SPC AC 021300
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0700 AM CST Wed Feb 02 2022
Valid 021300Z - 031200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected across the contiguous United
States today and tonight.
...Synopsis/Discussion...
The mid/upper-tropospheric pattern will be dominated this period by
progressive, positively tilted troughing from the Hudson Bay region
across the Rockies, to northwestern MX and the adjoining
subtropical/tropical eastern Pacific. This high-amplitude troughing
results from several fairly well-phased synoptic to subsynoptic
troughs, including a strong shortwave perturbation evident in
moisture-channel imagery over the Great Basin and western AZ. The
latter feature will strengthen and move southeastward to AZ and
northern Sonora by 00Z, spreading a strengthening plume of DCVA/
ascent aloft across parts of eastern AZ and central/southern NM,
west of the frontal zone described below. Isolated thunder may
occur in associated convection, with weak but sufficient
low/middle-level moisture. The mid/upper perturbation should pivot
eastward to southern CO and central/southern NM by 12Z tomorrow.
Farther east, a strong surface cold front was analyzed from southern
ON across central IN, to a weak low over northwestern AR, then
across extreme southeastern OK, north-central TX, the Edwards
Plateau, Davis Mountains area, and northwestward over central NM.
The front should move relatively slowly through 00Z, reaching
easternmost ON, southwestern OH, western portions of KY/TN, northern
MS, northern LA, south-central to far west TX, and central/north-
central NM. By 12Z, a weak frontal-wave low may develop along the
front over the Gulf and move inland over southwestern LA, in
response to the approaching trough. The front should extend from
there northeastward to WV and eastern NY, and southwestward across
the TX shelf waters to deep south TX.
Isolated to widely scattered thunderstorms are possible in two
initially separate plumes of lift that will offset in time:
1. A broad, somewhat triangular belt of low-level convergence today
into early evening, amidst weak CINH, extending from the central
Gulf north-northeastward across portions of MS/AL and southeastern
LA.
2. A swath of low-level warm advection and moisture transport from
the northwestern Gulf across south and east TX this evening,
shifting eastward/inland and extending over parts of LA, AR and MS
by 12Z. This area of ascent will be enhanced on its western rim by
frontal processes as the baroclinic zone moves into the outlook
area.
The air mass inland remains cool and stable. However, modifying
marine-layer air over the western Gulf (in the wake of the
convection and the mid/upper wave from 24-36 hours ago) will advect
northward/inland through the period, ahead of the cold front. Deep
shear will increase over the western plume tonight, and a few cells
(including low-end supercell potential) with small hail and strong
gusts cannot be ruled out tonight over parts of LA, with small hail
also possible from elevated/post-frontal convection over east TX.
Temperatures and dew points in the low/mid 60s may reach parts of LA
tonight ahead of the front, beneath weak low/middle-level lapse
rates. At least a shallow stable layer will remain at the surface
through most of the period, keeping any thunderstorm-gust or tornado
potential too conditional and isolated for a categorical outlook
area overnight.
Though severe potential appears more unconditional and organized on
day 2, some concern exists that surface-based parcels could reach
areas of supercell potential in central LA the last couple hours of
the overnight period. Moisture-return and prognostic trends will be
monitored for a more-certain unconditional threat in subsequent
outlooks.
..Edwards/Goss.. 02/02/2022
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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