Alert archive / New York / Flash Flood Warnings in 2021

Flash Flood Warning 15, NWS Buffalo, NY

July 20, 2021Niagara County, New York

NWS Buffalo, NY issued this flash flood warning at Jul 20, 2021, 4:49 PM EDT for Niagara County, New York. It was in force for 6 hr. 8 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
Jul 20, 2021, 4:49 PM EDT (20:49 UTC)
Expired
Jul 20, 2021, 10:23 PM EDT
In force
6 hr
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Flood severity
None

County Niagara County, NY

The radar

The Buffalo radar (KBUF), 35 km from the middle of the area, began a volume at 20:53 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
Jul 20, 5:37 PM EDTFLASH FLOOD1 S Lockport, NYREPORT OF ROAD CLOSURES DUE TO FLOODING WITH VEHICLES STRANDED IN THE TOWN OF LOCKPORT.
Jul 20, 5:50 PM EDTFLASH FLOOD1 Ne Lockport, NYREPORT OF ROAD CLOSURE ON MARKET ST IN THE TOWN OF LOCKPORT DUE TO FLOODING.
Jul 20, 5:50 PM EDTFLASH FLOOD1 Se Lockport, NYHIGH ST IN THE TOWN OF LOCKPORT CLOSED DUE TO FLOODING.
Jul 20, 6:20 PM EDTFLASH FLOOD3 N Sanborn, NYWATER FLOWING ACROSS THE ROADWAY ON TOWN LINE ROAD AT LOWER MOUNTAIN RD OVERPASS IN THE TOWN OF CAMBRIA.
Jul 20, 6:28 PM EDTFLASH FLOOD1 Ese Cambria Center, NYWATER FLOWING OVER THE ROAD WITH DEBRIS ON BLACKMAN RD WEST OF LOCKPORT.
Jul 20, 6:28 PM EDTFLASH FLOOD1 Nnw Lockport, NYREPORT OF ROAD CLOSURE DUE TO FLOODING WITH VEHICLES STRANDED IN THE TOWN OF LOCKPORT.
Jul 20, 7:45 PM EDTFLASH FLOOD1 Wsw Cambria Center, NYROUTE 425 CLOSED DUE TO FLOODING BETWEEN LOWER MOUNTAIN ROAD AND UPPER MOUNTAIN RD.
Jul 20, 8:10 PM EDTFLASH FLOOD3 S Lockport, NYSTATE OF EMERGENCY AND TRAVEL BAN ISSUED FOR ALL OF NIAGARA COUNTY DUE TO WIDESPREAD FLASH FLOODING.

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, 8.8 hours before the alert went out and 38 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 2021-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 574 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2021-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
574 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
893 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

083 
WGUS51 KBUF 202049
FFWBUF
NYC063-210045-
/O.NEW.KBUF.FF.W.0015.210720T2049Z-210721T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Buffalo NY
449 PM EDT Tue Jul 20 2021

The National Weather Service in Buffalo has issued a

* Flash Flood Warning for...
  Central Niagara County in western New York...

* Until 845 PM EDT.

* At 449 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 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...
  Lockport, Youngstown, Fort Niagara State Park, Cambria Center, 
  Ransomville, Rapids, Model City and Gasport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4319 7905 4321 7906 4322 7905 4325 7906
      4326 7907 4328 7908 4329 7893 4329 7890
      4321 7850 4310 7859

FLASH FLOOD...RADAR INDICATED

$$

Apffel
3 follow-up statements
830 
WGUS71 KBUF 202213
FFSBUF

Flash Flood Statement
National Weather Service Buffalo NY
613 PM EDT Tue Jul 20 2021

NYC063-210045-
/O.CON.KBUF.FF.W.0015.000000T0000Z-210721T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Niagara NY-
613 PM EDT Tue Jul 20 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM EDT THIS 
EVENING FOR CENTRAL NIAGARA COUNTY...

At 613 PM EDT, trained weather spotters reported thunderstorms 
producing flooding across the warned area. This includes multiple 
road closures in Lockport. Between 2 and 4 inches of rain have 
fallen. Additional rainfall amounts up to 1 inch are possible in the 
warned area. Flash flooding is ongoing.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters 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...
  Lockport, Youngstown, Fort Niagara State Park, Cambria Center, 
  Ransomville, Rapids, Model City and Gasport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4319 7905 4321 7906 4322 7905 4325 7906
      4326 7907 4328 7908 4329 7893 4329 7890
      4321 7850 4310 7859

FLASH FLOOD...OBSERVED

$$

Apffel
523 
WGUS51 KBUF 210021
FFWBUF
NYC063-210245-
/O.EXT.KBUF.FF.W.0015.000000T0000Z-210721T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Buffalo NY
821 PM EDT Tue Jul 20 2021

The National Weather Service in Buffalo has extended the

* Flash Flood Warning for...
  Central Niagara County in western New York...

