Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 180837

Area Forecast Discussion
National Weather Service Jackson MS
337 AM CDT Tue Jun 18 2019

Today and Tonight...As the axis of a shortwave continues to swing
through the region where a warm moist airmass resides, isolated to
scattered showers have remained ongoing overnight and into early
this morning.  Through the remainder of the morning and into this
afternoon, as daytime heating ensues as highs warm to the mid 80s
and lower 90s, and instability increases, scattered to numerous
showers and storms will again develop across the ArkLaMiss. This
will especially be the case across eastern portions of the CWA,
which will lie in closer proximity to the departing shortwave. Gusty
winds, lightning, and heavy downpours are expected with the most
intense storms.

The majority of today`s activity will begin to dissipate late this
afternoon into early this evening, but especially after sunset when
daytime heating is lost and instability begins to wane.  A shower or
two may again linger through the night, with some patchy fog
possible and low stratus development possible by day break
Wednesday. Otherwise, lows will fall to the low and middle 70s.

Wednesday through Monday: Mid level zonal flow rippled with weak
shortwaves will remain over the area at the beginning of the period.
A more robust wave does look to move into the area Wednesday night
into Thursday. This wave will bring rather impressive instability
and shear for this time of year with 7-8C/km mid level lapse rates,
vertical totals around 30, and 30-35 knots of deep layer shear (20-
25 knots of 0-1km shear). While the wave will bring a weak cold
front with it, the boundary does not look to move into the area, but
it will initiate the robust convection that will move across the
area late Wednesday night into Thursday, mainly over the north. Will
include much of north MS in the marginal severe threat Wednesday
night into Thursday.

Moving beyond Thursday, flow pattern will amplify as trough digs in
the west and ridge builds over the MS valley. While convection will
stay in the forecast, it will be more of the isolated variety and
confined mostly to northern sections. Of more concern will be the
bulding heat. The damp conditions with surface dewpoints around 75
will create high heat stress conditions beginning over far southwest
portions Thursday and further northeast over the area Friday where
max heat indices near 105 may be common. Will include a limited heat
stress for Friday in the HWO. The heat will continue into the
weekend, but heat indices should not be as high as deeper mixing
begins to pull down some drier air from aloft./GG/


06Z TAF discussion:
Despite lingering convection overcast skies across the area this
evening, VFR flight categories area being observed at TAF sites
across the area. Just as the case was this past morning, flight
categories are expected to fall to MVFR/IFR status overnight due to
developing low stratus and patchy fog.  The lingering overnight
convection will also be a likely cause for periodic degraded
ceilings and visibilties as well, if convection is observed on-site.
Much of the same is expected later this afternoon, as scattered to
numerous showers and storms are forecast to develop across the area
during the heat of the day.  Winds overnight will again be calm to
light from the southeast.  Winds through the morning will become
more west southwesterly, increasing to between 5-10 knots. /19/


Jackson       89  71  92  73 /  51  23  25  36
Meridian      90  71  93  74 /  70  28  28  25
Vicksburg     89  72  91  76 /  37  15  20  40
Hattiesburg   89  72  92  74 /  70  26  21  11
Natchez       89  72  91  74 /  43  14  17  21
Greenville    89  72  92  75 /  29  11  30  65
Greenwood     87  72  91  74 /  43  19  38  63




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