860
FXUS64 KJAN 211613
AFDJAN
Area Forecast Discussion
National Weather Service Jackson MS
1013 AM CST Sat Dec 21 2024
...New MESOSCALE UPDATE...
.MESOSCALE UPDATE...
Issued at 1011 AM CST Sat Dec 21 2024
All is generally on track for this near term update with a chilly
day underway. Have just made some minor T/Td adjustments to
account for recent obs trends. /EC/
&&
.DISCUSSION...
Issued at 359 AM CST Sat Dec 21 2024
Today and Tonight: Colder than normal and dry through the period.
Early morning satellite imagery/RAP analysis showed another
shortwave trough over the central Plains that will rotate around
the base of the mean upper level trough centered over the eastern
CONUS. This will help maintain northwest flow aloft across our CWA
through tonight and help a >1038mb high centered over the northern
Plains early this morning, track east across the Great Lakes region.
Together these features will help keep much of our CWA in the 40s
today. Our normal highs run in the mid 50s north to the lower 60s
south. Although the center of the large surface high will remain
north of our CWA tonight, decent radiational cooling of our cold dry
airmass will lead to the coldest night of the next seven days.
Temperatures will drop off rapidly after sunset and bottom out
Sunday morning in the mid to upper 20s. Normal lows run in the mid
to upper 30s. /22/
Through the Weekend
Sunday morning should be our last day of frigid overnight
temperatures that dip into the 20s. Expect widespread frost
development as a result of these cold temperatures crossing over our
mid 20 degree dew points. Tomorrow night most sectors to the west of
I-55 will bottom out above freezing, with eastern zones dipping
below before sunrise.
Monday through Friday
Moving onto Christmas week expect to rebound into temperatures that
are far above seasonal norms with highs in the mid 60s for areas
north of I-20, and low 70s to the south. Our lows will take a bit
longer to recover as our Gulf flow is not particularly robust and
remains more east-southeasterly until late next week. Good news is
that all counties/parishes will see lows above freezing, and reach
low 50s by Christmas night/Thursday morning. Rain and thunderstorms
will begin to make their way into the area the afternoon of
Christmas Eve from the northwest and affect the entire CWA by
Christmas morning. This is in response to southerly moisture on tap
combined with 500mb height falls out ahead of a minor trough set to
eject slowly from east Texas Christmas morning. This minor trough
will be absorbed into a much more substantial trough from central
Texas throughout the remainder of the week, which will elicit
widespread ascent out ahead of it, as significant height falls take
hold. Continued surface moisture that becomes more sturdy as the
week progresses, in conjunction with this aforementioned major
trough will culminate in effectively continuous rainfall for the
remainder of the week, with embedded thunderstorm activity.
Model resolutions with this system have continued to come into focus
providing more confidence in the overall forecast for Christmas
onwards. Rain totals (both 24hr and 7 day averages) for this
rainfall event remain within seasonal norms, so there is no
expectation of signaling any sort of heavy rain threat. As always
with systems that have had divergent resolutions we can not totally
rule out the possibility for heavy rain nor a small chance for more
dynamically supported embedded convective activity that could
produce local, isolated, strong winds.
In summary, the holiday week looks to be a wet and dreary one. If
there are any outdoor plans that don`t involve frolicking in the
rain, it would be advisable to have a backup plan. /OAJ/
&&
.AVIATION...
(12Z TAFS)
Issued at 619 AM CST Sat Dec 21 2024
VFR conditions wl prevail through the TAF period. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 49 28 55 33 / 0 0 0 0
Meridian 49 26 53 29 / 0 0 0 0
Vicksburg 49 27 56 33 / 0 0 0 0
Hattiesburg 52 29 56 32 / 0 0 0 0
Natchez 50 29 57 35 / 0 0 0 0
Greenville 44 28 51 32 / 0 0 0 0
Greenwood 47 27 53 34 / 0 0 0 0
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
EC/22/OAJ
NWS JAN Office Area Forecast Discussion
Mt Washington Wx CAM
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