Alert archive / New Jersey / Flash Flood Watches in 2020

Flash Flood Watch 3, NWS New York, NY

August 12, 2020Rockland County, Westchester County, New York; 4 counties in New Jersey

NWS New York, NY issued this flash flood watch at Aug 12, 2020, 5:25 AM EDT for Rockland County, Westchester County, New York; 4 counties in New Jersey. It took effect at Aug 12, 2020, 12:00 PM EDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued: Aug 12, 2020, 5:25 AM EDT (09:25 UTC)
In effect from: Aug 12, 2020, 12:00 PM EDT
Expired: Aug 12, 2020, 6:20 PM EDT
In force: 6 hr
Issued by: NWS New York, NY
Flood severity: None

Counties Bergen County, NJ, Essex County, NJ, Passaic County, NJ, Union County, NJ, Rockland County, NY, Westchester County, NY

The radar

The Brookhaven radar (KOKX), 106 km from the middle of the area, began a volume at 09:25 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, 9.4 hours before the alert went out and 194 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: 217 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 1733 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 83 m²/s²
0-3 km storm-relative helicity: 135 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

What forecasters said that day

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

NWS New York, NY wrote its last area forecast discussion before this flash flood watch went out at Aug 12, 1:48 AM EDT, 3 hours 37 minutes earlier.

Area forecast discussion, Aug 12, 1:48 AM EDT, 3 hours 37 minutes before

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Hazardous weather outlook, Aug 11, 4:06 PM EDT, 13 hours 19 minutes before

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The office that day

Everything else NWS New York, NY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 12, 1:22 PM EDT	Areal Flood Advisory	OKX	Nassau, Suffolk	83 min
Aug 12, 2:23 PM EDT	Areal Flood Advisory	OKX	Nassau	82 min
Aug 12, 2:56 PM EDT	Areal Flood Advisory	OKX	Nassau, Queens	94 min
Aug 12, 2:59 PM EDT	Special Weather Statement	OKX	Bronx	46 min
Aug 12, 3:04 PM EDT	Special Marine Warning	OKX		63 min
Aug 12, 3:14 PM EDT	Flash Flood Warning	OKX	Bronx, Nassau, New York, Queens	113 min
Aug 12, 3:45 PM EDT	Special Weather Statement	OKX	New York	45 min
Aug 12, 3:51 PM EDT	Severe Thunderstorm Warning	OKX	Bronx, New York	39 min
Aug 12, 3:59 PM EDT	Areal Flood Advisory	OKX	Bronx, New York	92 min
Aug 12, 4:33 PM EDT	Special Weather Statement	OKX	New York	27 min
Aug 12, 4:28 PM EDT	Severe Thunderstorm Warning	OKX	Bergen	17 min
Aug 12, 5:30 PM EDT	Areal Flood Advisory	OKX	Passaic	60 min
Aug 12, 4:49 PM EDT	Special Weather Statement	OKX		26 min

Nearby

Flash Flood Watches in New Jersey, 2020 Flash Flood Watches in New York, 2020 Every flash flood watch in 2020

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.