Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 28, NWS State College, PA

March 21, 1999Lancaster County, York County, Pennsylvania

NWS State College, PA issued this flash flood warning at Mar 21, 1999, 8:47 PM EST for Lancaster County, York County, Pennsylvania. It was in force for 5 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, 8:47 PM EST (01:47 UTC)
Expired: Mar 22, 1999, 2:00 AM EST
In force: 5 hr
Issued by: NWS State College, PA
Area: Whole counties

Counties Lancaster County, PA, York County, PA

The radar

The Sterling radar (KLWX), 141 km from the middle of the area, began a volume at 01:48 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.8 hours before the alert went out and 139 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 499 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: -185 m²/s²
0-3 km storm-relative helicity: -252 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 220148
FFWCTP
PAC071-133-220700-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE STATE COLLEGE PA
847 PM EST SUN MAR 21 1999

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE HAS ISSUED A

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

* UNTIL 200 AM EST.

* AT 830 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  HEAVY RAIN...AND A FEW EMBEDDED THUNDERSTORMS OVER THE REGION.
  THE RAIN WAS MOVING TO THE NORTH AT 30 MPH.

* RAIN...HEAVY AT TIMES...WILL CONTINUE TO PUSH NORTH INTO THE
  REGION FROM MARYLAND. ADDITIONAL THUNDERSTORMS ARE ALSO POSSIBLE.
  THE HEAVY RAIN WILL CAUSE SMALL STREAMS AND CREEKS TO RISE
  RAPIDLY.

  THE HEAVY RAIN WILL END BEFORE MIDNIGHT...AND STREAMS AND CREEKS
  WILL SLOWLY SUBSIDE OVERNIGHT.

<<<CALL TO ACTION>>>BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS
HARDER TO RECOGNIZE THE DANGER OF FLOODING.

.END/JUNG

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 Mar 21, 2:18 PM EST, 6 hours 29 minutes earlier.

Area forecast discussion, Mar 21, 2:18 PM EST, 6 hours 29 minutes before

CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
218 PM EST SUN MAR 21 1999

...EXCELLENT COORD WITH SURROUNDING OFFICES AND HPC...

...WORK ZONES OUT AROUND 3 PM...
...ZONES OUT AROUND 330 PM...

PER COORD CALLS...WILL DROP WINTER STORM WATCH IN WEST ZONES. WILL
KEEP WARNING GOING FOR THREE NE ZONES AND DOWNGRADE TO ADVISORY FOR
OTHER THREE NORTHERN ZONES THAT WERE IN WARNING.

JUST WHEN I THOUGHT IT WAS SAFE TO DRASTICALLY CUT TOTALS...GOT A
CALL AROUND 130 PM FROM A SPOTTER IN NORTHERN LYCOMING COUNTY (NORTH
OF IPT). THEY HAD TWO INCHES OF NEW SNOW ON THE GROUND WITH MODERATE
SNOW OCURRING LOOKS LIKE MODELS ARE ALL A BIT TOO WARM AND EVAP
COOLING IS STILL OVERCOMING WAA AT THIS TIME. THE QUESTION IS
WHEN...AND MAYBE FOR SOME AREAS...IF PRECIP WILL GO TO RAIN THIS
AFT AND EVE. IN LIGHT OF THIS WILL KEEP SOME HIER TOTALS IN THE
WARNING AREA (4 TO 8) AND ADV AREA (3-5).

MODEL...AND FORECASTER...CONSENSUS IS THAT BEST CHANCE OF WARNING
CRITERIA SNOWS WILL EXTEND FROM ADIRONDACKS BACK TOWARDS NE AND N
CENTRAL PA. ANY SNOW ACROSS FAR NW ZONES WILL COME FROM WEAKENING N
STREAM SYS SO NOT EXPECTING MUCH FROM BFD AND POINTS WEST.

SOME UPSLOPE IN LAURELS WILL RESULT IN LIGHT ACCUMULATIONS THERE
MAINLY IN THE SECOND PERIOD.

LOOKED AT FFG FOR LOER SUSQ AND DISCUSSED HYDRO SITUATION THERE WITH
RFC. CURRENT THINKING IS THAT FFG VALUES WILL NOT BE MET FOR WIDESPREAD
AREAS DOWN THERE AND THE RIVERS COULD HANDLE EXPECTED QPF. SO WILL
NOT GO WITH ANY WATCHES...BUT NEXT SHIFT WILL WATCH THIS CLOSELY.

LOOKS LIKE INSTABILITY SNOW SHOWERS PERSIST FOR MUCH OF MONDAY
MORNING. NEAR OR BELOW NORMAL TEMPS THRU END OF WEEK. LONG RANGE
MODELS NOW HINTING AT ANOTHER RAIN AND SNOW EVENT TOWRDS END OF THE
WEEK.

SHALL WE PRONOUNCE SPRING 1999 DOA?

.CTP...WINTER STORM WARNING FOR TONIGHT FOR PAZ037-041-042

       WINTER WEATHER ADVISORY TONIGHT FOR PAZ06-012-018

OSTUNO

Nearby

Flash Flood Warnings in Pennsylvania, 1999 Every 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.