Alert archive / Pennsylvania / Flash Flood Warnings in 1999
Flash Flood Warning 47, NWS State College, PA
NWS State College, PA issued this flash flood warning at Sep 6, 1999, 4:17 PM EDT for Lancaster County, York County, 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, 4:17 PM EDT (20:17 UTC)
- Expired
- Sep 6, 1999, 7:15 PM EDT
- In force
- 3 hr
- Issued by
- NWS State College, PA
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
Counties Lancaster County, PA, York County, PA
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 8.3 hours before the alert went out and 134 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
- 401 J/kg
- Mixed-layer CIN
- -45 J/kg
- Mixed-layer LCL
- 781 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 98 m²/s²
- 0-3 km storm-relative helicity
- 126 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KCTP 062022 FFWCTP PAC071-133-062315- BULLETIN - EAS ACTIVATION REQUESTED FLASH FLOOD WARNING NATIONAL WEATHER SERVICE STATE COLLEGE PA 417 PM EDT MON SEP 6 1999 THE NATIONAL WEATHER SERVICE IN STATE COLLEGE PA HAS ISSUED A * FLASH FLOOD WARNING FOR... EASTERN YORK COUNTY. WESTERN LANCASTER COUNTY. * UNTIL 715 PM EDT. * AT 413 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF THUNDERSTORMS WITH VERY HEAVY RAINFALL FROM ABOUT COLUMBIA TO SUNNYBURN. THE STORMS ARE MOVING NORTH AT 15 MPH. * THUNDERSTORMS ARE EXPECTED TO CONTINUE MOVING VERY SLOWLY OVER THE REGION THROUGH 5 PM...CAUSING LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE ROADWAY. VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED. MOVE TO HIGHER GROUND. .END/ LA CORTE LAT...LON 3974 7657 3972 7621 4027 7618 4010 7675
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, 2:50 PM EDT, 1 hour 27 minutes earlier.
Area forecast discussion, Sep 6, 2:50 PM EDT, 1 hour 27 minutes before
CENTRAL PENNSYLVANIA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 250 PM EDT MON SEP 6 1999 A FEW THUNDERSTORMS BEGINNING TO SHOW ROTATION...SO MAY HAVE TO CUT THIS A LITTLE SHORT. NOT QUITE THE WASHOUT IT APPEARED IT WOULD BE TODAY...BUT RAIN IS DEFINITELY ON THE WAY. DRY SLOT HUNG TOUGH ACROSS THE NORTHERN HALF OF PA THIS AFTERNOON. BUT DENNIS REMNANTS TAPPING INTO A DEEP MOIST TONGUE EXTENDING FROM S PA TO THE CAROLINA COAST. THIS MOIST TONGUE WILL SPREAD OVER CENTRAL PA TONIGHT BRINGING CATEGORICAL POPS FOR MOST. WITH THE EFFICIENCY OF TROPICAL SYSTEMS FOR PRODUCING RAIN...ADDED TO UPSLOPE SOUTHEASTERLY FLOW...THE REGION COULD SEE RAINFALL TOTALS REACH FFG VALUES (2-4 IN 3 HOURS). WILL EXTEND FLASH FLOOD WATCH TO INCLUDE ALL OF CENTRAL PA THROUGH TUESDAY MORNING. FEEL THERE IS REASONABLE POTENTIAL FOR MOISTURE TO WRAP WESTWARD AROUND THE CENTER OF CIRCULATION (LIKE CURRENTLY IN THE SOUTHWEST) AS REMNANTS DRIFT NORTH-NORTHEAST...SO WILL INCLUDE ALL NORTHERN COUNTIES NOW AS WELL. SYSTEM MOVES INTO SOUTH CENTRAL NY STATE LATE TOMORROW MORNING... AIDED BY A PUSH FROM A TROUGH MOVING ACROSS THE MIDWEST. CATEGORICAL RAIN FOR NORTHEASTERN PORTIONS WHILE TAPERING TO SHOWERS ELSEWHERE. OVERNIGHT SHIFT WILL HAVE TO ADDRESS WHETHER TO EXTEND THE FLASH FLOOD WATCH IN THE NE TOMORROW. TROUGH SLOWLY TRAVERSES PA TUE NIGHT INTO WED. MIGHT BE ABLE TO SCRAPE UP A 30 POP FOR THOSE PERIODS...BUT WILL LEAVE DRY FOR NOW. TEMPS ABOVE GUIDANCE TONIGHT AND TOMORROW NIGHT WITH DAYTIME HIGHS CLOSE TO FAN/FWC. .CTP...FLASH FLOOD WATCH FOR ALL OF CENTRAL PA THROUGH TUESDAY MORNING. RXR
The office that day
Everything else NWS State College, PA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 6, 2:37 PM EDT | Severe Thunderstorm Warning | CTP | Cambria | 53 min |
| Sep 6, 2:45 PM EDT | Severe Thunderstorm Warning | CTP | Bedford | 60 min |
| Sep 6, 3:01 PM EDT | Flash Flood Warning | CTP | Franklin, Fulton | 3 hr |
| Sep 6, 3:01 PM EDT | Flash Flood Warning | CTP | Bedford, Cambria, Somerset | 3 hr |
| Sep 6, 3:27 PM EDT | Severe Thunderstorm Warning | CTP | Cambria | 48 min |
| Sep 6, 3:56 PM EDT | Severe Thunderstorm Warning | CTP | Lancaster, York | 64 min |
| Sep 6, 4:32 PM EDT | Severe Thunderstorm Warning | CTP | Dauphin, Perry | 58 min |
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.