Alert archive / Pennsylvania / Flash Flood Warnings in 1999
Flash Flood Warning 48, NWS State College, PA
NWS State College, PA issued this flash flood warning at Sep 6, 1999, 9:07 PM EDT for 4 counties in Pennsylvania. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.
The facts
- Issued
- Sep 6, 1999, 9:07 PM EDT (01:07 UTC)
- Expired
- Sep 7, 1999, 12:00 AM EDT
- In force
- 3 hr
- Issued by
- NWS State College, PA
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
Counties Cumberland County, PA, Dauphin County, PA, Perry County, PA, York County, PA
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 00:00Z, 1.1 hours before the alert went out and 147 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
- 35 J/kg
- Mixed-layer CIN
- -19 J/kg
- Mixed-layer LCL
- 617 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 140 m²/s²
- 0-3 km storm-relative helicity
- 142 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 KCTP 070110 FFWCTP PAC041-043-099-133-070400- BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE STATE COLLEGE PA 907 PM EDT MON SEP 6 1999 THE NATIONAL WEATHER SERVICE IN STATE COLLEGE PA HAS ISSUED A * FLASH FLOOD WARNING FOR... YORK COUNTY. PERRY COUNTY. DAUPHIN COUNTY. CUMBERLAND COUNTY. * UNTIL MIDNIGHT EDT. * AT 906 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED LINE OF THUNDERSTORMS WITH VERY HEAVY RAINFALL THAT STRETCHED FROM MILLERSBURG DOWN TO YORK. THE THUNDERSTORMS WERE MOVING TO THE NORTH AT 20 MPH. THIS MOTION WOULD KEEP HEAVY RAIN FALLING OVER THE HARRISBURG METRO AREA THROUGH AT LEAST 10 PM. SLOW MOVING THUNDERSTORMS ARE PRODUCING TORRENTIAL RAINFALL IN THE WARNED AREA. RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING IN THE HARRISBURG METRO AREA. THE SMALLER CREEKS AND TRIBUTARIES OF THE SUSQUEHANNA RIVER WILL FILL TO CAPACITY QUICKLY. HIGHLY URBANIZED AREAS...ESPECIALLY AROUND THE CITY OF HARRISBURG CAN ALSO EXPECT UNDERPASSES AND STREETS TO FILL WITH WATER. BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE DANGERS OF FLOODS AND FLASH FLOODS. A FLASH FLOOD WARNING MEANS` THAT FLOODING IS IMMINENT OR OCCURRING. IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY. .END/DANGELO LAT...LON 3998 7695 3996 7675 4053 7665 4060 7710
What forecasters said that day
The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS State College, PA wrote its last area forecast discussion before this flash flood warning went out at Sep 6, 8:10 PM EDT, 57 minutes earlier.
Area forecast discussion, Sep 6, 8:10 PM EDT, 57 minutes before
CENTRAL PENNSYLVANIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 810 PM EDT MON SEP 6 1999 WELL IT TOOK FOREVER FOR DENNIS TO GET HERE..BUT IT IS HERE AND THE RAIN IS FALLING. WE HAD A BEAUTIFUL WEST TO EAST ORIENTED BAND OF RAIN MOVE THROUGH AROUND 5 PM WITH A BLINDING DOWNPOUR AND ABOUT .5 OF RAIN IN 5 MINUTES. LOTS OF REPORTS OF LOCALIZED DOWNPOURS...BUT NO REAL FLOODING TO SPEAK OF...YET. SOME SMALLER CREEKS AND STREAMS ARE CLOSE TO BANKFULL...BUT LARGER ONES ARENT EVEN CLOSE. THE SURFACE REFLECTION OF DENNIS IS HARD TO FIND AT 21Z...BUT IS PROBABLY SOMEWHERE BETWEEN EKN AND CHO. THE UPPER SYSTEM IS MORE IMPRESSIVE AS EVIDENCED BY THE SPIRALING RAIN SHIELD AND THE MASS FIELDS ON THE MODEL PROGS. ETA MODELS SHOW LOW LEVEL JET ON THE ORDER OF 35-45KT POINTED UP FROM THE SSE...CONTINUING INTO THE WEE HOURS AND FINALLY PULLING OFF EARLY TUES. 2 CONCERNS FOR WHERE THE HEAVIEST RAIN THREATS WILL BE. FIRST IS ALONG THE DEEP SLY FEED WHICH IS TAKING AIM AT THE CTRL AND ERN PARTS OF MY CWA. REGIONAL RADAR MOSAICS SHOW SHOWERS FEEDING NORTHWARD IN THE DEEP SLY FLOW ALL THE WAY FROM THE MID ATLANTIC. WATER VAPOR SHOWS TROPICAL PLUME CONNECTING TO ABOUT THE BAHAMAS. MODEL PRECIP WATERS TOP 2 INCHES SO THE JUICE IS NOT LACKING. OTHER AREA IS OVER NWRN PA WHERE RADAR LOOPS SUGGEST DEFORMATION ZONE IS FORMING. THIS COMBINED WITH A BAND WHICH HAS BEEN INCHING EAST THRU ERN OHIO CUD MAKE FOR PROBLEMS THERE. THIS AREA TOOK A GOOD SLUG OF RAIN LAST WEEK WHICH CAUSED MAJOR FLASH FLOODING. WILL CONTINUE THE FLASH FLOOD WATCH INTO TUES MORNING TO DEAL WITH THE RAIN OVERNIGHT. THE INITIAL SURGE OF RW/TRW WAS HANDLED FAIRLY WELL BY THE RADAR PRECIP ALGORITHM...WE ARE IN TROPICAL Z/R MODE. NOW HOWEVER...CLOUD TOPS ARE WARM...IN THE MID -20S...WITH RADAR TOPS ONLY IN THE LOWER 20S. THIS IS STARTING TO LOOK LIKE A CLASSIC WARM RAIN/LOW TOPPED CONVECTION EVENT...WHICH MEANS THE RADAR WILL START TO GROSSLY UNDERESTIMATE THE PRECIP. .CTP...FLASH FLOOD WATCH FOR ALL OF CENTRAL PA THROUGH TUESDAY MORNING. LA CORTE
The office that day
Everything else NWS State College, PA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 6, 11:37 PM EDT | Flash Flood Warning | CTP | Lycoming, Snyder, Union | 3 hr |
| Sep 6, 11:47 PM EDT | Flash Flood Warning | CTP | Cumberland, Dauphin, York | 3 hr |
| Sep 6, 11:47 PM EDT | Flash Flood Warning | CTP | Perry | 3 hr |
| Sep 7, 2:06 AM EDT | Flash Flood Warning | CTP | Northumberland | 3 hr |
| Sep 7, 2:25 AM EDT | Flash Flood Warning | CTP | Perry, Snyder, Union | 4 hr |
| Sep 7, 2:25 AM EDT | Flash Flood Warning | CTP | Dauphin, York | 4 hr |
| Sep 7, 2:25 AM EDT | Flash Flood Warning | CTP | Lycoming | 4 hr |
| Sep 7, 3:45 AM EDT | Flash Flood Warning | CTP | Tioga | 2 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.