Alert archive / Pennsylvania / Flash Flood Warnings in 1999
Flash Flood Warning 11, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Mar 21, 1999, 9:40 PM EST for Carbon County, Lehigh County, Monroe County, Pennsylvania. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Mar 21, 1999, 9:40 PM EST (02:40 UTC)
- Expired
- Mar 22, 1999, 2:00 AM EST
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Whole counties
Counties Carbon County, PA, Lehigh County, PA, Monroe County, PA
The radar
The Philadelphia radar (KDIX), 140 km from the middle of the area, began a volume at 02:26 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, 2.7 hours before the alert went out and 248 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1662 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 124 m²/s²
- 0-3 km storm-relative helicity
- 478 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KPHL 220241 FFWPHL PAC025-077-089-220700- BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 940 PM EST SUN MAR 21 1999 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * FLASH FLOOD WARNING FOR... CARBON COUNTY IN PENNSYLVANIA. MONROE COUNTY IN PENNSYLVANIA. LEHIGH COUNTY IN PENNSYLVANIA. * UNTIL 200 AM EST. * AT 940 PM NATIONAL WEATHER SERVICE RADAR SHOWED HEAVY RAINS OF 1 TO 1 1/2 INCHES WITHIN THE WARNED COUNTIES. ISOLATED THUNDERSTORMS HAVE ALSO BEEN OBSERVED. * SMALLER STREAMS AND POOR DRAINAGE AREAS ARE ESPECIALLY SUSCEPTIBLE TO FLOODING. * DO NOT DRIVE THROUGH FLOODED AREAS...THE WATER MAY BE DEEPER THAN YOU THINK. BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE DANGERS OF FLASH FLOODING. IF FLOODING IS OBSERVED...ACT QUICKLY. MOVE UP TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING. FOR THE LATEST STORM INFORMATION...PLEASE TUNE TO NOAA WEATHER RADIO...YOUR LOCAL RADIO OR TELEVISION STATIONS...OR YOUR CABLE TELEVISION OUTLET. .END RNS
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 21, 7:57 PM EST | Flash Flood Warning | PHI | Chester | 6 hr |
| Mar 21, 9:10 PM EST | Flash Flood Warning | PHI | Berks | 5 hr |
| Mar 21, 10:34 PM EST | Flash Flood Warning | PHI | Montgomery | 3 hr |
| Mar 21, 11:15 PM EST | Flash Flood Warning | PHI | Bucks | 3 hr |
| Mar 21, 11:50 PM EST | Flash Flood Warning | PHI | Philadelphia | 3 hr |
| Mar 22, 12:19 AM EST | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 3 hr |
| Mar 22, 12:19 AM EST | Flash Flood Warning | PHI | Carbon, Lehigh, Monroe, Northampton | 3 hr |
| Mar 22, 12:19 AM EST | Flash Flood Warning | PHI | Berks, Chester | 3 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 1999Every flash flood warning in 1999
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.