[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 030020
SWOMCD
SPC MCD 030019
VAZ000-TNZ000-NCZ000-KYZ000-GAZ000-ALZ000-030515-

Mesoscale Discussion 0023
NWS Storm Prediction Center Norman OK
0619 PM CST Sun Jan 02 2022

Areas affected...parts of the southern Appalachians and Southeast

Concerning...Heavy snow

Valid 030019Z - 030515Z

SUMMARY...Periods of moderate to heavy snow will likely develop
through this evening as temperatures begin to drop and forcing for
ascent strengthens markedly. Snow rates of 0.5-1 in/hour will be
possible with the strongest bands. Brief periods of mixed
precipitation including sleet and freezing rain may also develop.

DISCUSSION...As of 0015 UTC, a potent mid-level shortwave trough was
analyzed via WV imagery across the eastern ARKLATEX. To the south, a
90-100 kt jet streak was beginning to round the base of the
positively tilted trough moving onshore across southwestern LA. A
broad area of low pressure at the surface was centered across
western GA with an expanding precipitation shield noted to the
northwest of the low and ongoing convection.

Recent surface observations across southwestern TN and northern MS
have shown an increase in the occurrence of snow and mixed
precipitation types over the last few hours with diurnal cooling
taking place. Strong height falls from the approaching trough are
forecast to advect eastward over the next few hours as the trough
becomes negatively tilted, augmenting surface mass response and
deepening the aforementioned surface low. Low-level cold advection
should follow suit, accelerating the  change over, first to mixed
precipitation, and then quickly to snow of parts of the expanding
precipitation field. While temperatures remain mild, the rain/snow
line should move eastward with time concurrent with increasing
precipitation rates from strengthening 850-700 frontogenesis and the
development of convective bands owing to subtle buoyancy aloft.

Regional soundings show favorable profiles for periods of moderate
and occasional heavy snow expanding northeastward with time from
northern AL into eastern/central TN along the western slopes of the
southern Appalachians. Snow rates of 0.5 to 0.75 in/hr will be
possible for several hours resulting in reduced visibility and
potential travel issues. Localized 1+ in/hr rates may also be
possible beneath the heavier convective elements or near local
topography favorable for orographic enhancement. Snow may linger for
a few hours overnight before forcing and dry air to the west shift
precipitation northeastward.

..Lyons/Guyer.. 01/03/2022

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...GSP...MRX...JKL...FFC...OHX...BMX...HUN...

LAT...LON   36988294 36938250 36848214 36398195 36138206 35448303
            34568481 34348622 34328700 34378746 34628792 34938800
            35328770 35628707 36328547 36988294
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