Area Forecast Discussion Issued by NWS Mobile, AL
000
FXUS64 KMOB 100506
AFDMOB
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1206 AM CDT Sat Jun 10 2023
...New AVIATION...
.AVIATION...
(06Z TAFS)
Issued at 1206 AM CDT Sat Jun 10 2023
VFR conditions will prevail through the period. Any redeveloping
and/or lingering showers and storms south of Highway 84 this
evening will dissipate around midnight. Scattered showers and
storms will develop again Saturday afternoon area-wide, and
lingering into the evening hours. Brief reductions in ceilings
and visbys in and near storms will occur. Winds will be light and
variable overnight, becoming light southerly on Saturday. /22
&&
.PREV DISCUSSION... /issued 317 PM CDT Fri Jun 9 2023/
.New NEAR TERM, SHORT TERM, LONG TERM, MARINE...
NEAR TERM...
(Now through Saturday)
Issued at 317 PM CDT Fri Jun 9 2023
Another round of showers and thunderstorms are expected to
develop this afternoon. With better moisture levels stretching
southeast across the center of the forecast area (precipitable h20
levels around 1.6" at this time on the latest analysis),
combining with a weak southward moving surface boundary along the
Highway 84 corridor and a seabreeze developing along the coast at
this time expected to move inland, initial formation of showers
and thunderstorms are expected to be along the coast inland to
areas south of I-65. This convection is expected to last into the
evening hours. Light northwest to northerly steering winds will
guide most of the convection to the southeast to south, though
stronger outflows may lead to more inland development. With
MLCapes rising into the 1500-2000J/kg range, some of this
convection may become strong to marginally severe, with strong
winds and small hail possible. Another round is expected to
develop on Saturday, again in the afternoon over land areas.
Isolated showers and thunderstorms will be possible south of the
coast, with waterspouts possible along any outflow boundaries over
the Gulf waters.
High temperatures around seasonal norms are expected this
afternoon and Saturday, with a mean upper trough in place along
the East Coast limiting upper subsidence somewhat from an upper
ridge over the Plains. High temperatures in the upper 80s to low
90s expected this afternoon and Saturday. Tonight, guidance is
advertising weak northerly flow remaining in place, helping to
maintain a bit drier airmass over the northern half of the
forecast area. This drier air will bring better overnight cooling
and temperatures dropping to a bit below seasonal norms along and
north of highway 84. Low temperatures in the mid 60s north to
around 70 closer to the coast are expected tonight. /16
SHORT TERM...
(Saturday night through Monday night)
Issued at 317 PM CDT Fri Jun 9 2023
A series of shortwaves transit the southern tier of the U.S.
Saturday night into Monday night and beyond. Upper level troughing
and ultimately a cutoff upper level low becomes established across
the Great Lakes region during this time. The sub-tropical jet
becomes strong by the end of the period with strengthening
northwest flow aloft expected, particularly in association with
each mid to upper level shortwave. This in turn will boost our
rain chances at any given point in time, with better chances
likely during peak heating during the afternoon hours.
In addition to the boosted precip chances, severe weather
potential begins to increase somewhat as we move through the
period. Ample surface based instability will be present across the
area with generally 3,000 to 4,000j/kg SBCAPE during the day and
1,000 to 2,000j/kg of SBCAPE during the overnight. Deep layer
shear steadily increases during the period owing to the
strengthening flow aloft, with largely straight line hodographs
with some low level curvature. These values go from generally 20
to 30kts Sunday into Sunday night to 35 to 45kts by Monday into
Monday night. With all of that in mind, the most likely scenario
would be the potential for organized severe weather in the form of
MCS`s that develop upstream which then subsequently track into
the area. Predictability of these is low this far out, but at a
minimum some organized severe convection appears possible during
the period in addition to the typical diurnally forced
afternoon/evening strong to severe thunderstorms. Hazards with any
storms during the short term period will include damaging wind
gusts and small hail.
Forecast temperatures will remain warm with highs in the lower
90`s and lows generally in the upper 60`s and lower 70`s inland
while middle to upper 70`s persist nearer the coast. Heat index
values will also be on the rise as well, with some spots flirting
with a heat index value of 100 degrees on Monday afternoon,
particularly nearer the coast. A low risk of rip currents remains
through the period. MM/25
LONG TERM...
