Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 090943

Area Forecast Discussion
National Weather Service Mobile AL
443 AM CDT Fri Jun 9 2023


(Now through Saturday)
Issued at 443 AM CDT Fri Jun 9 2023

An upper level northwest flow pattern will continue today as the
area remains on the western side of an eastern states trough. A
few embedded shortwaves moving through the upper trough will push
a weak cold front into the area this afternoon. This will bring
some drier air into mainly interior zones behind the front.
Isolated to scattered showers and thunderstorms will continue
across the area mainly during the afternoon and early evening
hours. The coverage of showers and thunderstorms will be enhanced
near the coastal sea breeze this afternoon and not be able to move
very far north due to the northwest flow. Convective coverage
today will be highest across southern portions of the area as some
drier air works into northern portions of the area. The trough
moves east on Saturday, returning the area to westerly upper flow.
An approaching shortwave along with increased deep layer moisture
will bring a higher rain chance by Saturday afternoon. Highs will
generally be in the upper 80s and low 90s with mid and upper 80s
along the coast. /13


(Saturday Night through Thursday)
Issued at 443 AM CDT Fri Jun 9 2023

A powerful, anomalously deep upper-level low is expected to
develop over the Great Lakes region on Sunday and slowly meander
eastward through midweek. In addition, upper-level ridging will
also build over Mexico. For our area, the result of these two
features is a strengthening northwesterly flow pattern which
remains prominent throughout the entire period. Several embedded
shortwaves are expected to push through this flow, helping to
bring a period of active weather to our region. One key difference
to note in guidance this morning is that the ridge may not be as
strong as previously indicated. If this trend is correct, the
train of shortwaves could actually remain over our region as
opposed to being shunted northward during the Tuesday through
Thursday timeframe. The result of this would be a continuation of
active weather through midweek. Another uncertainty during this
period will be the location of a surface frontal boundary. As a
surface low pressure system develops in association with the upper
low, it quickly occludes over the Great Lakes region helping to
send a weak boundary into the southeast US, which eventually
stalls somewhere over Mississippi and Alabama. 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. We will
continue to monitor these trends and adjust PoPs accordingly,
especially as we approach midweek.

In addition to the sufficient forcing, ample moisture, and high
instability in place (CAPE values around 2000 J/kg on Sunday,
increasing to 3000-4000 J/kg by midweek), the strengthening
northwesterly flow pattern aloft will help to give way to increasing
deep-layer shear throughout the period. In fact, latest models
suggest that 0-6km bulk shear values could be between 25-35kts on
Sunday and Monday and increase further to 40-50kts for Tuesday
through Thursday. This would be supportive of more organized
convection as opposed to typical pulse-type storms that we normally
see during the summer. Throughout the period, in addition to
monitoring diurnally driven afternoon convection, eyes will also
point upstream as each shortwave disturbance pushes within the
northwesterly flow aloft. The overall environment supports the
development of several organized clusters of storms (MCS`s) that
would quickly dive southeastward as they follow the train of
shortwaves aloft. As mentioned before, 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. 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. Confidence/storm
coverage is higher for Sunday and Monday, where scattered to
locally numerous storms are forecast. However, moving into Tuesday
through Thursday, decided to cap PoPs at 20-40% for now due to
higher amounts of uncertainty.

Highs will generally be in the upper 80s to low 90s, with a few
interior locations reaching the mid 90s. Lows will range from the
upper 60s to low 70s inland to the mid to upper 70s closer to the
coast. /96


Issued at 443 AM CDT Fri Jun 9 2023

No impacts expected other than locally higher winds and seas
possible near thunderstorms. /13


Mobile      93  70  91  71  90  73  91  72 /  50  20  60  20  30  30  40  20
Pensacola   89  73  87  75  87  76  90  75 /  40  20  60  20  30  30  50  20
Destin      85  75  84  76  86  76  88  77 /  40  20  40  20  30  30  40  20
Evergreen   91  67  92  69  90  71  92  69 /  30  10  60  20  50  40  50  20
Waynesboro  91  67  92  68  92  70  91  67 /  40  20  60  30  40  40  30  20
Camden      89  65  92  69  91  69  90  67 /  20  10  40  30  50  50  50  20
Crestview   93  68  91  70  90  72  92  71 /  50  20  60  20  50  30  50  20




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