Alert archive / Connecticut / Flash Flood Warnings in 2021

Flash Flood Warning 25, NWS Boston/Norton, MA

August 23, 2021Capitol Planning Region, Connecticut

NWS Boston/Norton, MA issued this flash flood warning at Aug 23, 2021, 11:52 AM EDT for Capitol Planning Region, Connecticut. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 23, 2021, 11:52 AM EDT (15:52 UTC)
Expired
Aug 23, 2021, 3:00 PM EDT
In force
3 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), 95 km from the middle of the area, began a volume at 15:53 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 12:00Z, 3.9 hours before the alert went out and 95 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 2021-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 150 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, Brookhaven, NY at 12:00Z on 2021-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 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
150 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
711 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

042 
WGUS51 KBOX 231552
FFWBOX
CTC003-013-231900-
/O.NEW.KBOX.FF.W.0025.210823T1552Z-210823T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
1152 AM EDT Mon Aug 23 2021

The National Weather Service in Norton has issued a

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

* Until 300 PM EDT.

* At 1152 AM EDT, Doppler radar indicated heavy rain is moving into 
  the warned area. Flash flooding is expected to begin shortly. A 
  widespread 2 to 4 inches of rain fell on Sunday any additional 
  rainfall will lead to flash flooding and quick rises on streams.

  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, Southington, Glastonbury, Newington, Vernon, Windsor, 
  Wethersfield, Mansfield, South Windsor, Farmington, Windham, 
  Simsbury, Bloomfield, Berlin and Rocky Hill.

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 4192 7290 4189 7222 4173 7219 4174 7226
      4171 7224 4164 7233 4160 7234 4158 7247
      4165 7251 4163 7263 4164 7263 4163 7271
      4158 7275 4155 7285 4156 7295 4164 7294
      4164 7298 4180 7302 4181 7295 4187 7295

FLASH FLOOD...RADAR INDICATED

$$

KS
1 follow-up statement
880 
WGUS71 KBOX 231852
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
252 PM EDT Mon Aug 23 2021

CTC003-013-231902-
/O.EXP.KBOX.FF.W.0025.000000T0000Z-210823T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hartford CT-Tolland CT-
252 PM EDT Mon Aug 23 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 3 PM EDT THIS AFTERNOON FOR 
HARTFORD AND CENTRAL TOLLAND COUNTIES...

Though additional more scattered rain showers will move across the 
warned area this afternoon, heavy rain has ended and 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 for portions of 
northern Connecticut, Massachusetts and Rhode Island.

LAT...LON 4192 7290 4189 7222 4173 7219 4174 7226
      4171 7224 4164 7233 4160 7234 4158 7247
      4165 7251 4163 7263 4164 7263 4163 7271
      4158 7275 4155 7285 4156 7295 4164 7294
      4164 7298 4180 7302 4181 7295 4187 7295

$$

AL

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 22, 8:45 PM EDTAreal Flood WarningBOXCapitol Planning Region9 hr
Aug 23, 3:36 PM EDTAreal Flood WarningBOXCapitol Planning Region6 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.