Alert archive / Massachusetts / Flash Flood Warnings in 2018

Flash Flood Warning 20, NWS Boston/Norton, MA

August 4, 2018Bristol County, Plymouth County, Massachusetts; Newport County, Rhode Island

NWS Boston/Norton, MA issued this flash flood warning at Aug 4, 2018, 2:42 PM EDT for Bristol County, Plymouth County, Massachusetts; Newport County, Rhode Island. It was in force for 45 min. 2 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, 2:42 PM EDT (18:42 UTC)
Expired
Aug 4, 2018, 3:27 PM EDT
In force
45 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

Counties Bristol County, MA, Plymouth County, MA, Newport County, RI

The radar

The Boston radar (KBOX), 38 km from the middle of the area, began a volume at 18:41 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
Aug 4, 3:04 PM EDTFLOODFall River, MASIGNIFICANT STREET FLOODING ON I-195 NEAR BRAGA BRIDGE
Aug 4, 3:29 PM EDTFLOODDartmouth, MAROUTE 6 EASTBOUND DOWN TO 1 LANE BY METRO PIZZA

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, 6.7 hours before the alert went out and 92 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, Chatham, MA at 12:00Z on 2018-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 273 joules per kilogram.LCLLFCEL10008507005003002001001 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, Chatham, MA at 12:00Z on 2018-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 square meters per square second.193958Sfc1 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
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.

240 
WGUS51 KBOX 041842
FFWBOX
MAC005-023-RIC005-042045-
/O.NEW.KBOX.FF.W.0020.180804T1842Z-180804T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Boston/Norton has issued a

* Flash Flood Warning for...
  Southwestern Plymouth County in southeastern Massachusetts...
  Southeastern Bristol County in southeastern Massachusetts...
  Eastern Newport County in Rhode Island...

* Until 445 PM EDT.

* At 239 PM EDT...Doppler radar indicated heavy rain across the 
  warned area. Up to two inches of rain have already fallen. Flash 
  flooding is already occurring especially in the Fall River area.

* Some locations that will experience flooding include...
  New Bedford, Fall River, Taunton, Dartmouth, Bridgewater, Newport,
  Middleborough, Portsmouth, Middletown, Fairhaven, Tiverton,
  Westport, Carver, Lakeville, Acushnet, Freetown, Berkley,
  Mattapoisett, Rochester and Little Compton.

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 4195 7095 4194 7078 4160 7084 4159 7089
      4160 7090 4149 7121 4149 7122 4147 7126
      4147 7128 4146 7128 4144 7134

$$

Frank
1 follow-up statement
088 
WGUS71 KBOX 041927
FFSBOX

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

MAC005-023-RIC005-041937-
/O.CAN.KBOX.FF.W.0020.000000T0000Z-180804T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Plymouth MA-Bristol MA-Newport RI-
327 PM EDT SAT AUG 4 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN PLYMOUTH...SOUTHEASTERN
BRISTOL AND EASTERN NEWPORT COUNTIES IS CANCELLED...

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

LAT...LON 4195 7095 4194 7078 4160 7084 4159 7089
      4160 7090 4149 7121 4149 7122 4147 7126
      4147 7128 4146 7128 4144 7134

$$

Frank

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 5:56 AM EDTSpecial Weather StatementBOXFranklin, Hampden, Hampshire49 min
Aug 4, 7:02 AM EDTAreal Flood AdvisoryBOXHampden, Hampshire58 min
Aug 4, 7:53 AM EDTAreal Flood AdvisoryBOXHampden3 hr
Aug 4, 8:48 AM EDTAreal Flood AdvisoryBOXHampden, Hampshire, Worcester3 hr
Aug 4, 9:31 AM EDTSevere Thunderstorm WarningBOXWorcester44 min
Aug 4, 9:35 AM EDTTornado WarningBOXWorcester25 min
Aug 4, 9:57 AM EDTTornado WarningBOXWorcester32 min
Aug 4, 10:00 AM EDTAreal Flood AdvisoryBOXBristol, Middlesex, Norfolk, Worcester2 hr
Aug 4, 10:07 AM EDTTornado WarningBOXMiddlesex, Worcester38 min
Aug 4, 10:24 AM EDTFlash Flood WarningBOXMiddlesex, Norfolk, Worcester106 min
Aug 4, 10:54 AM EDTAreal Flood AdvisoryBOXBristol, Essex, Middlesex, Norfolk, Suffolk2 hr
Aug 4, 11:14 AM EDTAreal Flood AdvisoryBOXBarnstable, Bristol, Norfolk, Plymouth3 hr
Aug 4, 11:23 AM EDTFlash Flood WarningBOXEssex, Middlesex, Norfolk, Suffolk93 min
Aug 4, 11:31 AM EDTFlash Flood WarningBOXBristol3 hr
Aug 4, 11:43 AM EDTSpecial Weather StatementBOXSuffolk47 min
Aug 4, 11:46 AM EDTSpecial Marine WarningBOX119 min
Aug 4, 12:08 PM EDTFlash Flood WarningBOXBristol, Plymouth3 hr
Aug 4, 1:46 PM EDTSpecial Marine WarningBOX44 min
Aug 4, 1:47 PM EDTSpecial Marine WarningBOX43 min
Aug 4, 2:17 PM EDTFlash Flood WarningBOXBristol, Plymouth113 min
Aug 4, 4:10 PM EDTSpecial Marine WarningBOX35 min
Aug 4, 4:26 PM EDTSpecial Weather StatementBOXDukes34 min
Aug 4, 4:30 PM EDTSevere Thunderstorm WarningBOXBarnstable, Dukes45 min
Aug 4, 4:40 PM EDTSpecial Marine WarningBOX35 min
Aug 4, 5:14 PM EDTSpecial Marine WarningBOX15 min
Aug 4, 5:18 PM EDTSpecial Weather StatementBOXBarnstable42 min
Aug 4, 5:23 PM EDTAreal Flood AdvisoryBOXBarnstable2 hr
Aug 4, 5:36 PM EDTSpecial Weather StatementBOXMiddlesex39 min
Aug 4, 6:09 PM EDTSpecial Weather StatementBOXWorcester51 min
Aug 4, 6:36 PM EDTSpecial Weather StatementBOXHampden39 min
Aug 4, 6:58 PM EDTSpecial Weather StatementBOXWorcester47 min
Aug 4, 1:54 PM EDTSpecial Weather StatementBOXNewport66 min

Nearby

Flash Flood Warnings in Massachusetts, 2018Flash Flood Warnings in Rhode Island, 2018Every 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.