Alert archive / New Hampshire / Flash Flood Warnings in 2021

Flash Flood Warning 10, NWS Gray, ME

July 18, 2021Cheshire County, Hillsborough County, New Hampshire

NWS Gray, ME issued this flash flood warning at Jul 18, 2021, 9:01 PM EDT for Cheshire County, Hillsborough County, New Hampshire. It was in force for 3 hr. 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 18, 2021, 9:01 PM EDT (01:01 UTC)
Expired
Jul 19, 2021, 12:00 AM EDT
In force
3 hr
Issued by
NWS Gray, ME
Area
Storm-based polygon
Flood severity
None

Counties Cheshire County, NH, Hillsborough County, NH

The radar

The Boston radar (KBOX), 135 km from the middle of the area, began a volume at 01:03 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 00:00Z, 1.0 hours before the alert went out and 126 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 00:00Z on 2021-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 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 00:00Z on 2021-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 square meters per square second.19395878Sfc1 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
12 J/kg
Mixed-layer CIN
-208 J/kg
Mixed-layer LCL
527 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

458 
WGUS51 KGYX 190101
FFWGYX
NHC005-011-190400-
/O.NEW.KGYX.FF.W.0010.210719T0101Z-210719T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Gray ME
901 PM EDT Sun Jul 18 2021

The National Weather Service in Gray has issued a

* Flash Flood Warning for...
  Southern Cheshire County in southern New Hampshire...
  Southwestern Hillsborough County in southern New Hampshire...

* Until midnight EDT.

* At 901 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Given 
  the heavy rain that occurred last night, it will not take much 
  rain to produce flash flooding. Additional rainfall amounts up to 
  1 inch are possible in the warned area. Flash flooding is ongoing 
  or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Keene, Jaffrey, Swanzey, Peterborough, Rindge, Winchester, 
  Marlborough, Fitzwilliam, Greenfield, and Hancock.

This includes the following Rec locations...
	Mount Monadnock, North Pack Monadnock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 4277 7250 4299 7239 4296 7185 4271 7192
      4273 7246 4276 7248

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Tubbs
2 follow-up statements
682 
WGUS71 KGYX 190301
FFSGYX

Flash Flood Statement
National Weather Service Gray ME
1101 PM EDT Sun Jul 18 2021

NHC005-011-190400-
/O.CON.KGYX.FF.W.0010.000000T0000Z-210719T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cheshire NH-Hillsborough NH-
1101 PM EDT Sun Jul 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT TONIGHT 
FOR SOUTHERN CHESHIRESOUTHWESTERN HILLSBOROUGH COUNTIES...

At 1101 PM EDT, Rainfall continues across the area that has seen 
significant flash flooding over the past 24 hours.  Any rain will 
only exacerbate recent problems...and another one half inch of rain 
is possible through midnight.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Keene, Jaffrey, Swanzey, Peterborough, Rindge, Winchester, 
  Marlborough, Fitzwilliam, Greenfield, and Hancock.

This includes the following Rec locations...
	Mount Monadnock and North Pack Monadnock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 4277 7250 4299 7239 4296 7185 4271 7192
      4273 7246 4276 7248

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

ARNOTT
560 
WGUS71 KGYX 190352
FFSGYX

Flash Flood Statement
National Weather Service Gray ME
1152 PM EDT Sun Jul 18 2021

NHC005-011-190402-
/O.EXP.KGYX.FF.W.0010.000000T0000Z-210719T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cheshire NH-Hillsborough NH-
1152 PM EDT Sun Jul 18 2021

...FLASH FLOOD WARNING WILL EXPIRE AT MIDNIGHT EDT TONIGHT FOR 
SOUTHERN CHESHIRESOUTHWESTERN HILLSBOROUGH COUNTIES...

Rainfall rates are decreasing and while water levels remain high...
the risk for additional flash flooding has ended.  Please refer to 
other flood products for more information on the continuing flood 
threat along the Ashuelot River.

LAT...LON 4277 7250 4299 7239 4296 7185 4271 7192
      4273 7246 4276 7248

$$

ARNOTT

Nearby

Flash Flood Warnings in New Hampshire, 2021Every flash flood warning in 2021

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.