Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 59, NWS State College, PA

September 9, 1999Lancaster County, York County, Pennsylvania

NWS State College, PA issued this flash flood warning at Sep 9, 1999, 8:58 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 9, 1999, 8:58 PM EDT (00:58 UTC)
Expired
Sep 10, 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 Lancaster County, PA, York County, PA

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 1.0 hours before the alert went out and 245 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, Wallops Is Stn, VA at 00:00Z on 1999-09-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 534 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 00:00Z on 1999-09-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 square meters per square second.193958Sfc1 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
534 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
790 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCTP 100101
FFWCTP
PAC071-133-100400-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE STATE COLLEGE PA
858 PM EDT THU SEP 9 1999

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE PA HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  YORK COUNTY.
  LANCASTER COUNTY.

* UNTIL MIDNIGHT.

* AT 855 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  AN AREA OF SHOWERS AND THUNDERSTORM WITH VERY HEAVY RAINFALL OVER  
  YORK AND LANCASTER COUNTIES.

SLOW MOVING THUNDERSTORMS ARE PRODUCING TORRENTIAL RAINFALL IN THE
WARNED AREA. RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH 
FLOODING ALONG SMALLER STREAMS AND CREEKS AS WELL AS LOW LYING AREAS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS.

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/ ONDREJIK

LAT...LON 3997 7680 3977 7674 3976 7611 4015 7596
          4029 7616

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 9, 8:56 PM EDT, 2 minutes earlier.

Area forecast discussion, Sep 9, 8:56 PM EDT, 2 minutes before
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
856 PM EDT THU SEP 9 1999

I HAVE DECIDED...AT THE LAST MINUTE...TO UP POPS IN THE MID-UPR
SUSQ...WHICH MESHES WITH BGM THINKING FROM THEIR ADM.

BUSY EVENING IN CENTRAL PA. MINISUPERCELL MOVED THRU NW PA ERLIER
WHILE HVY RAINS FIRED UP IN THE LOER SUSQ. MEDIA REPORTS OF 2 INCHES
IN 20 MINUTES IN WESTERN LANCASTER COUNTY A COUPLE HOURS AGO. RADAR
LOOP SHOWING THUNDER HAS DIMINISHED WITH STEADY...BUT LESS
HEAVY...STRATIFORM RAIN CONTINUING.

WEST ZONES WILL DRY AND CLEAR OUT OVERNIGHT WITH MAIN CONCERN BEING
FAR EASTERN ZONES. MODEL SOUNDINGS INDICATE DEEP MOIST ATM IN SE PA
OVERNIGHT. THIS...COMBINED WITH LIFT PROVIDED BY UPR LVL JET MAX
SWINGING THRU...SHUD KEEP THE WET MACHINE GOING INTO 12Z FRI FOR MY
SE ZONES. QUESTION IS HOW FAR NORTH THE STEADY RAIN MAKES IT. LATEST
REGIONAL RADAR LOOP SHOWING A GOOD BATCH OF RAIN CROSSING MD-PA LINE
INTO SOUTH CENTRAL PA...WITH SHOWERS FILLING IN ON AN AXIS
STRETCHING UP TO UNV. THIS AREA WILL MOVE EAST INTO MID/UPR SUSQ IN
THE NEXT COUPLE HOURS...THEREFORE THE CHANGE NOTED ABOVE.

EAST ZONES DRY OUT BY NOON FRI. COOLER MORE TRANQUIL WEATHER OVER THE
WEEKEND. THE FLOYD FLOOD NEXT WEEK?? THIS IS TURNING IN TO ONE OF
THE WETTER DROUGHTS WEVE HAD IN A WHILE.

.CTP...NONE.

OSTUNO

In the hours before

Special weather statement, Sep 9, 3:55 PM EDT, 5 hours 3 minutes before
PAZ028-036-049>053-056>059-063>066-100157-

SEVERE WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE STATE COLLEGE PA
355 PM EDT THU SEP 9 1999

...ISOLATED SEVERE THUNDERSTORMS WITH VERY HEAVY DOWNPOURS ARE
POSSIBLE ACROSS THE LOWER AND MID-SUSQUEHANNA VALLEY TONIGHT...

