Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 222328
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
628 PM CDT Sun Sep 22 2019

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...
00Z issuance...VFR conditions and light southeast winds prevail
through the period. /49

&&

.PREV DISCUSSION... /issued 254 PM CDT Sun Sep 22 2019/

NEAR TERM /Now Through Monday/... A large upper high pressure
system over the southeast conus will shift slightly southwestward
over the next 24 hours in response to an upper low pressure system
moving eastward over the upper midwest and Great Lakes regions.
As the center of the upper high moves from the central
Alabama/Georgia state line to over southeast Mississippi and
southwest Alabama, this will reinforce the large-scale subsidence
over the forecast area. A surface ridge of high pressure extending
southwestward from a Bermuda high pressure system across the
southeast states to the northern Gulf of Mexico will shift
slightly southward and weaken as a surface trough passing well
north of the region sends a cold front through Kentucky and
Tennessee Monday afternoon. A dry weather pattern however will
remain through the near term, with only a few cumulus clouds
developing throughout the day Monday.

Low temperatures tonight will be near normal, ranging from 64 to
69 degrees inland areas, with lower 70s along the immediate coast.
High temperatures Monday will be 5 to 7 degrees above normal,
with low to mid 90s inland areas, and upper 80s at the beaches.
/22

SHORT TERM /Monday night Through Wednesday night/...Upper level
ridge axis centered over the central Gulf coast Monday night slips
slowly southward into the eastern Gulf Tuesday. This allows a
zone of high level westerlies to set up over the interior zones.
At same time, a surface front is draped from AR to central parts
of MS/AL on up across the coastal Carolinas. Embedded in the
frontal circulation will be a narrow zone of better environmental
moisture characterized by PWATs ~2.00". Considering frontal ascent
approaching from the north, passage of mid-level impulses in the
westerlies aloft and daytime instability, isolated to perhaps
scattered storms will be advertised by Tuesday afternoon over the
interior zones. The frontal circulation does not make much
southward progress, stalling over the southeast into the day
Wednesday. However, deep moisture eases southward to the coast and
with the development of a weak coastal sea-breeze, there could be
enough lift to help in the initiation of isolated showers and
thunderstorms.

As far as highs, unseasonable warmth continues. Highs in the
lower to mid 90s range some 8 to 10 degrees above climo. Little
change in overnight lows, remaining warm about 4 to 8 degrees
above seasonal. /10

LONG TERM /Thursday Through Sunday/...Upper ridge axis extends
across the FL peninsula and southeast states to close out the
week, before amplifying=>strengthening and expanding with its axis across
TX to over the southeast for the weekend. The North American
Ensemble has also shown a tendency to be stronger with the mid-
level ridge building over the deep south for Saturday and Sunday
than was shown a day ago with H50 heights of 594+ decameters shown
to be more expansive over the Ark-La-Tex and the MS Delta.
Overall, this remains some 2 to 3 standard deviations above the
climatological means. The massive deep layer ridge favors hot
temperatures and very meager rain chances during the medium range.
Forecasters wouldn`t be surprised if a few locations in our
interior approach the 100 degree mark, especially by the weekend
when the strength of the upper ridge is stronger. This of course
would set new records to close out the month of September. /10

MARINE...A light south to southeast wind flow will gradually become
east tonight as high pressure to the northeast shifts toward the
southwest. A southwest to westerly flow is then expected Monday
night through midweek as a cold front approaching the area from the
north stalls just north of the coast. A light onshore wind flow will
then resume late in the week as a ridge of high pressure becomes re-
established across the northeast Gulf of Mexico. /22

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through Monday evening for ALZ265-266.

FL...High Rip Current Risk through Monday evening for FLZ202-204-206.

MS...None.
GM...None.
&&

$$

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