WeathermanLeprechaun
Member
Given we have several risks outlined, I'm surprised that nobody has caught on and made this threads but here we go.
For tomorrow:
Ohio Valley/Lower Great Lakes into the Mid-Atlantic/Northeast...
An active severe-weather day is expected Saturday from parts of the
Ohio Valley and Lower Great Lakes into the Mid-Atlantic, as
scattered to widespread storms move through an increasingly
favorable environment. A 45% wind area has been added, resulting in
a categorical upgrade to Level-3/Enhanced Risk. The Enhanced Risk
area is a combination of multiple regimes which may eventually
overlap, with some areas potentially seeing multiple rounds of
strong to severe storms.
A mid/upper-level shortwave trough is forecast to move across the
northern Great Lakes vicinity through the day, before approaching
New England by evening. In conjunction with this shortwave trough, a
deepening surface low is expected to move across southern Quebec
toward northern Maine, as a trailing cold front moves through the
Great Lakes and eventually parts of the Mid Atlantic and Northeast.
A remnant surface front initially draped from southern NJ into
western PA will lift northeastward as an effective warm front, in
advance of the surface low and cold front.
As strengthening deep-layer wind fields overspread increasingly rich
moisture, a broad region from the Ohio Valley and Lower Great Lakes
into the Mid-Atlantic and parts of the Northeast will become
supportive of organized convection and severe-thunderstorm
potential. HRRR-based forecasts suggest that smoke will become less
prominent from west to east by afternoon, which should allow for
relatively strong diurnal heating and moderate destabilization in
areas not affected by early-day convection. Effective shear of 35-45
kt will support organized clusters and possibly occasional
supercells from the Lower Great Lakes into the northern Mid-Atlantic
and Northeast, while strong heating and steep low-level lapse rates
will result in a favorable wind-damage environment within the
somewhat weaker flow regime across the southern Mid-Atlantic and
parts of the Carolinas.
Elevated convection may be ongoing or else develop during the
morning across parts of PA/NY, within a warm-advection regime
associated with the returning warm front. Depending on the timing of
this convection and downstream heating/destabilization, some
intensification of ongoing convection may occur by early afternoon.
Additional development may occur along the southwest flank of
early-day convection and related outflow, which may intensify and
move across the northern Mid-Atlantic during the afternoon. In
addition to a wind-damage threat, some hail and tornado potential
may also evolve with any supercell development, given the presence
of favorable effective SRH.
Farther north, a broken band of storms is expected to develop along
the cold front and move across the Lower Great Lakes region,
eventually reaching a larger part of OH/PA/NY by late afternoon or
early evening. Additional storms may develop ahead of the frontal
convection, depending on the extent of heating in the wake of
early-day storms. Multiple wind-damage swaths may accompany this
convection, along with some potential for isolated hail. Rich
moisture and some enhancement to low-level SRH may also support a
tornado threat with any discrete or embedded supercells, especially
near the effective warm frontal zone or any remnant outflow
boundaries from morning convection.
For D4-8 period: A shortwave upper trough initially over the Canadian Prairies and
northern Plains will develop east/southeast across the Upper
Midwest/Great Lakes on Monday, then the Ohio Valley and Mid-Atlantic
vicinity on Tuesday. Meanwhile, another upper shortwave trough will
develop across the Great Lakes to the Northeast/Mid-Atlantic on
Wednesday. These features will support enhancement of mid/upper
level flow as a surface low tracks across Ontario/Quebec and New
England during this time. A trailing cold front will likewise
progress east/southeast over this three day period, with a very
moist and unstable airmass present ahead of the front. This overall
pattern will likely bring multiple days of severe storm potential
from the Upper Midwest/Great Lakes to portions of the Ohio Valley,
Northeast and Mid-Atlantic vicinity Monday through Wednesday,
necessitating severe probabilities. While these areas may shift some
over the coming day as the timing of mesoscale features and
influence of prior days convection becomes more clear, these general
regions are most likely to see at least isolated to widely scattered
damaging wind potential as the upper trough and surface cold front
sweep across the area.
