SPC AC 161628

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1128 AM CDT Mon May 16 2022

   Valid 161630Z - 171200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PARTS OF THE
   MID-ATLANTIC AND NORTHEAST...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EASTERN NM AND THE
   TX PANHANDLE...

   ...SUMMARY...
   Scattered damaging winds, isolated severe hail, and a couple brief
   tornadoes are likely into early evening across parts of the
   Mid-Atlantic and Northeast States. Scattered severe wind gusts and
   isolated large hail are also possible across a portion of the
   southern High Plains during the late afternoon and evening.

   ...Mid-Atlantic and Northeast...
   A shortwave trough over the Upper OH Valley/Lower Great Lakes will
   progress east-northeast into New England by tonight, as an
   associated surface cyclone deepens across the Saint Lawrence Valley
   and a trailing cold front likewise moves east and offshore tonight. 
   Low to mid 60s boundary-layer dewpoints are common ahead of the
   front and moderate surface heating in cloud breaks will support a
   plume of 500-1500 J/kg MLCAPE. Deep-layer flow/vertical shear will
   increase with the approach of the midlevel trough from the west,
   contributing to an environment supportive of organized line segments
   and some supercell structures.

   Scattered thunderstorms are ongoing within the warm conveyor regime
   ahead of the cold front across central PA into western NY. This
   activity will likely be the primary focus for damaging wind
   potential as it likely intensifies east across PA/NJ/NY. Additional
   thunderstorms should develop farther south, perhaps in multiple
   waves, emanating first off the lee trough and later along the cold
   front. With greater deep-layer shear across the Lower Mid-Atlantic
   region and potentially somewhat higher buoyancy if cloud breaks can
   become more pronounced, a mix of both isolated large hail along with
   scattered damaging winds are expected.

   ...Southern High Plains...
   Low-level moisture has spread westward into central NM on
   post-frontal easterly flow. Despite low-amplitude mid-level ridging,
   weak lee cyclogenesis and heating/mixing within the initially moist
   air mass will reduce convective inhibition this afternoon and allow
   scattered high-based thunderstorm development across the eastern
   half of NM. Storms will gradually grow upscale and spread eastward
   on consolidating outflows. Inverted-V profiles with large DCAPE
   (near 1500 J/kg) will favor scattered severe outflow gusts, some of
   which may reach 70-80 mph prior to the convection slowly weakening
   after dusk in the Panhandles to northwest TX.

   ...Central to northern High Plains, northern Rockies, and eastern
   Great Basin...
   Subtle embedded speed maxima will continue to move from the northern
   Great Basin/Pacific Northwest to the northern Rockies/High Plains,
   atop a weak baroclinic zone from central ID to southern MT. A
   lingering low to mid-level moisture plume and surface heating in
   cloud breaks will support MLCAPE up to about 500 J/kg, within a
   corridor of effective bulk shear of 30-40 kt and largely straight
   hodographs. This environment will support isolated to scattered
   storms this afternoon/evening focused on southern MT and far
   northern WY, some of which could have low-end/splitting supercell
   characteristics with marginally severe hail and localized severe
   gusts.

   Farther south, a few high-based storms may form this afternoon
   across northern UT and the central High Plains area of eastern
   CO/WY. Inverted-V profiles will favor a microburst threat with any
   deep convection in this corridor during the late afternoon to early
   evening.

   ...Southern LA vicinity...
   A weak MCV drifting southeast from western LA may enhance sea-breeze
   thunderstorm development across southern LA this afternoon. With
   moderately large buoyancy and persistence of modest mid-level
   northerlies, a few storms in this region may produce isolated severe
   hail and damaging winds from wet microbursts. 

   ...Southeast FL...
   A low-amplitude upper trough extends from central FL into the
   eastern Gulf with a belt of stronger mid to upper-level
   south-southwesterlies across the southeast portion of the peninsula.
   A few strong storms are possible with marginally severe hail and
   localized damaging winds.

   ..Grams/Wendt.. 05/16/2022

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