Alert archive / New Hampshire / Flash Flood Warnings in 2023

Flash Flood Warning 43, NWS Gray, ME

July 15, 2023Hillsborough County, New Hampshire

NWS Gray, ME issued this flash flood warning at Jul 15, 2023, 6:22 PM EDT for Hillsborough County, New Hampshire. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 15, 2023, 6:22 PM EDT (22:22 UTC)
Expired: Jul 15, 2023, 11:00 PM EDT
In force: 5 hr
Issued by: NWS Gray, ME
Area: Storm-based polygon
Flood severity: None

County Hillsborough County, NH

The radar

The Boston radar (KBOX), 117 km from the middle of the area, began a volume at 22:23 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

Brookhaven, NY (KOKX), launched 12:00Z, 10.4 hours before the alert went out and 247 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: 1125 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 596 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 100 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Gray, ME wrote its last area forecast discussion before this flash flood warning went out at Jul 15, 4:14 PM EDT, 2 hours 8 minutes earlier.

Area forecast discussion, Jul 15, 4:14 PM EDT, 2 hours 8 minutes before

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Hazardous weather outlook, Jul 15, 3:12 PM EDT, 3 hours 10 minutes before

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The office that day

Everything else NWS Gray, ME issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 15, 3:23 AM EDT	Flood Watch	GYX	Androscoggin, Cumberland, Franklin, Kennebec, Knox, Lincoln and 5 more	47 hr
Jul 15, 2:56 PM EDT	Small Craft Advisory	GYX		41 hr
Jul 15, 3:25 PM EDT	Areal Flood Advisory	GYX	Somerset	3 hr
Jul 15, 5:53 PM EDT	Areal Flood Advisory	GYX	Hillsborough, Merrimack	2 hr
Jul 15, 6:45 PM EDT	Areal Flood Advisory	GYX	Rockingham	2 hr

Nearby

Flash Flood Warnings in New Hampshire, 2023 Every flash flood warning in 2023

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.