Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tallahassee Florida
1016 am EDT Sat Mar 15 2014
Near term [through today]...
This morning's surface analysis put the tri-state region right in
the center of an area of high pressure. To our north, a surface
trough extends down The Spine of the Appalachians, westward into
the lower Mississippi Valley where it links up with a very weak
stationary boundary. Aloft, southwesterly southern stream flow
dominates locally, with a wavy northern stream pattern along it's
A saturated airmass, generated from synoptic scale ascent across
the Southern Plains, is streaming eastward in the fast mid/upper
flow pattern. As it does so, it is very gradually ascending over
the Cool Ridge. This is generating an area of light but isolated
showers across the southeast, through al/GA/SC.
Closer to the Florida coastline, southwesterly moist transport
along the 295k surface (or around 850 mb) is flowing over the
nocturnally cooled boundary layer resulting in another area of
isolated light showers. These light showers may spread into our
extreme western Panhandle counties this morning into the early
afternoon. Thereafter, gradual boundary layer warming should limit
the upslope component locally with low-level flow backing a bit,
taking on a more southerly component and focused more west of US
nearer to the developing area of low pressure.
All of the above result in a slight chance for a shower or two,
west of the Apalachicola River today, with a rather sharp gradient
in cloud cover, and subsequently temperatures east and west of the
river. Expect low 70s to the west, with mid 70s, and a few upper
70s to the east.
[through 12z sunday]...
VFR conditions will prevail at all terminals today. Expect
mid/upper clouds scattered around the region, with some lower
cigs around 5 kft at kdhn and kecp. Late tonight, MVFR ceilings
will gradually overspread kdhn and kecp with showers likely
holding off until around 12z.
Prev discussion [752 am edt]...
Short term [tonight through monday]...
expect an unsettled weather pattern as a potent low pressure system
develops over the Southern Plains and moves across the Gulf coastal
states. The 00z NAM and 00z GFS are in fairly good agreement with respect to
strength and placement of low and upper level features. Although the
12z European model (ecmwf) is a bit of an outlier, there is still a general agreement
on widespread rains across the tri-state region through the period.
The NAM and GFS are more robust showing a closed upper low tracking
along the Gulf Coast with the surface reflection just out ahead of
it through midday Monday before beginning to lift northeast Monday
evening. This scenario coupled with a moist and moderatly unstable
environment along with a forecast low level jet averaging between 40
and 50 kts brings a threat of severe storms with it. The latest day
2 severe weather outlook from Storm Prediction Center highlights the Florida Panhandle,
the westernmost Big Bend and a small portion of our southeast Alabama zones for
a slight risk after 12z Sunday as these areas enter the warm sector.
Model forecast soundings show mostly unidirectional flow with 0-6 km
shear around 45 kts. The greatest severe threat would be damaging
straight line winds. Although, a tornado threat would also be a
concern mainly along the coast of the Florida Panhandle midday
Sunday as the quall line interacts with the aforementioned low level
jet. Pops will be tapered likely west to silent 10% southeast Big Bend
tonight then likely to categorical for the remainder of the period.
Temps will be near seasonal levels.
Long term [monday night through saturday]...
the period looks mostly dry with mainly zonal flow locally. A weak
front may approach by Thursday with just a slight chance of light
showers. Seasonal temperatures are expected.
generally light to moderate winds and seas will continue through
today before the next low pressure system begins to affect the
area more significantly. On Sunday, advisory level southerly winds
are expected with increasing seas and surf. The increasing onshore
flow will result in more dangerous surf conditions and a high risk
for rip currents. West to northwest winds may stay elevated behind
the front on Monday with improving conditions by midweek.
low level moisture will be on the increase today as the Dry Ridge
of high pressure on Friday gradually pushes to the east of the Florida
Peninsula today out ahead of an approaching low pressure system
from the west. This low is expected to bring a widespread wetting
rain to the region on Sunday through Monday which will keep both
soil moistures and relative humidities high through early next
week, effectively eliminating the chances for any red flag
area rivers remain below flood stage. A period of moderate to
locally heavy rain is expected across the area Sunday and Sunday
night, with widespread amounts of 1-2 inches and locally higher
totals. The Big Bend area could see amounts of up to 3 inches
which would include the Suwannee River basin, but since rainfall
will be in the lower drainages this should not be problematic.
Overall expect some rises on area rivers with little to low
impact. The rest of the week looks dry allowing rivers to subside
Preliminary point temps/pops...
Tallahassee 76 56 73 63 74 / 0 30 80 80 80
Panama City 68 61 72 63 71 / 20 40 90 80 80
Dothan 70 59 72 61 69 / 30 60 90 70 80
Albany 73 55 72 61 68 / 0 40 90 80 90
Valdosta 78 53 75 63 74 / 0 20 70 80 80
Cross City 75 52 75 66 75 / 0 10 70 80 80
Apalachicola 68 61 70 63 73 / 0 30 80 90 80