Alert archive / Massachusetts / Areal Flood Warnings in 2021

Areal Flood Warning 39, NWS Boston/Norton, MA

October 31, 2021Bristol County, Plymouth County, Massachusetts

NWS Boston/Norton, MA issued this areal flood warning at Oct 31, 2021, 3:21 AM EDT for Bristol County, Plymouth County, Massachusetts. It was in force for 96 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
Oct 31, 2021, 3:21 AM EDT (07:21 UTC)
Expired
Oct 31, 2021, 4:57 AM EDT
In force
96 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

Counties Bristol County, MA, Plymouth County, MA

The radar

The Boston radar (KBOX), 37 km from the middle of the area, began a volume at 07:21 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, 7.4 hours before the alert went out and 183 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 2021-10-31Temperature 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 2021-10-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 63 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
854 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
63 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

814 
WGUS41 KBOX 310721
FLWBOX

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Boston/Norton MA
321 AM EDT Sun Oct 31 2021

MAC005-023-310915-
/O.NEW.KBOX.FA.W.0039.211031T0721Z-211031T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bristol MA-Plymouth MA-
321 AM EDT Sun Oct 31 2021

The National Weather Service in Norton has issued a

* Flood Warning for...
  Southeastern Bristol County in southeastern Massachusetts...
  Southern Plymouth County in southeastern Massachusetts...

* Until 515 AM EDT.

* At 321 AM EDT, Doppler radar indicated heavy rain due to 
  thunderstorms. Flooding is ongoing or expected to begin shortly in 
  the warned area. Between 1 and 2 inches of rain have fallen.

* Some locations that will experience flooding include...
  New Bedford, Dartmouth, Fairhaven, Acushnet and Mattapoisett.

Additional rainfall amounts of 0.5 to 1 inch are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4171 7101 4169 7081 4157 7083 4159 7103

$$

Chai
1 follow-up statement
679 
WGUS81 KBOX 310857
FLSBOX

Flood Statement
National Weather Service Boston/Norton MA
457 AM EDT Sun Oct 31 2021

MAC005-023-310907-
/O.CAN.KBOX.FA.W.0039.000000T0000Z-211031T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bristol MA-Plymouth MA-
457 AM EDT Sun Oct 31 2021

...FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN BRISTOL AND SOUTHERN 
PLYMOUTH COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4171 7101 4169 7081 4157 7083 4159 7103

$$

Chai

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 31, 2:01 AM EDTSpecial Marine WarningBOX59 min
Oct 31, 2:13 AM EDTSpecial Weather StatementBOXDukes47 min
Oct 31, 2:26 AM EDTSevere Thunderstorm WarningBOXBarnstable, Dukes, Plymouth31 min
Oct 31, 3:11 AM EDTSpecial Weather StatementBOXPlymouth64 min
Oct 31, 3:34 AM EDTSpecial Marine WarningBOX56 min

Nearby

Areal Flood Warnings in Massachusetts, 2021Every areal flood warning 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.