Alert archive / Connecticut / Flash Flood Warnings in 2020

Flash Flood Warning 9, NWS Boston/Norton, MA

July 13, 2020Northeastern Connecticut Planning Region, Connecticut

NWS Boston/Norton, MA issued this flash flood warning at Jul 13, 2020, 4:53 PM EDT for Northeastern Connecticut Planning Region, Connecticut. It was in force for 2 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
Jul 13, 2020, 4:53 PM EDT (20:53 UTC)
Expired
Jul 13, 2020, 7:12 PM EDT
In force
2 hr
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

County Northeastern Connecticut Planning Region, CT

The radar

The Boston radar (KBOX), 88 km from the middle of the area, began a volume at 20:56 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, 8.9 hours before the alert went out and 125 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 2020-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 246 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 2020-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 79 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
246 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
1066 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
79 m²/s²
0-3 km storm-relative helicity
111 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted.

858 
WGUS51 KBOX 132053
FFWBOX
CTC013-015-132345-
/O.NEW.KBOX.FF.W.0009.200713T2053Z-200713T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
453 PM EDT Mon Jul 13 2020

The National Weather Service in Boston/Norton has issued a

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

* Until 745 PM EDT.

* At 452 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain in northeast Connecticut. A spotter in Ashford reported 
  3.50 inches of rain in one hour earlier this afternoon. 
  Thunderstorms will bring another 1 to 3 inches of rain before 6 
  PM. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, urban areas, 
           highways, streets and underpasses as well as other 
           drainage and low lying areas.

* Some locations that will experience flooding include...
  Mansfield, Tolland, Woodstock, Willington, Ashford, Pomfret,
  Chaplin, Hampton and Eastford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4190 7233 4195 7203 4183 7199 4177 7228

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...2-3 INCHES IN 1 HOUR

$$

JWD
2 follow-up statements
539 
WGUS71 KBOX 132145
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
545 PM EDT Mon Jul 13 2020

CTC013-015-132345-
/O.CON.KBOX.FF.W.0009.000000T0000Z-200713T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Windham CT-Tolland CT-
545 PM EDT Mon Jul 13 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM EDT FOR
NORTHWESTERN WINDHAM AND CENTRAL TOLLAND COUNTIES...

At 542 PM EDT, Doppler radar indicated thunderstorms from Tolland to 
Eastford and Ashford, moving slowly east. These storms will bring 
rainfall rates as high as 2 to 3 inches per hour through 7 PM.

Some street flooding has been reported in Mansfield. Additional 
flooding is expected to occur soon.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flooding of small creeks and streams, urban areas, 
         highways, streets and underpasses as well as other drainage 
         and low lying areas.

Some locations that will experience flooding include...
Mansfield, Tolland, Woodstock, Willington, Ashford, Pomfret, Chaplin,
Hampton and Eastford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4190 7233 4195 7203 4183 7199 4177 7228

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...2-3 INCHES IN 1 HOUR

$$

JWD
598 
WGUS71 KBOX 132312
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
712 PM EDT Mon Jul 13 2020

CTC013-015-132322-
/O.CAN.KBOX.FF.W.0009.000000T0000Z-200713T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Windham CT-Tolland CT-
712 PM EDT Mon Jul 13 2020

...THE FLASH FLOOD WARNING FOR NORTHWESTERN WINDHAM AND CENTRAL
TOLLAND COUNTIES IS CANCELLED...

Thunderstorms with heavy rain have ended in northeast Connecticut. 

Any flooding will ease this evening, but continue to avoid any 
flooded roadways.

&&

LAT...LON 4190 7233 4195 7203 4183 7199 4177 7228

$$

JWD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 13, 1:28 PM EDTSpecial Weather StatementBOX47 min
Jul 13, 2:56 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region64 min
Jul 13, 4:10 PM EDTSpecial Weather StatementBOX50 min
Jul 13, 5:23 PM EDTSpecial Weather StatementBOX52 min
Jul 13, 7:06 PM EDTSevere Thunderstorm WarningBOXNortheastern Connecticut Planning Region54 min

Nearby

Flash Flood Warnings in Connecticut, 2020Every flash flood warning in 2020

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.