Areal Flood Advisory 81, NWS Mobile, AL

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
643 AM CDT Sat Jul 3 2021

.AVIATION...
12Z issuance...A weak frontal boundary moves southward to near the
coast today, where it will stall tonight. Numerous showers and
storms are expected to develop near the coast today with
progressively less coverage further inland. Light westerly winds
today, except for becoming southwest near the coast. MVFR
conditions will accompany the heavier showers and storms. /22

&&

.PREV DISCUSSION... /issued 438 AM CDT Sat Jul 3 2021/

NEAR TERM UPDATE /Now Through Sunday/...A positively tilted
upper trof over the eastern states slowly lifts northeastward
during the period. While the upper trof will be lifting away from
the region, an upper level weakness is left lingering over the
northern Gulf. While the progression of the upper trof allows for
drier air to flow into much of the area, the presence of the upper
level weakness acts as a wall of sorts, which in turn maintains
higher deep layer moisture content over the coastal counties
compared to further inland. A weak frontal boundary oriented east-
west across central Alabama/Mississippi progresses slowly
southward to near the coast through noon where it lingers through
Saturday night. Considering the distribution of moisture and
placement/movement of the frontal boundary, will start off the day
dry, followed by likely pops near the coast this afternoon with
pops tapering off to zero far inland. Pops will then taper off
from north to south through the overnight hours. The weak boundary
is expected to dissipate on Sunday while progressing inland
during the day (along with improving deep layer moisture
progressing further inland), and have gone with chance to good
chance pops for the central and southern portion of the area while
well inland will have mainly slight chance pops. Highs today and
Sunday will be in the upper 80s to lower 90s. Lows tonight range
from the mid/upper 60s well inland to the mid 70s along the coast.
A low risk of rip currents is expected through the period. /29
/22

SHORT TERM /Sunday night Through Monday night/...The aforementioned
upper trough in the near term continues lifting off to the
northeast. Our region remains in a general weak west-southwest
flow aloft as weak longwave upper level troughing left behind
lingers over our CWA through the period. At the surface, the
frontal boundary mentioned in the near term begins to wash out as
weak high pressure over eastern Gulf shifts north. Monday into
Monday night, Hurricane Elsa is expected to pass over Cuba, and
begin to entering the southeastern Gulf of Mexico.

As the weak frontal boundary becomes washed out Sunday night into
Monday, return flow is able to become more reestablished. PWATs
increase over the region to around 2-2.2 inches as moisture
spreads inland through the period. As this increasing moisture
spreads inland, so do the rain and storm chances with much of the
CWA under likely PoPs on Monday. Rain and storm chances taper of
Monday night before increasing again going into the extended.
Ultimately, weather moving forward will largely depend on how
Hurricane Elsa evolves through this period. Otherwise, low temps
through the short term remain generally near 70 far inland to low
to mid 70s closer to the coast. High temps on Monday are expected
to be in the upper 80s to low 90s north of I-10, with mid 80s
closer to the coast. JEH/88

EXTENDED TERM /Tuesday Through Friday/...Benign upper level flow
exists during the early portions of the extended period with the CWA
situated between two upper level ridges. We have the subtropical
ridge to the east stretching into the southwestern Atlantic, and
another ridge situated over the southwestern U.S. Tuesday. An upper
level trough during the short term period lifts out of the
northeastern U.S., however in its wake there is a weakness in the
mid to upper level ridging over the southeastern U.S. that will
allow for Elsa to track northward across Cuba and into the eastern
Gulf of Mexico. A surface high pressure will reside to the east of
Elsa, also aiding in the steering of the tropical cyclone and
promoting general southerlies to southeasterlies over the region.

The track of Elsa is uncertain, with the near term period being
critical in Elsa's future. Elsa's strength will determine its near
to short term track, and any differences of more than a few tenths
of a degree latitude will make a worlds difference heading into the
extended period. For now, model consensus keeps Elsa in the eastern
Gulf of Mexico or even into the southern half of the Florida
peninsula. Despite this, it is important to stay vigilant given the
uncertainties involved in future track/intensity, and we will
continue to monitor the evolution of Elsa over the coming days.

Outside of Elsa, a plume of higher PWATs will likely advect into the
region Tuesday into Wednesday, helping to increase rain and
thunderstorm chances across the region. Have opted to keep chance to
likely PoPs in the grids to account for this. Elsa will have moved
inland by Wednesday, and a fetch of deep, tropical moisture will
likely linger across the region into Thursday. Given this, have
continued likely PoPs for Thursday afternoon. After this, we return
to a more normal Summer-like pattern by Friday with chance for
showers and thunderstorms in the afternoon. Temperatures will be
dependent on cloud cover, however anticipating Elsa to remain far
enough east to allow for sufficient heating over the region.
Generally anticipate highs in the upper 80's to perhaps lower 90's
each day. Lows will be in the lower 70's.

Regardless of Elsa's track/intensity, this serves as a good reminder
to review your tropical preparedness plans and ensure you are ready
for if/when a tropical storm/hurricane comes your way. Preparedness
for the hurricane season can go a long way in ensuring you and your
families safety in the face of a tropical storm/hurricane. MM/25

MARINE...Small craft operating on the Gulf waters should exercise
caution today due to westerly winds of 13 to 18 knots. We will
continue to monitor the progression of Tropical Storm Elsa as it is
forecast to enter into the southwest Gulf of Mexico Monday
afternoon. Any impacts at this time would be late in the forecast
period (Tuesday night into Wednesday) with increasing long period
swells. Otherwise, light to moderate westerly winds will persist
through Saturday night, shifting southwesterly on Sunday then
southerly on Tuesday. /22

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&

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