000
ACUS02 KWNS 090600
SWODY2
SPC AC 090600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Sep 09 2016

Valid 101200Z - 111200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL KY
TO NORTHEAST OH, FAR NORTHWEST PA, AND FAR SOUTHWEST NY...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING
THE SLIGHT RISK FROM NORTHERN MIDDLE TN THROUGH THE UPPER OH
VALLEY TO NY...

...SUMMARY...
Strong to severe storms will be possible Saturday afternoon from
central KY through OH into northwest PA to far western NY, while a
marginal risk for a few strong to severe storms is forecast across
NY.  Damaging winds will be the primary threat.

...SYNOPSIS...
An amplified, progressive shortwave trough will move through the
Great Lakes and OH Valley region during the first half of
Saturday, and likely reach southern Quebec to NY/PA by 12z Sunday.
An attendant surface low will deepen this forecast period as it
tracks northeast from northern Lake Michigan and into Quebec to
the east of James Bay by the end of the forecast period.  A
trailing cold front should extend through the mid MS Valley and
Ozarks to north TX early Saturday morning, and advance quickly
eastward through the OH/TN Valleys and into the northeast states,
while the western extent moves southward approaching the northwest
Gulf Coast. In the northeast, a warm front will shift north from
PA/NJ through southern/central NY and southern New England through
Saturday afternoon.  Deep-layer wind fields will be strengthening
through the forecast period from west to east attendant to the
progressive midlevel trough

...OH/KY/NORTHWEST PA/WESTERN NY...
Southwesterly low-level flow developing across the OH Valley later
tonight will allow moisture return to be underway across the upper
OH Valley, with a narrow corridor of richer moisture expected in
the pre-frontal warm sector Saturday afternoon.  Although there
exists some potential for early day cloudiness, the degree of
moisture return and some surface heating should allow for MUCAPE
to be 1000 j/kg.  Greatest height falls (40-60-m per 12-hr at 500
mb) will be from KY through OH to northwest PA/western NY by peak
heating.  Storms are expected to develop Saturday afternoon as the
cold front moves through the slight risk area.  Effective bulk
shear of 30-35 kts should allow for organized storms with line
segments producing damaging winds as the primary severe threat.
However, a tornado threat will be possible into northeast OH to
far western NY where low-level hodographs should have the
greatest curvature.

...SOUTHERN AND CENTRAL NY...
The return of a very moist air mass is expected by Saturday
afternoon as the warm front moves north, and the warm sector
spreads into much of southern and central NY with surface dew
points in the upper 60s to around 70F.  Despite weak midlevel
lapse rates, surface heating of the rich moisture should result in
marginal to pockets of moderate instability.  Storm development
will be possible as the warm front advances northward, with
sufficient bulk shear for organized storms.  However, uncertainty
in destabilization suggests this region will remain a marginal
severe-weather threat.  Deep-layer winds will strengthen with the
approach of the Great Lakes/OH Valley trough Saturday night across
NY into western New England.  However, a stabilized boundary layer
should limit the potential for strong winds to reach the surface
with any storms along the cold front.

..Peters.. 09/09/2016

$$