Alert archive / Massachusetts / Flash Flood Warnings in 2018

Flash Flood Warning 33, NWS Boston/Norton, MA

September 18, 2018Barnstable County, Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Sep 18, 2018, 3:05 PM EDT for Barnstable County, Massachusetts. It was in force for 115 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
Sep 18, 2018, 3:05 PM EDT (19:05 UTC)
Expired
Sep 18, 2018, 5:00 PM EDT
In force
115 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

County Barnstable County, MA

The radar

The Boston radar (KBOX), 81 km from the middle of the area, began a volume at 19:09 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

Chatham, MA (KCHH), launched 12:00Z, 7.1 hours before the alert went out and 24 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 2018-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 165 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Chatham, MA at 12:00Z on 2018-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 124 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
165 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
648 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
124 m²/s²
0-3 km storm-relative helicity
148 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

440 
WGUS51 KBOX 181905
FFWBOX
MAC001-182100-
/O.NEW.KBOX.FF.W.0033.180918T1905Z-180918T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
305 PM EDT TUE SEP 18 2018

The National Weather Service in Boston/Norton has issued a

* Flash Flood Warning for...
  Barnstable County in southeastern Massachusetts...

* Until 500 PM EDT.

* At 305 PM EDT Doppler radar indicated thunderstorms with heavy 
  rainfall moving into the the warned area. Urban and poor 
  drainage flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Plymouth, Barnstable, Falmouth, Brewster, Provincetown, Yarmouth,
  Sandwich, Bourne, Dennis, Mashpee, Harwich, Chatham, Orleans,
  Eastham, Wellfleet, Truro, Gosnold and Hyannis.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4153 7000 4165 6999 4166 7004 4151 7069
      4165 7067 4179 7058 4181 7054 4173 7027
      4180 7003 4188 7001 4191 7005 4188 7005
      4200 7009 4204 7015 4202 7021 4209 7021
      4210 7019 4206 7007 4198 6998 4164 6993

$$

NMB
1 follow-up statement
996 
WGUS71 KBOX 182058
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
458 PM EDT TUE SEP 18 2018

MAC001-182103-
/O.EXP.KBOX.FF.W.0033.000000T0000Z-180918T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Barnstable MA-
458 PM EDT TUE SEP 18 2018

...THE FLASH FLOOD WARNING FOR BARNSTABLE COUNTY WILL EXPIRE AT 500
PM EDT...

Light to moderate rain will continue to fall over Cape Cod thru 6 
pm. However the heavy rain associated with thunderstorms has moved 
offshore. Minor poor drainage flooding may linger in some locales 
during early this evening, but the more widespread flood threat has 
come to an end. Therefore the Flash Flood Warning for Cape Cod has 
been allowed to expire. 

LAT...LON 4153 7000 4165 6999 4166 7004 4151 7069
      4165 7067 4179 7058 4181 7054 4173 7027
      4180 7003 4188 7001 4191 7005 4188 7005
      4200 7009 4204 7015 4202 7021 4209 7021
      4210 7019 4206 7007 4198 6998 4164 6993

$$

NMB

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 18, 7:54 AM EDTSpecial Weather StatementBOXFranklin, Hampshire81 min
Sep 18, 8:21 AM EDTSpecial Weather StatementBOXNorfolk54 min
Sep 18, 8:52 AM EDTFlash Flood WarningBOXFranklin, Hampshire, Middlesex, Worcester4 hr
Sep 18, 9:09 AM EDTSpecial Weather StatementBOXHampden, Worcester36 min
Sep 18, 9:32 AM EDTSpecial Weather StatementBOXEssex, Middlesex88 min
Sep 18, 9:50 AM EDTSpecial Weather StatementBOXHampden, Worcester85 min
Sep 18, 10:12 AM EDTSpecial Weather StatementBOXEssex48 min
Sep 18, 10:17 AM EDTFlash Flood WarningBOXEssex, Middlesex, Norfolk, Suffolk, Worcester4 hr
Sep 18, 10:34 AM EDTSpecial Weather StatementBOXEssex41 min
Sep 18, 10:45 AM EDTSevere Thunderstorm WarningBOXEssex, Middlesex30 min
Sep 18, 10:56 AM EDTSpecial Marine WarningBOX64 min
Sep 18, 10:58 AM EDTFlash Flood WarningBOXHampden, Hampshire, Worcester4 hr
Sep 18, 11:00 AM EDTTornado WarningBOXEssex15 min
Sep 18, 11:07 AM EDTRiver Flood WarningBOXWorcester9 hr
Sep 18, 11:09 AM EDTSpecial Marine WarningBOX66 min
Sep 18, 11:23 AM EDTFlash Flood WarningBOXBristol, Middlesex, Norfolk, Plymouth, Suffolk, Worcester4 hr
Sep 18, 11:58 AM EDTSpecial Marine WarningBOX62 min
Sep 18, 12:20 PM EDTSpecial Marine WarningBOX25 min
Sep 18, 12:32 PM EDTAreal Flood WarningBOXFranklin, Hampshire, Middlesex, Worcester4 hr
Sep 18, 12:49 PM EDTSpecial Marine WarningBOX86 min
Sep 18, 12:58 PM EDTSpecial Weather StatementBOXPlymouth62 min
Sep 18, 1:10 PM EDTSpecial Marine WarningBOX80 min
Sep 18, 1:31 PM EDTFlash Flood WarningBOXBristol, Plymouth4 hr
Sep 18, 2:01 PM EDTAreal Flood WarningBOXEssex, Middlesex, Norfolk, Suffolk, Worcester4 hr
Sep 18, 2:07 PM EDTSpecial Weather StatementBOXBristol, Plymouth38 min
Sep 18, 2:27 PM EDTSevere Thunderstorm WarningBOXBarnstable, Plymouth33 min
Sep 18, 2:31 PM EDTSpecial Marine WarningBOX44 min
Sep 18, 2:59 PM EDTSpecial Marine WarningBOX46 min
Sep 18, 3:04 PM EDTSevere Thunderstorm WarningBOXBarnstable41 min
Sep 18, 3:14 PM EDTAreal Flood WarningBOXBristol, Middlesex, Norfolk, Plymouth, Suffolk, Worcester3 hr
Sep 18, 3:22 PM EDTSpecial Marine WarningBOX53 min
Sep 18, 3:59 PM EDTSpecial Marine WarningBOX46 min
Sep 18, 4:01 PM EDTSmall Craft AdvisoryBOX60 hr

Nearby

Flash Flood Warnings in Massachusetts, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.