Alert archive / Massachusetts / Flash Flood Warnings in 2018

Flash Flood Warning 16, NWS Boston/Norton, MA

August 4, 20184 counties in Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Aug 4, 2018, 11:23 AM EDT for 4 counties in Massachusetts. It was in force for 93 min. 4 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: Aug 4, 2018, 11:23 AM EDT (15:23 UTC)
Expired: Aug 4, 2018, 12:56 PM EDT
In force: 93 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Flood severity: None

Counties Essex County, MA, Middlesex County, MA, Norfolk County, MA, Suffolk County, MA

The radar

The Boston radar (KBOX), 45 km from the middle of the area, began a volume at 15:26 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
Aug 4, 11:59 AM EDT	FLOOD	Weston, MA	HIGHLAND STREET HAS 6 TO 12 INCHES OF STREET FLOODING.
Aug 4, 12:07 PM EDT	FLOOD	Norwood, MA	6 TO 12 INCHES OF FLOODING NEAR THE T HANGARS ON THE NORTH RAMP OF NORWOOD MEMORIAL AIRPORT
Aug 4, 12:08 PM EDT	FLOOD	Milton, MA	SECTION OF CHURCHHILL STREET FLOODED OUT
Aug 4, 1:06 PM EDT	FLOOD	Quincy, MA	SECTION OF BRAINARD STREET FLOODED OUT

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

The nearest sounding before it

Chatham, MA (KCHH), launched 12:00Z, 3.4 hours before the alert went out and 106 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: 273 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 770 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

806 
WGUS51 KBOX 041523
FFWBOX
MAC009-017-021-025-041730-
/O.NEW.KBOX.FF.W.0016.180804T1523Z-180804T1730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
1123 AM EDT SAT AUG 4 2018

The National Weather Service in Boston/Norton has issued a

* Flash Flood Warning for...
  Central Norfolk County in eastern Massachusetts...
  Suffolk County in eastern Massachusetts...
  South central Essex County in northeastern Massachusetts...
  Southeastern Middlesex County in northeastern Massachusetts...

* Until 130 PM EDT.

* At 1122 AM EDT...Doppler radar indicated heavy rain across the 
  warned area. Up to one inch of rain has already fallen.
  Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Boston, Cambridge, Quincy, Lynn, Newton, Somerville, Waltham,
  Malden, Brookline, Medford, Weymouth, Revere, Arlington, Everett,
  Salem, Woburn, Braintree, Chelsea, Natick and Randolph.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Warning means that flooding will occur quickly, and
could be life threatening for those who try to drive through flooded
roads or underpasses. Find alternate routes. Those near small streams
need to get to higher ground immediately.

&&

LAT...LON 4249 7084 4247 7083 4244 7091 4241 7090
      4242 7096 4240 7097 4235 7093 4235 7086
      4228 7084 4227 7075 4220 7073 4222 7074
      4225 7077 4224 7077 4228 7087 4225 7088
      4225 7093 4216 7092 4209 7136 4248 7132

$$

Frank

1 follow-up statement

007 
WGUS71 KBOX 041656
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
1256 PM EDT SAT AUG 4 2018

MAC009-017-021-025-041706-
/O.CAN.KBOX.FF.W.0016.000000T0000Z-180804T1730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Norfolk MA-Suffolk MA-Essex MA-Middlesex MA-
1256 PM EDT SAT AUG 4 2018

...THE FLASH FLOOD WARNING FOR CENTRAL NORFOLK...SUFFOLK...SOUTH
CENTRAL ESSEX AND SOUTHEASTERN MIDDLESEX COUNTIES IS CANCELLED...

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

LAT...LON 4249 7084 4247 7083 4244 7091 4241 7090
      4242 7096 4240 7097 4235 7093 4235 7086
      4228 7084 4227 7075 4220 7073 4222 7074
      4225 7077 4224 7077 4228 7087 4225 7088
      4225 7093 4216 7092 4209 7136 4248 7132

$$

Frank

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 4, 5:56 AM EDT	Special Weather Statement	BOX	Franklin, Hampden, Hampshire	49 min
Aug 4, 7:02 AM EDT	Areal Flood Advisory	BOX	Hampden, Hampshire	58 min
Aug 4, 7:53 AM EDT	Areal Flood Advisory	BOX	Hampden	3 hr
Aug 4, 8:48 AM EDT	Areal Flood Advisory	BOX	Hampden, Hampshire, Worcester	3 hr
Aug 4, 9:31 AM EDT	Severe Thunderstorm Warning	BOX	Worcester	44 min
Aug 4, 9:35 AM EDT	Tornado Warning	BOX	Worcester	25 min
Aug 4, 9:57 AM EDT	Tornado Warning	BOX	Worcester	32 min
Aug 4, 10:00 AM EDT	Areal Flood Advisory	BOX	Bristol, Middlesex, Norfolk, Worcester	2 hr
Aug 4, 10:07 AM EDT	Tornado Warning	BOX	Middlesex, Worcester	38 min
Aug 4, 10:24 AM EDT	Flash Flood Warning	BOX	Middlesex, Norfolk, Worcester	106 min
Aug 4, 10:54 AM EDT	Areal Flood Advisory	BOX	Bristol, Essex, Middlesex, Norfolk, Suffolk	2 hr
Aug 4, 11:14 AM EDT	Areal Flood Advisory	BOX	Barnstable, Bristol, Norfolk, Plymouth	3 hr
Aug 4, 11:31 AM EDT	Flash Flood Warning	BOX	Bristol	3 hr
Aug 4, 11:43 AM EDT	Special Weather Statement	BOX	Suffolk	47 min
Aug 4, 11:46 AM EDT	Special Marine Warning	BOX		119 min
Aug 4, 12:08 PM EDT	Flash Flood Warning	BOX	Bristol, Plymouth	3 hr
Aug 4, 1:46 PM EDT	Special Marine Warning	BOX		44 min
Aug 4, 1:47 PM EDT	Special Marine Warning	BOX		43 min
Aug 4, 2:17 PM EDT	Flash Flood Warning	BOX	Bristol, Plymouth	113 min
Aug 4, 2:42 PM EDT	Flash Flood Warning	BOX	Bristol, Plymouth	45 min
Aug 4, 4:10 PM EDT	Special Marine Warning	BOX		35 min
Aug 4, 4:26 PM EDT	Special Weather Statement	BOX	Dukes	34 min
Aug 4, 4:30 PM EDT	Severe Thunderstorm Warning	BOX	Barnstable, Dukes	45 min
Aug 4, 4:40 PM EDT	Special Marine Warning	BOX		35 min
Aug 4, 5:14 PM EDT	Special Marine Warning	BOX		15 min
Aug 4, 5:18 PM EDT	Special Weather Statement	BOX	Barnstable	42 min
Aug 4, 5:23 PM EDT	Areal Flood Advisory	BOX	Barnstable	2 hr
Aug 4, 5:36 PM EDT	Special Weather Statement	BOX	Middlesex	39 min
Aug 4, 6:09 PM EDT	Special Weather Statement	BOX	Worcester	51 min
Aug 4, 6:36 PM EDT	Special Weather Statement	BOX	Hampden	39 min
Aug 4, 6:58 PM EDT	Special Weather Statement	BOX	Worcester	47 min

Nearby

Flash Flood Warnings in Massachusetts, 2018 Every flash flood warning in 2018

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.