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF
A COLD FRONT MOVING SLOWLY EAST ACROSS CENTRAL PENNSYLVANIA THIS
TONIGHT. A FEW THUNDERSTORMS COULD CONTAIN STRONG GUSTY WINDS OR
HAIL. THESE THUNDERSTORMS COULD ALSO CONTAIN VERY HEAVY
RAIN. HEAVY DOWNPOURS COULD CAUSE LOCALIZED FLOODING IN URBANIZED
AREAS WHERE STORMS PERSIST FOR OVER AN HOUR. THE BEST CHANCE FOR ANY
SEVERE WEATHER WILL BE THIS EVENING...BUT THE CHANCE OF
THUNDERSTORMS WILL CONTINUE THROUGH THE NIGHT.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL SOURCE OF
WEATHER INFORMATION...FOR THE LATEST FORECASTS AND STATEMENTS
ON TONIGHTS THUNDERSTORMS.

.END/ MSE

ADDITIONAL WEATHER INFORMATION CAN BE FOUND ON THE STATE COLLEGE
NATIONAL WEATHER SERVICE WEB-SITE AT:  HTTP://BOOKEND.MET.PSU.EDU
(ALL LOWER CASE)
Special weather statement, Sep 9, 3:55 PM EDT, 5 hours 3 minutes before
PAZ028-036-049>053-056>059-063>066-100157-

SEVERE WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE STATE COLLEGE PA
355 PM EDT THU SEP 9 1999

...ISOLATED SEVERE THUNDERSTORMS WITH VERY HEAVY DOWNPOURS ARE
POSSIBLE ACROSS THE LOWER AND MID-SUSQUEHANNA VALLEY TONIGHT...

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF
A COLD FRONT MOVING SLOWLY EAST ACROSS CENTRAL PENNSYLVANIA THIS
TONIGHT. A FEW THUNDERSTORMS COULD CONTAIN STRONG GUSTY WINDS OR
HAIL. THESE THUNDERSTORMS COULD ALSO CONTAIN VERY HEAVY
RAIN. HEAVY DOWNPOURS COULD CAUSE LOCALIZED FLOODING IN URBANIZED
AREAS WHERE STORMS PERSIST FOR OVER AN HOUR. THE BEST CHANCE FOR ANY
SEVERE WEATHER WILL BE THIS EVENING...BUT THE CHANCE OF
THUNDERSTORMS WILL CONTINUE THROUGH THE NIGHT.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL SOURCE OF
WEATHER INFORMATION...FOR THE LATEST FORECASTS AND STATEMENTS
ON TONIGHTS THUNDERSTORMS.

.END/ MSE

ADDITIONAL WEATHER INFORMATION CAN BE FOUND ON THE STATE COLLEGE
NATIONAL WEATHER SERVICE WEB-SITE AT:  HTTP://BOOKEND.MET.PSU.EDU
(ALL LOWER CASE)
Special weather statement, Sep 9, 3:57 PM EDT, 5 hours 1 minute before
PAZ028-036-049>053-056>059-063>066-100158-

SEVERE WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE STATE COLLEGE PA
357 PM EDT THU SEP 9 1999

...ISOLATED SEVERE THUNDERSTORMS WITH VERY HEAVY DOWNPOURS ARE
POSSIBLE ACROSS THE LOWER AND MID-SUSQUEHANNA VALLEY TONIGHT...

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF
A COLD FRONT MOVING SLOWLY EAST ACROSS CENTRAL PENNSYLVANIA TONIGHT.
A FEW THUNDERSTORMS COULD CONTAIN STRONG GUSTY WINDS OR HAIL. THESE
THUNDERSTORMS COULD ALSO CONTAIN VERY HEAVY RAIN. HEAVY DOWNPOURS
COULD CAUSE LOCALIZED FLOODING IN URBANIZED AREAS WHERE STORMS
PERSIST FOR OVER AN HOUR. THE BEST CHANCE FOR ANY SEVERE WEATHER WILL
BE THIS EVENING...BUT THE CHANCE OF THUNDERSTORMS WILL CONTINUE
THROUGH THE NIGHT.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL SOURCE OF
WEATHER INFORMATION...FOR THE LATEST FORECASTS AND STATEMENTS
ON TONIGHTS THUNDERSTORMS.

