139
ACUS01 KWNS 191632
SWODY1
SPC AC 191630

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Wed Jun 19 2024

Valid 191630Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LOWER AND MIDDLE
COASTS OF TEXAS...NORTHERN OHIO AND SOUTHEAST LOWER MICHIGAN...

...SUMMARY...
A few tornadoes are possible across south and southeast Texas later
this afternoon into tonight.  Scattered strong to locally
severe/damaging gusts are possible over portions of the southern
Great Lakes this afternoon into the early evening.

...Synopsis...
Water-vapor imagery late this morning shows an East Coast upper
ridge while a broad mid-level trough resides over the West.  The
upper ridge will build westward into the mid MS Valley as the
primary belt of westerlies retreats north of the international
border.  This westward expansion will encourage the tropical system
over the western Gulf basin to move into northeast Mexico,
considerably south of the Rio Grande Valley.

...Lower Great Lakes to northern New England...
While upper ridging will dominate this region, scattered convection
will once again develop from portions of the Ohio Valley
northeastward into New England, as surface temperatures warm through
the upper 80s the lower 90s F.  Area 88D VADs show a slightly
stronger belt of mid-level southwesterly flow over the southern
Great Lakes, which may act to influence storm organization and
potential storm intensity/severe risk later this afternoon.  Model
forecast soundings show a seasonably moist/unstable airmass
(2000-3000 J/kg MLCAPE) across much of this region.  Strong to
severe gusts (50-65 mph) capable of wind damage will be the primary
hazard with the stronger storms, especially if small clustering of
storms can occur. Based on the latest model guidance and visible
satellite observations, this appears most likely across parts of
northern OH into perhaps southeast Lower MI.

...South/southeast Texas...
Despite an initially poor lapse rate/weakly unstable environment
sampled with the 12 UTC Corpus Christi and Brownsville raobs, a
moist-tropical airmass will continue to advect into the region on
the northern periphery of Alberto, with MLCAPE likely rising into
the 500-1500 J/kg range near the Lower and Middle Coasts of TX by
later this afternoon.  Model guidance continues to indicate
low-level shear to increase, which will result in hodographs
enlarging by mid-late afternoon into tonight across the coastal
plain of TX (0-1 km SRH (100-200 m2/s2 0-1 km SRH).  The likely
cellular storm mode will also potentially be slightly more favorable
for a tornado risk, considering the environment scenario described
above.  As such, have increased tornado probabilities to 5 percent
(Slight Risk) near the Lower and Middle Coasts of TX.  Reference the
National Hurricane Center for the latest details on Tropical Storm
Alberto.

...Southern High Plains...
Radar/surface composite analysis late this morning shows a
persistent area of weak convection north of a south-southwest moving
outflow boundary from the TX Panhandle into northeast NM.
Considerable lingering clouds and related convection will probably
limit instability from near the TX/NM border and areas east.
However, west of the outflow appreciable moisture and heating will
contribute to scattered thunderstorm development later this
afternoon/evening.  Isolated large hail/severe gusts will be
possible with the stronger storms before diminishing by mid evening.

...Northern Missouri/eastern Iowa to southern Wisconsin...
To the east-northeast of lingering early morning convection across
northeast Kansas/northwest Missouri, cloud cover should generally
diminish today near the outflow augmented
southwest/northeast-oriented synoptic front across the region.
Potentially aided by an MCV, thunderstorms should redevelop and
intensify this afternoon as the boundary layer destabilizes, with as
much as 30 kt of effective shear maximized immediately near the
synoptic front. Isolated instances of localized wind damage could
occur.

..Smith/Lyons.. 06/19/2024

$$