Grenada, Mississippi 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

471
FXUS64 KJAN 180733
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
133 AM CST Sat Jan 18 2025

...New DISCUSSION...

.DISCUSSION...
Issued at 127 AM CST Sat Jan 18 2025

Through Sunrise Sunday...


Rain showers from a surge of Gulf moisture yesterday are now
clearing out of the eastern portions of the CWA. With renewed
onshore flow, temperatures and dew points will rise throughout the
day, briefly pushing highs above seasonal averages. Southeastern
areas are expected to reach the mid-70s, while most other locations
will see highs between 65-70F. In the far northwest, temperatures
may struggle to exceed 60F today.

An approaching cold front will move into the area after sunset
tonight, this in concert with nighttime cooling will cause a sharp
drop in temperatures. For example, the Jackson metro area, with an
afternoon high of 67F, is forecasted to plunge to the upper 20s
overnight-a dramatic 40F in just 12 hours. Similar trends will occur
across the region, with lows north of I-20 ranging from 25-30F and
south of I-20 between 30-35F. The only areas likely to remain above
freezing will be along and south of Highway 84, as the front is not
expected to fully clear these areas before sunrise.

No significant post-frontal weather is anticipated in the near term,
aside from breezy northerly winds and mostly clear skies. /OAJ/


Sunday through next week...

Attention continues to turn toward next week with increasing
confidence both for dangerous, long duration cold temperatures
and wind chills as well as for wintry precipitation for portions
of the area.

Sunday will feature much colder temperatures behind a departing cold
front that will usher in a very cold Arctic airmass. Highs Sunday
will fail to crack 50 degrees F area-wide and for those near and
north of I-20 highs likely stay around 40 F or less. The chill turns
increasingly hazardous overnight when lows will fall into the teens
across the area and possibly middle to lower teens for areas
north of I-20. Witch continued northerly winds, this will drive
wind chills down to near 10 degrees F in the colder spots.
Temperatures do rise a bit with only partly cloudy skies Monday,
but 15 degrees above 15 degrees is still only 30 degrees and highs
will struggle to move much above freezing for most of the area
with lower 40s F for the highway 84 corridor. Clouds increase
Monday night and temperatures won`t be quite as frigid, "only"
falling into the lower 20s F and upper 10s F. This increased cloud
cover will signal increases in mid level moisture and broad scale
upper lift as an upper disturbance begins to move toward the
area. With surface temperatures near or below freezing through the
day Tuesday, any precipitation that falls will be of the wintry
variety.

The forecast remains complex: multiple short/long wave troughs
composited from more than a single branch of the jet stream are
poised to merge into a robust trough axis embedded within the
existing very broad trough that will take up residence across the
central and eastern CONUS over the next few days. This composited
trough will interact with a closed low that has been trapped, and
may at least in part continue to be trapped, underneath a deep
layer ridge off of the coast of the Pacific Northwest.

This complex interaction will be what allows for substantial lift
across the area despite the cold, dry airmass that will be in place.
As winds aloft veer southerly amid increasing mid level warm
advection, surface trajectories will remain of cold origin.
Currently, and unusually, it appears this will result in a lack of
melting through the column for any descending precipitation. With
saturation and lift in the dendritic/snow growth zone,
precipitation likely begins its journey downward from the clouds
as snow and with the cold profiles will likely remain that way.
Given the very dry air in place, some of this snowfall will likely
be sublimated at the onset but soon enough most areas along and
south of the I-20 corridor at least will begin to see a few
flakes. As the most vigorous southerlies aloft approach the coast,
it`s not out of the question that some folks near the highway 84
corridor could see some brief mixing in of sleet pellets which
could affect snowfall total accumulation, but overall snow will
be the dominant precipitation type. And while snow certainly will
bring perhaps substantial hazard impacts to travel and certainly
would have deleterious affects on temperature with lows at night
colder should snow blanket the ground, impacts to power
infrastructure would be less likely than with equal liquid
equivalents of freezing rain for example.

Concerning accumulations, a wide range of possibilities remain. As a
current best estimate, (and of course this is subject to change!) it
appears that given temperatures will be cold for everyone, that
accumulations will be driven more by total precipitation amount than
anything else. While colder profiles further north will result in
improved liquid equivalent to snow total ratios, areas south of I-20
will likely see greater total precipitation amounts and therefor
higher snowfall accumulation totals. A conservative estimate using a
blend of 12/18/00Z model output as guidances suggests that areas
near the I-20 corridor could expect to see at least a dusting of
snow with total increasing sharply to the south. It appears now that
there is a better chance than not of a band of snow with totals 2 to
3 inches with possibly localized higher totals occuring somewhere
across the southern half of the area.

With temperatures warmer to the south, but still sub freezing, this
could favor a zone of heavier, lower liquid:snow ratios which could
pose some risk of downing weaker branches and the like. And of
course with that as a possibility it couldn`t be ruled out that an
unfortunately placed limb could fall onto power lines somewhere.
Regardless, the primary impacts will almost certainly be to travel
and roads could become treacherous in some areas. With extended cold
to follow, areas with higher snowfall accumulations onto roadways
may be challenging or near impossible to traverse for multiple
days, particularly roadways that are rural or less traveled.

Dangerous cold continues into mid week following our winter weather
episode and depending on exactly where the heaviest snow falls and
how much does fall this could have impacts on temperatures beyond,
and perhaps more severely cold, than what is currently indicated by
the explicit forecast products.

Depending on snow cover, most areas will reach a few degrees
above freezing on Wednesday with highs near 40 F as some minor
moderating of the Arctic airmass begins. Lows remain quite cold
however and mid/upper 10s F to near 20 F will be likely for most
Wednesday night. Thursday will be a bit warmer still, with highs
in the middle 40s F. The next substantial precipitation chances
likely arrive near the end of the next week and temperatures then
will be more of the close-but-uncertain variety at that time in
terms of supporting additional wintry weather. For now, will not
advertise a risk for wintry weather but should temperatures be
even modestly cooler than currently forecast that would prove
problematic. One system at a time is often a good policy when the
pace of events allow, so we will wait for the early week event to
get a little closer before beginning to speculate too much on what
might come next. It`ll definitely be something to watch as we get
a little closer. /86/


&&

.AVIATION...
(06Z TAFS)
Issued at 1141 PM CST Fri Jan 17 2025

VFR ceilings around 8-10kft exist across the area, with light rain
expected to persist overnight, generally clearing from west to
east from 18/08-10Z Saturday. Ceilings from MVFR stratus will
build in overnight, with some possible temporary reductions to
IFR at GLH & GWO. Other than some isolated rain showers in the
north through around midday Saturday, main concern remains with
lifting of the MVFR stratus to VFR ceilings. Main areas where this
will be likely is central to southern TAF sites along & south of
I-20 (JAN, HKS, MEI, HBG, PIB & HEZ). Gusty southerly winds,
sustained around 15mph & gusts between 20-25mph, are possible,
before a cold front moves through & shift northerly around midday
in the Delta & majority of the area by the end of the TAF period.
/DC/OAJ/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       68  30  38  19 /  10   0   0   0
Meridian      70  33  40  17 /  10  10   0   0
Vicksburg     67  31  39  19 /   0   0   0   0
Hattiesburg   74  37  44  19 /  20  10   0   0
Natchez       67  33  40  20 /   0   0   0   0
Greenville    59  29  35  17 /  10   0   0   0
Greenwood     62  28  35  16 /  20   0   0   0

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&

$$

OAJ/LP/OAJ