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Area forecast discussion...updated 
National Weather Service Mobile Alabama
1202 am CDT sun Jul 31 2016

Discussion...updated for latest aviation discussion below.


flight categories are expected to remain VFR across area terminals
through the overnight hours. An exception could be in locales that
received rain showers/thunderstorms and rain Saturday afternoon, where some patchy br might be
seen. More rain showers/thunderstorms and rain are expected to move onshore the Alabama/Florida coasts
by late Sunday morning, with additional convection developing inland
after 31/1800 UTC. Even though flight categories should largely
remain VFR, there may be some local categorical ceiling/visibility reductions
in vicinity of any shra/tsra. /02/


Previous discussion... /issued 1124 PM CDT Sat Jul 30 2016/

Discussion...see updated information for land areas below. /02/

spotty showers continue to weaken across areas along and north of the
US-84 corridor at late evening. Elsewhere, dry conditions prevailed
and should continue to do so until the early morning hours. As
previously mentioned, isolated showers should develop over the Gulf
of Mexico (after 2 am) and could affect the immediate coastal areas
through sunrise.

Somewhat disheartening is a peek upstream toward the arklamiss, where
a complex of thunderstorms continues trekking eastward. Infrared
satellite imagery shows some cloud top cooling associated with this
system as it moves across the Mississippi River. MLCAPE values drop
below 500 j/kg as cin increases across east-central Mississippi. With
greater instability expected to remain closer to the coast, i'm still
somewhat confident that areas away from the coast will see mainly dry
conditions through sunrise.

With this update, precipitation probabilities have been adjusted
through sunrise. /02/

Previous discussion... /issued 933 PM CDT Sat Jul 30 2016/

Discussion...see updated information for land areas below. /02/

latest subjective upper-air analysis shows little significant change
in the overall weather pattern across our region. A weakness in the
upper ridge continues extending from the upper Midwest into
the Tennessee Valley.

Today's convection continues to wane both in coverage and intensity
at mid-evening with the loss of daytime heating. Ongoing convection
will likely continue for another couple of hours until dissipating,
leaving much of the area dry for the rest of the nighttime hours.
The exception could be the immediate coastal areas. Isolated
showers are expected to develop over the nearshore Gulf of Mexico
waters between midnight and 3 am, and could move onshore toward

Overall, no significant change has been made to the ongoing forecast
at mid-evening. There have been some minor tweaks, especially to
the pop forecast, based upon observational trends. An additional
update or two to lower precipitation probabilities further and
refine timing marine shower development is possible before midnight.

Previous discussion... /issued 652 PM CDT Sat Jul 30 2016/

Discussion...updated for latest aviation discussion below. /02/

expect convective coverage to diminish with the loss of daytime
heating, with mostly VFR flight categories anticipated through the
night. Latest probabilistic guidance suggests the possibility of
lower cigs/vsbys toward sunrise along and just north of the ih-10
corridor. But confidence is too low for inclusion in tafs at this
time. Expect another round of rain showers/thunderstorms and rain moving onshore late Sunday
morning with additional rain showers/thunderstorms and rain possible by Sunday afternoon.
Flight categories may be locally reduced in vicinity of any
shra/tsra. /02/

Previous discussion... /issued 354 PM CDT Sat Jul 30 2016/

Near term /now through Sunday/...deep upper ridge will continue
over much of the deep south and central Gulf states through sun. To
the north a passing mid level impulse moves from the mid MS River
Valley to the Appalachians...stretching down across the MS and al
late this afternoon and overnight providing slightly better forcing
or lift for showers and thunderstorms to develop upstream over la
and MS this afternoon maintaining strength while tracking east over
central and lower parts of al this afternoon and early tonight. With
this pattern expect better coverage of showers and thunderstorms
over northern sections of the forecast area later this afternoon and
early tonight becoming more isolated in coverage further to the
south. By late tonight and early sun with the higher sfc temps along
the coast and offshore the better instability shifts south resulting
in more isolated to scattered showers and thunderstorms offshore and
along the coast early Sun morning transitioning inland by late
morning and afternoon as daytime heating increases. Latest model
soundings show slightly higher CAPES and mid level lapse rates for
today compared to yesterday suggesting a few stronger storms will be
possible with gusty straight line winds...frequent cloud to ground
lightning and periods of very heavy rain. With pwats still hovering
around 2 inches for most locations some minor flooding mainly local
will also be possible with the some of the stronger thunderstorms
today and on sun. For sun expect about the same coverage of precip
throughout the day with a little less intensity with some of the
stronger storms by late afternoon due to less forcing in the mid
levels. As for temps lows will continue range from the mid 70s for
inland areas and the upper 70s to lower 80s along the immediate
coast. Highs on sun will range from the lower to middle 90s for
inland areas and the upper 80s to lower 90s along the immediate
coast. 32/ee

Short term /Sunday night through Tuesday night/...very little
change in sensible weather expected from Sunday night through
Tuesday night. A moist airmass is expected to remain over the
region with deep layer ridging continuing aloft. Precipitable
water (pwat) amounts are expected to remain the two inch
region. Diurnally driven convection will continue likely producing
some heavy downpours at times but severe weather potential looks to
remain on the low end of the risk spectrum as vertical shear remains
low and wet bulb zero (wbz) temperatures generally remain
elevated...14000' and higher. The forecast area looks to fall more under
the eastern flank of the ridge over the Southern Plains by Tuesday and
exposed to minor waves propagating southward down it could
potentially enhance convection and possibly inject enough dry air in
the mid levels to lower wbz heights Tuesday and Tuesday night. The
GFS projects this but the European model (ecmwf) does not. Temperatures and
precipitation probabilities will trend near to a little higher than
climatological norms.

Long term /Wednesday through Saturday/...overall little change
anticipated in the weather pattern over the region. Deep layer
ridging remains in place with precipitable water values remaining in the 2 inch
area. Moderate afternoon instability will continue but limited shear
and elevated wbz heights will keep the threat of widespread severe
weather minimal. A hot and humid pattern will persist with
temperatures continuing to trend near to a little warmer than normal.

We are monitoring the evolution of the two tropical disturbances in
the Atlantic. At this time...we are not anticipating any impacts
locally but things could change so we will continue to watch their
evolution closely. Please refer to the National Hurricane Center for
the latest updates.

Marine...high pressure will continue over the eastern and north
central Gulf through much of next week...leading to a light south to
southwest wind flow to continue through the forecast pd...with a
light west to northwest flow developing near the coast each night.
Latest progs from TPC show a fast moving tropical wave over the
Caribbean and SW Gulf by mid to late week possibly leading to better
coverage of showers and thunderstorms over much of the Gulf by late
in the forecast period. Better swell will also be possible moving
northward into the northern Gulf late in the week. Tides could also
run a tad higher than predicated levels by mid to late week. For now
the system looks to move into lower Mexico late in the period.
Otherwise...winds and seas will be higher near isolated to scattered
showers and thunderstorms through the forecast period. 32/ee


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