Alert archive / Massachusetts / Flash Flood Warnings in 2021

Flash Flood Warning 32, NWS Boston/Norton, MA

September 1, 20214 counties in Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Sep 1, 2021, 10:57 PM EDT for 4 counties in Massachusetts. It was in force for 8 hr. 1 report 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
Sep 1, 2021, 10:57 PM EDT (02:57 UTC)
Expired
Sep 2, 2021, 6:50 AM EDT
In force
8 hr
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

Counties Franklin County, MA, Hampshire County, MA, Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 117 km from the middle of the area, began a volume at 02:59 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
Sep 2, 2:21 AM EDTFLOOD1 Wnw Ayer, MABISHOP ROAD CLOSED FROM FORT DEVENS TO MACPHERSON ROAD DUE TO FLOODING.

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 00:00Z, 3.0 hours before the alert went out and 120 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 00:00Z on 2021-09-02Temperature 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 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Albany, NY at 00:00Z on 2021-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -26 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
3 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
525 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
-26 m²/s²
0-3 km storm-relative helicity
36 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

549 
WGUS51 KBOX 020257
FFWBOX
MAC011-015-017-027-021100-
/O.NEW.KBOX.FF.W.0032.210902T0257Z-210902T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
1057 PM EDT Wed Sep 1 2021

The National Weather Service in Norton has issued a

* Flash Flood Warning for...
  Worcester County in central Massachusetts...
  Northwestern Middlesex County in northeastern Massachusetts...
  Franklin County in western Massachusetts...
  Hampshire County in western Massachusetts...

* Until 700 AM EDT Thursday.

* At 1057 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Between 0.5 and 1.5 inches of rain have fallen. 
  Additional rainfall amounts of 2 to 4 inches are possible in the 
  warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  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...
  Worcester, Westfield, Leominster, Fitchburg, Holyoke, Amherst, 
  Northampton, Greenfield, Orange, Deerfield, Ludlow, Gardner, 
  Hudson, South Hadley, Holden, Auburn, Easthampton, Belchertown, 
  Northborough and Oxford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4264 7295 4270 7295 4274 7302 4270 7154
      4264 7150 4239 7158 4228 7188 4219 7189
      4215 7220 4219 7226 4224 7222 4219 7240
      4223 7240 4223 7262 4228 7261 4229 7261
      4218 7269 4224 7291 4234 7290 4233 7306

FLASH FLOOD...RADAR INDICATED

$$

Frank
3 follow-up statements
255 
WGUS71 KBOX 020734
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
334 AM EDT Thu Sep 2 2021

MAC011-020744-
/O.CAN.KBOX.FF.W.0032.000000T0000Z-210902T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin MA-
334 AM EDT Thu Sep 2 2021

...FLASH FLOOD WARNING IS CANCELLED FOR FRANKLIN COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

A Flash Flood Watch remains in effect until 200 PM EDT Thursday for 
portions of central Massachusetts, eastern Massachusetts, 
northeastern Massachusetts and western Massachusetts.

LAT...LON 4223 7262 4229 7261 4218 7269 4224 7291
      4234 7290 4233 7306 4256 7298 4241 7270
      4242 7238 4233 7235 4230 7236 4231 7235
      4266 7223 4272 7228 4270 7154 4264 7150
      4239 7158 4228 7188 4219 7189 4215 7220

$$

MAC015-017-027-021100-
/O.CON.KBOX.FF.W.0032.000000T0000Z-210902T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hampshire MA-Middlesex MA-Worcester MA-
334 AM EDT Thu Sep 2 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 AM EDT THIS MORNING 
FOR WORCESTER, NORTHWESTERN MIDDLESEX AND HAMPSHIRE COUNTIES...

At 334 AM EDT, Doppler radar indicated heavy rain across the warned 
area. Between 2 and 3 inches of rain have fallen. Additional 
rainfall amounts up to 1 inch are possible in the warned area. Flash 
flooding is ongoing or expected to begin shortly.

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...
  Worcester, Chicopee, Westfield, Leominster, Fitchburg, Holyoke, 
  Amherst, Northampton, Orange, Ludlow, Gardner, Hudson, South 
  Hadley, Holden, Auburn, Easthampton, Belchertown, Northborough, 
  Oxford and Clinton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4223 7262 4229 7261 4218 7269 4224 7291
      4234 7290 4233 7306 4256 7298 4241 7270
      4242 7238 4233 7235 4230 7236 4231 7235
      4266 7223 4272 7228 4270 7154 4264 7150
      4239 7158 4228 7188 4219 7189 4215 7220

FLASH FLOOD...RADAR INDICATED

$$

Frank
931 
WGUS71 KBOX 020832
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
432 AM EDT Thu Sep 2 2021

MAC015-017-027-021100-
/O.CON.KBOX.FF.W.0032.000000T0000Z-210902T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hampshire MA-Middlesex MA-Worcester MA-
432 AM EDT Thu Sep 2 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 AM EDT THIS MORNING 
FOR WORCESTER, NORTHWESTERN MIDDLESEX AND HAMPSHIRE COUNTIES...

At 432 AM EDT, The heavy rain that has resulted in areas  of urban 
and small stream flash flooding early this morning, will be exiting 
the region through 6 am. Between 2 and 4 inches of rain have fallen. 
However, small rivers and streams were still rising and some roads 
will remain flooded and impassable through the morning commute.

