Alert archive / Pennsylvania / Mesoscale Discussions in 2017
Mesoscale Discussion 1306
The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2017, 4:43 PM EDT for 16 counties in New Jersey; 12 counties in New York; 17 counties in Pennsylvania. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- Jul 13, 2017, 4:43 PM EDT (20:43 UTC)
- Expired
- Jul 13, 2017, 5:45 PM EDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
All 45 counties
Bergen County, NJ, Burlington County, NJ, Camden County, NJ, Essex County, NJ, Gloucester County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Bronx County, NY, Dutchess County, NY, Kings County, NY, Nassau County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Queens County, NY, Richmond County, NY, Rockland County, NY, Suffolk County, NY, Westchester County, NY, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Perry County, PA, Philadelphia County, PA, Schuylkill County, PA, York County, PA
The radar
The Philadelphia radar (KDIX), 92 km from the middle of the area, began a volume at 20:43 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
Brookhaven, NY (KOKX), launched 12:00Z, 8.7 hours before the alert went out and 162 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
- 572 J/kg
- Mixed-layer CIN
- -82 J/kg
- Mixed-layer LCL
- 1449 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 103 m²/s²
- 0-3 km storm-relative helicity
- 140 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.3
The text
As transmitted.
244
ACUS11 KWNS 132044
SWOMCD
SPC MCD 132043
RIZ000-CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-132145-
Mesoscale Discussion 1306
NWS Storm Prediction Center Norman OK
0343 PM CDT Thu Jul 13 2017
Areas affected...Eastern Pennsylvania...much of New
Jersey...southern New York...and Connecticut
Concerning...Severe Thunderstorm Watch 412...413...
Valid 132043Z - 132145Z
The severe weather threat for Severe Thunderstorm Watch 412, 413
continues.
SUMMARY...The severe threat continues across portions of WWs 412 and
413.
DISCUSSION...Scattered storms have evolved into a couple of linear
segments over the past hour or so over northwestern portions of the
discussion area at this time, extending from far western Connecticut
(around 30 SW BDL southwestward to around 30 S POU) and in eastern
Pennsylvania (from around 15 NW ABE westward to around 25 N CXY).
More isolated convection has evolved out ahead of these linear
segments recently. A threat for damaging wind gusts/tree damage
remains possible with each of the individual storms and linear
segments - especially where a moderately unstable airmass exists
that has been undisturbed by previous convection.
Northwest of the linear segments, overturning and low-level
stabilization has led to a substantial decrease in the severe threat
for the remainder of the afternoon. Most recent status messages for
WWs 412 and 413 indicate areas where the threat has decreased
recently, and northwestern portions of these watches may be
cancelled early.
..Cook.. 07/13/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BOX...OKX...ALY...PHI...BGM...CTP...
LAT...LON 40667710 40887621 41237511 41687408 41947313 41957222
41747173 41247163 40867191 40487303 40087376 39747457
39707554 39837676 39907731 40047748 40357744 40667710SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 13, 11:09 AM EDT | Mesoscale Discussion | SPC | 2 hr | |
| Jul 13, 1:57 PM EDT | Severe Thunderstorm Watch | SPC | Greater Bridgeport Planning Region, Capitol Planning Region, Northwest Hills Planning Region, Lower Connecticut River Valley Planning Region, Naugatuck Valley Planning Region, Southeastern Connecticut Planning Region and 1 more | 5 hr |
| Jul 13, 2:33 PM EDT | Mesoscale Discussion | SPC | Burlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 3 more | 57 min |
| Jul 13, 2:57 PM EDT | Severe Thunderstorm Watch | SPC | Burlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 4 more | 6 hr |
| Jul 13, 6:23 PM EDT | Mesoscale Discussion | SPC | Burlington, Camden, Gloucester, Ocean | 97 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2017Mesoscale Discussions in New Jersey, 2017Mesoscale Discussions in New York, 2017Every mesoscale discussion in 2017
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.