Gail
Member
- Messages
- 486
- Location
- Caledonia, MS
Jackson’s thoughts…
Thursday and Friday: A much anticipated winter storm is
continuing to come into somewhat clearer focus. As a sharp upper
trough pivots across the central CONUS, surface cyclogenesis will
ensue along the northwestern Gulf coast Thursday. The system will
track eastward along the coast into Friday, spreading precip
northward across our area late Thursday into Friday. A seemingly
consistent trend in model guidance is for later arrival of precip
on Thursday, around or after sunset in many areas. Clouds will
increase substantially earlier in the day, though temps are
expected to rise into the 40s across most of the area.
Thursday late afternoon and evening, temps will dip some with the
loss of the insolation, and with wetbulb temps in the 30s, some
additional cooling will occur at precip onset. While surface temp
advection will be quite weak, strong 850 mb warm advection will
occur overnight especially along and south of the I-20 corridor,
resulting in a growing low level warm layer aloft. Forecast low
temps are near or just above freezing over much of the southern
half and near or just below freezing over the northern half. This
should ensure a cold rain over roughly the southern third of the
area. Over the central tier, there may be enough cold air before
the warm layer aloft grows for snow or sleet at the onset of
precip, but it is very likely to transition to cold rain as the
column saturates and low level WAA increases. At this time, any
accumulations appear most likely to be negligible, but there is
still low potential for at least brief travel impacts in these
areas.
Things will be most interesting across our northern tier areas,
where it will be a bit colder at onset and a mostly subfreezing
wetbulb profile implies evap cooling potential at onset. In many of
these areas, 850 mb WAA will be weaker, resulting in thermal
profiles that are more isothermal near the freezing mark as
saturation occurs. This still leaves considerable uncertainty, as
just a few degrees will mean the difference between mostly very
cold rain, a rain/snow mix, and mostly snow. For snow accums,
lower SLRs and any p-type changes will cut in to storm totals.
It`s rather possible there will be snow/sleet accumulations that
are wiped out by a transition to rain. However, if the colder
solution prevails, this is the area with the higher ceiling for
impacts from accumulating snow. As a result, the Winter Storm
Watch has been expanded to include the remainder of the US 82
corridor in our area.
Most areas may transition to rain for a period on Friday morning as
the pocket of warmer 850mb air shifts across the area. However,
with cooling during the afternoon, a transition back to snow is
possible in these areas before precip tapers off by Friday
afternoon or early evening.
with no power outages. But I would prefer to avoid power outages without having rain melting the snow. And as dangerous as it is, I admit I find freezing rain a fascinating weather phenomenon, even more so when thunderstorms are involved. I know people are gonna hate me for saying that but it's true. 
