Alert archive / Massachusetts / Flash Flood Warnings in 2023

Flash Flood Warning 49, NWS Boston/Norton, MA

July 29, 2023Essex County, Middlesex County, Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Jul 29, 2023, 8:07 PM EDT for Essex County, Middlesex County, Massachusetts. It was in force for 53 min. 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
Jul 29, 2023, 8:07 PM EDT (00:07 UTC)
Expired
Jul 29, 2023, 9:00 PM EDT
In force
53 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

Counties Essex County, MA, Middlesex County, MA

The radar

The Boston radar (KBOX), 61 km from the middle of the area, began a volume at 00:10 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
Jul 29, 8:45 PM EDTFLOODLynn, MASeveral streets flooded due to heavy rainfall. They include Marion street, Boston at Bridge street, Commercial street at Lynnway, Alley street and Western Ave at Fox Hill Bridge. Time estimated from radar.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Gray, ME (KGYX), launched 00:00Z, 0.1 hours before the alert went out and 166 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, Gray, ME at 00:00Z on 2023-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Gray, ME at 00:00Z on 2023-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
446 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
339 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

228 
WGUS51 KBOX 300007
FFWBOX
MAC009-017-300100-
/O.NEW.KBOX.FF.W.0049.230730T0007Z-230730T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
807 PM EDT Sat Jul 29 2023

The National Weather Service in Norton has issued a

* Flash Flood Warning for...
  Southeastern Essex County in northeastern Massachusetts...
  East Central Middlesex County in northeastern Massachusetts...

* Until 900 PM EDT.

* At 807 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...
  Cambridge, Lynn, Somerville, Malden, Medford, Revere, Peabody, 
  Arlington, Everett, Salem, Billerica, Beverly, Woburn, Watertown, 
  Lexington, Gloucester, Melrose, Saugus, Danvers and Wakefield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4245 7103 4244 7102 4243 7103 4242 7103
      4237 7118 4254 7126 4260 7105 4266 7084
      4269 7072 4257 7062 4247 7091 4243 7100
      4243 7101 4244 7101 4245 7102

FLASH FLOOD...RADAR INDICATED

$$

RM

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 8:03 PM EDTSevere Thunderstorm WarningBOXBristol, Norfolk, Plymouth42 min
Jul 29, 8:21 PM EDTSevere Thunderstorm WarningBOXBristol, Plymouth39 min
Jul 29, 8:23 PM EDTSpecial Marine WarningBOX52 min
Jul 29, 8:29 PM EDTSpecial Marine WarningBOX33 min
Jul 29, 8:32 PM EDTTornado WarningBOXBristol, Plymouth28 min
Jul 29, 8:39 PM EDTSevere Thunderstorm WarningBOXBarnstable, Bristol, Dukes, Plymouth66 min
Jul 29, 8:52 PM EDTSpecial Marine WarningBOX38 min
Jul 29, 8:54 PM EDTSpecial Marine WarningBOX66 min
Jul 29, 9:06 PM EDTSpecial Marine WarningBOX54 min
Jul 29, 9:16 PM EDTSevere Thunderstorm WarningBOXBarnstable29 min
Jul 29, 9:19 PM EDTSpecial Marine WarningBOX56 min
Jul 29, 9:44 PM EDTSpecial Weather StatementBOXDukes46 min
Jul 29, 9:47 PM EDTSpecial Marine WarningBOX58 min
Jul 29, 10:09 PM EDTSpecial Weather StatementBOXNantucket66 min
Jul 29, 10:34 PM EDTSpecial Marine WarningBOX22 min
Jul 30, 8:44 AM EDTRip Current StatementBOXBarnstable, Bristol, Dukes, Nantucket11 hr

Nearby

Flash Flood Warnings in Massachusetts, 2023Every flash flood warning in 2023

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.