST
In force: 11 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

County Nantucket County, MA

The radar

The Boston radar (KBOX), 115 km from the middle of the area, began a volume at 22:54 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

Brookhaven, NY (KOKX), launched 12:00Z, 10.9 hours before the alert went out and 240 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: 191 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 601 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 262 m²/s²
0-3 km storm-relative helicity: 370 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

As transmitted.

762 
WFUS51 KBOX 122252
TORBOX
MAC019-122315-
/O.NEW.KBOX.TO.W.0016.211112T2252Z-211112T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Boston/Norton MA
552 PM EST Fri Nov 12 2021

The National Weather Service in Boston/Norton has issued a

* Tornado Warning for...
  Nantucket County in southeastern Massachusetts...

* Until 615 PM EST.
    
* At 551 PM EST, a severe thunderstorm capable of producing a tornado
  was located near Nantucket, moving northeast at 45 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* This dangerous storm will be near...
  Nantucket around 605 PM EST.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 4124 7000 4124 7012 4128 7023 4128 7020
      4130 7019 4130 7010 4128 7009 4130 7009
      4129 7007 4130 7003 4130 7007 4132 7000
      4135 7002 4133 7004 4134 7004 4136 7003
      4139 7005 4129 6997 4126 6996
TIME...MOT...LOC 2251Z 222DEG 40KT 4124 7014 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...0.00 IN

$$

RM

1 follow-up statement

324 
WWUS51 KBOX 122303
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
603 PM EST Fri Nov 12 2021

MAC019-122312-
/O.CAN.KBOX.TO.W.0016.000000T0000Z-211112T2315Z/
Nantucket MA-
603 PM EST Fri Nov 12 2021

...THE TORNADO WARNING FOR NANTUCKET COUNTY IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.  However gusty winds are
still possible with this thunderstorm.

LAT...LON 4124 7000 4124 7012 4128 7023 4128 7020
      4130 7019 4130 7010 4128 7009 4130 7009
      4129 7007 4130 7003 4130 7007 4132 7000
      4135 7002 4133 7004 4134 7004 4136 7003
      4139 7005 4129 6997 4126 6996
TIME...MOT...LOC 2302Z 222DEG 40KT 4129 7008 

$$

RM

The office that day

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

Issued	Product	Office	Counties	Lasted
Nov 12, 3:13 AM EST	Wind Advisory	BOX	Barnstable, Bristol, Dukes, Essex, Nantucket, Norfolk and 1 more	16 hr
Nov 12, 12:48 PM EST	Special Weather Statement	BOX	Worcester	42 min
Nov 12, 1:33 PM EST	Special Weather Statement	BOX	Norfolk	42 min
Nov 12, 1:35 PM EST	Special Weather Statement	BOX	Worcester	40 min
Nov 12, 3:12 PM EST	Areal Flood Warning	BOX	Bristol	3 hr
Nov 12, 3:20 PM EST	Special Weather Statement	BOX	Essex, Middlesex	40 min
Nov 12, 3:24 PM EST	Special Marine Warning	BOX		27 min
Nov 12, 3:31 PM EST	Special Weather Statement	BOX	Suffolk	44 min
Nov 12, 3:41 PM EST	Special Marine Warning	BOX		30 min
Nov 12, 4:54 PM EST	Small Craft Advisory	BOX		5 hr
Nov 12, 5:30 PM EST	Special Marine Warning	BOX		45 min

Nearby

Tornado Warnings in Massachusetts, 2021 Every tornado warning in 2021 Tornadoes 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.