Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 242038

Area Forecast Discussion
National Weather Service Jackson MS
338 PM CDT Thu May 24 2018

.Friday night through Wednesday night...A very wet long term forecast
is in store for the ArkLaMiss. Convection will be ongoing across
the area Friday evening as abundant moisture combines with decent
lapse rates and upper level troughing across the area. Most of the
convection will dissipate during the evening hours, but some
showers/storms could persist into the overnight. Little will
change on Saturday as 1.7-1.9 PWATS continue over the area, and
this combines with decent mid level lapse rates. Expect diurnal
convection to form over much of the area once again, diminishing
during the evening hours. With all of the moisture and cloud
cover, expect high temperatures to top out in the mid/upper 80s

As we progress through the weekend all eyes shift to the gulf as a
potential tropical system develops. There is still uncertainty as
for the development of this system, but NHC currently has a 90%
chance of formation over the next 5 days. The potential
development and movement of the system will dictate our weather
for Sunday through Tuesday. Both the GFS/ECMWF are in decent
agreement that any potential system would begin to affect the area
on Monday. For now, will begin to mention the potential for heavy
rains/flooding in graphicast and HWO beginning on Monday, as WPC
has increased rainfall amounts for these areas./15/

Rest of today through tomorrow...

Convection has been slow to develop this afternoon due to lingering
debris clouds from last night`s storms that were slow to dissipate.
Nonetheless, convection is starting to increase across southern and
eastern portions of the area with a few showers and storms over
areas of the Delta where gaps in the morning cloud cover were
present. Overall thinking hasn`t changed much with convection
expected to continue to increase in coverage across at least the
south and east portions of the area with composite outflow boundary
interactions helping to generate new activity further northwest
towards the Natchez Trace corridor, however the northwest extent
remains uncertain as the environment has been slower to recover from
the morning clouds. Latest mesoanalysis still indicates the
potential for a few of these storms to become strong to possibly
severe with the main threat confined to wet microbursts and small
hail. In addition, PWATs near 1.75" will support the threat for
locally heavy rainfall and isolated flash flooding due to weak flow
aloft. As we head into tonight, activity will begin to wane with the
loss of daytime heating, however a few showers and storms could
linger during the overnight hours. A weak shortwave trough will
encroach on the region overnight from the northwest and will provide
enough support to help keep these lingering showers around overnight.

For tomorrow, the presence of the aforementioned trough and
plentiful moisture will combine with daytime heating for another
round of showers and thunderstorms. Latest guidance is in good
agreement that showers and storms should get an earlier start with
showers possible as early as the early to mid morning hours with
coverage increasing through the late morning into the afternoon. As
has been the case this week, 3000-4000 J/kg of SBCAPE and 6-6.5 C/km
mid-level lapse rates will support a continued diurnal threat for a
few isolated wet microbursts and small hail in addition to locally
heavy rain. Due to the limited coverage will not mention the severe
or flash flooding threat in the HWO/graphics. Greater cloud coverage
will keep high temperatures cooler with mid to upper 80s across the
area. /TW/


18Z TAF discussion:
The main focus for this TAF period will be for afternoon showers
and thunderstorms across the area. The greatest coverage will be
across south and east portions at JAN/HKS/HBG/PIB/MEI from early
afternoon through the early evening hours. VFR conditions are
expected to prevail through the period outside of any showers and
storms where brief MVFR ceilings and IFR visibilities will be
possible. Some areas of fog could develop late tonight into early
tomorrow morning, but confidence in formation is low and dependent
on where rainfall occurs today so will hold off on any visibility
restrictions in the TAFs for now. Additionally, showers and
thunderstorms look to get an early start tomorrow with coverage
increasing by the late morning hours. /TW/


Jackson       71  85  69  87 /  46  55  38  56
Meridian      71  87  68  87 /  45  55  43  65
Vicksburg     71  87  70  89 /  35  53  29  48
Hattiesburg   71  86  68  87 /  36  55  36  63
Natchez       71  85  69  88 /  45  55  31  50
Greenville    73  88  71  88 /  32  45  26  48
Greenwood     72  86  70  88 /  20  53  29  47





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