Area forecast discussion
National Weather Service Mobile Alabama
440 am CDT Thursday may 23 2013
Short term [today through Friday night]...axis of main upper trough that
brought convection to the region yesterday is now east of the County warning forecast area
resulting in a much drier weather pattern today and tonight. As the
upper trough shifts further east today a sharp middle to upper ridge over
the south central Continental U.S. Will continue to amplify and gradually shift
east overnight and early Friday. Ahead of this upper ridge a broad
surface ridge dives south from Canada eventually bringing cooler
drier air the region beginning early Friday continuing through the
first part of the weekend. For today expect mostly sunny skies with
a moderate SW flow developing by late morning and afternoon.
Afternoon highs will climb to the upper 80s to lower 90s inland and
in the middle 80s near the coast. Afternoon relative humidities will be
lower than yesterday. As result with more sun then clouds combined
with lower humidities and a good afternoon seabreeze from the SW
conditions will feel rather pleasant. For tonight cooler drier air
advects southward with maybe a stray shower or thunderstorms forming
on the leading edge of this airmass mostly near the coast and
offshore early this evening. Tonights lows will range from the lower
60s inland and in the middle to upper 60s near the coast. Still could
see some fog early this morning with the better development just
inland from the coast and areas to the west. 32/ee
The wet microburst risk for today is low.
An upper level ridge of high pressure will continue to amplify from
the western Gulf of Mexico through much of the Mississippi Valley and
upper midwestern states Friday...while an upper level trough continues
to slowly move eastward across the East Coast and Middle Atlantic
States. Northwest flow aloft will be prevalent across our area
between these two features Friday...and a deep layer dry airmass
spreading southeastward to the Gulf Coast will support mostly sunny
and dry conditions across the region. A surface ridge of high
pressure will meanwhile build from the Great Lakes region to the Gulf
Coast Friday...allowing for a continued northerly surface flow across
the County warning forecast area. Slightly cooler temperatures are expected Friday afternoon...
particularly across northern portions of the forecast area...where
highs should range from the lower to middle 80s. Temperatures should
mostly warm to the middle to upper 80s across our southern tier of
counties. The surface ridge will continue to build from the Ohio
Valley to the Gulf Coast Friday night. A much drier surface airmass
will also spread into the forecast area...with dewpoints likely
falling into the upper 40s to lower 50s across most locations by
early Saturday morning. This dry airmass...along with continued
mostly clear skies should support below normal temperatures Saturday
morning. We expect lows to range from around 50 to the lower 50s
across interior portions of the County warning forecast area...and in the middle 50s to around
60 near the coast. /21
Long term [memorial day weekend through wednesday]...upper level
ridging will continue to extend from the western Gulf of Mexico to
near the Gulf Coast region this upcoming Holiday weekend. A deep
layer dry airmass looks to stay in place across the forecast area
Saturday and Sunday. Other than a gradual increase in high cloud
cover...skies should generally remain mostly clear through the
weekend with no rain expected. Surface high pressure should remain
oriented from the Ohio Valley to the vicinity of the northeastern
Gulf of Mexico this weekend. Continued warm afternoon temperatures
are expected...slowly trending upward a few degrees by Sunday. Early
morning lows Sunday should remain below normal with the dry airmass
staying in place across the region.
The upper ridge over the Gulf will flatten Monday...with west to
northwest flow aloft anticipated over much of the Mississippi Valley
and southeastern Continental U.S.. shortwave troughiness within this flow regime
currently looks to stay well to the north of our County warning forecast area Memorial Day...
so we will maintain a dry forecast across the region. Little change
in temperatures are expected for Monday...with highs ranging from
the upper 80s to around 90 inland...to the middle 80s near the beaches.
Medium range solutions then show agreement with strengthening an
upper level ridge of high pressure in the vicinity of either the
Mississippi Valley or the Gulf Coast Tuesday and Wednesday. Rain
chances look very minimal underneath this pattern...so will maintain
a dry forecast through next Wednesday. /21
&&
Aviation...[12z issuance]...MVFR to IFR conditions through about
14z this morning followed by VFR conditions today and tonight. Still
expect some low stratus and fog early this morning followed by some
scattered low clouds mixed with scattered to broken high clouds later in the day. A
cold front will approach from the north late today and tonight
possibly leading to an isolated shower or thunderstorm near the
coast late in the day or early this evening. Winds will become
mostly southwest at 8 to 12 knots with higher gusts in the afternoon
becoming northwest at 5 to 10 knots early Friday morning. 32/ee
&&
Marine...high pressure over much of the northern Gulf will become
reinforced late Friday through Sat in the wake of a cold front that
moves across the region late Friday and Friday night. Ahead of the front a
moderate SW flow will develop later today and continue through this
evening then shift north and gradually build to near 20 knots late
Friday and through Sat morning. Seas will build to 3 to 5 feet Friday
night and early Sat mostly well offshore. A moderate east to
southeast wind flow is expected later in the weekend continuing
through middle week as strong high pressure builds along the eastern
Seaboard. Also could see a stray shower or thunderstorms this
evening ahead of the cooler air moving in from the north. 32/ee
&&
Fire weather...relative humidity values will remain above critical
thresholds today though a slightly drier airmass will move into
interior portions of the region. Higher dispersions are expected
this afternoon with mixing heights increasing to around 6000-7000 feet
above ground level. A much drier airmass will then spread into the region Friday
through the weekend. Minimum afternoon relative humidity is expected
to fall to near critical levels across our Alabama counties
Friday...then across much of the region by Saturday afternoon. Given
the marginality of critical relative humidity values over our Alabama
counties...and that higher kbdi values and wind speeds may stay just
east of our area...confidence is not high enough to issue a Fire
Weather Watch Friday at this time. There is a better chance for critical fire
weather conditions Saturday...and later shifts will monitor for
potential watch issuance. /21
&&
Preliminary point temps/pops...
Mobile 88 65 88 58 85 / 00 20 05 00 00
Pensacola 88 69 87 63 85 / 00 10 05 00 00
Destin 83 70 86 66 82 / 00 10 00 00 00
Evergreen 91 61 86 52 85 / 05 10 00 00 00
Waynesboro 90 62 85 51 86 / 05 10 05 00 00
Camden 90 61 83 51 84 / 05 10 00 00 00
Crestview 91 61 89 52 87 / 00 05 00 00 00
&&
Mob watches/warnings/advisories...
Alabama...none.
Florida...none.
MS...none.
GM...none.
&&
$$
32/21
