Alert archive / Massachusetts / Flash Flood Warnings in 2021

Flash Flood Warning 3, NWS Boston/Norton, MA

July 9, 2021Hampden County, Hampshire County, Massachusetts; Capitol Planning Region, Connecticut

NWS Boston/Norton, MA issued this flash flood warning at Jul 9, 2021, 8:19 AM EDT for Hampden County, Hampshire County, Massachusetts; Capitol Planning Region, Connecticut. It was in force for 6 hr. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 9, 2021, 8:19 AM EDT (12:19 UTC)
Expired
Jul 9, 2021, 2:15 PM EDT
In force
6 hr
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

Counties Capitol Planning Region, CT, Hampden County, MA, Hampshire County, MA

The radar

The Brookhaven radar (KOKX), 109 km from the middle of the area, began a volume at 12:23 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.

What was reported inside it

TimeReportWhereRemark
Jul 9, 9:36 AM EDTFLOODWethersfield, CTCRYSTAL STREET, HARDING STREET, GREENFIELD ST, AND KNOTT STREET IMPASSABLE TO FLOODING.
Jul 9, 11:30 AM EDTFLOODBerlin, CTSECTION OF NORTON ROAD WAS CLOSED DUE TO FLOODING. ADDITIONAL ROADS THAT ARE PRONE TO FLOODING WERE CLOSED AS WELL.
Jul 9, 1:00 PM EDTFLOODTolland, CT120 TO 130 BLOCK OF SHENIPSIT ROAD FLOODED. 90 BLOCK AND 100 BLOCK OF OLD STANFORD ROAD FLOODED. 70 BLOCK OF CHARTER ROAD HEAVILY FLOODED ON ROADWAY. 70 BLOCK OF SKUNGAMAUG ROAD FLOODED. WATER OVER ROAD ON CIDER MILL ROAD AND GRANT HILL.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 0.3 hours before the alert went out and 126 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 12:00Z on 2021-07-09Temperature 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 12:00Z on 2021-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.193958Sfc1 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
-156 J/kg
Mixed-layer LCL
764 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
88 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

290 
WGUS51 KBOX 091219
FFWBOX
CTC003-013-MAC013-015-091815-
/O.NEW.KBOX.FF.W.0003.210709T1219Z-210709T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
819 AM EDT Fri Jul 9 2021

The National Weather Service in Norton has issued a

* Flash Flood Warning for...
  Hartford County in northern Connecticut...
  Tolland County in northern Connecticut...
  Hampden County in western Massachusetts...
  Southern Hampshire County in western Massachusetts...

* Until 215 PM EDT.

* At 819 AM EDT, Doppler radar indicated heavy rain in Hartford to 
  Springfield Corridor and surrounding communities. Between 0.5 and 
  1.5 inches of rain have fallen. Additional rainfall amounts of 1 
  to 3 inches are possible in the warned area during this morning. 
  Flash flooding is expected to begin shortly.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar and observations.

  IMPACT...Flash flooding of small streams, urban areas,
           highways, streets and underpasses as well as other
           poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Springfield, Hartford, New Britain, West Hartford, Bristol, 
  Manchester, Chicopee, East Hartford, Enfield, Southington, 
  Westfield, Holyoke, Glastonbury, Newington, Vernon, Windsor, 
  Northampton, Agawam, West Springfield and Wethersfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be aware of your surroundings and do not drive on flooded roads.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, which can become very dangerous in 
heavy rains. Campers and hikers should avoid streams or creeks.

&&

LAT...LON 4204 7301 4204 7305 4215 7307 4214 7303
      4228 7300 4230 7224 4167 7229 4161 7233
      4158 7247 4165 7251 4163 7263 4164 7263
      4155 7285 4156 7295 4164 7294 4164 7298
      4180 7302 4181 7295 4197 7289 4197 7303

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

NB
1 follow-up statement
034 
WGUS71 KBOX 091427
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
1027 AM EDT Fri Jul 9 2021

CTC003-013-MAC013-015-091815-
/O.CON.KBOX.FF.W.0003.000000T0000Z-210709T1815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hartford CT-Tolland CT-Hampden MA-Hampshire MA-
1027 AM EDT Fri Jul 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 215 PM EDT THIS 
AFTERNOON FOR HARTFORD, TOLLAND, HAMPDEN AND SOUTHERN HAMPSHIRE 
COUNTIES...

At 1027 AM EDT, Doppler radar indicated persistent heavy rain bands 
over the greater Hartford and Springfield areas. The heaviest 
rainfall has been near and south of Hartford, with 1 to 3 inches of 
rainfall. To the north into the Springfield area, around an inch of 
rain has fallen. In the warning area, additional 1 to 2 inches of 
rainfall is expected during the next few hours. Localized higher 
amounts are possible. As a result, flash flooding is expected.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar.

IMPACT...Flash flooding of small streams, urban areas, highways,
         streets and underpasses as well as other poor drainage
         and low-lying areas.

Some locations that will experience flash flooding include...
  Springfield, Hartford, New Britain, West Hartford, Bristol, 
  Manchester, Chicopee, East Hartford, Enfield, Southington, 
  Westfield, Holyoke, Glastonbury, Newington, Vernon, Windsor, 
  Northampton, Agawam, West Springfield and Wethersfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4204 7301 4204 7305 4215 7307 4214 7303
      4228 7300 4230 7224 4167 7229 4161 7233
      4158 7247 4165 7251 4163 7263 4164 7263
      4155 7285 4156 7295 4164 7294 4164 7298
      4180 7302 4181 7295 4197 7289 4197 7303

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR

$$

NB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 9, 9:11 AM EDTFlash Flood WarningBOXBristol, Middlesex, Norfolk, Worcester7 hr
Jul 9, 9:32 AM EDTFlash Flood WarningBOXBristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk6 hr
Jul 9, 12:19 PM EDTRiver Flood WarningBOXNorfolk, Suffolk4 hr
Jul 9, 12:19 PM EDTRiver Flood WarningBOXEssex8 hr
Jul 9, 12:19 PM EDTRiver Flood WarningBOXMiddlesex37 hr
Jul 9, 2:24 PM EDTAreal Flood WarningBOXHampden, Worcester8 hr
Jul 9, 3:24 PM EDTAreal Flood WarningBOXBristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk5 hr
Jul 9, 3:41 PM EDTAreal Flood WarningBOXBristol, Middlesex, Norfolk, Worcester5 hr
Jul 9, 4:52 PM EDTSmall Craft AdvisoryBOX22 hr
Jul 9, 7:50 PM EDTSpecial Weather StatementBOXHampden40 min
Jul 9, 12:28 PM EDTAreal Flood WarningBOXNortheastern Connecticut Planning Region3 hr
Jul 9, 7:47 PM EDTSpecial Weather StatementBOX43 min

Nearby

Flash Flood Warnings in Massachusetts, 2021Flash Flood Warnings in Connecticut, 2021Every flash 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.