Alert archive / Connecticut / Flash Flood Warnings in 2021

Flash Flood Warning 23, NWS Boston/Norton, MA

August 22, 2021Capitol Planning Region, Connecticut

NWS Boston/Norton, MA issued this flash flood warning at Aug 22, 2021, 1:37 PM EDT for Capitol Planning Region, Connecticut. It was in force for 4 hr. 2 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
Aug 22, 2021, 1:37 PM EDT (17:37 UTC)
Expired
Aug 22, 2021, 5:30 PM EDT
In force
4 hr
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

County Capitol Planning Region, CT

The radar

The Brookhaven radar (KOKX), 90 km from the middle of the area, began a volume at 17:41 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
Aug 22, 3:00 PM EDTFLOOD2 Ssw Manchester, CT22 PROSPECT ST IN MANCHESTER FLOODED WHICH RESULTED IN THE EVACUATION OF A 60 UNIT CONDO COMPLEX NEARBY.
Aug 22, 3:11 PM EDTFLOOD1 Ne Wethersfield, CTNORTHBOUND SIDE OF INTERSTATE 91 IN THE VICINITY OF EXIT 25 CLOSED DUE TO HIGH WATER RESULTING IN A MAJOR TRAFFIC JAM. RELAYED BY BROADCAST MEDIA, AMATEUR RADIO AND NWS SAVI TEAM MEMBERS.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 5.6 hours before the alert went out and 90 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 12:00Z on 2021-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 36 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2021-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 130 square meters per square second.193958Sfc1 km3 km6 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
36 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
563 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
130 m²/s²
0-3 km storm-relative helicity
163 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

585 
WGUS51 KBOX 221737
FFWBOX
CTC003-222130-
/O.NEW.KBOX.FF.W.0023.210822T1737Z-210822T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
137 PM EDT Sun Aug 22 2021

The National Weather Service in Norton has issued a

* Flash Flood Warning for...
  Central Hartford County in northern Connecticut...

* Until 530 PM EDT.

* At 137 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Between 0.5 and 1.5 inches of rain have fallen. The 
  expected rainfall rate is 1 to 2 inches in 1 hour. Additional 
  rainfall amounts of 2 to 4 inches are possible in the warned area. 
  Flash flooding is ongoing or expected to begin shortly, with sharp 
  rises on rivers and streams over bankfull with urban flooding 
  anticipated in the Greater Hartford metro area.

  HAZARD...Flash flooding caused by heavy rain.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and 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...
  Hartford, New Britain, West Hartford, Bristol, Manchester, East 
  Hartford, Enfield, Southington, Glastonbury, Newington, Windsor, 
  Wethersfield, South Windsor, Farmington, Simsbury, Bloomfield, 
  Berlin, Rocky Hill, Avon and Plainville.

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 4156 7290 4162 7290 4167 7296 4173 7287
      4179 7284 4187 7284 4195 7276 4197 7263
      4192 7252 4164 7253 4163 7271 4161 7272
      4159 7275 4158 7275 4157 7280 4155 7282
      4157 7283 4157 7285 4155 7285 4156 7288

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

$$

AL/KS
3 follow-up statements
242 
WGUS71 KBOX 221922
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
322 PM EDT Sun Aug 22 2021

CTC003-222130-
/O.CON.KBOX.FF.W.0023.000000T0000Z-210822T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hartford CT-
322 PM EDT Sun Aug 22 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM EDT THIS 
AFTERNOON FOR CENTRAL HARTFORD COUNTY...

