Alert archive / Massachusetts / Flash Flood Warnings in 2021

Flash Flood Warning 6, NWS Boston/Norton, MA

July 14, 2021Hampshire County, Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Jul 14, 2021, 7:16 PM EDT for Hampshire County, Massachusetts. It was in force for 53 min. 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 14, 2021, 7:16 PM EDT (23:16 UTC)
Expired: Jul 14, 2021, 8:09 PM EDT
In force: 53 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Flood severity: None

County Hampshire County, MA

The radar

The Boston radar (KBOX), 113 km from the middle of the area, began a volume at 23:18 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

Albany, NY (KALY), launched 12:00Z, 11.3 hours before the alert went out and 123 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: 20 J/kg
Mixed-layer CIN: -211 J/kg
Mixed-layer LCL: 871 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 129 m²/s²
0-3 km storm-relative helicity: 134 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

492 
WGUS51 KBOX 142316
FFWBOX
MAC015-150215-
/O.NEW.KBOX.FF.W.0006.210714T2316Z-210715T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
716 PM EDT Wed Jul 14 2021

The National Weather Service in Norton has issued a

* Flash Flood Warning for...
  Southeastern Hampshire County in western Massachusetts...

* Until 1015 PM EDT.

* At 716 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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...
  Amherst, South Hadley, Belchertown, Granby, Hadley, Pelham and New 
  Salem.

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 4226 7252 4231 7255 4236 7246 4237 7243
      4240 7237 4239 7236 4238 7237 4237 7236
      4235 7236 4233 7235 4232 7235 4231 7236

FLASH FLOOD...RADAR INDICATED

$$

RM

1 follow-up statement

032 
WGUS71 KBOX 150009
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
809 PM EDT Wed Jul 14 2021

MAC015-150019-
/O.CAN.KBOX.FF.W.0006.000000T0000Z-210715T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hampshire MA-
809 PM EDT Wed Jul 14 2021

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

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

LAT...LON 4226 7252 4231 7255 4236 7246 4237 7243
      4240 7237 4239 7236 4238 7237 4237 7236
      4235 7236 4233 7235 4232 7235 4231 7236

$$

RM

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 14, 12:32 AM EDT	Dense Fog Advisory	BOX	Barnstable, Bristol, Dukes, Essex, Middlesex, Nantucket and 4 more	9 hr
Jul 14, 3:36 AM EDT	Special Weather Statement	BOX	Hampden, Hampshire	39 min
Jul 14, 4:15 AM EDT	Special Weather Statement	BOX	Hampden, Hampshire	45 min
Jul 14, 4:46 PM EDT	Special Weather Statement	BOX	Worcester	44 min
Jul 14, 4:53 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Worcester	52 min
Jul 14, 5:30 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampshire, Worcester	45 min
Jul 14, 6:05 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampden, Hampshire, Worcester	40 min
Jul 14, 6:38 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampden, Hampshire, Worcester	52 min
Jul 14, 7:31 PM EDT	Special Weather Statement	BOX	Worcester	44 min
Jul 14, 7:33 PM EDT	Special Weather Statement	BOX	Hampden	42 min
Jul 14, 7:46 PM EDT	Severe Thunderstorm Warning	BOX	Franklin, Hampden, Hampshire, Worcester	26 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.