228
ACUS01 KWNS 062002
SWODY1
SPC AC 062000

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Thu Jun 06 2024

Valid 062000Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
MID-ATLANTIC STATES...EASTERN HALF OF THE FLORIDA PENINSULA... AND
WESTERN OKLAHOMA AND THE TEXAS PANHANDLE......

...SUMMARY...
Scattered severe thunderstorms are possible this afternoon into the
early evening for parts of the Mid-Atlantic states due to 50-65 mph
damaging gusts.  Scattered severe thunderstorms are also possible
over the eastern half of the Florida Peninsula and parts of western
Oklahoma and the Texas Panhandle.  Large hail (1 to 1.75 inches in
diameter) and severe gusts (60-70 mph) will be the hazards with the
stronger thunderstorms.

...20z Update...

An update was made to expand the Slight Risk further southwest into
the Texas Panhandle. CAM signals are split on the evolution of
convection this afternoon, with a few solutions showing outflow
moving southward with additional thunderstorm development further
southwest and others indicating more limited coverage with southward
extent. Given deep layer flow will likely lead to storm motions
largely southeastward off of the boundary located across the
Oklahoma Panhandle, it is likely that a southward moving outflow
with additional storm development into the evening is a likely
outcome. Visible satellite shows cu development is ongoing northwest
of Amarillo as of 1950z.

Otherwise, only minor adjustments were made to the Marginal across
the Florida Peninsula to account for ongoing activity. The sea
breeze circulation can be observed moving inland, with cumulus
developing along this boundary. Additional thunderstorm development
is likely through the afternoon with risk of damaging wind and hail.

A Severe Thunderstorm Watch remains in effect across the eastern US
from southern PA southward to Virginia. Thunderstorm activity is
ongoing within this region along a cold front and surface trough.
Potential for damaging wind with thunderstorm activity will continue
in this region into the evening.

..Thornton/Goss.. 06/06/2024

.PREV DISCUSSION... /ISSUED 1127 AM CDT Thu Jun 06 2024/

...NY into the Carolinas this afternoon/evening...
Radar/satellite imagery late this morning shows a mid-level
vorticity maximum moving east along the NY/PA border ahead of a
mid-level trough over the Great Lakes.  The larger-scale trough will
move into NY/PA by this evening.  A surface cold front and
pre-frontal lee trough will push east during the day and into the
Mid-Atlantic states this afternoon/evening.  Visible-satellite
imagery shows considerable mid- to high-level cloud cover delaying
heating from northern VA into NY.  However, very moist low levels
(upper 60s to lower 70s surface dewpoints) and breaks in the cloud
cover will yield moderate buoyancy by early to mid afternoon.  Some
enhancement in 700-mb flow was noted on area WSR-88D VADs (more
recently at KLWX (Sterling, VA) where westerly flow has increased
from 35 to 45 kt in the 2-4 km layer.  Scattered thunderstorms will
preferentially develop on the aforementioned surface boundaries and
spread east into the destabilizing airmass.  Several bands of
multicells are forecast from NC into the Chesapeake/Delaware Bay
vicinity.  It is here where slightly greater coverage of 50-65 mph
gusts capable of wind damage are forecast.  Farther north, more
isolated strong to locally severe/damaging storms are expected over
NY where less instability is forecast.  Farther south, some modest
enhancement in 850-700 mb flow will overspread the Carolina Piedmont
into the coastal plain, but lower expected storm coverage and less
confidence in storm intensity precludes higher severe probabilities
at this time.

...Eastern half of the FL Peninsula this afternoon...
Water-vapor imagery shows an upper low centered near Daytona Beach
slowly migrating east into the adjacent Gulf Stream waters, as a
positively tilted mid-level trough extends from the central Gulf
Coast into the GA/SC vicinity.  Model guidance indicates the East
Coast sea breeze will preferentially focus thunderstorm development
this afternoon.  Strong heating underway over the interior part of
the Peninsula will result in very steep 0-3 km lapse rates (around 9
deg C/km).  Surface temperatures warming into the mid 90s away from
the coast and dewpoints in the lower 70s will contribute to 3000
J/kg MLCAPE.  Seasonally cool midlevel temperatures (-8 to -10 C at
500 mb) and the large buoyancy will support some threat for isolated
large hail (1-1.75 inch diameter) where vertical shear is slightly
enhanced by the sea breeze.  The large buoyancy will also result in
substantial water-loaded downdrafts with the potential for isolated
wind damage (55-65 mph gusts).

...TX Panhandle/western OK this afternoon/evening...
A weak surface cold front will drift southward from KS into northern
OK and the TX/OK Panhandles by later this afternoon/evening.  Weak
lee cyclogenesis across eastern NM will induce southerly low-level
flow and northward moisture advection across TX/OK to the south of
the front.  Strong surface heating and the increase in low-level
moisture will contribute to moderate buoyancy by mid-late afternoon
(MLCAPE >1500 J/kg), in an environment of steep low-level lapse
rates/deep mixing.  Low-level convergence/ascent along the front
should focus thunderstorm development by mid-late afternoon from
northwest OK into the TX Panhandle, and storms will subsequently
spread southward through the evening.  Moderate buoyancy, inverted-V
profiles and northwesterly effective bulk shear of 35-40 kt will
favor a mix of multicell clusters and high-based supercells capable
of producing severe outflow gusts (mainly 60-70 mph) and isolated
large hail (1-1.5 inch diameter).

$$