Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Mobile Alabama
510 am CDT sun Apr 26 2015

Short term...(today through tuesday)...for today through tonight...
much quieter weather has settled across the central
Gulf Coast region...with regional radar imagery detecting no
precipitation across the region as of 4 am CDT. Regional surface
analysis shows a weak surface ridge of high pressure stretching
across the southeastern Gulf of Mexico early this morning...while a
surface cold front was located from near the Red River valley of
Texas/OK eastward to the Tennessee Valley. A much drier deep layer
airmass has settled across our forecast area early this morning with
precipitable water values estimated between 0.75 and 1 inch.

The weak frontal boundary to our north is forecast to move southward
toward central portions of MS/al/GA by late this afternoon...with a
generally light west to southwest surface flow expected in advance
of this feature across our County warning forecast area. A zonal flow pattern aloft will
prevail across the region today...but a drier airmass will remain in
place across most of the region with precipitable water values only
forecast to rise to around 1 inch over inland areas to around 1.25
in. Near the coast. Given the overall lack of deep layer moisture
and lift...the prospects for convection are minimal across most
inland portions of the County warning forecast area today. The exception may be near the
immediate coast where a weak afternoon seabreeze may develop... so
will keep a slight chance of showers and storms generally south of
the I-10 corridor through this afternoon. If isolated convection
does manage to develop...a strong to severe storm cannot be ruled
out given that MLCAPE values could rise to 500-1000 j/kg along with
deep layer shear values around 50 knots. Otherwise...low level
thermal ridging over the area will support near record warmth today
with highs reaching into the upper 80s to around 90 over much of the
region. A weak shortwave passing across the northern Gulf could
support isolated convective development over coastal portions of the
County warning forecast area late tonight...and will maintain slight chance probability of precipitation generally
south of a Beaumont MS...Citronelle Alabama...Crestview Florida line. Lows
tonight should range from the upper 50s to lower 60s over the
interior to the middle 60s near the coast.

The record highs for today are 89 at Mobile (last set in 1989) and
88 at Pensacola (last set in 1988). /21

Monday through an upper low moves from over the nm/Texas
border to just west of the miss develops a surface low off
the Texas coast then takes it east along...but south...of the northern
Gulf Coast to become centered south of kpns by Tuesday evening. This
is consistent with yesterday's forecast...which helps to add
confidence to the forecast. Speaking of the the surface
low moves east of Texas and passes south of the la coast...there is an
increasing chance of rain...with most of it being isentropic upglide
induced. Best chance for rain Wills tart out mainly along and south
of the coast...then gradually move inland late Monday night into
Tuesday as the surface low approaches the marine portion of the forecast area.
With this path...organizing a warm front along an old surface
boundary laid out with the past system...any chance for severe
weather will br limited to the immediate coast and points south. Am a
bit concerned with the possibility of water problems over the coastal
counties. If the path of the surface low shifts north the risk of
water and strong storms shifts north and becomes more of a problem
for the coast and inland. At this point...just increasing coverage of
rain showers and thunderstorms and rain is expected.

Long term...(tuesday night on)...Tuesday night through
Wednesday...some upper energy dives south over the eastern
Continental U.S....slowing the eastward progression of the upper low over the
southeastern Continental U.S. Whilst deorganizing it. The forecast area comes under Post
system northerly flow...bringing in cooler air and some Post-frontal
stratus/rain. Temperatures well below seasonal expected Wednesday expected.

Wednesday night through Friday night...the disorganized upper
dynamics move off and surface high pressure moves over the
southeastern Continental U.S.. drier...cooler air moves over the forecast area...with the
diurnal temperature range opening up. Temperatures remain below seasonal for this
period of the forecast...with nary a raincloud in sight.

Saturday through Sunday...the surface high moves off tot he
east...leaving a surface ridge stretching west over the northern
Gulf Coast. With onshore flow restored to the area...moisture levels
are on the increase and temperatures moderate back towards seasonal levels.


24.12z terminal forecast discussion...patchy IFR ceilings
and MVFR to IFR fog are possible through around 15z this morning
with VFR otherwise prevailing thereafter. West winds increase to 5-
10 knots over inland areas today...with southwest winds 10-15 knots
possible near the immediate coast to the south of a seabreeze
boundary. /21


Marine...a light to moderate west to southwest flow will prevail
over the marine area today in advance of an approaching cold front.
The front is expected to stall offshore tonight. A light to moderate
east to southeast flow develops Monday into Tuesday as an area of
low pressure develops over the northern Gulf and moves eastward
through Tuesday. Showers and storms will increase in coverage Monday
and Tuesday as the low approaches. A stronger offshore flow will
develop in the wake of this system Wednesday...with wind speeds
potentially reaching Small Craft Advisory levels early Wednesday
morning through Wednesday evening. /21


Preliminary point temps/pops...
Mobile 89 64 80 64 78 / 10 20 40 50 60
Pensacola 87 66 81 68 78 / 20 20 40 50 60
Destin 84 69 80 67 78 / 20 20 30 40 50
Evergreen 88 60 79 59 79 / 10 10 20 40 30
Waynesboro 88 60 78 58 68 / 10 10 10 50 60
Camden 88 59 78 56 73 / 05 10 10 40 40
Crestview 90 61 83 64 81 / 10 20 30 40 40


Mob watches/warnings/advisories...


National Weather Service Glossary of Abbreviations