Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 5, NWS State College, PA

January 18, 1999Lancaster County, Pennsylvania

NWS State College, PA issued this flash flood warning at Jan 18, 1999, 4:05 PM EST for Lancaster 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 counties it named.

The facts

Issued
Jan 18, 1999, 4:05 PM EST (21:05 UTC)
Expired
Jan 18, 1999, 7:00 PM EST
In force
3 hr
Issued by
NWS State College, PA
Area
Whole counties

County Lancaster County, PA

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.1 hours before the alert went out and 157 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, Washington/Dulle, VA at 12:00Z on 1999-01-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 1999-01-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 601 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
408 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
601 m²/s²
0-3 km storm-relative helicity
602 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KCTP 182106
FFWCTP
PAC071-190005-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE STATE COLLEGE PA
405 PM EST MON JAN 18 1999

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE HAS CONTINUED THE

* FLASH FLOOD WARNING FOR...
  LANCASTER COUNTY IN SOUTHEASTERN PENNSYLVANIA.

* UNTIL 700 PM EST.

* AT 400 PM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THAT
  THE HEAVIEST RAINS WERE MOVING EAST OF LANCASTER COUNTY.
  HOWEVER...THE COMBINATION OF EARLIER RAINS AND SNOWMELT WILL KEEP
  THE THREAT OF FLOODING GOING INTO THIS EVENING.

* RECENT MELTING CONDITIONS COULD ALSO RESULT IN THE FORMATION OF
  ICE JAMS ALONG STREAMS AND CREEKS THIS EVENING. WATER COULD BACK
  UP BEHIND THE JAMS...CAUSING FLOODING.

DON'T DRIVE INTO AREAS WHERE WATER COVERS THE ROAD!

.END/MSE


&

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 Jan 18, 3:30 PM EST, 35 minutes earlier.

Area forecast discussion, Jan 18, 3:30 PM EST, 35 minutes before
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
330 PM EST MON JAN 18 1999

...WORK ZONES OUT AT 245 AS PHLADMCTP...
...ZONES OUT BY 4 PM AS PHLZFPCTP...

CDFRNT WILL MOVE EAST OF THE AREA BY THIS EVENING TAKING THE HEAVY
RAIN WITH IT. HOWEVER...WILL KEEP THE FLASH FLOOD WATCH GOING
THROUGH THE EVENING IN LOWER SUSQ VALL...WHERE FLOODING IS PRESENTLY
OCCURRING.

TONIGHT...AS UPPER LOW PASSES TO OUR NORTH...WRAP AROUND MOISTURE
WILL ASCEND THE APPALACHIANS RESULTING IN SNOW SHOWERS FROM THE NW
MTNS SOUTHWARD THRU THE LAURELS. LATEST RUC SUGGESTS POSSIBLE
ADDITIONAL ACCUMS AROUND 1 INCH. TO THE EAST...DRY SLOT CURRENTLY
ENTERING W PA...WILL CLEAR THINGS OUT RAPIDLY IN THE SUSQ VALL THIS
EVENING. FOR THE RIDGE/VALLEY REGION...WILL USE VARIABLY CLDY
OVERNIGHT WITH SCT FLURRIES.

TUESDAY...SOUNDINGS SHOW INVERSIONS LOWERING AS COLD POOL LIFTS OUT
OF THE AREA. UPSLOPE CLOUDINESS AND FLURRIES OVER THE N AND W MTNS
WILL ERODE TO MSUNNY SKIES BY AFTN. ELSEWHERE...SOUNDINGS SUPPORT
MSUNNY FOR THE BALANCE OF THE DAY.  HOURLY ETA 2-METER TEMPS FRM PSU
SUGGEST AFTN HIGHS FM THE M 30S NW MTNS TO THE M 40S LOWER SUSQ.

WK DISTURBANCES IN ZONAL FLOW THEN PROGGED TO AFFECT THE AREA LATE
TUES NITE AND WEDNESDAY. MODEL CONSENSUS WUD PLACE S PA IN LINE FOR
THE CHANCE OF SOME LIGHT SNOW OR RAIN TUES NITE AND WED.

.CTP...FLASH FLOOD WATCH THROUGH MIDNIGHT FOR THE SUSQ VALLEY.

FITZGERALD

In the hours before

Special weather statement, Jan 18, 11:06 AM EST, 4 hours 59 minutes before
PAZ036-056-057-059-063>066-182115-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1106 AM EST MON JAN 18 1999

...SLIGHT RISK OF DAMAGING THUNDERSTORM WINDS THIS AFTERNOON...

A COLD FRONT WILL SWEEP EAST ACROSS PENNSYLVANIA THIS AFTERNOON. AS
THE FRONT MOVES THROUGH...IT WILL BRING A PERIOD OF RAIN...ALONG WITH
WIDELY SCATTERED THUNDERSTORMS. WINDS JUST ABOVE THE SURFACE ARE VERY
STRONG FROM THE SOUTHWEST. THEREFORE...ANY THUNDERSTORMS THAT FORM
WILL BRIEFLY BE CAPABLE OF CAUSING THESE STRONG WINDS TO DECEND TO
THE GROUND. SOME GUSTS WILL LIKELY EXCEED 40 MPH AND COULD BE
POTENTIALLY DAMAGING. ANYONE WITH PROPERTY CONCERNS THAT ARE
VULNERABLE TO HIGH WINDS SHOULD MONITOR THIS SITUATION CLOSELY.

.END/

YOU CAN FIND INFORMATION ON THE FLOOD POTENTIAL WITH THIS SYSTEM
IN THE FLASH FLOOD WATCH (PHLFFACTP) ISSUED THIS MORNING.
ADDITIONAL WEATHER INFORMATION FOR CENTRAL PENNSYLVANIA CAN BE FOUND
AT THE STATE COLLEGE NATIONAL WEATHER SERVICE WORLD WIDE WEB SITE.
THE ADDRESS IS:

HTTP://BOOKEND.MET.PSU.EDU    (ALL LOWER CASE)

FITZGERALD

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 18, 10:33 AM ESTFlash Flood WarningCTPLancaster3 hr
Jan 18, 1:25 PM ESTFlash Flood WarningCTPLancaster4 hr
Jan 18, 1:33 PM ESTSevere Thunderstorm WarningCTPCentre, Huntingdon, Mifflin77 min
Jan 18, 1:33 PM ESTSevere Thunderstorm WarningCTPBedford, Franklin, Fulton77 min
Jan 18, 1:33 PM ESTSevere Thunderstorm WarningCTPBlair77 min
Jan 18, 2:19 PM ESTSevere Thunderstorm WarningCTPCumberland, Dauphin, Juniata, Northumberland, Perry, Snyder61 min
Jan 18, 2:19 PM ESTSevere Thunderstorm WarningCTPAdams, York61 min
Jan 18, 2:19 PM ESTSevere Thunderstorm WarningCTPUnion61 min
Jan 18, 2:28 PM ESTSevere Thunderstorm WarningCTPLycoming47 min
Jan 18, 3:03 PM ESTFlash Flood WarningCTPColumbia, Lycoming, Montour, Northumberland, Sullivan4 hr
Jan 18, 3:03 PM ESTFlash Flood WarningCTPLebanon, Schuylkill4 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.