Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 111, NWS State College, PA

June 19, 1998Somerset County, Pennsylvania

NWS State College, PA issued this severe thunderstorm warning at Jun 19, 1998, 2:47 AM EDT for Somerset County, Pennsylvania. It was in force for 48 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jun 19, 1998, 2:47 AM EDT (06:47 UTC)
Expired
Jun 19, 1998, 3:35 AM EDT
In force
48 min
Issued by
NWS State College, PA
Area
Whole counties

County Somerset County, PA

The radar

The Pittsburgh radar (KPBZ), 119 km from the middle of the area, began a volume at 06:50 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.

What was reported inside it

TimeReportWhereRemark
Jun 19, 3:15 AM EDTHail 0.88Bakersville, PA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 00:00Z, 6.8 hours before the alert went out and 103 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, Pittsburgh, PA at 00:00Z on 1998-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 261 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, Pittsburgh, PA at 00:00Z on 1998-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 57 square meters per square second.19395878Sfc1 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
261 J/kg
Mixed-layer CIN
-158 J/kg
Mixed-layer LCL
1510 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
57 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

The text

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

799 
WUUS01 KCTP 190648 RRA
SVRCTP
PAC111-190735-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE STATE COLLEGE PA
247 AM EDT FRI JUN 19 1998

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOMERSET COUNTY IN SOUTHWESTERN PENNSYLVANIA

* UNTIL 335 AM EDT

* AT 245 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER CONFLUENCE...MOVING SOUTHEAST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ADDISON SPRINGS  300 AM EDT
  MOUNT DAVIS      310 AM EDT

DAMAGING WINDS AND LARGE HAIL ARE LIKELY. GO INSIDE A STURDY
BUILDING AND STAY AWAY FROM WINDOWS

HEAD

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jun 19, 2:30 AM EDT, 17 minutes earlier.

Area forecast discussion, Jun 19, 2:30 AM EDT, 17 minutes before
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
230 AM EDT FRI JUN 19 1998

...WRKZONES WILL BE SENT TO PHL AND PIT VIA ADMCTP...HOPEFULLY
BEFORE 3 AM...

...DISCUSSION...

TOUGH TO WORD FORECAST TODAY AS TIMING AND PLACEMENT OF CONVECTION
WILL BE PROBLEM. ALREADY SOME ACTIVITY FIRING ALONG LEADING EDGE OF
BAROCLINIC ZONE WHERE STABILITY IS SLOWLY ERODING. MESO DATA
INDICATES STRONG LI GRADIENT SET UP OVER SW PA WITH -2 TO -5 FROM
LAURELS TO OHIO BORDER. LAPS AND PSU MESO ANALS SHOW VIRTUALLY NO
THETA-E ADVECTION ONE WAY OR ANOTHER WITH LITTLE OR NO CAPE/LI
CHANGE IN TIME. THERE IS SOME INDICATION OF WEAK MOISTURE
CONVERGENCE STRETCHING FROM SE TO NW ACROSS WRN PA WHICH HELPS
EXPLAIN DEVELOPING CONVECTION.

ETA SHOWS NW FLOW BREAKING DOWN THRU THE MORNING HOURS AS UPPER
RIDGE FLATTENS AND MOVES EAST. THE ASSOC BAROCLINIC ZONE WEAKENS AS
WELL WHICH WILL ONLY MAKE TIMING AND PLACEMENT OF DEVELOPING
CONVECTION MORE DIFFICULT. FIRST IMPRESSION IS TO BE A TAD MORE
PESSIMISTIC MOST OF MY CWA TODAY. FIRST BATCHES OF RW/TRW SHOULD
PROBABLY FIZZLE AS LI GRAD WEAKENS IN TIME AND LOW LEVEL FLOW
BECOMES MORE WESTERLY. THEN PM HOURS PROB SEE MORE DIURNALLY DRIVEN
PRECIP DEVELOP AS HUMID AIR MAKES RETURN OVER MOST OF REGION.
ORIENTATION OF RH FIELDS AND UPPER FLOW SUGGEST WORST WX OVER SW PA
TAPERING TO BEST WX OVER NE PA.

TONIGHT LOOKS MORE INTERESTING THAN MODEL OUTPUT SEEMS TO SUGGEST.
FLOW ALOFT GOES WESTERLY WITH ETA PAINTING A COUPLED UPPER JET SETUP
SLIDING ACROSS. MODELS STILL SHOW FAIRLY UNSTABLE AIR THRU 06Z WITH
NICE LOW LEVEL THETA-E RIDGE POKING NORTHWARD INTO REGION. WHILE
VORTICITY ADVECTIONS LOOK WEAK...DECENT LOBE OF HIGH PV AIR IS MADE
TO OOZE ACROSS DURING THE OVERNIGHT. BIGGEST FEATURE PROBABLY
DRIVING MODEL TENDENCIES TO DRY THINGS OUT IS SHOT OF LOW LEVEL COOL
THETA-E ADVECTION. CURRENT WORDING PAINTBRUSHES POPS OVERNIGHT. WILL
PROB TRY AND FINE TUNE A BIT TO EMPHASIZE LATTER HALF OF OVERNIGHT
BEING WORSE THAN FIRST HALF.

LA CORTE

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 6:32 AM EDTFlash Flood WarningCTPSomerset5 hr
Jun 19, 6:41 AM EDTFlash Flood WarningCTPBedford5 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1998Every severe thunderstorm warning in 1998

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.