Alert archive / Pennsylvania / Mesoscale Discussions in 2016

Mesoscale Discussion 1317

July 18, 20168 states

The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2016, 11:40 AM EDT for 8 states. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Jul 18, 2016, 11:40 AM EDT (15:40 UTC)
Expired
Jul 18, 2016, 1:15 PM EDT
In force
95 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 79 counties

New Castle County, DE, Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Middlesex County, MA, Norfolk County, MA, Worcester County, MA, Baltimore County, MD, Carroll County, MD, Cecil County, MD, Harford County, MD, Bergen County, NJ, Essex County, NJ, Hudson County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Passaic County, NJ, Somerset County, NJ, Sussex County, NJ, Union County, NJ, Warren County, NJ, Albany County, NY, Bronx County, NY, Columbia County, NY, Delaware County, NY, Dutchess County, NY, Fulton County, NY, Greene County, NY, Herkimer County, NY, Kings County, NY, Montgomery County, NY, New York County, NY, Orange County, NY, Putnam County, NY, Queens County, NY, Rensselaer County, NY, Richmond County, NY, Rockland County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Ulster County, NY, Warren County, NY, Washington County, NY, Westchester County, NY, Adams County, PA, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Franklin County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Philadelphia County, PA, Pike County, PA, Schuylkill County, PA, Wayne County, PA, Wyoming County, PA, York County, PA, Bristol County, RI, Kent County, RI, Providence County, RI, Bennington County, VT

The radar

The Albany radar (KENX), 133 km from the middle of the area, began a volume at 15:42 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

Brookhaven, NY (KOKX), launched 12:00Z, 3.7 hours before the alert went out and 161 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-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2016-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2016-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 128 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1 J/kg
Mixed-layer CIN
-127 J/kg
Mixed-layer LCL
1554 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
128 m²/s²
0-3 km storm-relative helicity
123 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 18, 12:05 PM EDTSevere Thunderstorm WatchSPCGreater 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 more8 hr
Jul 18, 3:21 PM EDTMesoscale DiscussionSPC84 min
Jul 18, 6:49 PM EDTMesoscale DiscussionSPC86 min
Jul 18, 1:42 PM EDTSevere Thunderstorm WatchSPCKent, New Castle, Sussex6 hr
Jul 18, 3:09 PM EDTMesoscale DiscussionSPCKent, New Castle, Sussex66 min
Jul 18, 6:22 PM EDTMesoscale DiscussionSPCSussex113 min
Jul 18, 10:32 AM EDTMesoscale DiscussionSPCClinton, Essex, Franklin, Hamilton, Herkimer, Lewis and 3 more118 min
Jul 18, 11:12 AM EDTSevere Thunderstorm WatchSPCClinton, Essex, Franklin, Jefferson, Lewis, Oswego and 1 more9 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2016Mesoscale Discussions in New York, 2016Mesoscale Discussions in New Jersey, 2016Every mesoscale discussion in 2016

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.