(Tuesday through Friday)
Issued at 317 PM CDT Fri Jun 9 2023
Through the period, a generally northwesterly to westerly flow
aloft persists as a deep anomalous low pressure located over the
Great Lakes tracks east into the northeast CONUS late in the week,
with ridging building over the Gulf. Several embedded shortwave
impulses are expected to move through the flow aloft through the
week, which will help PoP chances stay around through the period,
some potentially active weather days. One reason for this is that
guidance is now hinting that the ridging previously forecast over
the Gulf will not be as strong. This will allow the shortwave
parade through the week to end up over our region instead of being
shunted north, thus resulting in a continuation of active weather
through the period. At the surface, uncertainty remains through
the period as to where the frontal boundary from the short term
will end up. As a surface low pressure system develops in
association with the low pressure aloft, it quickly occludes over
the Great Lakes region helping to send a weak frontal boundary
into the southeast US. This boundary then looks to stall through
most of the week somewhere over MS/AL. If this boundary is able to
push in and stall over our region, it could provide a low-level
focus for storms to develop and/or move along.
In terms of sensible weather, latest models continue to suggest
that 0-6km bulk shear values could be between 40-50kts through the
period. These values are supportive of more organized convection
as opposed to typical pulse-type storms that we normally see
during the summer. Thus, throughout the period, in addition to
monitoring diurnally driven afternoon convection, eyes will also
point upstream as each shortwave disturbance pushes within the
northwesterly to westerly flow aloft. This is because the overall
environment supports the development of several organized clusters
of storms (MCS`s) that would quickly dive southeastward as they
follow the parade of shortwaves aloft. However, as previously
mentioned, storm coverage (and MCS tracks) will largely depend on
the location of the surface frontal boundary as well as the
strength of the ridge, especially as we head into midweek.
Ultimately it boils down to that a stronger ridge/further north
stalled boundary should help to keep any MCS that develops to our
north, which in turn would lead to lower PoPs/lower severe risk. A
weaker ridge/stalled boundary over our region may allow for the
MCS`s to track into our region, leading to higher PoPs/higher
severe risk. As of now, confidence in strong to severe storms
continues to have an overall poor predictability and will be
dictated by how the synoptic and mesoscale environment through the
week pans out. Given that trends in the evolution of this system
will dictate PoP chances and potential severe weather through the
week, we will continue to monitor these trends and adjust
accordingly moving forward. For now, will continue to follow NBM
guidance for PoP chances through the week which keeps values
generally in the 20-40% range given the uncertainty that still
remains.
As for temps, highs are forecast to generally range in the upper
80s to low 90s, with some interior locations reaching the mid 90s.
Lows are forecast to gradually warm through the period ranging
from the upper 60s to low 70s inland to the mid to upper 70s
closer to the coast on Tuesday, climbing into low to mid 70s
inland with upper 70s to near 80 as that coast by Friday. Lastly,
rip current risk looks to remain low through Tuesday, but will
likely increase through the week as onshore flow increases. JEH/88
MARINE...
Issued at 317 PM CDT Fri Jun 9 2023
Weak, diurnally driven winds expected through the forecast. No
impacts expected other than locally higher winds and waves near
daily thunderstorms. /16
&&
.PRELIMINARY POINT TEMPS/POPS...
Mobile 71 89 72 90 70 90 73 91 / 30 50 20 50 20 30 10 20
Pensacola 75 86 76 89 74 90 75 90 / 30 60 20 50 20 30 10 20
Destin 76 86 77 88 76 89 76 87 / 20 60 20 40 30 30 10 20
Evergreen 68 89 69 89 67 90 69 93 / 30 60 40 50 20 30 10 30
Waynesboro 68 90 68 89 66 89 69 93 / 40 50 40 50 20 30 10 30
Camden 68 89 66 87 64 88 67 91 / 30 60 60 50 20 30 20 30
Crestview 69 90 71 90 69 92 70 93 / 30 60 20 50 20 40 10 30
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&
$$
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