Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 172019

Area Forecast Discussion
National Weather Service Jackson MS
319 PM CDT Sat Aug 17 2019


Tonight and tomorrow:

It has been another warm day across the region as temperatures have
reached into the lower to mid 90s. A few spots in eastern
Mississippi have reached closer to the upper 90s, but this is where
some of driest air has been able to mix down. Dewpoints are ranging
from the lower 70s in the west to the upper to mid 60s in the east.
Heat indices have been kept fairly well in check because of this
with most locations seeing max heat indices around 100 to 101. As
the ridge remains over the region, moisture will slowly continue to
increase across the region. This will mean a little more in the way
of showers and storms tomorrow, with the most likely area being
across southern counties and western parishes. This should be where
the best moisture resides as well. Temperatures tomorrow will again
be in the mid 90s, but additional cloud cover and rain chances
suggest that some of these highs could fall short. In addition,
dewpoints will be higher tomorrow, which will help increase heat
index values. Inherited limited risk for tomorrow could be ok but
new guidance suggests that we might fall just shy of the near 105
degree threshold. The best location for this would be generally
along and west of the MS River, but opted not to continue at this
time for tomorrow. Drier air should hold on in the east and this is
where heat indices will hover around 100 degrees. /28/

Sunday night through late next week:

Warm, humid & active week of storms is expected through next week.
The mid-level ridge will have begun to retrograde to the west,
leading to perturbed pattern with north-northeasterly flow aloft.
This will gradually transition to the ridge axis to build west.
However, with a shortwave trough moving through the region on
Monday, we should actually keep good low-level convergence along a
washed out boundary & some isentropic lift & increased moisture near
the 2 inch mark. Weak troughing aloft will set up over the
Appalachians & East Coast, with perturbed shortwave energy situated
just over us through mid-late week. With the surface ridge of high
pressure building to the northeast & building mid-level ridge, this
will lead to increase in dewpoints into the mid-upper 70s &
increasing heat & humidity through the week. With increasing
subsidence & slight drying aloft, we should have a little less
coverage of convection across the northwest Delta & northern areas.
A longwave trough will swing through the Great Lakes & Canada,
bringing another front & higher coverage of storms down into the Mid-
South & Mid-Mississippi Valley around Thursday into the weekend. The
Euro continues to depict a persistent tropical wave & some surface
reflection in the west-northwest Gulf by late next week. Nothing to
be concerned at the moment but may be something to keep an eye on,
even if it at most only increases deeper tropical moisture & heavy
rain potential after into next weekend.

In terms of sensible weather, expect rain & storms to be on the
increase, especially on Monday as shortwave trough swings through
the area & stalls across the region through mid-week. Due to these
scattered storm chances, heat stress may be a little more confined
to the Delta or slightly harder to come by Monday. However, with
building mid-level ridge through mid-week & increasing thermal
warmth, we should be able to reach near or a few degrees above the
105 degree mark, especially around mid-week (i.e. Tuesday-
Wednesday). Decided to keep a "Limited" heat stress in the
HWO/graphics potential to the ArkLaMiss Delta due to more isolated-
scattered diurnal convection in this area. However, extended it east
across the Highway 82 corridor as that seems to be a typical hot
spot, especially in the Golden Triangle. There remains potential for
an "Elevated" & heat advisory across the Delta but confidence
remains low due to scattered coverage. As mentioned before, there
remains favorable juxtaposition of perturbed flow, lapse
rates/vertical totals & microburst composite parameters for some
organized wet microburst potential & gusty winds. There might be
some organized convective potential on Monday & also on Wednesday
from any complex off in the Ozarks, but there remains enough
question marks to assess potential as we get closer. /DC/

18Z TAF discussion:
VFR conditions will prevail through the period. Dry weather is
expected across the area, with the exception possibly being at
KPIB/KHBG. Here there could be a shower or storm this afternoon
but confidence in affecting the TAF site is not high. Southerly
winds will occur today around 5kts or less. Calm winds will occur
overnight at most locations. No significant aviation concerns are
expected. /28/


Jackson       74  94  75  92 /   3  38  16  46
Meridian      73  95  74  93 /   2  14  15  43
Vicksburg     74  94  75  94 /   4  43  13  41
Hattiesburg   73  93  75  92 /   4  48  20  60
Natchez       75  94  75  91 /   8  47  16  50
Greenville    73  94  75  93 /   2  28  13  32
Greenwood     73  94  75  92 /   1  16  11  37





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