Alert archive / Massachusetts / Flash Flood Warnings in 2018

Flash Flood Warning 23, NWS Boston/Norton, MA

August 8, 2018Middlesex County, Worcester County, Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Aug 8, 2018, 7:44 PM EDT for Middlesex County, Worcester County, Massachusetts. It was in force for 67 min. 8 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 8, 2018, 7:44 PM EDT (23:44 UTC)
Expired: Aug 8, 2018, 8:51 PM EDT
In force: 67 min
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Flood severity: None

Counties Middlesex County, MA, Worcester County, MA

The radar

The Boston radar (KBOX), 62 km from the middle of the area, began a volume at 23:47 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 8, 7:45 PM EDT	FLOOD	Hudson, MA	SEVERAL STREETS FLOODED
Aug 8, 7:54 PM EDT	FLOOD	Maynard, MA	THREE FEET OF WATER AT THOMPSON AND SUBURY STREET
Aug 8, 7:55 PM EDT	FLOOD	Acton, MA	SIGNIFICANT STREET FLOODING AT KELLY CORNER ON RTE 27
Aug 8, 7:59 PM EDT	FLOOD	Maynard, MA	BASEMENT FLOODING ON ACTON STREET
Aug 8, 8:02 PM EDT	FLOOD	Hudson, MA	SEVERAL STREETS IMPASSABLE DUE TO FLOODING
Aug 8, 8:04 PM EDT	HEAVY RAIN 3.21	Stow, MA
Aug 8, 8:12 PM EDT	FLOOD	Hudson, MA	SIGNIFICANT FLOODING AT MARLBORO ROAD AND REED STREET
Aug 8, 8:14 PM EDT	FLOOD	Maynard, MA	SIGNIFICANT STREET FLOODING ON PARKER STREET BY BOYS CLUB

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, 11.7 hours before the alert went out and 149 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: 227 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 951 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: -2 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

716 
WGUS51 KBOX 082344
FFWBOX
MAC017-027-090145-
/O.NEW.KBOX.FF.W.0023.180808T2344Z-180809T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
744 PM EDT WED AUG 8 2018

The National Weather Service in Boston/Norton has issued a

* Flash Flood Warning for...
  East central Worcester County in central Massachusetts...
  Central Middlesex County in northeastern Massachusetts...

* Until 945 PM EDT.

* At 744 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to two inches of rain have 
  already fallen in some areas. Flash flooding is expected to begin 
  shortly.

* Some locations that will experience flooding include...
  Framingham, Billerica, Marlborough, Chelmsford, Westford, Acton,
  Hudson, Concord, Sudbury, Northborough, Bedford, Maynard,
  Southborough, Littleton, Ayer, Stow, Harvard, Boxborough, Bolton
  and Carlisle.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding will occur quickly and could become life threatening for
those who try to drive through flooded roads or underpasses. Find
alternate routes and avoid flooded areas.

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 4246 7134 4235 7144 4231 7160 4253 7160
      4261 7135 4257 7122

$$

Belk

1 follow-up statement

858 
WGUS71 KBOX 090051
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
851 PM EDT WED AUG 8 2018

MAC017-027-090101-
/O.CAN.KBOX.FF.W.0023.000000T0000Z-180809T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Worcester MA-Middlesex MA-
851 PM EDT WED AUG 8 2018

...THE FLASH FLOOD WARNING FOR EAST CENTRAL WORCESTER AND CENTRAL
MIDDLESEX COUNTIES IS CANCELLED...

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

LAT...LON 4246 7134 4235 7144 4231 7160 4253 7160
      4261 7135 4257 7122

$$

Belk

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 7, 8:50 PM EDT	Areal Flood Advisory	BOX	Hampden	55 min
Aug 8, 3:29 AM EDT	Heat Advisory	BOX	Bristol, Essex, Franklin, Hampden, Hampshire, Middlesex and 4 more	15 hr
Aug 8, 2:09 PM EDT	Special Weather Statement	BOX	Plymouth	36 min
Aug 8, 3:05 PM EDT	Special Weather Statement	BOX	Norfolk	40 min
Aug 8, 3:14 PM EDT	Areal Flood Advisory	BOX	Norfolk, Suffolk	39 min
Aug 8, 3:54 PM EDT	Areal Flood Advisory	BOX	Norfolk, Worcester	66 min
Aug 8, 4:47 PM EDT	Special Weather Statement	BOX	Hampden	43 min
Aug 8, 4:54 PM EDT	Special Weather Statement	BOX	Franklin	51 min
Aug 8, 4:58 PM EDT	Special Weather Statement	BOX	Franklin	47 min
Aug 8, 5:48 PM EDT	Special Weather Statement	BOX	Franklin	57 min
Aug 8, 6:27 PM EDT	Special Weather Statement	BOX	Worcester	48 min
Aug 8, 7:28 PM EDT	Special Weather Statement	BOX	Middlesex	47 min
Aug 8, 7:38 PM EDT	Areal Flood Advisory	BOX	Essex, Middlesex, Worcester	82 min
Aug 8, 7:50 PM EDT	Severe Thunderstorm Warning	BOX	Essex, Middlesex, Suffolk, Worcester	55 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.