Area Forecast Discussion
Issued by NWS Jackson, MS

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FXUS64 KJAN 242039
AFDJAN

Area Forecast Discussion
National Weather Service Jackson MS
339 PM CDT Sat Jun 24 2017

.DISCUSSION...
tonight and Sunday: Convection is beginning to develop in south-
central Louisiana and the local CAM guidance is indicating better
potential some of this could advect to the north-northeast and
make it into the Highway 84 corridor over the next few hours and a
few showers & storms may develop closer to the I-20 corridor. For
now going to maintain the flash flood watch in the southern tier
of counties in the Pine Belt through 7PM. Maintaining this in the
HWO/graphics as well.

As the front slowly moves to the south, expect convection to wind
down later tonight after 02-04Z, with only some lingering chances
remaining in the Highway 84 and 98 corridors. Models are slower to
amplify the trough to the north over the northern CONUS and bring
the big anomalous drier air in tonight and keep the strong surface
ridging/surface high off to the northwest over the central Plains to
mid-Mississippi Valley. We will dry out some potentially in the
Highway 82 corridor where PWs will fall near an inch and a half but
the front will hang near the Gulf Coast and still will have decent
moisture lingering into tonight and Sunday. Lows will be slightly
below normal in the north in the mid-upper 60s.

As a strong jet streak pivots through the upper trough through the
Plains Sunday, this will help to amplify the longwave trough over
most of the the CONUS east of the Rockies. Expect this to help drive
the anomalous surface ridging/low PWs down into our area by Sunday
afternoon with the center of the surface high over the central
Plains into Missouri. Areas in the north PWs will fall less than an
inch with near 1.75 to 2 inch PWs again south of I-20 and 850mb
Theta E near 330-335K+. This and a weak shortwave moving over the
ArkLaTex will help again spark some potential for some showers and
thunderstorms mainly south of the I-20 corridor and more coverage in
the Highway 84 corridor. Heavy downpours are again possible but not
enough confidence in coverage to mention in the HWO/graphics. In
addition, there will be limited lapse rates/instability so not
expecting any stronger convection. Highs will warm to the mid 80s, a
few degrees below normal. /DC/

Sunday night through Friday: Northwesterly mid level flow
pattern will dominate the first half of the period as convergence
over the northeast supports surface high pressure from the OH into
the lower MS river valleys. Flow around the high pressure area will
keep the Gulf of Mexico cut off with atypically dry air (dewpoints
in the 50s and 60s) remaining over the region. This dryness will
stretch the diurnal temperature range making the heat each afternoon
more bearable, as well as, allow overnight lows to dip down into the
60s.

A more zonal mid level flow pattern will replace the troughiness in
the east by Thursday with surface high pressure moving to the
southeast and winds becoming more southerly. With surface dewpoints
rising back into the upper 60s and 70s, a return to diurnally driven
convection will commence through the end of the period as the
diurnal temperature range shrinks./26/

&&

.AVIATION...
18Z TAF discussion:
Some brief MVFR ceilings are ongoing behind the cold front near
GWO, at STF, CBM, GTR, MEI & NMM but these should lift by around
24/1900. Elsewhere & the rest of this afternoon VFR conditions are
expected areawide. Some VCTS are possible near HKS, JAN, MEI, NMM
after 24/20-21Z & -TSRA at PIB & HBG after 24/21-23Z or so. Any
TAF site impacted could observe brief MVFR to IFR ceiling &/or
visibility restrictions. These rain & storm chances will linger
through around 25/02-04Z. Winds will mainly be from the north-
northwest today around 7-10kts becoming light tonight. Some brief
MVFR visibility restrictions due to patchy fog are possible
tomorrow morning around PIB & HBG around 25/11Z. /DC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       70  86  62  87 /  13  12   8   8
Meridian      69  86  60  87 /  16  10   8   9
Vicksburg     69  86  63  88 /   9  17   9   9
Hattiesburg   72  87  65  87 /  33  44  14  17
Natchez       70  84  64  87 /  27  39  14  13
Greenville    65  85  63  88 /   4   3   5   7
Greenwood     65  84  61  87 /   3   4   4   5

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...Flash Flood Watch until 7 PM CDT this evening for MSZ072>074.

LA...None.
AR...None.

&&


$$


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