Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 271549 AAA
AFDJAN

Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
1049 AM CDT WED JUL 27 2016

.UPDATE...

Morning upper air analysis shows the mid-level low spinning over
northeast Louisiana. This feature has helped advect between 2-2.25
inch PW`s across the region. Based on the situational awareness
table, the NAEFS/GEFS show this moisture to be in the 99th
percentile. This anomalous moisture in addition to increasing
moisture convergence/transport and 850mb theta-e`s near 340K and very
light Corfidi vectors, with some near calm or from the northeast and
convection moving the opposite direction, will help very efficient
tropical downpours and flash flooding to be possible. The best
dynamic lift and ongoing showers currently are in the Delta, where
near 1-2 inches of rain have occurred with training convection.
Expect a gradual increase of moisture transport over the next few
hours or so from the south and east as the mid-level low gradually
lifts north-northeast. For now, left the limited in the HWO/graphics
for the same general region. The best widespread convection and QPF
looks to remain in the western portions of the region while areas in
the east, could warm slightly warmer, bringing the risk for
thunderstorms and very efficient downpours to be possible. Thus, did
not trim it back to the Delta due to the possibility of some better
instability in the east and more chances for thunderstorms producing
heavy rain in this tropical environment. Also cut highs slightly due
to widespread cloud cover and rain, especially in the west this
afternoon. Rest of the updates are out. /DC/

&&

.AVIATION...Still seeing an abundance of MVFR/IFR category stratus
across the region at mid morning thanks to a weak low pressure
rotating broadly near GLH. Expect ceilings to gradually show an
improving trend in most areas into the afternoon although at least
patchy MVFR will remain possible in all areas through the remainder
of the day with the worst persistent ceiling issues likely at
GLH/GWO/HKS/JAN. Current issues with showers and a few storms are
around this GLH/GWO/HKS/JAN axis although convection should expand
east to encompass the remainder of area sites as we go into the
afternoon. Any thunderstorms could produce heavy rainfall rates and
associated vis reductions. Expect SHRA/TSRA activity to generally
wind down this evening with a repeat of stratus development possible
late tonight into early Thursday morning, mainly along the
GLH/GWO/GTR corridor. /BB/EC/

&&

.PREV DISCUSSION... /issued 455 AM CDT WED JUL 27 2016/

DISCUSSION...

Today through Thursday night...

The threat for locally heavy rainfall over much of the ArkLaMiss
continues in the near term. As of early this morning, the mid level
low center was roughly located over northeast LA per latest radar
loops. It is expected to continue moving slowly north then northeast
around the western periphery of a subtropical high center before
shearing out and leaving behind a weak mid/upper level trough axis
across northern portions of the ArkLaMiss as we go into late week.
Accordingly, the best rainfall chances will shift from most of the
area today to northern portions of the forecast area Thursday and
Thursday night.

A combination of very moist air (precipitable water values
approaching 2.5 inches), anomalous southerly flow of 20-30kts (~ 2
to 3 +SD per NAEFS), and lift will continue to create a favorable
environment for heavy rainfall and localized flash flooding, so will
continue to reflect this limited threat in the HWO/graphic, but will
expand the area a bit farther east to match up better with WPC
excessive rainfall risk area. The convective precipitation will be
mainly diurnal and focused in the late morning/afternoon/early
evening hours. /EC/

Long Term (Friday through Tuesday)...Above normal rain chances will
continue through early next week, but a return to above normal
temperatures may be in the offing.

By Friday, the subtle upper trough axis will remain over the eastern
U.S. and a corridor of plenteous moisture (with PW forecast to be as
high as around 2 - 2 1/4 in) will still exist over the Lower MS
Valley. These features will linger into the weekend, bringing a
continuation of higher rain chances. PoPs will be sustained in the
higher-end chance to likely categories each day. Certainly some
folks will receive heat relief courtesy of the increased precip
coverage, but outside of the rain, high temps will remain near
normal.

Minor changes are afoot heading into next week. The weak upper
trough will be superseded by a building mid/upper level ridge over
the nation`s mid-section. This ridge is expected to remain "dirty"
and atmospheric moisture will continue to be plentiful, so rain
chances will remain above normal through the end of the forecast
period. However, daytime highs will likely begin to tick back up a
degree or two, and heat stress could once again become more of a
concern. /DL/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       86  74  89  73 /  49  44  49  35
Meridian      89  74  94  74 /  39  36  33  25
Vicksburg     85  75  87  74 /  53  49  57  37
Hattiesburg   86  74  91  74 /  39  36  29  23
Natchez       83  73  86  72 /  51  44  48  30
Greenville    86  74  85  73 /  65  62  67  42
Greenwood     85  74  85  72 /  63  59  67  40

&&

.JAN Watches/Warnings/Advisories...
MS...None.
LA...None.
AR...None.
&&

$$

DC/DL/BB


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