Alert archive / Pennsylvania / Mesoscale Discussions in 2004
Mesoscale Discussion 1313
The Storm Prediction Center issued this mesoscale discussion at Jun 17, 2004, 12:05 PM EDT for 39 counties in Pennsylvania. It was in force for 115 min.
The area
The outline as issued.
The facts
- Issued
- Jun 17, 2004, 12:05 PM EDT (16:05 UTC)
- Expired
- Jun 17, 2004, 2:00 PM EDT
- In force
- 115 min
- Issued by
- the Storm Prediction Center
All 39 counties
Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Blair County, PA, Bradford County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Crawford County, PA, Cumberland County, PA, Dauphin County, PA, Elk County, PA, Forest County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Lawrence County, PA, Lycoming County, PA, McKean County, PA, Mercer County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Snyder County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA
The radar
The State College radar (KCCX), 45 km from the middle of the area, began a volume at 16:06 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Pittsburgh, PA (KPIT), launched 12:00Z, 4.1 hours before the alert went out and 160 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.
- Mixed-layer CAPE
- 1052 J/kg
- Mixed-layer CIN
- -18 J/kg
- Mixed-layer LCL
- 745 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 151 m²/s²
- 0-3 km storm-relative helicity
- 136 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 3.6
The text
As transmitted, in the capitals the NWS used until 2016.
000 ACUS11 KWNS 171606 SWOMCD SPC MCD 171605 PAZ000-171800- MESOSCALE DISCUSSION 1313 NWS STORM PREDICTION CENTER NORMAN OK 1105 AM CDT THU JUN 17 2004 AREAS AFFECTED...NW AND CNTRL PA CONCERNING...SEVERE THUNDERSTORM POTENTIAL VALID 171605Z - 171800Z A THREAT FOR WIND DAMAGE WILL INCREASE OVER THE NEXT FEW HOURS AS CELLS DEVELOP AND MOVE EWD ACROSS NW AND CNTRL PA. A WW MAY BECOME NECESSARY BY EARLY AFTERNOON. SFC ANALYSIS CURRENTLY SHOWS A QUASI-STATIONARY FRONT ACROSS NEW YORK WITH A LOW NEAR LAKE ERIE. SOUTH OF THE BOUNDARY...SFC DEWPOINTS ARE IN THE LOWER TO MID 70S F WHERE MLCAPE IS INCREASING...CURRENTLY RANGING FROM 1000 TO 1500 J/KG. AN AXIS OF LOW-LEVEL CONVERGENCE IS LOCATED IN NRN OH EXTENDING ENEWD ACROSS LAKE ERIE AND LAKE ONTARIO WHERE SCATTERED THUNDERSTORMS HAVE DEVELOPED. STORM COVERAGE SHOULD GRADUALLY INCREASE AS A BAND OF PVA MOVES EWD ACROSS WRN PA EARLY THIS AFTERNOON. OBJECTIVE ANALYSIS SHOWS A LOW TO MID-LEVEL SPEED MAX LOCATED ACROSS OH AND NW PA AND THIS IS HELPING CREATE MODERATE DEEP LAYER SHEAR OF 30 TO 35 KT. AS THE INSTABILITY CONTINUES TO INCREASE THROUGH EARLY AFTERNOON...THE ENVIRONMENT WILL BECOME MORE FAVORABLE FOR MULTICELL SEVERE STORMS. STEEP LOW-LEVEL LAPSE RATES AND HIGH SFC MOISTURE CONTENT WILL FAVOR WIND DAMAGE AS THE PRIMARY THREAT. ..BROYLES.. 06/17/2004 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...BGM...CTP...PBZ...CLE... 41967860 41878039 40998050 40218046 40057828 40097651 41167636 41947643
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 17, 1:45 PM EDT | Severe Thunderstorm Watch | SPC | Allegheny, Armstrong, Beaver, Bedford, Blair, Bradford and 40 more | 6 hr |
| Jun 17, 2:35 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Berks, Bucks, Chester, Delaware, Lancaster and 7 more | 6 hr |
| Jun 17, 4:22 PM EDT | Mesoscale Discussion | SPC | Adams, Bedford, Berks, Blair, Bucks, Cambria and 37 more | 83 min |
| Jun 17, 7:37 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Chester, Delaware and 7 more | 53 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2004Every mesoscale discussion in 2004
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.