Alert archive / Massachusetts / Tornado Warnings in 2020

Tornado Warning 4, NWS Boston/Norton, MA

August 4, 2020Franklin County, Massachusetts

NWS Boston/Norton, MA issued this tornado warning at Aug 4, 2020, 9:30 AM EDT for Franklin County, Massachusetts. It was in force for 13 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, 9:30 AM EDT (13:30 UTC)
Expired: Aug 4, 2020, 9:43 AM EDT
In force: 13 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Franklin County, MA

The radar

The Albany radar (KENX), 107 km from the middle of the area, began a volume at 13:31 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

Albany, NY (KALY), launched 12:00Z, 1.5 hours before the alert went out and 87 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.

934 
WFUS51 KBOX 041330
TORBOX
MAC011-041400-
/O.NEW.KBOX.TO.W.0004.200804T1330Z-200804T1400Z/

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

The National Weather Service in Boston/Norton has issued a

* Tornado Warning for...
  Northwestern Franklin County in western Massachusetts...

* Until 1000 AM EDT.
    
* At 930 AM EDT, a severe thunderstorm capable of producing a tornado
  was located over Colrain, or 8 miles northwest of Greenfield,
  moving northeast at 30 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...
  Colrain around 940 AM EDT.
  Leyden around 945 AM EDT.

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 4274 7284 4274 7274 4273 7263 4259 7267
      4263 7289
TIME...MOT...LOC 1330Z 208DEG 25KT 4267 7275 

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

$$

Frank

2 follow-up statements

535 
WWUS51 KBOX 041335
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
935 AM EDT Tue Aug 4 2020

MAC011-041400-
/O.CON.KBOX.TO.W.0004.000000T0000Z-200804T1400Z/
Franklin MA-
935 AM EDT Tue Aug 4 2020

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1000 AM EDT FOR NORTH
CENTRAL FRANKLIN COUNTY...
    
At 935 AM EDT, a severe thunderstorm capable of producing a tornado
was located over Colrain, or 8 miles northwest of Greenfield, moving
northeast at 30 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...
  Leyden around 945 AM EDT.

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 4274 7282 4274 7274 4273 7263 4263 7266
      4264 7282
TIME...MOT...LOC 1335Z 208DEG 25KT 4270 7273 

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

$$

Frank

419 
WWUS51 KBOX 041343
SVSBOX

Severe Weather Statement
National Weather Service Boston/Norton MA
943 AM EDT Tue Aug 4 2020

MAC011-041353-
/O.CAN.KBOX.TO.W.0004.000000T0000Z-200804T1400Z/
Franklin MA-
943 AM EDT Tue Aug 4 2020

...THE TORNADO WARNING FOR NORTH CENTRAL FRANKLIN COUNTY IS
CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning has been cancelled.

LAT...LON 4274 7282 4274 7274 4273 7263 4263 7266
      4264 7282
TIME...MOT...LOC 1342Z 208DEG 25KT 4275 7269 

$$

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, 1:57 PM EDT	Tornado Warning	BOX	Middlesex, Worcester	25 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.