Alert archive / New York / Flash Flood Warnings in 2004

Flash Flood Warning 6, NWS Buffalo, NY

May 21, 2004Allegany County, New York

NWS Buffalo, NY issued this flash flood warning at May 21, 2004, 12:56 AM EDT for Allegany 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
May 21, 2004, 12:56 AM EDT (04:56 UTC)
Expired
May 21, 2004, 3:00 AM EDT
In force
2 hr
Issued by
NWS Buffalo, NY
Area
Counties, with a storm outline in the text

County Allegany County, NY

The radar

The Buffalo radar (KBUF), 113 km from the middle of the area, began a volume at 04:59 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 00:00Z, 4.9 hours before the alert went out and 109 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 00:00Z on 2004-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1163 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 00:00Z on 2004-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 284 square meters per square second.19395878Sfc1 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
1163 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
875 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
284 m²/s²
0-3 km storm-relative helicity
339 m²/s²
Significant tornado parameter
2.2
Supercell composite
9.4

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS51 KBUF 210457
FFWBUF
NYC003-210700-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE BUFFALO NY
1256 AM EDT FRI MAY 21 2004

THE NATIONAL WEATHER SERVICE IN BUFFALO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  ALLEGANY COUNTY IN WESTERN NEW YORK

* UNTIL 300 AM EDT

* AT 1253 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 5 MILES NORTH OF ALFRED...
  MOVING EAST AT 25 MPH.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

LAT...LON 4236 7798 4214 7801 4198 7757 4219 7746

$$

APB
2 follow-up statements
000 
WGUS71 KBUF 210550
FFSBUF
NYC003-210700-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BUFFALO NY
150 AM EDT FRI MAY 21 2004

...A FLASH FLOOD WARNING CONTINUES UNTIL 300 AM EDT FOR ALLEGANY
COUNTY...

AT 145 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A THUNDERSTORM PRODUCING HEAVY RAIN.  THIS STORM WAS 
LOCATED 6 MILES SOUTH OF ALFRED...OR ABOUT 13 MILES SOUTHWEST OF 
HORNELL...MOVING SOUTHEAST AT 20 MPH.

THE STORM WAS MOVING OVER AN AREA THAT RECEIVED VERY HEAVY RAIN 
EARLIER.  EAST VALLEY CREEK AND RAILROAD BROOK ARE THE MOST LIKELY 
AREAS FOR FLOODING.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL 
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

LAT...LON 4236 7798 4214 7801 4198 7757 4219 7746

$$

APB
000 
WGUS71 KBUF 210652
FFSBUF
NYC003-210710-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE BUFFALO NY
252 AM EDT FRI MAY 21 2004

...THE FLASH FLOOD WARNING FOR ALLEGANY COUNTY WILL BE ALLOWED TO 
EXPIRE AT 3 AM.  THE HEAVY RAIN HAS MOVED OUT OF THE COUNTY.

LAT...LON 4236 7798 4214 7801 4198 7757 4219 7746

$$

APB

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 8:29 PM EDTSevere Thunderstorm WarningBUFGenesee31 min
May 20, 8:40 PM EDTSevere Thunderstorm WarningBUFLivingston65 min
May 21, 2:25 AM EDTSevere Thunderstorm WarningBUFCattaraugus, Chautauqua50 min
May 21, 2:28 AM EDTSevere Thunderstorm WarningBUFChautauqua47 min
May 21, 5:45 AM EDTFlash Flood WarningBUFChautauqua3 hr

Nearby

Flash Flood Warnings in New York, 2004Every flash flood warning in 2004

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.