Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 172134

Area Forecast Discussion
National Weather Service Jackson MS
434 PM CDT Fri Aug 17 2018


Tonight and Saturday:

Satellite and area radars showing convective clusters over
central and southeast AR developing along and just to the north of
0-3km theta-e axis. While other convective areas exist over east
and southeast MS, the storms approaching from AR will have the
best potential for severe given vertical totals in the upper 20s
and 20-40 knots of deep layer shear driving them southeast. Cold
pool boundary moving rapidly south along instability gradient
looks to link up with cluster over southeast AR by late afternoon
with the resulting MCS continuing southeast along the theta-e
gradient during the early evening. The best potential for damaging
wind will exist during this time frame as the system moves into
northeast LA and west central MS. CAM guidance indicating 30-40
knots of max hourly gusts as this area moves into the Jackson
Metra area around sunset, but this may be underdone a bit given
favorable microburst composite parameter.

Convection will wind down somewhat by late evening, but further
development along surface baroclinic zone over AR seems likely after
midnight which will move into the area in continued mid level
northwest flow. Multiple outflow boundaries, mid level northwest
flow and afternoon heating will make for another convectively active
day Saturday./26/

Saturday night through next week:

The ArkLaMiss will experience a few active and wet mid August
days this weekend and into early next week before a rare August
cold front sweeps through the region by midweek next week.

By Saturday evening, a stalled surface front that will stretch
from New England down into the lower MS River Valley. This front
will continue to serve as a focus for convective initiation for
storms in our region through Sunday. The better coverage of
storms will remain north of the I-20 corridor, closer to the
boundary. Pwats will range from 2"-2.5" through the period
providing the storms ample moisture to tap into. Storms during
this period will be efficient rain producers and some training of
storms is possible, but there was not enough confidence in the
flash flooding threat to extend the limited threat beyond
Saturday. There will be enough instability and shear around on
Sunday to support some severe storms with the primary threat
being gusty winds.

A deeper disturbance will begin to cross the Plains as we get into
early next week, eventually crossing the MS River Valley and into
the Great Lakes region. WPC has noted that surface low pressure
records for the upper Ohio Valley region in August could be in
jeopardy as the strong surface low associated with this
disturbance pushes east dragging a strong cold front with it. A
very moist airmass will still be in place over the ArkLaMiss as
the front approaches the region from the west late Monday into
Tuesday. Storms along and ahead of the front will also be
efficient rain producers with flash flooding becoming a threat
once again. A cooler, drier airmass will begin to filter into the
region behind the front, resulting in a dry end to the week.


18Z TAF discussion:
An active convective period will be in store for most TAF sites
through this evening. Abundant cloud cover this afternoon will
lead to periods of MVFR ceilings, especially where storms occur as
visibilities will be reduced and winds will be gusty. The
convection will wind down somewhat by late evening, but
possibilities will continue overnight and through the end of the


Jackson       73  89  73  91 /  79  59  43  63
Meridian      73  88  73  91 /  52  57  37  67
Vicksburg     75  93  74  92 /  76  67  50  59
Hattiesburg   74  91  73  91 /  25  48  20  68
Natchez       74  93  73  91 /  34  37  30  59
Greenville    74  90  72  89 /  44  59  50  60
Greenwood     73  87  73  90 /  62  66  50  55




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