Alert archive / Massachusetts / Flash Flood Watches in 2021

Flash Flood Watch 5, NWS Boston/Norton, MA

August 4, 20215 counties in Rhode Island; 7 counties in Massachusetts; Northeastern Connecticut Planning Region, Connecticut

NWS Boston/Norton, MA issued this flash flood watch at Aug 4, 2021, 3:11 AM EDT for 5 counties in Rhode Island; 7 counties in Massachusetts; Northeastern Connecticut Planning Region, Connecticut. It took effect at Aug 4, 2021, 8:00 PM EDT. It was in force for 17 hr.

The area

The counties it named.

The facts

Issued
Aug 4, 2021, 3:11 AM EDT (07:11 UTC)
In effect from
Aug 4, 2021, 8:00 PM EDT
Expired
Aug 5, 2021, 12:48 PM EDT
In force
17 hr
Issued by
NWS Boston/Norton, MA
Flood severity
None

Counties Northeastern Connecticut Planning Region, CT, Bristol County, MA, Essex County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI

The radar

The Boston radar (KBOX), 18 km from the middle of the area, began a volume at 07:13 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 00:00Z, 7.2 hours before the alert went out and 177 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, Brookhaven, NY at 00:00Z on 2021-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Brookhaven, NY at 00:00Z on 2021-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -22 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1760 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
-22 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

861 
WGUS61 KBOX 040711
FFABOX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Boston/Norton MA
311 AM EDT Wed Aug 4 2021

MAZ005>007-013>021-RIZ001>008-041515-
/O.NEW.KBOX.FF.A.0005.210805T0000Z-210805T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Central Middlesex MA-Western Essex MA-Eastern Essex MA-Western
Norfolk MA-Southeast Middlesex MA-Suffolk MA-Eastern Norfolk MA-
Northern Bristol MA-Western Plymouth MA-Eastern Plymouth MA-Southern
Bristol MA-Southern Plymouth MA-Northwest Providence RI-Southeast
Providence RI-Western Kent RI-Eastern Kent RI-Bristol RI-Washington
RI-Newport RI-Block Island RI-
Including the cities of Quincy, Foxborough, West Warwick, 
Providence, Foster, Warwick, Smithfield, Lowell, Lawrence, 
Mattapoisett, West Greenwich, Brockton, New Bedford, Norwood, 
Coventry, Plymouth, Newport, Bristol, New Shoreham, Gloucester, 
Westerly, Cambridge, Narragansett, Fall River, Taunton, Boston, 
Framingham, and East Greenwich
311 AM EDT Wed Aug 4 2021

...FLASH FLOOD WATCH IN EFFECT FROM THIS EVENING THROUGH THURSDAY 
MORNING...

The National Weather Service in Norton has issued a

* Flash Flood Watch for portions of Massachusetts and Rhode Island, 
  including the following areas, in Massachusetts, Central Middlesex 
  MA, Eastern Essex MA, Eastern Norfolk MA, Eastern Plymouth MA, 
  Northern Bristol MA, Southeast Middlesex MA, Southern Bristol MA, 
  Southern Plymouth MA, Suffolk MA, Western Essex MA, Western 
  Norfolk MA and Western Plymouth MA. In Rhode Island, Block Island 
  RI, Bristol RI, Eastern Kent RI, Newport RI, Northwest Providence 
  RI, Southeast Providence RI, Washington RI and Western Kent RI.

* From this evening through Thursday morning.

* Showers and a few thunderstorms will bring heavy rainfall to 
  portions of Rhode Island and eastern Massachusetts tonight. 
  Rainfall amounts of 1 to 3 inches with locally up to 4 inches are 
  possible. The axis of heaviest rainfall is somewhat uncertain and 
  may still shift east or west.

* Heavy rainfall may cause street flooding and result in rapid rises 
  on small streams and creeks.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

KJC
4 follow-up statements
227 
WGUS61 KBOX 041424
FFABOX

Flood Watch
National Weather Service Boston/Norton MA
1024 AM EDT Wed Aug 4 2021

MAZ005>007-013>021-RIZ001>008-042230-
/O.CON.KBOX.FF.A.0005.210805T0000Z-210805T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Central Middlesex MA-Western Essex MA-Eastern Essex MA-
Western Norfolk MA-Southeast Middlesex MA-Suffolk MA-
Eastern Norfolk MA-Northern Bristol MA-Western Plymouth MA-
Eastern Plymouth MA-Southern Bristol MA-Southern Plymouth MA-
Northwest Providence RI-Southeast Providence RI-Western Kent RI-
Eastern Kent RI-Bristol RI-Washington RI-Newport RI-
Block Island RI-
Including the cities of Framingham, Lowell, Lawrence, Gloucester,
Foxborough, Norwood, Cambridge, Boston, Quincy, Taunton, 
Brockton, Plymouth, Fall River, New Bedford, Mattapoisett, 
Foster, Smithfield, Providence, Coventry, West Greenwich, 
East Greenwich, Warwick, West Warwick, Bristol, Narragansett, 
Westerly, Newport, and New Shoreham
1024 AM EDT Wed Aug 4 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 8 PM EDT THIS EVENING
THROUGH THURSDAY MORNING...

