Alert archive / Massachusetts / Winter Storm Watches in 2021

Winter Storm Watch 7, NWS Boston/Norton, MA

April 15, 2021Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this winter storm watch at Apr 15, 2021, 3:37 AM EDT for Middlesex County, Worcester County, Massachusetts. It took effect at Apr 15, 2021, 8:00 PM EDT. It was in force for .

The area

The counties it named.

The facts

Issued
Apr 15, 2021, 3:37 AM EDT (07:37 UTC)
In effect from
Apr 15, 2021, 8:00 PM EDT
Expired
Apr 15, 2021, 3:25 PM EDT
In force
Issued by
NWS Boston/Norton, MA

Counties Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 67 km from the middle of the area, began a volume at 07:37 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 00:00Z, 7.6 hours before the alert went out and 181 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, Albany, NY at 00:00Z on 2021-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Albany, NY at 00:00Z on 2021-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 square meters per square second.1939587897Sfc1 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
3 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
2373 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

613 
WWUS41 KBOX 150737
WSWBOX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Boston/Norton MA
337 AM EDT Thu Apr 15 2021

MAZ002-008-152045-
/O.UPG.KBOX.WS.A.0006.210416T0000Z-210417T0000Z/
/O.NEW.KBOX.WS.W.0005.210416T0000Z-210417T0000Z/
Western Franklin MA-Western Hampshire MA-
Including the cities of Charlemont and Chesterfield
337 AM EDT Thu Apr 15 2021

...WINTER STORM WARNING IN EFFECT FROM 8 PM THIS EVENING TO 8 PM
EDT FRIDAY...

* WHAT...Heavy wet snow expected. Total snow accumulations of 5 to
  8 inches with localized amounts up to 10 inches possible above
  1500 feet.

* WHERE...Western Franklin MA and Western Hampshire MA Counties.

* WHEN...From 8 PM this evening to 8 PM EDT Friday.

* IMPACTS...Travel could be very difficult. Some power outages are
  possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

&&

$$

MAZ009-152045-
/O.UPG.KBOX.WS.A.0006.210416T0000Z-210417T0000Z/
/O.NEW.KBOX.WW.Y.0013.210416T0000Z-210417T0000Z/
Western Hampden MA-
Including the city of Blandford
337 AM EDT Thu Apr 15 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO
8 PM EDT FRIDAY...

* WHAT...Wet snow expected. Total snow accumulations of 4 to 6 
  inches.

* WHERE...Western Hampden MA County.

* WHEN...From 8 PM this evening to 8 PM EDT Friday.

* IMPACTS...Travel could be very difficult. A few power outages
  are possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

&&

$$

MAZ003-010-152045-
/O.NEW.KBOX.WW.Y.0013.210416T0000Z-210417T0000Z/
Eastern Franklin MA-Eastern Hampshire MA-
Including the cities of Greenfield, Orange, Amherst, 
and Northampton
337 AM EDT Thu Apr 15 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO
8 PM EDT FRIDAY...

* WHAT...Wet snow expected. Total snow accumulations of 2 to 5 
  inches.

* WHERE...Eastern Franklin MA and Eastern Hampshire MA Counties.

* WHEN...From 8 PM this evening to 8 PM EDT Friday.

* IMPACTS...Travel could be very difficult. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

&&

$$

MAZ004-026-152045-
/O.NEW.KBOX.WS.A.0007.210416T0000Z-210417T0000Z/
Northern Worcester MA-Northern Middlesex MA-
Including the cities of Barre, Fitchburg, and Ayer
337 AM EDT Thu Apr 15 2021

...WINTER STORM WATCH IN EFFECT FROM THIS EVENING THROUGH FRIDAY
EVENING...

* WHAT...Heavy wet snow possible. Total snow accumulations of 4 to
  7 inches possible with the highest amounts at or above 1000
  feet.

* WHERE...Northern Worcester MA and Northern Middlesex MA 
  Counties.

* WHEN...From this evening through Friday evening.

* IMPACTS...Travel could be very difficult. Some power outages are
  possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts for updates on this situation. 

&&

$$

Frank
1 follow-up statement
483 
WWUS41 KBOX 151925
WSWBOX

URGENT - WINTER WEATHER MESSAGE
National Weather Service Boston/Norton MA
325 PM EDT Thu Apr 15 2021

MAZ002-008-160900-
/O.CON.KBOX.WS.W.0005.210416T0000Z-210417T0000Z/
Western Franklin MA-Western Hampshire MA-
Including the cities of Charlemont and Chesterfield
325 PM EDT Thu Apr 15 2021

...WINTER STORM WARNING REMAINS IN EFFECT FROM 8 PM THIS EVENING
TO 8 PM EDT FRIDAY...

* WHAT...Heavy wet snow expected. Total snow accumulations of 5 
  to 8 inches with localized amounts of 10 inches possible above 
  1500 feet.

* WHERE...Western Hampshire MA and Western Franklin MA Counties.

* WHEN...From 8 PM this evening to 8 PM EDT Friday.

* IMPACTS...Travel could be very difficult. The hazardous 
  conditions could impact the morning or evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

&&

$$

MAZ004-026-160900-
/O.UPG.KBOX.WS.A.0007.210416T0000Z-210417T0000Z/
/O.EXB.KBOX.WW.Y.0013.210416T0000Z-210417T0600Z/
Northern Worcester MA-Northern Middlesex MA-
Including the cities of Barre, Fitchburg, and Ayer
325 PM EDT Thu Apr 15 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 PM THIS EVENING TO
2 AM EDT SATURDAY...

* WHAT...Wet snow expected. Total snow accumulations of 2 to 5
  inches with localized amounts greater than 6 inches possible 
  above 1000 feet.

* WHERE...Northern Worcester MA and Northern Middlesex MA 
  Counties.

* WHEN...From 8 PM this evening to 2 AM EDT Saturday.

* IMPACTS...Travel could be very difficult. The hazardous
  conditions could impact the morning or evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

&&

$$

MAZ003-009-010-160900-
/O.CON.KBOX.WW.Y.0013.210416T0000Z-210417T0000Z/
Eastern Franklin MA-Western Hampden MA-Eastern Hampshire MA-
Including the cities of Greenfield, Orange, Blandford, Amherst, 
and Northampton
325 PM EDT Thu Apr 15 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 8 PM THIS
EVENING TO 8 PM EDT FRIDAY...

* WHAT...Wet snow expected. Total snow accumulations of 2 to 5 
  inches.

* WHERE...Western Hampden MA, Eastern Hampshire MA and Eastern 
  Franklin MA Counties.

* WHEN...From 8 PM this evening to 8 PM EDT Friday.

* IMPACTS...Travel could be very difficult. The hazardous 
  conditions could impact the morning or evening commute.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

&&

$$

BL

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 15, 3:37 AM EDTWinter Storm WarningBOXFranklin, Hampshire, Middlesex, Worcester40 hr
Apr 15, 3:37 AM EDTWinter Weather AdvisoryBOXFranklin, Hampden, Hampshire, Middlesex, Worcester40 hr
Apr 15, 3:40 AM EDTGale WarningBOX48 hr

Nearby

Winter Storm Watches in Massachusetts, 2021Every winter storm watch 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.