Alert archive / Massachusetts / Flash Flood Warnings in 2021

Flash Flood Warning 9, NWS Boston/Norton, MA

July 17, 2021Worcester County, Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Jul 17, 2021, 4:48 PM EDT for Worcester County, Massachusetts. It was in force for 3 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 17, 2021, 4:48 PM EDT (20:48 UTC)
Expired: Jul 17, 2021, 7:53 PM EDT
In force: 3 hr
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Flood severity: None

County Worcester County, MA

The radar

The Boston radar (KBOX), 63 km from the middle of the area, began a volume at 20:49 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

Time	Report	Where	Remark
Jul 17, 5:21 PM EDT	FLOOD	Worcester, MA	CARS STUCK IN FLOOD WATERS ON MILBURYROAD AND MCKEON ROAD
Jul 17, 5:24 PM EDT	FLOOD	Worcester, MA	WATER UP TO CAR WINDSHIELDS ON DALE STREET
Jul 17, 6:05 PM EDT	FLOOD	Worcester, MA	5 CARS STUCK IN FLOOD WATERS ON DEWEY STREET AND PARKER STREET

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, 8.8 hours before the alert went out and 169 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1203 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 1054 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 46 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

As transmitted.

372 
WGUS51 KBOX 172048
FFWBOX
MAC027-180000-
/O.NEW.KBOX.FF.W.0009.210717T2048Z-210718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
448 PM EDT Sat Jul 17 2021

The National Weather Service in Norton has issued a

* Flash Flood Warning for...
  Southeastern Worcester County in central Massachusetts...

* Until 800 PM EDT.

* At 448 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  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...
  Worcester, Shrewsbury, Grafton, Webster, Southbridge, Auburn, 
  Northbridge, Oxford, Millbury, Charlton, Spencer, Dudley, 
  Leicester, Sutton, Douglas and Upton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4222 7197 4230 7178 4214 7159 4210 7175
      4207 7200

FLASH FLOOD...RADAR INDICATED

$$

BL

4 follow-up statements

883 
WGUS71 KBOX 172111
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
511 PM EDT Sat Jul 17 2021

MAC027-180000-
/O.CON.KBOX.FF.W.0009.000000T0000Z-210718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Worcester MA-
511 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING 
FOR SOUTHEASTERN WORCESTER COUNTY...

At 511 PM EDT, trained weather spotters reported cars stuck on a 
flooded roadway on Park Avenue in Worcester, MA at 459 PM. Between 1 
to 3 inches of rain have fallen. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters reported.

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...
  Worcester, Shrewsbury, Grafton, Webster, Southbridge, Auburn, 
  Northbridge, Oxford, Millbury, Charlton, Spencer, Dudley, 
  Leicester, Sutton, Douglas and Upton.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4222 7197 4230 7178 4214 7159 4210 7175
      4207 7200

FLASH FLOOD...OBSERVED

$$

BL

680 
WGUS71 KBOX 172214
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
614 PM EDT Sat Jul 17 2021

MAC027-180000-
/O.CON.KBOX.FF.W.0009.000000T0000Z-210718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Worcester MA-
614 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING 
FOR SOUTHEASTERN WORCESTER COUNTY...

At 614 PM EDT, trained weather spotters reported several vehicles 
stuck in street flooding on Dewey Street at Parker Street in 
Worcester, MA at 605 PM. Between 1 and 3 inches of rain have fallen. 
Additional rainfall amounts up to 1 inch are possible in the warned 
area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters reported.

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...
  Worcester, Shrewsbury, Grafton, Webster, Southbridge, Auburn, 
  Northbridge, Oxford, Millbury, Charlton, Spencer, Dudley, 
  Leicester, Sutton, Douglas and Upton.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4222 7197 4230 7178 4214 7159 4210 7175
      4207 7200

FLASH FLOOD...OBSERVED

$$

BL

444 
WGUS71 KBOX 172317 RRC
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
717 PM EDT Sat Jul 17 2021

MAC027-180000-
/O.CON.KBOX.FF.W.0009.000000T0000Z-210718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Worcester MA-
717 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING 
FOR SOUTHEASTERN WORCESTER COUNTY...

At 717 PM EDT, trained weather spotters reported several vehicles 
stuck in street flooding on Dewey Street at Parker Street in 
Worcester, MA at 605 PM. Between 1 and 3 inches of rain have fallen. 
Additional rainfall amounts up to 1 inch are possible in the warned 
area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters reported.

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...
  Worcester, Shrewsbury, Grafton, Auburn, Northbridge, Oxford, 
  Millbury, Charlton, Spencer, Leicester, Sutton and Upton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4222 7197 4230 7178 4214 7159 4210 7175
      4212 7183

FLASH FLOOD...OBSERVED

$$

BL

921 
WGUS71 KBOX 172353
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
753 PM EDT Sat Jul 17 2021

MAC027-180003-
/O.CAN.KBOX.FF.W.0009.000000T0000Z-210718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Worcester MA-
753 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN WORCESTER 
COUNTY...

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

A Flash Flood Watch remains in effect until 600 AM EDT Sunday for 
portions of northern Connecticut and Massachusetts.

LAT...LON 4222 7197 4230 7178 4214 7159 4210 7175
      4212 7183

$$

BL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 2:37 PM EDT	Special Weather Statement	BOX	Franklin	38 min
Jul 17, 2:45 PM EDT	Special Weather Statement	BOX	Plymouth	45 min
Jul 17, 2:53 PM EDT	Special Weather Statement	BOX	Hampshire	52 min
Jul 17, 2:53 PM EDT	Severe Thunderstorm Warning	BOX	Bristol, Norfolk	52 min
Jul 17, 3:36 PM EDT	Areal Flood Warning	BOX	Bristol	114 min
Jul 17, 4:05 PM EDT	Severe Thunderstorm Warning	BOX	Worcester	34 min
Jul 17, 4:15 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Worcester	60 min
Jul 17, 4:34 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Worcester	36 min
Jul 17, 4:38 PM EDT	Severe Thunderstorm Warning	BOX	Hampden, Hampshire	67 min
Jul 17, 4:58 PM EDT	Flash Flood Warning	BOX	Hampden	2 hr
Jul 17, 5:10 PM EDT	Severe Thunderstorm Warning	BOX	Middlesex, Worcester	65 min
Jul 17, 5:34 PM EDT	Special Weather Statement	BOX	Hampshire	41 min
Jul 17, 5:35 PM EDT	Flash Flood Warning	BOX	Hampden, Hampshire	3 hr
Jul 17, 6:04 PM EDT	Flash Flood Warning	BOX	Hampden, Hampshire	3 hr
Jul 17, 6:05 PM EDT	Severe Thunderstorm Warning	BOX	Bristol	26 min
Jul 17, 7:49 PM EDT	Areal Flood Warning	BOX	Hampden, Worcester	116 min

Nearby

Flash Flood Warnings in Massachusetts, 2021 Every 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.