Alert archive / Massachusetts / Flash Flood Warnings in 2018

Flash Flood Warning 4, NWS Boston/Norton, MA

July 5, 2018Franklin County, Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Jul 5, 2018, 2:55 PM EDT for Franklin County, Massachusetts. It was in force for 37 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
Jul 5, 2018, 2:55 PM EDT (18:55 UTC)
Expired
Jul 5, 2018, 3:32 PM EDT
In force
37 min
Issued by
NWS Boston/Norton, MA
Area
Storm-based polygon
Flood severity
None

County Franklin County, MA

The radar

The Albany radar (KENX), 127 km from the middle of the area, began a volume at 18:58 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

Albany, NY (KALY), launched 12:00Z, 6.9 hours before the alert went out and 109 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, Albany, NY at 12:00Z on 2018-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 18 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, Albany, NY at 12:00Z on 2018-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.1939Sfc1 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
18 J/kg
Mixed-layer CIN
-162 J/kg
Mixed-layer LCL
1108 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

384 
WGUS51 KBOX 051855
FFWBOX
MAC011-052100-
/O.NEW.KBOX.FF.W.0004.180705T1855Z-180705T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
255 PM EDT THU JUL 5 2018

The National Weather Service in Boston/Norton has issued a

* Flash Flood Warning for...
  Central Franklin County in western Massachusetts...

* Until 500 PM EDT.

* At 253 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Localized rainfall rates of 2 
  to 3 inches per hour are occurring with the strongest storms. 
  Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Greenfield, Deerfield, Montague, Sunderland, Northfield, Conway,
  Leverett, Erving, Shutesbury, Gill, Whately and Wendell.

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 4264 7241 4247 7238 4242 7268 4254 7271

$$

KJC
1 follow-up statement
601 
WGUS71 KBOX 051932
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
332 PM EDT THU JUL 5 2018

MAC011-051941-
/O.CAN.KBOX.FF.W.0004.000000T0000Z-180705T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Franklin MA-
332 PM EDT THU JUL 5 2018

...THE FLASH FLOOD WARNING FOR CENTRAL FRANKLIN COUNTY 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 4264 7241 4247 7238 4242 7268 4254 7271

$$

KJC

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 5, 3:39 AM EDTSmall Craft AdvisoryBOX58 hr
Jul 5, 1:07 PM EDTSpecial Weather StatementBOXFranklin38 min
Jul 5, 2:23 PM EDTSpecial Weather StatementBOXFranklin52 min
Jul 5, 3:30 PM EDTFlash Flood WatchBOXBarnstable, Bristol, Essex, Middlesex, Norfolk, Plymouth and 1 more24 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.