264
ACUS01 KWNS 051254
SWODY1
SPC AC 051252

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0752 AM CDT Fri Jul 05 2024

Valid 051300Z - 061200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE UPPER OHIO VALLEY INTO THE CENTRAL AND SOUTHERN APPALACHIANS...

...SUMMARY...
Scattered severe thunderstorms will be possible midday into the
afternoon across parts of the upper Ohio Valley into the central and
southern Appalachians.  Damaging gusts 50-65 mph will be the primary
severe hazard.

...Synopsis...
Water-vapor imagery this morning shows a mid-level shortwave trough
and associated low moving east across the mid to upper MS Valley and
into the western Great Lakes.  A belt of strong southwesterly 500-mb
flow (50-60 kt) will move through the base of the trough from the
lower MO Valley east-northeastward through IN/OH and into the Lower
Great Lakes through early evening.  Upstream of this disturbance, a
lower amplitude shortwave trough will move southeastward from AB
into MT during the day.

...Eastern Great Lakes/Ohio Valley/Southern and Central
Appalachians...
A convectively augmented lead disturbance over the lower OH Valley
will continue to progress eastward today ahead of a larger-scale
trough forecast to pivot east across the OH Valley.  An ongoing
squall line from southern IN to the AL/TN border, will move east
into a very moist and destabilizing airmass.  Surface analysis shows
a reservoir of lower to mid 70s deg F dewpoints from north-central
AL north-northeastward through the central Appalachians and OH River
vicinity.  A belt of stronger mid-level southwesterly flow will
likely remain north of the OH River, but some enhancement to 2-6 km
flow (reference Memphis, Paducah, Fort Campbell, and Evansville
WSR-88D VADs) will likely spread downstream across TN/KY and into
southern OH and WV.  Visible-satellite imagery denotes strong
heating will occur ahead of the MCS, thereby contributing to upwards
of 1500-3000 J/kg MLCAPE by early afternoon (2400 J/kg MLCAPE per
Nashville 12 UTC raob).  Organized multicells (via the MCS) will be
capable of scattered 50-65 mph gusts and wind damage.  Farther south
into the southern Appalachians and Carolinas/VA Piedmont, weaker
flow but very moist/unstable conditions later today will support
scattered thunderstorms and an isolated risk for damaging gusts with
the stronger wet microbursts.

Farther north, more uncertainty and potentially lower strong/severe
storm coverage will extend from Lower MI across the southern/Lower
Great Lakes into PA and west-central New York.  A hail threat
may also develop in parts of Lower Michigan, ahead of the
upper-level trough, where mid-level temperatures will be cooler
which will aid in steeper mid-level lapse rates.  Localized damaging
gusts will be the main severe risk.

...Eastern New Mexico...
Southwestern periphery of stronger mid-level northwesterly flow will
glance the southern High Plains in between a mid-level anticyclone
centered near the northern CA coast and the larger-scale trough over
the Midwest.  Strong heating and moist upslope flow (dewpoints near
60 F) will contribute to initially isolated storms preferentially
developing over the higher terrain by early to mid afternoon.  Model
guidance shows MLCAPE peaking in the 1500 to 2000 J/kg range, with
0-6 km shear around 30 kt.  Some organization of storms is possible,
mainly via multicells and perhaps transient supercell structures.
Isolated severe gusts/hail may accompany the stronger thunderstorms.

...MT...
Aforementioned mid-level impulse will move into central/eastern MT
this afternoon/evening.  Strong heating amidst 40s dewpoints will
yield weak buoyancy (500-1000 J/kg MLCAPE) but steep lapse rates.  A
few stronger storms may be capable of locally severe gusts for a few
hours late this afternoon before this activity subsides later this
evening.

..Smith/Bentley.. 07/05/2024

$$