Alert archive / New York / Flash Flood Warnings in 2021

Flash Flood Warning 21, NWS Buffalo, NY

August 25, 2021Allegany County, Livingston County, Wyoming County, New York

NWS Buffalo, NY issued this flash flood warning at Aug 25, 2021, 7:36 PM EDT for Allegany County, Livingston County, Wyoming County, New York. It was in force for 2 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
Aug 25, 2021, 7:36 PM EDT (23:36 UTC)
Expired
Aug 25, 2021, 9:46 PM EDT
In force
2 hr
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Flood severity
None

Counties Allegany County, NY, Livingston County, NY, Wyoming County, NY

The radar

The Buffalo radar (KBUF), 68 km from the middle of the area, began a volume at 23:36 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

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 11.6 hours before the alert went out and 64 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, Buffalo Intl Airport, NY at 12:00Z on 2021-08-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 446 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, Buffalo Intl Airport, NY at 12:00Z on 2021-08-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 85 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
446 J/kg
Mixed-layer CIN
-103 J/kg
Mixed-layer LCL
1134 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

267 
WGUS51 KBUF 252336
FFWBUF
NYC003-051-121-260345-
/O.NEW.KBUF.FF.W.0021.210825T2336Z-210826T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Buffalo NY
736 PM EDT Wed Aug 25 2021

The National Weather Service in Buffalo has issued a

* Flash Flood Warning for...
  Northern Allegany County in western New York...
  Western Livingston County in western New York...
  Southeastern Wyoming County in western New York...

* Until 1145 PM EDT.

* At 736 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts up to 0.5 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  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...
  Letchworth State Park, Portageville, Pike, Castile, Silver 
  Springs, Gainesville, Hunt and Rossburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4252 7816 4257 7815 4263 7814 4268 7810
      4269 7803 4268 7794 4264 7794 4257 7797
      4248 7805 4249 7814

FLASH FLOOD...RADAR INDICATED

$$

HSK
2 follow-up statements
627 
WGUS71 KBUF 260054
FFSBUF

Flash Flood Statement
National Weather Service Buffalo NY
854 PM EDT Wed Aug 25 2021

NYC003-051-121-260345-
/O.CON.KBUF.FF.W.0021.000000T0000Z-210826T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegany NY-Livingston NY-Wyoming NY-
854 PM EDT Wed Aug 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM EDT THIS 
EVENING FOR NORTHERN ALLEGANY, WESTERN LIVINGSTON AND SOUTHEASTERN 
WYOMING COUNTIES...

At 854 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 2.5 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

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...
  Letchworth State Park, Portageville, Pike, Castile, Silver 
  Springs, Gainesville, Hunt and Rossburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4252 7816 4257 7815 4263 7814 4268 7810
      4269 7803 4268 7794 4264 7794 4257 7797
      4248 7805 4249 7814

FLASH FLOOD...RADAR INDICATED

$$

HSK
144 
WGUS71 KBUF 260146
FFSBUF

Flash Flood Statement
National Weather Service Buffalo NY
946 PM EDT Wed Aug 25 2021

NYC003-051-121-260156-
/O.CAN.KBUF.FF.W.0021.000000T0000Z-210826T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Allegany NY-Livingston NY-Wyoming NY-
946 PM EDT Wed Aug 25 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHERN ALLEGANY, WESTERN 
LIVINGSTON AND SOUTHEASTERN WYOMING COUNTIES...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 4252 7816 4257 7815 4263 7814 4268 7810
      4269 7803 4268 7794 4264 7794 4257 7797
      4248 7805 4249 7814

$$

HSK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 25, 5:00 PM EDTSpecial Marine WarningBUF60 min
Aug 25, 6:56 PM EDTSpecial Weather StatementBUFLivingston64 min
Aug 25, 7:15 PM EDTSpecial Weather StatementBUFWayne45 min
Aug 25, 7:50 PM EDTSpecial Weather StatementBUFLivingston40 min

Nearby

Flash Flood Warnings in New York, 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.