FXUS64 KMOB 082333

Area Forecast Discussion
National Weather Service Mobile AL
633 PM CDT Wed Jul 8 2020

00Z issuance...A small cluster of convection was tracking east
southeast over the coast this evening at 20 to 30 kts. KPNS will
see the passage of tsra between 09.00-09.01Z, bringing reduced
cigs to MVFR categories and perhaps localized strong wind gusts up
to around 30 kts. KMOB and KBFM is behind the convection with
residual shra in the forecast in the near term for these two
sites. Cigs mostly at high levels. Winds light and variable. /10


.PREV DISCUSSION... /issued 331 PM CDT Wed Jul 8 2020/

NEAR TERM UPDATE /Now Through Thursday/...Scattered to numerous
storms have already developed over Southeastern Mississippi and
Southwestern Alabama in advance of a subtle shortwave moving over
central Mississippi. Storms will continue to quickly march east
throughout the afternoon before dissipating sometime this evening
as the trough quickly moves out of the area. The rather early
start to the storms will likely be a big limiting factor on any
severe potential this afternoon. CAPE values are highest west of
I-65 and drop off the further east you go. This will 1. likely
lead to a weakening trend in the storms as they cross our area and
2. keep any major severe threat over southeastern Mississippi and
extreme southwestern Alabama. Storms should subside later

Looking at the bigger picture, upper level ridging over New Mexico will
begin to strengthen as we go into Thursday leading to
northwesterly winds aloft. At the surface, high pressure will
remain anchored over the Central Gulf leading to light west to
southwesterly flow tomorrow. With the northwesterly flow aloft,
mid-level drier air will begin to work its way into the area. This
will likely lead to potentially more CAPE values and microburst
risk; however, dry air entrainment and lack of a true forcing
mechanism will likely limit coverage. One potential area of focus
will be along what appears to be a weak convergence zone that
stretches from about Meridian MS southeast towards the Florida
Panhandle. Along this zone will be the best chances for afternoon
showers and thunderstorms.

Temperatures Today will remain steady in the mid to upper 80s
except where ongoing storms have cooled temperatures into the low
to mid 70s. Tomorrow will likely see slightly higher temperatures
with the lower storm coverage and the presence of the upper
ridge. Temperatures will likely climb into the low 90s along the
coast with upper 80s further inland where storms will be more
likely. BB/03

SHORT TERM /Thursday night Through Saturday night/...Upper level
ridging will build over the Southwestern U.S. through the end of
this week into the first part of the weekend. As this occurs, an
upper trough will dig southeast from the Northern Plains into the
Southeast U.S. This will transition the mid and upper level flow
from zonal to northwesterly over the Deep South. A series of subtle
shortwaves will move through the flow aloft and initiate scattered
to numerous showers and thunderstorms through the period, with the
greatest coverage during peak instability each day. In fact, by the
weekend the upper pattern favors the development of upstream
mesoscale convective systems over the Middle Mississippi into the
western Tennessee Valley/s with enhanced mid level flow aloft. These
MCS/s should weaken with southeastward extent but may serve to send
mesoscale outflow boundaries into our area where new convective
development is expected. These mesoscale details are difficult to
predict at these more extended ranges and will ultimately determine
where the areas of higher convective coverage will occur.

Models continue to suggest drier mid level air overspreading the
very moist low levels with weak deep layer shear. This should serve
to increase our wet microburst risk through the short-term forecast
period. A few severe wind gusts will be possible both Friday and
Saturday afternoon with the most intense storms.

High temperatures should remain seasonably hot with highs reaching
the lower 90s, with dewpoints well into the 70s. This will result in
heat indices between 100 and 105 degrees each day. Lows will remain
in the 70s. /JLH

EXTENDED TERM /Sunday Through Wednesday/...The forecast area
will remain positioned between a large upper level ridge to the west
and a seasonably deep upper trough along the East Coast.
Northwesterly flow aloft will continue to favor MCS development to
our northwest with outflow boundaries likely serving as convective
initiating boundaries to the southeast over our forecast area
through Sunday night. Scattered to potentially numerous showers and
thunderstorms can again be expected through the end of the weekend.
Temperatures and humidity levels will remain seasonably high.

The upper trough over the eastern states will gradually lift out
towards the northeast by early next week as the mid and upper level
ridge to our west builds eastward. The Gulf Coast should remain to
the south of the ridge axis with the flow becoming
northeasterly/easterly. Although pops will lower as compared to
early in the forecast period, there should still be lowered heights
along the central Gulf Coast and continued chances for mainly
diurnally enhanced showers and thunderstorms through early next

Temperatures should increase by early next week with highs
ranging from the lower to middle 90s, with lows in the 70s. These
high temperatures combined with dewpoints well into the 70s. This
may result in heat indices approaching heat advisory criteria of
greater than 108 degrees. This potential will be monitored over the
next several days. /JLH

MARINE...Moderate westerly winds may result in eventually needing
Small Craft Exercise Caution wording mainly over the open Gulf
waters Thursday night into Friday and also Sunday night. No other
impacts are forecast except winds and waves higher near showers and
thunderstorms. /29/03




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