Area Forecast Discussion
Issued by NWS Jackson, MS

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942
FXUS64 KJAN 210336
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
936 PM CST Mon Nov 20 2017

.UPDATE...
Updated for evening discussion.

&&

.DISCUSSION...
No major changes have been made with this evening update. Cold and
dry conditions will prevail overnight, isolated areas of patchy
frost may appear before sunrise. /SKH/

Prior discussion below:

Tonight through Tuesday:

Overall a quiet & cooler than normal night is expected tonight as
the surface high pressure slowly builds off to the east. As that
surface high drifts off the Atlantic seaboard, our area will
continue to be in better return flow & dewpoints will slowly
moderate into the lower 30s through the night. Due to a generally
light pressure gradient, especially over the eastern half of the
area, & PWs generally around a quarter of an inch, expect lows to
continue to bottom out overnight in the low-mid 30s. Some areas in
the Golden Triangle & northeastern third of the area could fall near
freezing overnight. Due to just enough moisture around, patchy frost
is again possible overnight. If enough wind stays up overnight, that
might limit frost potential overnight. Due to the widespread freeze
this morning, being past the growing season & all areas experiencing
a freeze, we will not be introducing any type of freeze products in
our HWO/graphics.

As a deep longwave trough amplifies over the Great Lakes Tuesday,
our area will continue to be under northwest flow aloft & continuing
low level southerly return flow. This will help drive a dry cold
front down towards region by Tuesday afternoon-evening. Our thermal
profiles should warm enough ahead of it(3+ deg C at 925mb) to help
us warm about 5-8 degrees tomorrow to near normals in the mid 60s or
so. As the western portions of the trough somewhat is less phased in
the western Gulf, some showers are possible along the Gulf Coast.
However, the best forcing & moisture will remain off to our south,
keeping the rain chances to our south & our area will remain dry.
Due to increasing moisture, with dewpoints climbing into the upper
30s to low-mid 40s, fire weather concerns will not be an issue. /DC/

Tuesday night through Monday...

The overall forecast remains mostly unchanged through the long term
period with dry and cool conditions persisting as negative phases of
both the North Atlantic and Arctic Oscillations help foster strong
Greenland blocking and continued troughing over the East Coast. A
series of shortwave troughs and associated dry cold fronts are
progged to traverse the ArkLaMiss in the northwesterly mid and upper-
level flow through the period with the strongest of these shortwaves
diving through the Southern Plains and into the northern Gulf of
Mexico during the day on Wednesday. This shortwave will help to push
a dry cold front through the region with the front located south and
east of the CWA by Thursday morning. A weaker shortwave trough will
quickly follow Wednesday night, but with such dry profiles (PWATs
less than 0.5 inches) only a few passing clouds are expected. A
somewhat more pronounced wave and jet streak will help push through
another dry cold front Saturday night/Sunday. No rain is expected
during the long term period so low end fire weather concerns cannot
be entirely ruled out primarily on Wednesday/Thursday and
Saturday/Sunday during the frontal passages. In terms of temps,
daytime highs will start off cool in the mid to upper 50s on
Wednesday behind the first cold front and will gradually warm
through the week into the mid to upper 60s by the weekend ahead of
the second cold front. A few nights of freezing temps are
expected Wednesday and Thursday nights mainly along and north of
I-20 and in the Golden Triangle. /TW/

&&

.AVIATION...
00Z TAF discussion:
VFR conditions are expected to prevail through the period with
mostly clear skies. Winds will be out of the south and light
through the night. /28/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       36  68  43  59 /   0   1   0   0
Meridian      35  67  42  60 /   0   0   0   0
Vicksburg     35  67  43  57 /   0   1   0   0
Hattiesburg   37  68  45  64 /   0   2   0   0
Natchez       37  68  45  58 /   0   6   0   0
Greenville    35  63  40  52 /   0   1   0   0
Greenwood     35  65  39  54 /   0   1   0   0

&&

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

&&


$$

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