Alert archive / Massachusetts / Tornado Warnings in 2020

Tornado Warning 5, NWS Boston/Norton, MA

August 4, 2020Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this tornado warning at Aug 4, 2020, 1:57 PM EDT for Middlesex County, Worcester County, Massachusetts. It was in force for 25 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: Aug 4, 2020, 1:57 PM EDT (17:57 UTC)
Expired: Aug 4, 2020, 2:22 PM EDT
In force: 25 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

Counties Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 99 km from the middle of the area, began a volume at 18:01 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 4, 12:43 PM EDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 6.0 hours before the alert went out and 156 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: 71 J/kg
Mixed-layer CIN: -67 J/kg
Mixed-layer LCL: 818 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 135 m²/s²
0-3 km storm-relative helicity: 223 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

131 
WFUS51 KBOX 041757
TORBOX
MAC017-027-041845-
/O.NEW.KBOX.TO.W.0005.200804T1757Z-200804T1845Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Boston/Norton MA
157 PM EDT Tue Aug 4 2020

The National Weather Service in Boston/Norton has issued a

* Tornado Warning for...
  Northwestern Worcester County in central Massachusetts...
  Northwestern Middlesex County in northeastern Massachusetts...

* Until 245 PM EDT.
    
* At 157 PM EDT, a severe thunderstorm capable of producing a tornado
  was located over Ashburnham, or near Fitchburg, moving northwest at
  55 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 tornadic thunderstorm will remain over mainly rural areas of
  NORTHWESTERN WORCESTER AND NORTHWESTERN MIDDLESEX COUNTIES.

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.

&&

LAT...LON 4271 7179 4253 7172 4246 7211 4272 7224
TIME...MOT...LOC 1757Z 154DEG 49KT 4266 7189 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Frank

2 follow-up statements

320 
WWUS51 KBOX 041808
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
208 PM EDT Tue Aug 4 2020

MAC017-027-041845-
/O.CON.KBOX.TO.W.0005.000000T0000Z-200804T1845Z/
Worcester MA-Middlesex MA-
208 PM EDT Tue Aug 4 2020

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 245 PM EDT FOR
NORTHWESTERN WORCESTER AND NORTHWESTERN MIDDLESEX COUNTIES...
    
At 208 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Ashburnham, or 7 miles northwest of Fitchburg,
moving north at 40 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.

Locations impacted include...
Leominster, Fitchburg, Gardner, Athol, Winchendon, Lunenburg,
Townsend, Templeton, Westminster, Ashburnham, Barre, Hubbardston,
Princeton, Ashby, Phillipston, Royalston and Petersham.

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.

&&

LAT...LON 4271 7179 4253 7172 4246 7211 4272 7224
TIME...MOT...LOC 1808Z 159DEG 33KT 4268 7192 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

Frank

523 
WWUS51 KBOX 041822
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
222 PM EDT Tue Aug 4 2020

MAC017-027-041831-
/O.CAN.KBOX.TO.W.0005.000000T0000Z-200804T1845Z/
Worcester MA-Middlesex MA-
222 PM EDT Tue Aug 4 2020

...THE TORNADO WARNING FOR NORTHWESTERN WORCESTER AND NORTHWESTERN
MIDDLESEX COUNTIES IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

A Tornado Watch remains in effect until 900 PM EDT for central and
northeastern Massachusetts.

LAT...LON 4271 7179 4253 7172 4246 7211 4272 7224
TIME...MOT...LOC 1820Z 154DEG 49KT 4285 7203 

$$

Frank

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 4, 3:24 AM EDT	Coastal Flood Advisory	BOX	Bristol, Plymouth	17 hr
Aug 4, 8:37 AM EDT	Special Weather Statement	BOX	Berkshire	23 min
Aug 4, 8:45 AM EDT	Tornado Warning	BOX	Franklin, Hampshire	45 min
Aug 4, 9:27 AM EDT	Severe Thunderstorm Warning	BOX	Franklin	15 min
Aug 4, 9:30 AM EDT	Tornado Warning	BOX	Franklin	13 min
Aug 4, 3:07 PM EDT	Special Marine Warning	BOX		38 min
Aug 4, 3:44 PM EDT	Special Marine Warning	BOX		91 min
Aug 4, 4:14 PM EDT	Special Marine Warning	BOX		31 min
Aug 4, 4:58 PM EDT	Tornado Warning	BOX	Middlesex, Worcester	21 min
Aug 4, 5:10 PM EDT	Special Marine Warning	BOX		50 min

Nearby

Tornado Warnings in Massachusetts, 2020 Every tornado warning in 2020 Tornadoes 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.