Alert archive / New York / Flash Flood Warnings in 2021

Flash Flood Warning 20, NWS Buffalo, NY

August 21, 2021Cattaraugus County, Chautauqua County, New York

NWS Buffalo, NY issued this flash flood warning at Aug 21, 2021, 6:00 PM EDT for Cattaraugus County, Chautauqua County, New York. It was in force for 4 hr. 2 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
Aug 21, 2021, 6:00 PM EDT (22:00 UTC)
Expired
Aug 21, 2021, 10:00 PM EDT
In force
4 hr
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Flood severity
None

Counties Cattaraugus County, NY, Chautauqua County, NY

The radar

The Buffalo radar (KBUF), 99 km from the middle of the area, began a volume at 22:03 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.

What was reported inside it

TimeReportWhereRemark
Aug 21, 6:55 PM EDTFLASH FLOODGerry, NYRT60/GERRY LEVANT RD CLOSED.
Aug 21, 7:05 PM EDTFLASH FLOODFalconer, NYEAST ROSS MILS RD CLOSED.

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

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 10.0 hours before the alert went out and 99 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 2021-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 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 2021-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 square meters per square second.193958Sfc1 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
2 J/kg
Mixed-layer CIN
-203 J/kg
Mixed-layer LCL
1298 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

273 
WGUS51 KBUF 212200
FFWBUF
NYC009-013-220200-
/O.NEW.KBUF.FF.W.0020.210821T2200Z-210822T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Buffalo NY
600 PM EDT Sat Aug 21 2021

The National Weather Service in Buffalo has issued a

* Flash Flood Warning for...
  West Central Cattaraugus County in western New York...
  Southern Chautauqua County in western New York...

* Until 1000 PM EDT.

* At 600 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Some areas have already 
  received as much as two inches of rain and another one to two 
  inches of rain will be possible. 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...
  Jamestown, Lakewood, Falconer, Clymer, Jamestown West, Long Point 
  State Park, Chautauqua Institution, Frewsburg, Chautauqua, Busti, 
  Gerry, Conewango, Ellington, Leon, Randolph, Celoron, Sherman, 
  Sinclairville, Panama and Cherry Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4231 7899 4207 7900 4201 7928 4200 7970
      4219 7966

FLASH FLOOD...RADAR INDICATED

$$

RSH
1 follow-up statement
498 
WGUS71 KBUF 212342
FFSBUF

Flash Flood Statement
National Weather Service Buffalo NY
742 PM EDT Sat Aug 21 2021

NYC009-013-220200-
/O.CON.KBUF.FF.W.0020.000000T0000Z-210822T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cattaraugus NY-Chautauqua NY-
742 PM EDT Sat Aug 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 PM EDT THIS 
EVENING FOR WEST CENTRAL CATTARAUGUS AND SOUTHERN CHAUTAUQUA 
COUNTIES...

At 742 PM EDT, Doppler radar indicated that while the heavy rain is 
now diminishing, between 2 and 3.5 inches of rain has fallen across 
the warned area, which has lead to flash flooding according to 
reports from local law enforcement.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement reported.

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...
  Jamestown, Lakewood, Falconer, Clymer, Jamestown West, Long Point 
  State Park, Chautauqua Institution, Frewsburg, Chautauqua, Busti, 
  Gerry, Conewango, Ellington, Leon, Randolph, Celoron, Sherman, 
  Sinclairville, Panama and Cherry Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4231 7899 4207 7900 4201 7928 4200 7970
      4219 7966

FLASH FLOOD...OBSERVED

$$

JJR

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 21, 1:31 PM EDTSpecial Weather StatementBUFJefferson44 min
Aug 21, 2:18 PM EDTSpecial Weather StatementBUFJefferson, Lewis57 min
Aug 21, 3:09 PM EDTSpecial Weather StatementBUFJefferson66 min
Aug 21, 3:13 PM EDTSpecial Marine WarningBUF47 min
Aug 21, 5:21 PM EDTSpecial Weather StatementBUFChautauqua54 min
Aug 21, 6:55 PM EDTSpecial Weather StatementBUFCattaraugus50 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.