SPC AC 141937
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0137 PM CST Fri Feb 14 2025
Valid 142000Z - 151200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Widely scattered weak thunderstorm development is likely across
parts of the southern Great Basin into Four Corners vicinity, and
across parts of the lower Mississippi Valley, late this afternoon
into evening. More widespread weak thunderstorm development is
probable across Arkansas into the lower Ohio Valley late this
evening into early Saturday.
...20Z Outlook Update...
Above a residual cold/stable boundary-layer, a moistening southerly
return flow is in the process of developing off the western Gulf
Basin. Associated destabilization, rooted around the 850 mb level,
has supported the initiation of some thunderstorm activity within a
broader convective band across parts of southern Louisiana into
southeastern Texas, in the presence of forcing for ascent aided by
warm advection. However, warming farther aloft is ongoing, and
likely to increasingly suppress thunderstorm development near
northwestern Gulf coastal areas into this evening. To the
north-northeast of this regime, strengthening lower/mid-tropospheric
warm advection and destabilization are likely to support a more
concentrated area of thunderstorm development focused across the
Arkansas into lower Ohio Valley vicinity, downstream of the
significant short wave trough forecast to dig across the southern
Rockies and adjacent portions of the northern Mexican Plateau by 12Z
Saturday.
Beneath the mid-level cold core of this trough, ongoing insolation
is contributing to boundary-layer destabilization across the
southern Great Basin through Four Corners region. Forecast
soundings continue to suggest that thermodynamic profiles will
become supportive of widely scattered convection capable of
producing lightning, before this potential diminishes during the
evening with the onset of diurnal boundary-layer cooling.
..Kerr.. 02/14/2025
.PREV DISCUSSION... /ISSUED 1016 AM CST Fri Feb 14 2025/
...Synopsis...
Water-vapor imagery this morning shows a large-scale upper trough
over the West. This feature will amplify through late tonight as a
100-kt 500mb speed max moves through the base of the trough and into
northern Sonora and Chihuahua. A belt of strong southwesterly
mid-level flow will extend downstream of this upper trough into the
southern Great Plains northeastward through the OH Valley. The
gradual moistening of a low-level conveyor belt from the northwest
Gulf Coast into the lower OH Valley will facilitate
shower/thunderstorm development beginning late this evening but
mainly into the overnight.
Despite lee cyclone development initially over eastern CO today but
evolving into western OK tonight, a cool low-level airmass of
continental origin will only slowly modify across the Mid South. As
a result, the poleward transport of moisture atop a cool boundary
layer will promote elevated buoyancy ranging from around 1000 J/kg
MUCAPE over southeast OK to 250 J/kg in the lower OH Valley.
Relatively marginal mid-level lapse rates will probably limit
overall updraft vigor and thereby limit hail potential (perhaps
locally sub severe) with the strongest storms.
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