Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 260607 AAA
AFDMOB

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
107 AM CDT Sun Mar 26 2017

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

&&

.AVIATION...
06Z issuance...MVFR to IFR cigs and visibilities through about
26.14z followed by VFR to MVFR cigs through about 27.04z followed
by MVFR cigs and visibilities through 27.06z. A few isolated
showers or thunderstorms will also be possible through this
afternoon. Winds will be southeast to south at 4 to 10 knots
through the forecast period. 32/ee

&&

.PREV DISCUSSION... /issued 854 PM CDT Sat Mar 25 2017/

DISCUSSION...See updated information for land and marine areas below.

UPDATE...Latest upper air analysis shows an upper low to be
located over NE MO and continuing to move NNE. This is acting to
further detach the kinematics and forcing from the warm sector
over the Central Gulf Coast Region. As a result, frontal zone is
being stretched and sheared (winds are a bit more westerly below
500 hPa which is given the frontal band a little bit of a shove
eastward). 26.00 UTC data show the base of the mid- and upper wave
to be currently moving through our area and upward motion along
and ahead of the aforementioned frontal band is gradually being
replaced by large scale subsidence. The three GOES-R WV bands
show drier air advecting into the mid-levels across our area, and
with now rain-soaked grounds will likely have some patchy dense
fog. Not really buying into a second, but brief, round of
precipitation during the late night hours (sfc front already
begins to retreat NWD as a warm front as south flow becomes re-
established). Any additional overnight isolated showers should
remain north of I-20. The current line of thunderstorms will exit
the area by 1030 PM CDT. Lowered rain chances regionwide
significantly after midnight.

With northward moving swell continuing, most of Sunday will still
have a `High` Risk of rip currents. Have extended the High Risk
until late Sunday.

Just sent new ZFP, HWO, PFM and CFW for updates. Also shipped new
set of grids reflecting changes through Sunrise. /23 JMM

MARINE...Lowered winds to be more reflective of current observations,
as expecting a southerly wind flow to become re-established
generally in the 12-16 knot range generally behind the departing
deep convective line. Small Craft Advisory will likely be cancelled
by the 1030 PM CDT Marine update. /23 JMM

PREV DISCUSSION... /issued 649 PM CDT Sat Mar 25 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
00Z issuance...A line of thunderstorms currently entering the
western Florida panhandle will continue to push east, impacting
PNS roughly around or shortly after 26.01z. Frequent lightning,
small hail, gusty winds, and lowered cigs/vis can be expected
within and around the thunderstorms. In the wake of this line,
cigs/vis improve briefly before light southerly flow becomes
reestablished and low clouds and potentially some patchy dense fog
redevelop late tonight. Southerly winds and VFR conditions prevail
Sunday as cloud cover gradually decreases through the afternoon. /49

PREV DISCUSSION... /issued 351 PM CDT Sat Mar 25 2017/

NEAR TERM /Now Through Sunday/...Radar will be active late
afternoon and evening upcoming with regard to storms. Radar trends
show a line of storms from central Alabama, southwest to off the
south central Louisiana coast. These storms are forming within a
favored environment of moisture, lift and instability to the
south and east of a vigorous upper level storm system centered
over central MO. This system remains in place thru much of the
night, then ejects northeast across the upper Mid-West on Sunday.
The more active eastward side of the long wave trof, where the
best deep layer ascent is positioned, moves across the forecast
area this evening. The deep layer ascent, coincident with a north
to south band of deep layer moisture (pwats ~1.3 inches) supports
maintaining categorical pops over the eastern half of the forecast
area this evening. Latest forecasts of high resolution models
bring squall line, mentioned earlier, eastward over the region
tonight. Instances of damaging winds and marginally severe large
hail (around a quarter size or so) looks to be the main impacts
in any storms that become severe in the late afternoon and
evening. As the main dynamics lift northeast late this evening and
overnight, the severe weather threat ends. High level southwest
flow continues on Sunday ahead of next storm system moving east
across the southern Plains. Out of respect for subtle mid level
impulses embedded in these type flows aloft, a small chance of
showers and storms will be mentioned for Sunday.

Overnight lows in the lower to mid 60s. Highs on Sunday, mid 80s
interior to mid to upper 70s along the beaches. /10

SHORT TERM /Sunday night Through Tuesday night/...A weak upper
level ridge over the Gulf of Mexico Sunday evening will shift
eastward over the western Atlantic by late Monday night. Meanwhile
an upper level trough over the southern plains will move due east
Sunday night and Monday, but is forecast to weaken as it
approaches the southeast conus. The surface high pressure ridge
across the southeastern states and eastern gulf will remain
largely intact as a surface low forming across the southern
plains also moves east to the Ohio River Valley region and also
weakens. A weak cold front associated with the surface low will
approach the region from the northwest, but not reach the
forecast area as it is expected to stall. It will be dry Sunday
night, followed by isolated to low-end scattered showers and
thunderstorms Monday and Tuesday with the next system.

Low temperatures Sunday night will range from 58 to 62 degrees
inland areas, with mid 60s along the beaches. Warm temperatures
will continue on Monday and Tuesday with afternoon highs ranging
from 77 to 82 degrees, except for the mid along the immediate
coastal sections. Low temperatures Monday and Tuesday nights will
be 2 to 4 degrees warmer compared to Sunday night. /22

LONG TERM /Wednesday Through Saturday/...An upper level ridge
extending from the southeastern Gulf of Mexico to western Ontario,
Canada will shift eastward, reaching the western Atlantic by late
in the week. Further to the west, a large upper level trough
extending along the front range of the Rocky Mountains to central
Mexico will also shift eastward. An embedded upper low pressure
area within the trough over western New Mexico will lift
northeast to the upper midwest through Thursday night as the
southern extent of the upper trough swings eastward across the
deep south. The surface high pressure ridge across the
southeastern states and eastern gulf will move eastward as a
surface low forming across the southern plains lifts northeast to
the Great Lakes region. A weak cold front associated with the
surface low will approach the forecast area from the west Thursday
night.

Other then a few showers midweek, it will be dry Wednesday and
Wednesday night. Scattered to numerous showers and thunderstorms
will then accompany the next system on Thursday and Thursday
night. The precipitation will then taper off from west to east on
Friday in the wake of the front followed by high pressure building
in from the west. Above normal temperatures will continue through
the long term. /22

MARINE...Winds, waves and seas will be locally higher with the
passage of a line of storms this evening. Some of the marine
storms potentially severe late this afternoon into the evening.
Due to a moderate to strong onshore flow and seas upwards of
around 7 feet through this evening, small craft advisories have
been extended thru 11 PM this evening for the open Alabama and
western Florida Gulf waters. The advisory over southern Mobile Bay
and the Mississippi sound will be left unchanged, expiring at 7
PM and will likely be replaced by exercise caution headlines.
After tonight, high pressure to the east maintains a light onshore
component of flow through the middle of next week with a lowering
trend in seas. /10

&&

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

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

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

$$

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