Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 290459
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1159 PM CDT Sat Mar 28 2020

.AVIATION...
06Z issuance...A mixed bag of MVFR and VFR conditions are present
across the area. A weak cold front will enter the area late
tonight and slowly progress from northwest to southeast before
stalling near the coast. Ahead of the front, winds will remain
light out of the south. MVFR cigs will likely continue to fill in
and while a few IFR cigs may be in the vicinity, confidence is
extremely low with little guidance support. Some areas of patchy
fog may develop but VISBYS should remain above IFR. A few showers
and storms will be possible along the front. Winds will become
northwesterly tomorrow evening behind the front. BB/03

&&

.PREV DISCUSSION... /issued 1022 PM CDT Sat Mar 28 2020/

NEAR TERM /Now Through Sunday night/...Finally a little change
from the beastly ridge that has brought record highs and dry
weather for what seems like the whole month of March. A strong
upper trough currently centered over the northern plains will
continue to progress eastward tonight as a deepening surface low
near Iowa continues to occlude. Adjacent to the surface low, a
polar front will continue to surge southeastward across
Mississippi. Showers and storms will accompany the front all the
way to our doorstep. Unfortunately with the upper forcing
displaced well off to the north, most of the rain will likely fall
apart. High resolution guidance continues to have a rather lame
and wimpy line of "showers?" move into our northwestern zones late
tonight and approaching the I-65 corridor between 9 am and noon.

With the front loosing its forcing and the upper trough quickly
moving off to the northeast, the line or whats left of it will
probably slow and stall somewhere east of I-65. I wen`t ahead and
lowered the chance of rain for tomorrow given the high res
guidance and most areas will probably not see rain tomorrow. Dry
conditions will move in behind the front with better rain chances
returning in the short term.

Outside of the chance of rain, there could be some patchy fog
ahead of the front early tomorrow morning. Given dewpoints in the
low 70s and continued southerly flow, the pattern supports some
fog much like last night. Low temperatures will remain warm
tonight with high 60s inland and near 70 at the coast. Even with
the presence of the front, temperatures will likely warm up into
the low 80s tomorrow and given how weak the front is don`t expect
much of a cooldown if any from this one. For a good cool down you
will have to look towards the extended period. High risk of rip
currents will as continue through tomorrow with the continued
southerly flow. BB/03

PREV DISCUSSION... /issued 644 PM CDT Sat Mar 28 2020/

NEAR TERM UPDATE /Now Through Sunday night/...Overall the
near term forecast remains on track with no changes during this
cycle. We still expect a rather weak and piddly line of storms to
move into the area late tonight associated with a weak cold front.
The best chance of rain remains north and west of I-65.
Temperatures will remain mild tonight with southerly winds
continuing. With the continued southerly wind, a high risk of rip
currents will continue into tomorrow. BB/03

AVIATION...
00Z issuance...VFR conditions across the area will continue into
the night. Winds will remain southerly through midnight as a weak
front will approach the area tonight. Ahead of the boundary, cigs
might drop to MVFR values tonight and persist into the morning.
Some area of patchy fog could be possible but kept visbys in the
MVFR category. Showers and a few storms will be possible late
tonight north and west of I-65 but should diminish throughout the
night. By tomorrow ceilings should rise in the wake of the front
as winds turn out north northwest by tomorrow night. BB/03

PREV DISCUSSION... /issued 408 PM CDT Sat Mar 28 2020/

NEAR TERM UPDATE /Now Through Sunday/...The upper level ridge
will begin to break down and move eastward today as a trough makes
its way over the central CONUS. This feature will quickly develop
into a cutoff low that will progress northeastward up through the
upper Mississippi Valley and over the Great Lakes region by late
weekend. This will then result in a more zonal pattern by late
weekend for the northern Gulf coast. Coincident with the upper
levels, a surface low pressure system will track across the
central Plains and over the Great Lakes through the weekend. A
cold front associated with this low will track across the ARKLATEX
region this evening and overnight tonight. By tomorrow morning,
the front will be on our doorstep with FROPA expected tomorrow
evening.

Sensible weather will consist of dry conditions for the rest of this
afternoon and this evening. Some mid-level clouds have formed and
are streaming in from the south this afternoon as well. Some patchy
fog development is possible over the inland areas late tonight,
particularly in the east as shown by model probabilities. However,
any fog will quickly dissipate by tomorrow morning. Clouds will also
be on the increase overnight as a cold front approaches the region
from the northwest. Hi-Res models show a line of showers and
embedded thunderstorms traversing the southeastern CONUS late
tonight, but weakening substantially over time through tomorrow
morning and afternoon with FROPA. Models indicate around 500 to 700
J/kg of MLCAPE, with around 1000 J/kg along and just ahead of the
front as it passes over the region. Although, it will remain to be
seen whether the convective inhibition present will hinder any
thunderstorm development. Nevertheless, there is at least a slight
chance of a few embedded thunderstorms tomorrow with the amount of
elevated instability shown by model guidance. Showers and any
embedded storms will then gradually decrease through the afternoon.

