Mesoscale Discussion 1213

Issued

Jul 1, 2017, 4:10 PM EDT (20:10 UTC)

Expired

Jul 1, 2017, 6:15 PM EDT

In force

2 hr

Issued by

the Storm Prediction Center

The Albany radar (KENX), 116 km from the middle of the area, began a volume at 20:12 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.

956 
ACUS11 KWNS 012011
SWOMCD
SPC MCD 012010 
MEZ000-NHZ000-MAZ000-VTZ000-CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-DCZ000-VAZ000-012215-

Mesoscale Discussion 1213
NWS Storm Prediction Center Norman OK
0310 PM CDT Sat Jul 01 2017

Areas affected...Portions of
VT...NH...NY...CT...MA...PA...NJ...MD...VA...DC

Concerning...Severe Thunderstorm Watch 388...389...

Valid 012010Z - 012215Z

The severe weather threat for Severe Thunderstorm Watch 388, 389
continues.

SUMMARY...The threat for severe weather continues across remaining
valid portions of Severe Thunderstorm Watch number 388 and 389.  A
local watch extension across a small portion of southwest Maine may
be needed in the near term.

DISCUSSION...Within Severe Thunderstorm Watch 388, severe
thunderstorms were in progress from the Mohawk Valley region of New
York east/northeast across central Vermont/New Hampshire as of
2000Z.  This area is located along a differential heating boundary
from earlier widespread rain and thunderstorms, and the
near-storm/downstream environment remains characterized by generally
weak surface-based buoyancy and 35-40 kts of deep-layer shear. 
Latest objective analysis and area VWP data also depict effective
SRH values at or above 200 m/s2 across northern portions of the
watch area.  This environment will continue to support a severe wind
risk, and the more discrete storms will be capable of low-level
rotation and some tornado potential.  Given latest radar trends, a
local watch extension may be needed into portions of the WFO GYX
County Warning Area over southwest Maine.

Within Severe Thunderstorm Watch 389, a mostly linear storm mode had
been noted, although a cluster of strong storms has recently
developed west of Allentown PA. Several reports of wind damage and
near severe gusts have been received within the watch area. With
moderate surface-based buoyancy and 35-40 kts of deep-layer shear, a
continued damaging wind threat will accompany the line of storms as
it moves into eastern portions of the watch area during the
remainder of this afternoon and into early evening.

..Bunting.. 07/01/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...AKQ...
CTP...LWX...

LAT...LON   39627572 39157543 38487651 38617771 39327750 40397705
            41327662 41657641 42487600 43087538 43577425 43907322
            44117224 44117120 44027065 43687078 42207178 41737280
            41137430 39627572

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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.