At 322 PM EDT, Doppler radar indicated bands of heavy rain moving 
northwestward. Broadcast media webcam indicated part of the 
northbound side of Interstate 91 between exits 25 and 27 in 
Wethersfield is closed due to high water. In addition, the river 
gage on the Hockanum River at East Hartford is experiencing sharp 
rises due to runoff. Between 1.5 and 2 inches of rain have fallen. 
The expected rainfall rate is 0.5 to 1 inch in 1 hour, with 
additional rainfall amounts up to 2 inches are possible in the 
warned area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and 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...
  Hartford, New Britain, West Hartford, Bristol, Manchester, East 
  Hartford, Enfield, Southington, Glastonbury, Newington, Windsor, 
  Wethersfield, South Windsor, Farmington, Simsbury, Bloomfield, 
  Berlin, Rocky Hill, Avon and Plainville.

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 4156 7290 4162 7290 4167 7296 4173 7287
      4179 7284 4187 7284 4195 7276 4197 7263
      4192 7252 4164 7253 4163 7271 4161 7272
      4159 7275 4158 7275 4157 7280 4155 7282
      4157 7283 4157 7285 4155 7285 4156 7288

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...0.5-1 INCH IN 1 HOUR

$$

AL/KS
573 
WGUS71 KBOX 222109
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
509 PM EDT Sun Aug 22 2021

CTC003-222130-
/O.CON.KBOX.FF.W.0023.000000T0000Z-210822T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hartford CT-
509 PM EDT Sun Aug 22 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM EDT THIS 
AFTERNOON FOR CENTRAL HARTFORD COUNTY...

At 509 PM EDT, rain is now lightening up in intensity. However 
flooding impacts remain. The northbound side of Interstate 91 
between exits 25 and 27 in Wethersfield was closed due to high 
water. Excessive runoff has also led to sharp rises on the North 
Branch of the Park River in Hartford, which is one foot below flood 
stage of 8 feet. At 8 feet, flooding occurs in the parking lot of 
the University of Hartford campus. The Hockanum River near East 
Hartford also is rising, and is 1.5 feet below its flood stage of 
9.5 feet. At 9.5 feet, flooding occurs on Burnside Ave in East 
Hartford. Between 1.5 and 2 inches of rain have fallen. Flash 
flooding is already occurring.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Broadcast media and amateur radio.

IMPACT...Flash flooding of small creeks and 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...
  Hartford, New Britain, West Hartford, Bristol, Manchester, East 
  Hartford, Enfield, Southington, Glastonbury, Newington, Windsor, 
  Wethersfield, South Windsor, Farmington, Simsbury, Bloomfield, 
  Berlin, Rocky Hill, Avon and Plainville.

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 4156 7290 4162 7290 4167 7296 4173 7287
      4179 7284 4187 7284 4195 7276 4197 7263
      4192 7252 4164 7253 4163 7271 4161 7272
      4159 7275 4158 7275 4157 7280 4155 7282
      4157 7283 4157 7285 4155 7285 4156 7288

FLASH FLOOD...OBSERVED

$$

AL
311 
WGUS71 KBOX 222126
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
526 PM EDT Sun Aug 22 2021

CTC003-222136-
/O.EXP.KBOX.FF.W.0023.000000T0000Z-210822T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hartford CT-
526 PM EDT Sun Aug 22 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 530 PM EDT THIS AFTERNOON FOR 
CENTRAL HARTFORD COUNTY...

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

A Flood Watch remains in effect until 800 PM EDT Monday for portions 
of northern Connecticut, Massachusetts and Rhode Island.

LAT...LON 4156 7290 4162 7290 4167 7296 4173 7287
      4179 7284 4187 7284 4195 7276 4197 7263
      4192 7252 4164 7253 4163 7271 4161 7272
      4159 7275 4158 7275 4157 7280 4155 7282
      4157 7283 4157 7285 4155 7285 4156 7288

$$

AL

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 22, 1:28 PM EDTFlash Flood WarningBOXCapitol Planning Region, Northeastern Connecticut Planning Region4 hr
Aug 22, 1:53 PM EDTFlash Flood WarningBOXCapitol Planning Region4 hr
Aug 22, 4:11 PM EDTAreal Flood WarningBOXCapitol Planning Region4 hr

Nearby

Flash 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.