Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 116, NWS State College, PA

July 17, 1999Potter County, Pennsylvania

NWS State College, PA issued this severe thunderstorm warning at Jul 17, 1999, 4:32 PM EDT for Potter County, Pennsylvania. It was in force for 58 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: Jul 17, 1999, 4:32 PM EDT (20:32 UTC)
Expired: Jul 17, 1999, 5:30 PM EDT
In force: 58 min
Issued by: NWS State College, PA
Area: Whole counties

County Potter County, PA

The radar

The State College radar (KCCX), 92 km from the middle of the area, began a volume at 20:32 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

Time	Report	Where	Remark
Jul 17, 5:15 PM EDT	Thunderstorm Wind	Austin, PA	A dozen trees were down in Homer township near Austin.

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

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 8.5 hours before the alert went out and 147 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: 99 J/kg
Mixed-layer CIN: -148 J/kg
Mixed-layer LCL: 1562 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: -3 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Jul 17, 2:30 AM EDT, 14 hours 2 minutes earlier.

Area forecast discussion, Jul 17, 2:30 AM EDT, 14 hours 2 minutes before

CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
230 AM EDT SAT JUL 17 1999

ANOTHER HOT DAY IN STORE FOR THE CTP-33.

UPPER LEVEL RIDGE WILL PROVIDE ANOTHER MOSTLY SUNNY DAY FOR MOST OF
THE AREA TODAY. UPPER LEVEL SHORTWAVE/PV LOBE WILL MOVE ACROSS THE
REGION THIS AFTERNOON/TONIGHT. THIS DOES LITTLE EXCEPT HELP TO ERODE THE
CAP OVER THE EXTREME WESTERN COUNTIES. WILL INTRODUCE THE RARELY
USED 20 POPS ONLY FOR THE LAUREL HIGHLANDS TODAY...ALTHOUGH ISOLATED
CONVECTION IS ALSO POSSIBLE ACROSS THE NORTHERN MTNS.

850 TEMPS A DEGREE OR TWO WARMER TODAY THAN FRIDAY...SO WILL BE
FORECASTING MAX TEMPS A LITTLE WARMER THAN YSTDY. THIS WOULD GIVE
MDT A RECORD...AND IPT CLOSE TO A RECORD. WILL HEADLINE ZONES
ACCORDINGLY. ALSO HAVE DECIDED TO HOIST A HEAT ADVISORY FOR THE
LOWER SUSQ VALLEY TODAY. WITH MAX TEMPS IN THE LOW 100S...HEAT
INDEXES WILL TOP OUT ABOVE 105 THIS AFTERNOON.

FRONT SAGS SOUTH TOMORROW. WITH LEE SIDE TROF DEVELOPING ACROSS THE
LOWER SUSQ VALLEY...SEE LITTLE SFC CONVERGENCE FOR THE FRONT TO WORK
WITH. STILL...LOWERING MID LEVEL TEMPS BY SEVERAL DEGREES WILL
LIKELY ERODE THE CAP...AND WE SHOULD SEE SCATTERED CONVECTION BREAK
OUT. ATTM...AM LEANING ON GOING SOMEWHAT ABOVE MOS ON POPS FOR
SUNDAY...BUT STILL REMAINING IN THE CHANCE CATEGORY. ALSO WILL
PROBABLY INTRODUCE LOW CHANCE POPS FOR THE NW AND LAURELS OVERNIGHT
TONIGHT...WITH THE FRONT SINKING SOUTH.

AS FOR THE EXTENDED...NEW AVN AND NOGAPS NOW SHOW A DRY MONDAY/TUESDAY
BEHIND THE FRONT WITH HIGH BUILDING IN. WILL DROP PCPN FROM MONDAY
IN ALL ZONES...AND JUST KEEP CHANCE SHOWERS/TSRA ACROSS SOUTHERN
ZONES SUNDAY NIGHT.

.CTP...HEAT ADVISORY...PAZ056-057-059-063>066.

JUNG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 3:47 PM EDT	Severe Thunderstorm Warning	CTP	Cambria, Somerset	43 min
Jul 17, 4:15 PM EDT	Severe Thunderstorm Warning	CTP	Huntingdon, Mifflin	45 min
Jul 17, 4:20 PM EDT	Flash Flood Warning	CTP	Somerset	3 hr
Jul 17, 5:15 PM EDT	Severe Thunderstorm Warning	CTP	Centre	60 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1999 Every severe thunderstorm 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.