Alert archive / New York / Flash Flood Warnings in 2021

Flash Flood Warning 18, NWS Buffalo, NY

August 10, 2021Jefferson County, Lewis County, New York

NWS Buffalo, NY issued this flash flood warning at Aug 10, 2021, 10:47 PM EDT for Jefferson County, Lewis County, New York. 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 outline as issued.

The facts

Issued
Aug 10, 2021, 10:47 PM EDT (02:47 UTC)
Expired
Aug 11, 2021, 3:48 AM EDT
In force
5 hr
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Flood severity
None

Counties Jefferson County, NY, Lewis County, NY

The radar

The Ft Drum radar (KTYX), 23 km from the middle of the area, began a volume at 02:48 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, 2.8 hours before the alert went out and 196 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, Albany, NY at 00:00Z on 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 159 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, Albany, NY at 00:00Z on 2021-08-11The 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
159 J/kg
Mixed-layer CIN
-71 J/kg
Mixed-layer LCL
984 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
85 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

As transmitted.

712 
WGUS51 KBUF 110247
FFWBUF
NYC045-049-110845-
/O.NEW.KBUF.FF.W.0018.210811T0247Z-210811T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Buffalo NY
1047 PM EDT Tue Aug 10 2021

The National Weather Service in Buffalo has issued a

* Flash Flood Warning for...
  East Central Jefferson County in central New York...
  Northern Lewis County in central New York...

* Until 445 AM EDT.

* At 1047 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 3 inches of 
  rain have fallen. Additional rainfall amounts up to 1 inch 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...
  Carthage, Denmark, Copenhagen, Castorland and Indian River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4388 7579 4410 7532 4403 7526 4393 7535
      4382 7572

FLASH FLOOD...RADAR INDICATED

$$

SJW
2 follow-up statements
794 
WGUS71 KBUF 110614
FFSBUF

Flash Flood Statement
National Weather Service Buffalo NY
214 AM EDT Wed Aug 11 2021

NYC045-049-110845-
/O.CON.KBUF.FF.W.0018.000000T0000Z-210811T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson NY-Lewis NY-
214 AM EDT Wed Aug 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 AM EDT EARLY THIS 
MORNING FOR EAST CENTRAL JEFFERSON AND NORTHERN LEWIS COUNTIES...

At 214 AM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2.5 and 3 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...
  Carthage, Denmark, Copenhagen, Castorland and Indian River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4388 7579 4410 7532 4403 7526 4393 7535
      4382 7572

FLASH FLOOD...RADAR INDICATED

$$

JLA
832 
WGUS71 KBUF 110748
FFSBUF

Flash Flood Statement
National Weather Service Buffalo NY
348 AM EDT Wed Aug 11 2021

NYC045-049-110758-
/O.CAN.KBUF.FF.W.0018.000000T0000Z-210811T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson NY-Lewis NY-
348 AM EDT Wed Aug 11 2021

...FLASH FLOOD WARNING IS CANCELLED FOR EAST CENTRAL JEFFERSON AND 
NORTHERN LEWIS COUNTIES...

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

LAT...LON 4388 7579 4410 7532 4403 7526 4393 7535
      4382 7572

$$

JLA

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 9:29 PM EDTSpecial Weather StatementBUFJefferson31 min
Aug 10, 10:04 PM EDTSpecial Weather StatementBUFLewis41 min
Aug 11, 4:38 AM EDTSpecial Weather StatementBUFChautauqua, Erie, Niagara52 min
Aug 11, 5:37 AM EDTSpecial Weather StatementBUFChautauqua53 min
Aug 11, 5:41 AM EDTSpecial Marine WarningBUF64 min
Aug 11, 6:09 AM EDTSevere Thunderstorm WarningBUFCattaraugus, Chautauqua, Erie51 min
Aug 11, 6:27 AM EDTSpecial Marine WarningBUF93 min
Aug 11, 6:40 AM EDTSevere Thunderstorm WarningBUFErie, Genesee, Wyoming65 min
Aug 11, 6:48 AM EDTSpecial Marine WarningBUF42 min
Aug 11, 7:16 AM EDTSevere Thunderstorm WarningBUFAllegany, Cattaraugus, Genesee, Livingston, Monroe, Wyoming59 min
Aug 11, 7:39 AM EDTSpecial Weather StatementBUFGenesee, Monroe81 min
Aug 11, 7:46 AM EDTSevere Thunderstorm WarningBUFGenesee, Livingston, Monroe, Ontario, Orleans50 min
Aug 11, 7:55 AM EDTSevere Thunderstorm WarningBUFLivingston, Monroe, Ontario, Wayne50 min
Aug 11, 8:09 AM EDTSpecial Marine WarningBUF96 min
Aug 11, 8:25 AM EDTSpecial Weather StatementBUFWayne65 min
Aug 11, 9:18 AM EDTSpecial Weather StatementBUFOswego27 min
Aug 11, 1:44 PM EDTSmall Craft AdvisoryBUF6 hr
Aug 11, 6:52 PM EDTSpecial Weather StatementBUFChautauqua38 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.