Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 261125 AAA

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
625 AM CDT Sun Mar 26 2017

.DISCUSSION...Updated for latest aviation discussion below.


12Z issuance...MVFR to IFR cigs and visibilities through about
26.14z followed by VFR to MVFR cigs through about 27.04z followed
by MVFR to IFR cigs and visibilities through 27.12z. A few
isolated showers or thunderstorms will also be possible through
this afternoon. Winds will be southeast to south at 4 to 10 knots
through the forecast period. 32/ee


.PREV DISCUSSION... /issued 517 AM CDT Sun Mar 26 2017/

NEAR TERM /Now Through Sunday night/...Deep low center which
help bring showers and thunderstorms to the forecast area on Sat
was just southwest of the Great Lakes region this morning progged
to lift ne through tonight followed by another deepening system
moving from the rockies to the central plains states this
afternoon and tonight. Near the surface high pressure along the
eastern seaboard will retrograde southwest and west over the se
conus and north central gulf through tonight leading to a better
pressure gradient developing across the north central gulf states
late tonight and early mon morning. For today expect residual
clouds and precip to continue over much of the eastern half of the
forecast area early today lifting slowly east and northeast this
afternoon thus leading to better sunshine for most locations in
the forecast area by mid to late afternoon. Although model
soundings show increased instability later this morning and this
afternoon a well defined warm layer/cap at around 12k ft is noted
in the column affecting all locations limiting the coverage of
precip throughout the day. Again the best coverage of precip will
be over the eastern half of the forecast area with maybe an
isolated thunderstorm embedded in isolated to scattered
rainshowers. With still limited moisture in the lower levels of
the boundary layer rainfall totals should remain below .10 inches
for all areas through this afternoon. With limited forcing in the
mid levels the threat for strong to severe thunderstorm
development will be very low to nil. As mentioned above with
plenty of residual moisture lingering in the lower levels of the
boundary layer through tonight will continue mention patchy dense
fog for all inland areas early this morning...reforming again
mostly after midnight tonight continuing through early mon

Day time temps will be warmer today due to less mixing and better
sunshine by afternoon leading to highs in the lower to middle 80s
for all inland areas and the mid to upper 70s along the immediate
coast...due to the cooler sea surface temps and a persistent onshore
flow. For lows tonight have opted to go a degree or 2 above the
warmer mos numbers due to increasing clouds after midnight. 32/ee

SHORT TERM /Monday Through Tuesday night/...A fairly moist
southwest flow pattern aloft will continue across our forecast
area Monday on the base of a shortwave trough that will be lifting
across the Lower Mississippi and Tennessee Valley regions. A moist
southerly low level flow pattern will also continue Monday as
surface high pressure continues to nose from the western Atlantic
to the northern Gulf of Mexico, and surface low pressure moves
northeastward from the Plains to the Upper Midwest. Short range
guidance remains in agreement with the development of isolated to
scattered showers and thunderstorms across our forecast area
Monday as lift spreads overhead on the base of the shortwave
trough axis. The best coverage of convection looks to be favored
generally northwest of the I-65 corridor, and especially interior
southeast MS and southwest AL, where we will carry a 40-50% chance
of convection. We will need to monitor for a few strong storms
over our northwestern zones Monday afternoon, where a combination
of healthy instability (MLCAPE values around 1000 J/KG), deep
layer shear values around 40 knots, a bit steeper mid level lapse
rates will be co-located to aid in better storm organization.
There is a marginal risk of severe storms clipping Wayne and
Choctaw counties, but any storm northwest of I-65 may be capable
of producing strong/gusty winds and potentially some hail. We will
continue to mention potential of strong storms over those
interior areas Monday in the HWO. Highs Monday should range in the
upper 70s to lower 80s over the interior, and in the mid 70s near
the beaches. There may be some lingering convection over interior
areas at least into Monday evening. Otherwise, we expect partly to
mostly cloudy skies Monday night, with overnight lows in the lower
to mid 60s.

Shortwave ridging aloft may amplify a bit across our forecast area
by Tuesday. However, weak embedded impulses on the northern fringe
of the ridge axis may interact with a continued moist and
unstable airmass to aid in the development of isolated to
scattered showers and thunderstorms, primarily over interior
portions of our area Tuesday afternoon. Convection should quickly
diminish with loss of daytime heating, and we have a dry forecast
for Tuesday night. Highs Tuesday should range in the lower to mid
80s inland, with readings in the mid 70s to around 80 near the
coast. Lows Tuesday night should once again range in the lower to
mid 60s. /21

LONG TERM /Wednesday Through Saturday/...It looks like we get a
break in convective activity on Wednesday and Wednesday night as
medium range guidance is in agreement with placement of a deep
layer dry and subsident airmass over our CWA along continued
shortwave ridging aloft. Mostly sunny and warm temperatures will
continue Wednesday with highs once again warming into the lower
to mid 80s inland, and mid 70s to around 80 near the coast.
Overnight lows Wednesday night continue to range in the upper 50s
to lower 60s inland, with mid 60s along the beaches.

The next system we will be monitoring closely will be a rather
deep upper level low that will move from the vicinity of the TX/OK
Panhandles Wednesday, and eastward across the KS/OK/MO/AR
vicinity by Thursday. The 26.00Z operational GFS/ECMWF show some
agreement with ejecting a potent shortwave trough northeastward
across the Mississippi River Valley Thursday, then across the
central Gulf Coast states Thursday night in advance of the upper
level low. Though there are some differences on timing, large
scale ascent will generally spread across our region Thursday
afternoon into Thursday evening/night, with scattered to numerous
showers and thunderstorms likely to impact our area during this
time frame. This system appears that it could bring a better
potential for severe weather across our area Thursday into
Thursday night given potential for the development of rather
strong level jet (35-50 knots of 850 mb flow), up to around 1000
J/KG of MLCAPE, and steep mid level lapse rates (7-7.5 C/km). We
may be looking at a potential for all modes of severe weather with
this system, and will continue to highlight in the HWO. There is
also a signal for potential of locally heavy rainfall Thursday
afternoon and evening. Storm chances should decrease from west to
east late Thursday night into Friday morning as the shortwave
trough moves east of the region, with a drier forecast on tap
Friday into Saturday. Temperatures remain warm through the
extended forecast period. /21

MARINE...Expect mostly a moderate onshore flow to continue over
the marine area through midweek as high pressure near the surface
becomes reestablish along the eastern seaboard combined with a
developing low pressure system moving east over the mid section of
the country. seas at 2 to 5 feet early today will subside to 2 to
3 feet through midweek then build to 4 to 6 ft late thu into Fri.
isolated showers and thunderstorms will be possible mostly this
morning...reforming again by Mon afternoon on Mon night. 32/ee


AL...High Rip Current Risk through this evening for ALZ265-266.

FL...High Rip Current Risk through this evening for FLZ202-204-206.



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