Alert archive / Massachusetts / Flash Flood Warnings in 2018

Flash Flood Warning 12, NWS Boston/Norton, MA

July 25, 2018Franklin County, Hampden County, Hampshire County, Massachusetts

NWS Boston/Norton, MA issued this flash flood warning at Jul 25, 2018, 11:32 AM EDT for Franklin County, Hampden County, Hampshire County, Massachusetts. It was in force for 2 hr. 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: Jul 25, 2018, 11:32 AM EDT (15:32 UTC)
Expired: Jul 25, 2018, 1:51 PM EDT
In force: 2 hr
Issued by: NWS Boston/Norton, MA
Area: Storm-based polygon
Flood severity: None

Counties Franklin County, MA, Hampden County, MA, Hampshire County, MA

The radar

The Albany radar (KENX), 90 km from the middle of the area, began a volume at 15:33 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
Jul 25, 11:53 AM EDT	HEAVY RAIN 2.07	Plainfield, MA
Jul 25, 12:48 PM EDT	HEAVY RAIN 2.4	Chester, MA
Jul 25, 12:53 PM EDT	HEAVY RAIN 2.22	Cummington, MA
Jul 25, 12:57 PM EDT	HEAVY RAIN 2.96	Worthington, MA

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

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 3.5 hours before the alert went out and 76 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: 111 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 701 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 246 m²/s²
0-3 km storm-relative helicity: 261 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted.

786 
WGUS51 KBOX 251532
FFWBOX
MAC011-013-015-251830-
/O.NEW.KBOX.FF.W.0012.180725T1532Z-180725T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boston/Norton MA
1132 AM EDT WED JUL 25 2018

The National Weather Service in Boston/Norton has issued a

* Flash Flood Warning for...
  Western Hampshire County in western Massachusetts...
  Northwestern Franklin County in western Massachusetts...
  Western Hampden County in western Massachusetts...

* Until 230 PM EDT.

* At 1130 AM EDT Doppler radar indicated torrential rain across the 
  warned area. Up to two inches of rain have already fallen. Flash 
  flooding is expected to begin shortly.  A few gravel could become 
  washed out along with small stream flash flooding.

* Some locations that will experience flooding include...
  Westfield, Monroe, Huntington, Buckland, Russell, Ashfield,
  Colrain, Westhampton, Granville, Chester, Charlemont, Blandford,
  Chesterfield, Worthington, Goshen, Cummington, Montgomery, Heath,
  Plainfield and Middlefield.

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 4215 7307 4215 7303 4227 7300 4231 7300
      4233 7306 4238 7307 4239 7301 4266 7295
      4267 7300 4270 7295 4270 7302 4274 7302
      4273 7274 4204 7285 4205 7306 4210 7307

$$

Frank

2 follow-up statements

073 
WGUS71 KBOX 251715
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
115 PM EDT WED JUL 25 2018

MAC011-013-015-251830-
/O.CON.KBOX.FF.W.0012.000000T0000Z-180725T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hampshire MA-Franklin MA-Hampden MA-
115 PM EDT WED JUL 25 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 PM EDT FOR
WESTERN HAMPSHIRE...NORTHWESTERN FRANKLIN AND WESTERN HAMPDEN
COUNTIES...

At 110 PM EDT, Doppler radar indicated that the torrential rain has 
at least temporarily exited the region. However...2 to 3 inches of 
rain fell within a couple hours in many locations. There is the 
potential for additional showers developing over the next hour or 
two...so the potential for localized flash flooding continues.

Some locations that may experience flooding include...
Monroe, Huntington, Buckland, Russell, Ashfield, Colrain, 
Westhampton, Granville, Chester, Charlemont, Blandford, 
Chesterfield, Worthington, Goshen, Cummington, Montgomery, Heath, 
Plainfield and Middlefield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

&&

LAT...LON 4215 7307 4215 7303 4227 7300 4231 7300
      4233 7306 4238 7307 4239 7301 4266 7295
      4267 7300 4270 7295 4270 7302 4274 7302
      4273 7274 4204 7285 4205 7306 4210 7307

$$

Frank

996 
WGUS71 KBOX 251751
FFSBOX

Flash Flood Statement
National Weather Service Boston/Norton MA
151 PM EDT WED JUL 25 2018

MAC011-013-015-251759-
/O.CAN.KBOX.FF.W.0012.000000T0000Z-180725T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hampshire MA-Franklin MA-Hampden MA-
151 PM EDT WED JUL 25 2018

...THE FLASH FLOOD WARNING FOR WESTERN HAMPSHIRE...NORTHWESTERN
FRANKLIN AND WESTERN HAMPDEN COUNTIES IS CANCELLED...

The heavy rain has ended so the flash flood warning has been 
cancelled.  Please continue to heed any remaining road closures.  A 
Flash Flood Watch remains in effect through tonight as additional 
showers with heavy rainfall are expected.

LAT...LON 4215 7307 4215 7303 4227 7300 4231 7300
      4233 7306 4238 7307 4239 7301 4266 7295
      4267 7300 4270 7295 4270 7302 4274 7302
      4273 7274 4204 7285 4205 7306 4210 7307

$$

Frank

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 25, 9:39 AM EDT	Flash Flood Watch	BOX	Bristol, Essex, Franklin, Hampden, Hampshire, Middlesex and 4 more	18 hr
Jul 25, 2:32 PM EDT	Special Weather Statement	BOX	Norfolk	43 min
Jul 25, 3:04 PM EDT	Special Weather Statement	BOX	Essex, Suffolk	26 min
Jul 25, 3:26 PM EDT	Special Weather Statement	BOX	Essex	34 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.