Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 182, NWS State College, PA

August 18, 1998Adams County, Pennsylvania

NWS State College, PA issued this severe thunderstorm warning at Aug 18, 1998, 2:02 PM EDT for Adams County, Pennsylvania. It was in force for 33 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 18, 1998, 2:02 PM EDT (18:02 UTC)
Expired
Aug 18, 1998, 2:35 PM EDT
In force
33 min
Issued by
NWS State College, PA
Area
Whole counties

County Adams County, PA

The radar

The Sterling radar (KLWX), 102 km from the middle of the area, began a volume at 18:06 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 12:00Z, 6.0 hours before the alert went out and 104 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 1998-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 575 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, Washington/Dulle, VA at 12:00Z on 1998-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 square meters per square second.1939Sfc1 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
575 J/kg
Mixed-layer CIN
-54 J/kg
Mixed-layer LCL
1109 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
91 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 181801 RRA
SVRCTP
PAC001-181835-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE STATE COLLEGE PA
202 PM EDT TUE AUG 18 1998

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN ADAMS COUNTY IN SOUTH CENTRAL PENNSYLVANIA

* UNTIL 235 PM EDT

* AT 200 PM EDT...STATE COLLEGE DOPPLER RADAR INDICATED A SEVERE
  THUNDERSTORM WITH LARGE HAIL 7 MILES EAST OF GETTYSBURG OR 3
  MILES WEST OF MCSHERRYTOWN...MOVING EAST AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  MCSHERRYTOWN AT 205 PM EDT
  ABBOTTSTOWN AT 210 PM EDT

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

BOOKBINDER/LAMBERT/WINTHER

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 Aug 18, 10:05 AM EDT, 3 hours 57 minutes earlier.

Area forecast discussion, Aug 18, 10:05 AM EDT, 3 hours 57 minutes before
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1005 AM EDT TUE AUG 18 1998

...WRKZNS SENT TO PHL/PIT VIA ADMCTP WITH THE MAJOR CHANGES BEING
1)  INCREASED POPS ACROSS THE CENT AND NORTH...AND
2)  TIMING OF CLEARING AND MUCH LESS HUMID CONDITIONS ACROSS THE NW
    2/3S

...DISCUSSION...

UPPER VORT MAX CURRENTLY NEAR KBUF AS DEPICTED BY WTR VAPOR LOOP
APPEARS TO BE A FEW HRS AHEAD (EAST) OF MODEL POSITIONS AT 12Z...MVG
EAST AROUND 30 KTS.

SFC COLD FRONT ON A LINE FROM KBUF TO KERI AND KCLE AT 13Z WILL
PROGRESS STEADILY SE ACROSS WESTERN AND CENTRAL PA DURING THE EARLY
TO MID AFTERNOON REACHING THE LWR SUSQ VALLEY BETWEEN 21Z AND 23Z.

QPF NOT IMPRESSIVE AT ALL BEING GENERALLY .10 OR LESS ON ETA/NGM
WITH THE PRIMARY LARGE SCALE DYNAMIC LIFT SCOOTING OFF TO THE NORTH
ACROSS CENTRAL NEW YORK. SFC BASED CAPES AOA 1000 J/KG PROGGED BY
THE ETA CROSS THE CENT AND LWR SUSQ WILL ACT TO ENHANCE THE POTENCY
OF THE CONVECTION AS IT MOVES INTO THE CONVERGENCE ALONG THE LEE
TROUGH IN THAT AREAS. NOT OUT OF THE QUESTION TO SEE A BKN SQUALL
LINE WITH LOCAL .50 QPF ACROSS THE SE 1/3 OF THE STATE DURING THE
MID/LT AFTERNOON.  HOWEVER...LIMITED SUNSHINE/WEAK LLVL THETA-E
CONVERGENCE WILL BE AN INHIBITING FACTOR FOR SIGNIF RAIN.

SPRAWLING 1030 MB SFC SOUTHWEST OF JAMES BAY WILL MOVE ESE BRINGING
AN ALMOST FALL-LIKE AIRMASS INTO THE REGION FOR LATER TNGT THROUGH
THURS...WITH PLEASANT/LOW HUMIDITY.

NOTCHED UP TEMPS A FEW DEG ACROSS THE CENTRAL COUNTIES...OTHERWSIE
PREV FCST MAXS LOOK FINE.

WENT FOR CATEGORICAL (OCCASIONAL) SHRA/TSRA ACROSS THE NCENT/NE MTNS
THIS AFTERNOON...BUT TAPERED POPS TO ONLY 20 ACROSS THE NW MTNS IN
LINE WITH CFROPA TIMING. RAISED POPS A TAD (TO LIKELY) ACROSS THE
CENTRAL THIRD OF THE CWA AND KEPT WORDING AS SCATTERED ACROSS THE
SOUTH.

.CTP...NONE.

LAMBERT

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 1:03 PM EDTSevere Thunderstorm WarningCTPLebanon62 min
Aug 18, 2:23 PM EDTSevere Thunderstorm WarningCTPYork47 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.