Alert archive / Pennsylvania / Flash Flood Warnings in 1999

Flash Flood Warning 30, NWS State College, PA

July 17, 1999Somerset County, Pennsylvania

NWS State College, PA issued this flash flood warning at Jul 17, 1999, 4:20 PM EDT for Somerset 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: Jul 17, 1999, 4:20 PM EDT (20:20 UTC)
Expired: Jul 17, 1999, 7:15 PM EDT
In force: 3 hr
Issued by: NWS State College, PA
Area: Whole counties

County Somerset County, PA

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 8.3 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-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: 727 J/kg
Mixed-layer CIN: -84 J/kg
Mixed-layer LCL: 1569 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 15 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 172026 COR
FFWCTP
PAC111-172315-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING...CORRECTED MOVEMENT OF STORM
NATIONAL WEATHER SERVICE STATE COLLEGE PA
420 PM EDT SAT JUL 17 1999

THE NATIONAL WEATHER SERVICE IN STATE COLLEGE PA HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN SOMERSET COUNTY.

* UNTIL 715 PM EDT.

* AT 414 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  THUNDERSTORM WITH VERY HEAVY RAINFALL 8 MILES SOUTHWEST OF         
  BELMONT...OR ABOUT OVER JEROME...MOVING NORTHWEST AT LESS THAN 5   
  MPH.

* THUNDERSTORM WITH EXCESSIVE RAINFALL WAS IN THE VICINITY OF        
  BENSON...JEROME AND DAVIDSVILLE.

SLOW MOVING THUNDERSTORMS ARE PRODUCING TORRENTIAL RAINFALL IN THE
WARNED AREA. RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH 
FLOODING IN THE BOSWELL AND JEROME AREAS OF NORTHERN SOMERSET 
COUNTY. 

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED. MOVE TO
HIGHER GROUND.

.END/ NICOSIA

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 Jul 17, 2:30 AM EDT, 13 hours 50 minutes earlier.

Area forecast discussion, Jul 17, 2:30 AM EDT, 13 hours 50 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, 4:32 PM EDT	Severe Thunderstorm Warning	CTP	Potter	58 min
Jul 17, 5:15 PM EDT	Severe Thunderstorm Warning	CTP	Centre	60 min

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.