.END/ MSE

ADDITIONAL WEATHER INFORMATION CAN BE FOUND ON THE STATE COLLEGE
NATIONAL WEATHER SERVICE WEB-SITE AT:  HTTP://BOOKEND.MET.PSU.EDU
(ALL LOWER CASE)
Special weather statement, Sep 9, 3:57 PM EDT, 5 hours 1 minute before
PAZ028-036-049>053-056>059-063>066-100158-

SEVERE WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE STATE COLLEGE PA
357 PM EDT THU SEP 9 1999

...ISOLATED SEVERE THUNDERSTORMS WITH VERY HEAVY DOWNPOURS ARE
POSSIBLE ACROSS THE LOWER AND MID-SUSQUEHANNA VALLEY TONIGHT...

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF
A COLD FRONT MOVING SLOWLY EAST ACROSS CENTRAL PENNSYLVANIA TONIGHT.
A FEW THUNDERSTORMS COULD CONTAIN STRONG GUSTY WINDS OR HAIL. THESE
THUNDERSTORMS COULD ALSO CONTAIN VERY HEAVY RAIN. HEAVY DOWNPOURS
COULD CAUSE LOCALIZED FLOODING IN URBANIZED AREAS WHERE STORMS
PERSIST FOR OVER AN HOUR. THE BEST CHANCE FOR ANY SEVERE WEATHER WILL
BE THIS EVENING...BUT THE CHANCE OF THUNDERSTORMS WILL CONTINUE
THROUGH THE NIGHT.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL SOURCE OF
WEATHER INFORMATION...FOR THE LATEST FORECASTS AND STATEMENTS
ON TONIGHTS THUNDERSTORMS.

.END/ MSE

ADDITIONAL WEATHER INFORMATION CAN BE FOUND ON THE STATE COLLEGE
NATIONAL WEATHER SERVICE WEB-SITE AT:  HTTP://BOOKEND.MET.PSU.EDU
(ALL LOWER CASE)
Special weather statement, Sep 9, 4:10 PM EDT, 4 hours 48 minutes before
PAZ004>006-010-011-017-100210-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
410 PM EDT THU SEP 9 1999

...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS EVENING ACROSS
PORTIONS OF NORTH CENTRAL PENNSYLVNAIA...

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF
A COLD FRONT MOVING SLOWLY EAST ACROSS WESTERN AND CENTRAL
PENNSYLVANIA THIS EVENING. A FEW ISOLATED THUNDERSTORMS COULD CONTAIN
STRONG DAMAGING WINDS OR LARGE HAIL. THE THUNDERSTORMS WILL BE EAST
OF THE AREA BY LATE THIS EVENING.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL SOURCE OF
WEATHER INFORMATION...FOR THE LATEST FORECASTS AND STATEMENTS
ON TONIGHTS THUNDERSTORMS.

.END/ MSE

ADDITIONAL WEATHER INFORMATION CAN BE FOUND ON THE STATE COLLEGE
NATIONAL WEATHER SERVICE WEB-SITE AT:  HTTP://BOOKEND.MET.PSU.EDU
(ALL LOWER CASE)
Special weather statement, Sep 9, 4:10 PM EDT, 4 hours 48 minutes before
PAZ004>006-010-011-017-100210-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
410 PM EDT THU SEP 9 1999

...ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE THIS EVENING ACROSS
PORTIONS OF NORTH CENTRAL PENNSYLVNAIA...

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF
A COLD FRONT MOVING SLOWLY EAST ACROSS WESTERN AND CENTRAL
PENNSYLVANIA THIS EVENING. A FEW ISOLATED THUNDERSTORMS COULD CONTAIN
STRONG DAMAGING WINDS OR LARGE HAIL. THE THUNDERSTORMS WILL BE EAST
OF THE AREA BY LATE THIS EVENING.

STAY TUNED TO NOAA WEATHER RADIO...OR YOUR FAVORITE LOCAL SOURCE OF
WEATHER INFORMATION...FOR THE LATEST FORECASTS AND STATEMENTS
ON TONIGHTS THUNDERSTORMS.

.END/ MSE

ADDITIONAL WEATHER INFORMATION CAN BE FOUND ON THE STATE COLLEGE
NATIONAL WEATHER SERVICE WEB-SITE AT:  HTTP://BOOKEND.MET.PSU.EDU
(ALL LOWER CASE)

The office that day

Everything else NWS State College, PA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 9, 10:45 PM EDTFlash Flood WarningCTPUnion3 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.