Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 281746
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1246 PM CDT TUE JUN 28 2016

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

&&

.AVIATION...
18Z issuance...vfr to mvfr conditions through 29.18z. lower cigs and
visibilities mainly in and around scattered to numerous showers and
thunderstorms with the best coverage occurring this afternoon and
early this evening and along the immediate coast and offshore early
wed morning...up through about 15z. winds will be mostly south to
southwest at 5 to 10 knots later this afternoon and early this
evening becoming light and variable this later this evening and
overnight becoming east to southeast at 5 to 8 knots later wed
morning. 32/ee

&&

.PREV DISCUSSION... /issued 651 AM CDT TUE JUN 28 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
12Z issuance...VFR conditions prevail at the beginning of the period
with spotty convection mainly near the Alabama coast. This will be
followed by numerous showers and thunderstorms developing across the
area through the day, with MVFR to IFR conditions in the convection.
The convection diminishes gradually during the evening and expect
isolated showers/storms to linger overnight. A northerly flow
prevails over interior areas today with a southerly flow initially
closer to the coast which becomes northerly tonight as well. /29

PREV DISCUSSION... /issued 355 AM CDT TUE JUN 28 2016/

NEAR TERM /Now Through Tuesday night/...An upper trof continues to
amplify over the eastern states through tonight with an embedded
shortwave slowly moving southward across the area.  A weak
deformation zone seen near 300 mb also lingers over the forecast
area through the period.  Within this unsettled pattern, a weak and
diffuse surface trof oriented generally east-west over the forecast
area is replaced by a weak cold front approaching from the north
which moves into the area this afternoon, then moves to near the
coast overnight.  Deep layer moisture remains high over the area
through the period with precipitable water values near 2.0 inches,
or about 135 percent of normal.  Expect mainly isolated convection
early this morning to increase in coverage to numerous mainly north
of the immediate coast through much of the afternoon, then shifting
southward to predominately over the southern portion of the area
overnight as the frontal boundary nears the coast.  MLCape values
increase to 1500-2000 J/kg by midday then diminish gradually to 500-
750 J/kg over the southern portion of the area overnight, with 100-
500 J/kg further inland.  Shear values remain very low through the
period and expect some storms to become strong to possibly
marginally severe mainly during the afternoon and early evening
hours when the best instability will be present.  With a weak
steering flow and abundant deep layer moisture, the storms will also
be capable of locally heavy rainfall which could lead to localized
flooding.  Highs today will be mostly in the lower 90s, except for
around 90 well inland and near the coast. Lows tonight will be
mostly in the lower 70s. /29

SHORT TERM /Wednesday Through Thursday night/...Guidance is
advertising shortwave energy diving into an upper trough over the
eastern conus. How this energy differs amongst the models is in its
effect on a surface trough/boundary stretching sw-ne across the fa.
Most leave and weaken the boundary, whilst the GFS is off model out,
pushing the boundary south a bit, along with any precip. Have went
with a blended approach for the forecast, resulting in a southward
shift in the axis of higher pops, to off the coast by Wednesday
night, but not as far south as the GFS is advertising. Am still
expecting likely shra/tsra along and just north of the coast
Wednesday as a result. Wednesday night through Thursday night, as
the boundary/trough weakens, a surface ridge stretching west over the
Gulf of Mexico regains control and brings back moist onshore flow,
and with that, a chance of afternoon/evening Gulf breeze induced
shra/tsra. with respect to temps, with increased cloud cover along
and north of the boundary Wednesday, most of the fa will see temps a
bit below seasonal (upper 80s to around 90). With the
weakening/shifting of the boundary and a restoration of onshore flow,
temps moderate upward, with lows around seasonal Wednesday night, a
bit above Thursday night. Temps a bit above seasonal highs expected
Thursday.

LONG TERM /Friday Through Monday/...For Friday through the coming
weekend. guidance is advertising an upper ridge re-building over the
northern Gulf of Mexico, with a surface ridge stretching west over
the Gulf becoming more organized. With moisture levels increasing to
around 2", rain chances rise to around seasonal. Temps around to a
bit above during the day (low to mid 90s), with overnight low above
seasonal (low to mid 70s) expected.

MARINE...A weak cold front approaching from the north moves to near
the coast late tonight and stalls, then lingers near the coast
through much of the week.  A generally light to moderate
southwesterly flow prevails over the marine area through the period.
The frontal boundary will bring an increased chance of rain through
midweek. Strong gusty winds, locally higher waves and frequent
lightning can be expected with the stronger storms. /29

&&

.MOB Watches/Warnings/Advisories...
AL...None.
FL...None.
MS...None.
GM...None.
&&

$$

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