* Until 1045 PM EDT.

* At 821 PM EDT, trained weather spotters and law enforcement have 
  reported several areas of flash flooding due to earlier 
  thunderstorms that produced heavy rain across the warned area. 
  Between 2 and 4 inches of rain have fallen. Flash flooding is 
  ongoing.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Trained spotters and 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 is ongoing.

* Some locations that will experience flash flooding include...
  Lockport, Youngstown, Fort Niagara State Park, Cambria Center, 
  Ransomville, Rapids, Model City and Gasport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4319 7905 4321 7906 4322 7905 4325 7906
      4326 7907 4328 7908 4329 7893 4329 7890
      4321 7850 4310 7859

FLASH FLOOD...OBSERVED

$$

SJW
919 
WGUS71 KBUF 210223
FFSBUF

Flash Flood Statement
National Weather Service Buffalo NY
1023 PM EDT Tue Jul 20 2021

NYC063-210233-
/O.CAN.KBUF.FF.W.0015.000000T0000Z-210721T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Niagara NY-
1023 PM EDT Tue Jul 20 2021

...FLASH FLOOD WARNING IS REPLACED BY A FLOOD WARNING FOR CENTRAL 
NIAGARA COUNTY...

The flash flood warning has been replaced by another flood warning 
since there still are remaining impacts from the flash flooding.

LAT...LON 4319 7905 4321 7906 4322 7905 4325 7906
      4326 7907 4328 7908 4329 7893 4329 7890
      4321 7850 4310 7859

$$

Apffel

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 2:13 PM EDTSpecial Marine WarningBUF62 min
Jul 20, 2:57 PM EDTSpecial Weather StatementBUFNiagara48 min
Jul 20, 3:14 PM EDTSpecial Marine WarningBUF61 min
Jul 20, 3:23 PM EDTSevere Thunderstorm WarningBUFNiagara67 min
Jul 20, 3:39 PM EDTSpecial Marine WarningBUF81 min
Jul 20, 3:48 PM EDTSpecial Marine WarningBUF87 min
Jul 20, 4:08 PM EDTSevere Thunderstorm WarningBUFJefferson, Lewis67 min
Jul 20, 4:23 PM EDTSevere Thunderstorm WarningBUFErie, Genesee, Niagara, Orleans67 min
Jul 20, 4:42 PM EDTSevere Thunderstorm WarningBUFNiagara48 min
Jul 20, 4:46 PM EDTSpecial Marine WarningBUF59 min
Jul 20, 4:55 PM EDTSpecial Marine WarningBUF48 min
Jul 20, 4:58 PM EDTSpecial Marine WarningBUF92 min
Jul 20, 5:00 PM EDTSpecial Weather StatementBUFGenesee30 min
Jul 20, 5:10 PM EDTSpecial Marine WarningBUF2 hr
Jul 20, 5:13 PM EDTSevere Thunderstorm WarningBUFJefferson, Lewis, Oswego62 min
Jul 20, 5:28 PM EDTSpecial Weather StatementBUFOswego47 min
Jul 20, 5:30 PM EDTSevere Thunderstorm WarningBUFErie, Genesee, Niagara, Orleans60 min
Jul 20, 5:43 PM EDTSpecial Marine WarningBUF92 min
Jul 20, 5:43 PM EDTSevere Thunderstorm WarningBUFOswego62 min
Jul 20, 5:56 PM EDTSpecial Weather StatementBUFGenesee, Monroe, Ontario, Orleans34 min
Jul 20, 6:07 PM EDTSevere Thunderstorm WarningBUFCayuga, Jefferson, Lewis, Oswego, Wayne38 min
Jul 20, 6:21 PM EDTFlash Flood WarningBUFErie, Niagara4 hr
Jul 20, 6:26 PM EDTSpecial Marine WarningBUF34 min
Jul 20, 6:30 PM EDTSpecial Weather StatementBUFErie, Genesee30 min
Jul 20, 6:37 PM EDTSevere Thunderstorm WarningBUFErie, Genesee, Niagara46 min
Jul 20, 6:46 PM EDTSpecial Weather StatementBUFLewis29 min
Jul 20, 6:52 PM EDTSpecial Marine WarningBUF67 min
Jul 20, 7:24 PM EDTSpecial Weather StatementBUFErie, Genesee, Livingston, Ontario, Wyoming36 min
Jul 20, 7:38 PM EDTSevere Thunderstorm WarningBUFLivingston, Monroe, Ontario, Wayne31 min
Jul 20, 7:58 PM EDTSpecial Weather StatementBUFLivingston, Wyoming92 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.