The Flash Flood Watch continues for

* Portions of Massachusetts and Rhode Island, including the 
  following areas, in Massachusetts, Central Middlesex MA, 
  Eastern Essex MA, Eastern Norfolk MA, Eastern Plymouth MA, 
  Northern Bristol MA, Southeast Middlesex MA, Southern Bristol 
  MA, Southern Plymouth MA, Suffolk MA, Western Essex MA, 
  Western Norfolk MA, and Western Plymouth MA. In Rhode Island, 
  Block Island RI, Bristol RI, Eastern Kent RI, Newport RI, 
  Northwest Providence RI, Southeast Providence RI, Washington 
  RI, and Western Kent RI. 

* From 8 PM EDT this evening through Thursday morning

* Showers and a few thunderstorms will bring heavy rainfall to 
  portions of Rhode Island and eastern Massachusetts tonight. 
  Rainfall amounts of 1 to 3 inches with locally up to 4 inches 
  are possible. The axis of heaviest rainfall is somewhat 
  uncertain and may still shift east or west. 

* Heavy rainfall may cause street flooding and result in rapid 
  rises on small streams and creeks. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action
should Flash Flood Warnings be issued.

&&

$$
023 
WGUS61 KBOX 041846
FFABOX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Boston/Norton MA
246 PM EDT Wed Aug 4 2021

CTZ004-MAZ012-050815-
/O.EXA.KBOX.FF.A.0005.210805T0000Z-210805T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Windham CT-Southern Worcester MA-
Including the cities of Worcester, Willimantic, Milford, and Putnam
246 PM EDT Wed Aug 4 2021

...FLASH FLOOD WATCH IN EFFECT FROM 8 PM EDT THIS EVENING THROUGH 
THURSDAY MORNING...

The National Weather Service in Norton has expanded the

* Flash Flood Watch to include portions of northern Connecticut and 
  central Massachusetts, including the following areas, in northern 
  Connecticut, Windham CT. In central Massachusetts, Southern 
  Worcester MA.

* From 8 PM EDT this evening through Thursday morning.

* Showers and a few thunderstorms will bring heavy rainfall to 
  portions of Rhode Island and eastern Massachusetts tonight. 
  Rainfall amounts of 1 to 3 inches with locally up to 4 inches 
  are possible. The axis of heaviest rainfall is somewhat 
  uncertain and may still shift east or west. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

MAZ005>007-013>021-RIZ001>008-050815-
/O.CON.KBOX.FF.A.0005.210805T0000Z-210805T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Central Middlesex MA-Western Essex MA-Eastern Essex MA-Western
Norfolk MA-Southeast Middlesex MA-Suffolk MA-Eastern Norfolk MA-
Northern Bristol MA-Western Plymouth MA-Eastern Plymouth MA-Southern
Bristol MA-Southern Plymouth MA-Northwest Providence RI-Southeast
Providence RI-Western Kent RI-Eastern Kent RI-Bristol RI-Washington
RI-Newport RI-Block Island RI-
Including the cities of Quincy, Foxborough, West Warwick, 
Providence, Foster, Warwick, Smithfield, Lowell, Lawrence, 
Mattapoisett, West Greenwich, Brockton, New Bedford, Norwood, 
Coventry, Plymouth, Newport, Bristol, New Shoreham, Gloucester, 
Westerly, Cambridge, Narragansett, Fall River, Taunton, Boston, 
Framingham, and East Greenwich
246 PM EDT Wed Aug 4 2021

...FLASH FLOOD WATCH REMAINS IN EFFECT FROM 8 PM EDT THIS EVENING 
THROUGH THURSDAY MORNING...

The Flash Flood Watch continues for

* Portions of Massachusetts and Rhode Island, including the 
  following areas, in Massachusetts, Central Middlesex MA, Eastern 
  Essex MA, Eastern Norfolk MA, Eastern Plymouth MA, Northern 
  Bristol MA, Southeast Middlesex MA, Southern Bristol MA, Southern 
  Plymouth MA, Suffolk MA, Western Essex MA, Western Norfolk MA and 
  Western Plymouth MA. In Rhode Island, Block Island RI, Bristol RI, 
  Eastern Kent RI, Newport RI, Northwest Providence RI, Southeast 
  Providence RI, Washington RI and Western Kent RI.

* From 8 PM EDT this evening through Thursday morning.

* Showers and a few thunderstorms will bring heavy rainfall to 
  portions of Rhode Island and eastern Massachusetts tonight. 
  Rainfall amounts of 1 to 3 inches with locally up to 4 inches 
  are possible. The axis of heaviest rainfall is somewhat 
  uncertain and may still shift east or west. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

BW
850 
WGUS61 KBOX 050719
FFABOX

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Boston/Norton MA
319 AM EDT Thu Aug 5 2021

CTZ004-MAZ012-050830-
/O.CAN.KBOX.FF.A.0005.000000T0000Z-210805T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Windham CT-Southern Worcester MA-
Including the cities of Worcester, Willimantic, Milford, and Putnam
319 AM EDT Thu Aug 5 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of northern Connecticut and 
central Massachusetts, including the following areas, in northern 
Connecticut, Windham CT. In central Massachusetts, Southern 
Worcester MA has been cancelled.