Temperatures will continue to be well above seasonal norms this
afternoon, with highs in the mid to upper 80s expected. Lows tonight
will then be in the mid to upper 60s inland to around 70 degrees
right along the coast. Highs tomorrow will be a bit cooler due to
FROPA, with temperatures in the lower 80s expected in the west and
mid to upper 80s likely in the east.

Lastly, a HIGH risk of rip currents continues through Sunday, mainly
due to 2 ft/6-10 sec onshore swell. /26

SHORT TERM /Sunday night Through Tuesday night/...A deep layer
ridge of high pressure will extend from the southern Gulf of
Mexico through the FL peninsula and adjacent western Atlantic on
Sunday night. West to southwest flow aloft will be prevalent
across the north central Gulf Coast region to the northwest of
this feature. A weak shortwave trough within this flow pattern
will allow the weak surface cold front to sink southward through
the forecast area and become positioned over the far northern Gulf
by 12Z Monday morning. Little in the way of moisture or ascent is
currently indicate with guidance trends, so will keep a dry
forecast going on Sunday night. Temperatures will be a little
cooler as surface high pressure builds into the area with light
northerly flow, and expect Sunday night lows to range in the upper
50s to lower 60s over interior areas, and in the mid 60s along the
immediate coast.

The upper level ridge of high pressure will flatten over the far
southern Gulf Monday into Monday night, while the next upper level
trough located over the vicinity of the Four Corners Region early
Monday morning moves eastward toward the central plains states
and adjacent Lower Missouri/Mid-Mississippi Valley regions Monday
into Monday night. Surface high pressure located over the
Tennessee Valley and northern MS/AL Monday gradually weakens into
Monday night as surface low pressure over northwest TX Monday
moves toward the Lower Mississippi Valley by late Monday
night/early Tuesday morning. The frontal boundary over the
northern Gulf early Monday morning will slowly retreat northward
near the immediate coast through Monday afternoon, before lifting
north as a warm front across the rest of the CWA late Monday night
into early Tuesday morning. Deep layer moisture gradually trends
upward across southeast MS and interior southwest AL Monday and
Monday evening, and weak ascent could support the development of a
few showers over these zones during this time frame. Moisture/
ascent will increase across the region late Monday night into
early Tuesday morning as the shortwave trough lifts toward the
Mid-Mississippi Valley region (and as the surface low moves from
the Lower MS Valley toward central MS/AL). Showers along with a
chance of thunderstorms will spread across the region late Monday
night and especially into Tuesday morning. We will maintain likely
POPs over southeast MS and interior southwest AL late Monday
night (with chance POPs spreading over most of the rest of the
forecast area during this time frame), before POPs become
categorical (~80-90%) in nature over most of the CWA Tuesday
morning. Surface dewpoints rising into the mid 60s to around 70
degrees will allow for an increasingly unstable airmass Tuesday
morning, with MLCAPE values potentially as high as 500-1000 J/KG
across much of the region. Deep layer/effective shear is also
quite strong over our area (>65 knots). These factors could
support a damaging wind threat over the area as convection quickly
moves east across our area Tuesday morning. There could also a
brief opportunity for a tornado given a narrow zone of 0-1km storm
relative helicity values between 200-300 m2/s2 over the region,
but the tornado threat seems lower at this time. Drier and cooler
conditions follow for Tuesday night. /21

EXTENDED TERM /Wednesday Through Saturday/...Cooler and dry
conditions are expected Wednesday and Thursday as dry northwest
flow aloft Wednesday transitions to shortwave ridging aloft by
Thursday. Moistening zonal flow may return late in the extended
period, which could allow POPs to trend upward again Friday into
Saturday. We added low POPs mainly over central and southern
zones Friday and Friday night, with slight chance POPs area wide
Saturday. /21

MARINE...Moderate southerly winds will continue through this
afternoon, then diminish tonight and become southwesterly early
Sunday. A light southeasterly flow will then develop Monday, then
switch to a moderate to strong southwesterly flow early Tuesday
ahead of a strong cold front approaching from the west. Showers and
storms are also expected ahead and along the front on Tuesday. A
moderate northerly flow is then expected to develop late Tuesday
night as the front moves through the area. With these conditions, a
Small Craft Advisory may be needed Tuesday and Tuesday night.
Northerly winds will persist through Wednesday but decrease to be
light through the day. Light east/northeast winds are then expected
on Thursday. /26

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through late Sunday night for ALZ265-266.

FL...High Rip Current Risk through late Sunday night for FLZ202-204-
     206.

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

$$

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