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...
  Worcester, Chicopee, Westfield, Leominster, Fitchburg, Holyoke, 
  Amherst, Northampton, Orange, Ludlow, Gardner, Hudson, South 
  Hadley, Holden, Auburn, Easthampton, Belchertown, Northborough, 
  Oxford and Clinton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4223 7262 4229 7261 4218 7269 4224 7291
      4234 7290 4233 7306 4256 7298 4241 7270
      4242 7238 4233 7235 4230 7236 4231 7235
      4266 7223 4272 7228 4270 7154 4264 7150
      4239 7158 4228 7188 4219 7189 4215 7220

FLASH FLOOD...RADAR INDICATED

$$

Frank
515 
WGUS71 KBOX 021050
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
650 AM EDT Thu Sep 2 2021

MAC015-017-027-021100-
/O.CAN.KBOX.FF.W.0032.000000T0000Z-210902T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hampshire MA-Middlesex MA-Worcester MA-
650 AM EDT Thu Sep 2 2021

...FLASH FLOOD WARNING FOR WORCESTER, NORTHWESTERN MIDDLESEX AND 
HAMPSHIRE COUNTIES HAS BEEN REPLACED WITH A FLOOD WARNING...

LAT...LON 4223 7262 4229 7261 4218 7269 4224 7291
      4234 7290 4233 7306 4256 7298 4241 7270
      4242 7238 4233 7235 4230 7236 4231 7235
      4266 7223 4272 7228 4270 7154 4264 7150
      4239 7158 4228 7188 4219 7189 4215 7220

$$

NB

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 9:13 PM EDTFlash Flood WarningBOXHampden10 hr
Sep 1, 9:24 PM EDTSpecial Marine WarningBOX66 min
Sep 1, 9:37 PM EDTFlash Flood WarningBOXWorcester10 hr
Sep 1, 10:01 PM EDTFlash Flood WarningBOXEssex, Middlesex, Norfolk, Suffolk8 hr
Sep 1, 10:32 PM EDTFlash Flood WarningBOXBristol, Norfolk, Plymouth10 hr
Sep 1, 10:45 PM EDTSpecial Marine WarningBOX45 min
Sep 1, 11:02 PM EDTFlash Flood WarningBOXEssex, Middlesex8 hr
Sep 1, 11:21 PM EDTTornado WarningBOXBarnstable, Bristol, Dukes, Plymouth54 min
Sep 1, 11:24 PM EDTSpecial Marine WarningBOX66 min
Sep 1, 11:32 PM EDTSpecial Marine WarningBOX58 min
Sep 1, 11:32 PM EDTSpecial Marine WarningBOX58 min
Sep 1, 11:56 PM EDTTornado WarningBOXBarnstable, Dukes49 min
Sep 2, 12:08 AM EDTFlash Flood WarningBOXBarnstable, Dukes8 hr
Sep 2, 12:20 AM EDTSpecial Marine WarningBOX55 min
Sep 2, 12:22 AM EDTTornado WarningBOXDukes53 min
Sep 2, 12:25 AM EDTSpecial Marine WarningBOX65 min
Sep 2, 12:45 AM EDTTornado WarningBOXBarnstable, Dukes60 min
Sep 2, 1:07 AM EDTSpecial Marine WarningBOX83 min
Sep 2, 1:15 AM EDTTornado WarningBOXDukes28 min
Sep 2, 1:51 AM EDTRiver Flood WarningBOXWorcester31 hr
Sep 2, 1:56 AM EDTTornado WarningBOXBarnstable26 min
Sep 2, 2:34 AM EDTFlash Flood Warning Considerable damage threatBOXBristol, Plymouth6 hr
Sep 2, 3:42 AM EDTRiver Flood WarningBOXNorfolk, Suffolk11 hr
Sep 2, 5:14 AM EDTSpecial Marine WarningBOX46 min
Sep 2, 5:26 AM EDTFlash Flood Warning Considerable damage threatBOXBarnstable, Bristol, Dukes, Plymouth3 hr
Sep 2, 5:30 AM EDTRiver Flood WarningBOXMiddlesex22 hr
Sep 2, 5:49 AM EDTSpecial Marine WarningBOX42 min
Sep 2, 6:02 AM EDTFlash Flood WarningBOXEssex, Middlesex, Norfolk, Suffolk3 hr
Sep 2, 6:14 AM EDTSpecial Marine WarningBOX25 min
Sep 2, 6:50 AM EDTAreal Flood WarningBOXFranklin, Hampden, Hampshire, Middlesex, Worcester6 hr
Sep 2, 7:04 AM EDTAreal Flood WarningBOXBristol, Essex, Middlesex, Norfolk, Plymouth, Suffolk and 1 more11 hr
Sep 2, 7:25 AM EDTFlash Flood Warning Considerable damage threatBOXHampden, Hampshire, Worcester6 hr
Sep 2, 7:43 AM EDTAreal Flood WarningBOXBristol, Norfolk, Plymouth, Worcester6 hr
Sep 2, 7:54 AM EDTAreal Flood WarningBOXBarnstable, Dukes, Plymouth6 hr
Sep 2, 8:14 AM EDTRiver Flood WarningBOXHampden, Hampshire13 hr
Sep 2, 8:20 AM EDTRiver Flood WarningBOXWorcester32 hr
Sep 2, 8:20 AM EDTRiver Flood WarningBOXMiddlesex, Worcester60 hr
Sep 2, 9:25 AM EDTRiver Flood WarningBOXBristol, Plymouth64 hr
Sep 2, 10:40 AM EDTSmall Craft AdvisoryBOX17 hr
Sep 2, 12:51 PM EDTAreal Flood WarningBOXFranklin, Hampden, Hampshire, Middlesex, Norfolk, Worcester6 hr
Sep 2, 1:28 PM EDTAreal Flood WarningBOXHampden6 hr
Sep 2, 1:42 PM EDTAreal Flood WarningBOXBristol, Norfolk, Plymouth, Worcester6 hr
Sep 2, 5:59 PM EDTRiver Flood WarningBOXEssex, Middlesex25 hr

Nearby

Flash Flood Warnings in Massachusetts, 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.