Alert archive / Pennsylvania / Mesoscale Discussions in 2015
Mesoscale Discussion 939
The Storm Prediction Center issued this mesoscale discussion at Jun 8, 2015, 1:31 PM EDT for Washington County, Maryland; 37 counties in Pennsylvania. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Jun 8, 2015, 1:31 PM EDT (17:31 UTC)
- Expired
- Jun 8, 2015, 3:30 PM EDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 80%
All 38 counties
Washington County, MD, Adams County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Cambria County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Fayette County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Indiana County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Lycoming County, PA, Mifflin County, PA, Monroe County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Union County, PA, Westmoreland County, PA, York County, PA
The radar
The State College radar (KCCX), 69 km from the middle of the area, began a volume at 17:31 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
Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 5.5 hours before the alert went out and 164 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1116 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 333 m²/s²
- 0-3 km storm-relative helicity
- 360 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
905
ACUS11 KWNS 081731
SWOMCD
SPC MCD 081731
PAZ000-MDZ000-WVZ000-081930-
MESOSCALE DISCUSSION 0939
NWS STORM PREDICTION CENTER NORMAN OK
1231 PM CDT MON JUN 08 2015
AREAS AFFECTED...MOST OF PA
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 081731Z - 081930Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...SCATTERED DISCRETE STORMS SHOULD POSE A RISK FOR A COUPLE
TORNADOES ALONG WITH ISOLATED DAMAGING WINDS AND MARGINAL HAIL.
CONVECTION MAY EVENTUALLY GROW UPSCALE TOWARDS EARLY EVENING WITH A
PREDOMINANT WIND RISK.
DISCUSSION...SEVERAL DISCRETE SHOWERS AND ISOLATED TSTMS HAVE
DEVELOPED ACROSS PARTS OF SWRN TO CNTRL PA. SURFACE WINDS ARE VEERED
W OF A TROUGH THAT EXTENDS ROUGHLY FROM TIOGA TO FULTON COUNTIES AS
OF 17Z. THIS TROUGH AND THE AREA JUST E OF IT SHOULD BE THE MAIN
CORRIDOR FOR A TORNADO RISK...ESPECIALLY WITH NRN EXTENT WHERE
LOW-LEVEL HODOGRAPHS ARE ENLARGED WITH AROUND 40-KT 0-1 KM SHEAR PER
BGM VWP DATA. WITH TIME...MORNING CAMS FAVOR CONSOLIDATION OF STORMS
BY LATE AFTERNOON. AMIDST STRONG 700-MB SWLYS...THE RISK FOR
DAMAGING WINDS MAY INCREASE TOWARDS ERN PA.
..GRAMS/HART.. 06/08/2015
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PHI...BGM...CTP...LWX...PBZ...
LAT...LON 41617726 41557678 41297534 40977519 40357544 39937582
39607639 39537759 39717968 39918006 40557960 41607829
41617726SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 8, 1:10 PM EDT | Mesoscale Discussion | SPC | Allegany, Garrett | 2 hr |
| Jun 8, 2:34 PM EDT | Tornado Watch | SPC | Allegany, Anne Arundel, Baltimore, Carroll, Charles, Frederick and 6 more | 5 hr |
| Jun 8, 2:40 PM EDT | Severe Thunderstorm Watch | SPC | Garrett | 6 hr |
| Jun 8, 4:46 PM EDT | Mesoscale Discussion | SPC | Baltimore, Carroll, Frederick, Harford, Howard, Montgomery and 3 more | 59 min |
| Jun 8, 7:07 PM EDT | Mesoscale Discussion | SPC | Anne Arundel, Baltimore, Carroll, Charles, Frederick, Harford and 4 more | 53 min |
| Jun 8, 7:24 PM EDT | Severe Thunderstorm Watch | SPC | Anne Arundel, Baltimore, Carroll, Charles, Harford, Howard and 3 more | 2 hr |
| Jun 8, 1:39 PM EDT | Tornado Watch | SPC | Bradford, Lackawanna, Luzerne, Pike, Susquehanna, Wayne and 1 more | 6 hr |
| Jun 8, 2:58 PM EDT | Mesoscale Discussion | SPC | Bradford, Columbia, Lackawanna, Luzerne, Lycoming, Monroe and 6 more | 92 min |
| Jun 8, 3:20 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Carbon, Centre, Chester and 25 more | 85 min |
| Jun 8, 4:13 PM EDT | Tornado Watch | SPC | Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more | 4 hr |
| Jun 8, 7:12 PM EDT | Mesoscale Discussion | SPC | Lackawanna, Luzerne, Pike, Wayne | 93 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2015Mesoscale Discussions in Maryland, 2015Every mesoscale discussion in 2015
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.