For tomorrow:
Ohio Valley/Lower Great Lakes into the Mid-Atlantic/Northeast...
An active severe-weather day is expected Saturday from parts of the
Ohio Valley and Lower Great Lakes into the Mid-Atlantic, as
scattered to widespread storms move through an increasingly
favorable environment. A 45% wind area has been added, resulting in
a categorical upgrade to Level-3/Enhanced Risk. The Enhanced Risk
area is a combination of multiple regimes which may eventually
overlap, with some areas potentially seeing multiple rounds of
strong to severe storms.
A mid/upper-level shortwave trough is forecast to move across the
northern Great Lakes vicinity through the day, before approaching
New England by evening. In conjunction with this shortwave trough, a
deepening surface low is expected to move across southern Quebec
toward northern Maine, as a trailing cold front moves through the
Great Lakes and eventually parts of the Mid Atlantic and Northeast.
A remnant surface front initially draped from southern NJ into
western PA will lift northeastward as an effective warm front, in
advance of the surface low and cold front.
As strengthening deep-layer wind fields overspread increasingly rich
moisture, a broad region from the Ohio Valley and Lower Great Lakes
into the Mid-Atlantic and parts of the Northeast will become
supportive of organized convection and severe-thunderstorm
potential. HRRR-based forecasts suggest that smoke will become less
prominent from west to east by afternoon, which should allow for
relatively strong diurnal heating and moderate destabilization in
areas not affected by early-day convection. Effective shear of 35-45
kt will support organized clusters and possibly occasional
supercells from the Lower Great Lakes into the northern Mid-Atlantic
and Northeast, while strong heating and steep low-level lapse rates
will result in a favorable wind-damage environment within the
somewhat weaker flow regime across the southern Mid-Atlantic and
parts of the Carolinas.
Elevated convection may be ongoing or else develop during the
morning across parts of PA/NY, within a warm-advection regime
associated with the returning warm front. Depending on the timing of
this convection and downstream heating/destabilization, some
intensification of ongoing convection may occur by early afternoon.
Additional development may occur along the southwest flank of
early-day convection and related outflow, which may intensify and
move across the northern Mid-Atlantic during the afternoon. In
addition to a wind-damage threat, some hail and tornado potential
may also evolve with any supercell development, given the presence
of favorable effective SRH.
Farther north, a broken band of storms is expected to develop along
the cold front and move across the Lower Great Lakes region,
eventually reaching a larger part of OH/PA/NY by late afternoon or
early evening. Additional storms may develop ahead of the frontal
convection, depending on the extent of heating in the wake of
early-day storms. Multiple wind-damage swaths may accompany this
convection, along with some potential for isolated hail. Rich
moisture and some enhancement to low-level SRH may also support a
tornado threat with any discrete or embedded supercells, especially
near the effective warm frontal zone or any remnant outflow
boundaries from morning convection.
For D4-8 period: A shortwave upper trough initially over the Canadian Prairies and
northern Plains will develop east/southeast across the Upper
Midwest/Great Lakes on Monday, then the Ohio Valley and Mid-Atlantic
vicinity on Tuesday. Meanwhile, another upper shortwave trough will
develop across the Great Lakes to the Northeast/Mid-Atlantic on
Wednesday. These features will support enhancement of mid/upper
level flow as a surface low tracks across Ontario/Quebec and New
England during this time. A trailing cold front will likewise
progress east/southeast over this three day period, with a very
moist and unstable airmass present ahead of the front. This overall
pattern will likely bring multiple days of severe storm potential
from the Upper Midwest/Great Lakes to portions of the Ohio Valley,
Northeast and Mid-Atlantic vicinity Monday through Wednesday,
necessitating severe probabilities. While these areas may shift some
over the coming day as the timing of mesoscale features and
influence of prior days convection becomes more clear, these general
regions are most likely to see at least isolated to widely scattered
damaging wind potential as the upper trough and surface cold front
sweep across the area.