The heaviest rainfall is expected to fall to east of the area. 
Flooding is no longer expected to pose a threat.

$$

MAZ005>007-013>021-RIZ001>008-052000-
/O.EXT.KBOX.FF.A.0005.000000T0000Z-210805T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Central Middlesex MA-Western Essex MA-Eastern Essex MA-Western
Norfolk MA-Southeast Middlesex MA-Suffolk MA-Eastern Norfolk MA-
Northern Bristol MA-Western Plymouth MA-Eastern Plymouth MA-Southern
Bristol MA-Southern Plymouth MA-Northwest Providence RI-Southeast
Providence RI-Western Kent RI-Eastern Kent RI-Bristol RI-Washington
RI-Newport RI-Block Island RI-
Including the cities of Quincy, Foxborough, West Warwick, 
Providence, Foster, Warwick, Smithfield, Lowell, Lawrence, 
Mattapoisett, West Greenwich, Brockton, New Bedford, Norwood, 
Coventry, Plymouth, Newport, Bristol, New Shoreham, Gloucester, 
Westerly, Cambridge, Narragansett, Fall River, Taunton, Boston, 
Framingham, and East Greenwich
319 AM EDT Thu Aug 5 2021

...FLASH FLOOD WATCH NOW IN EFFECT THROUGH 6 PM THIS AFTERNOON...

The Flash Flood Watch is now in effect for

* Portions of Massachusetts and Rhode Island, including the 
  following areas, in Massachusetts, Central Middlesex MA, Eastern 
  Essex MA, Eastern Norfolk MA, Eastern Plymouth MA, Northern 
  Bristol MA, Southeast Middlesex MA, Southern Bristol MA, Southern 
  Plymouth MA, Suffolk MA, Western Essex MA, Western Norfolk MA and 
  Western Plymouth MA. In Rhode Island, Block Island RI, Bristol RI, 
  Eastern Kent RI, Newport RI, Northwest Providence RI, Southeast 
  Providence RI, Washington RI and Western Kent RI.

* Through this afternoon.

* Periods of showers and a few thunderstorms will continue to bring 
  locally heavy rain to Rhode Island and portions of eastern 
  Massachusetts through late this afternoon. Up to an additional one 
  and a half inches of rain is forecast through this afternoon, with 
  total rainfall ranging between 2 to 3 inches. Locally higher 
  rainfall amounts are possible in areas that experience persistent 
  heavy rains.

* Heavy rainfall may cause street flooding in urban areas and in 
  low-lying and poor drainage areas. It may also result in rapid 
  rises on small streams and creeks.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be prepared to take action 
should Flash Flood Warnings be issued.

&&

$$

AL
618 
WGUS61 KBOX 051648
FFABOX

Flood Watch
National Weather Service Boston/Norton MA
1248 PM EDT Thu Aug 5 2021

MAZ005>007-013>021-RIZ001>008-051800-
/O.CAN.KBOX.FF.A.0005.000000T0000Z-210805T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Central Middlesex MA-Western Essex MA-Eastern Essex MA-Western
Norfolk MA-Southeast Middlesex MA-Suffolk MA-Eastern Norfolk MA-
Northern Bristol MA-Western Plymouth MA-Eastern Plymouth MA-Southern
Bristol MA-Southern Plymouth MA-Northwest Providence RI-Southeast
Providence RI-Western Kent RI-Eastern Kent RI-Bristol RI-Washington
RI-Newport RI-Block Island RI-
Including the cities of Quincy, Foxborough, West Warwick, 
Providence, Foster, Warwick, Smithfield, Lowell, Lawrence, 
Mattapoisett, West Greenwich, Brockton, New Bedford, Norwood, 
Coventry, Plymouth, Newport, Bristol, New Shoreham, Gloucester, 
Westerly, Cambridge, Narragansett, Fall River, Taunton, Boston, 
Framingham, and East Greenwich
1248 PM EDT Thu Aug 5 2021

...FLASH FLOOD WATCH IS CANCELLED...

The Flash Flood Watch for portions of Massachusetts and Rhode 
Island, including the following areas, in Massachusetts, Central 
Middlesex MA, Eastern Essex MA, Eastern Norfolk MA, Eastern Plymouth 
MA, Northern Bristol MA, Southeast Middlesex MA, Southern Bristol 
MA, Southern Plymouth MA, Suffolk MA, Western Essex MA, Western 
Norfolk MA and Western Plymouth MA. In Rhode Island, Block Island 
RI, Bristol RI, Eastern Kent RI, Newport RI, Northwest Providence 
RI, Southeast Providence RI, Washington RI and Western Kent RI has 
been cancelled.

The Flood Watch is cancelled. Flooding is no longer expected to pose 
a threat. Please continue to heed remaining road closures.

$$

Nearby

Flash Flood Watches in Massachusetts, 2021Flash Flood Watches in Rhode Island, 2021Flash Flood Watches in Connecticut, 2021Every flash flood 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.