Updated Aviation Discussion.
.NEAR TERM [Today and Tonight]…
The basic summary of the forecast for today and tonight is:
PERSISTENCE. Overall things should not be much different from
what occurred yesterday (Monday). With continued easterly FLOW,
the LOW-level MOISTURE content may slowly increase through the
next 24 hours. However, we are still expecting continued easterly
flow on the southern periphery of a low-level RIDGE axis, and HIGH
temperatures in the low 80s.
In the TROPICS, Tropical STORM Sandy formed yesterday to the south
of Jamaica in the western Caribbean. It is the 18th named storm of
the 2012 Atlantic season. The forecast calls for steady northward
motion, which would carry it east of the Florida peninsula with
very little CHANCE of any sort of impacts on our local area.
.SHORT TERM [Wednesday Through Thursday]…
During the middle of the week – the short term period – we should
begin to see some subtle changes in the regional weather pattern.
The low-level ridge axis and ANTICYCLONE should gradually begin to
erode on the southern and western periphery with a TROUGH digging
into the central US and the gradual northward motion of T.S. Sandy
near eastern Cuba. AS a consequence of this subtle change, we
should see a slight increase in the temperatures – with highs in
the MID 80s and lows in the upper 50s to around 60. NORMAL values
at Tallahassee are 80/55, so this would represent temperatures
around 5 degrees above normal. The continued easterly flow would
typically lead to a steady increase of ISOLATED–SCATTERED showers
each day, particularly across the eastern parts of the area and
the coastal waters. However, in this case, upper level ridging
remains rather pronounced and forecast models maintain fairly dry
AIR aloft. With the global models not producing any QPF across the
area, we have likewise opted to keep a dry forecast.
.LONG TERM [Thursday NIGHT through Tuesday]…
Despite the somewhat nearby presence of Tropical Storm Sandy
(which is forecast to become a HURRICANE as it begins to move
northward out of the Caribbean and through the Bahamas), an
essentially POP free FCST is indicated through the entire extended
period. This period will start off quite warm on Friday, with a
warm and somewhat humid easterly flow allowing TEMPS to climb into
the mid to upper 80s over the region. Then, a weakening cold FRONT
is expected to gradually move through the CWA over the weekend as
Sandy begins to pull further away well off to the N and E of the
FL peninsula. While progressively much cooler and drier air will
filter in from the NW through the beginning of next week behind
the front, it appears that any moisture out ahead of it (that
could otherwise spawn isolated showers) will steadily dissipate
off to our west, resulting in only silent 10% POPS for our region.
By Monday and Tuesday, the cool and dry air will have a solid
foothold over the Tri-State area, such that High Temps are
expected to be limited to the upper 60s to the lower 70s at best,
with Low Temps falling into the mid 40s to the lower 50s.
[Through 12Z Wednesday]
VFR conditions are expected to continue through the TAF period, with
generally light ENE winds and FEW–SCT Stratocu between 4 and 5 kft,
mainly during the daylight hours.
We are having a brief SURGE of easterly winds overnight that meets
Small Craft ADVISORY criteria (20-25 knots or so). This was
supported by the tower observations at K and C Tower, as well as
Buoy 42036. Additionally, an ASCAT pass at around 0220z and an
OSCAT pass around 0600z showed evidence of a building area of
20-25 KNOT winds over a sizable portion of our coastal waters. The
SC.Y was issued for all but the Apalachee Bay zone. The eastern
leg adjacent to Taylor and Dixie Counties expires earlier at 10z
(as winds should subside there most rapidly), and in the rest of
the waters at 12z. We are already seeing evidence of the winds
relaxing on the latest observations, so the expiration times seem
appropriate. More NOCTURNAL surges of easterly winds are expected
the next several nights. With the models underestimating the WIND
speeds in this most recent event by 5-7 knots, it is possible that
we could see advisory-level winds again at some point. However,
confidence is highest in SCEC conditions (15-20kt) each night.
Despite the gradual warming trend which is expected to result in
MAX Temps recovering into the mid to perhaps mid to upper 80s for
the middle and end of this week, afternoon surface dewpoints will
be slowly on the rise as well in the moistening northeasterly
flow. This should keep afternoon relative humidities safely away
from Red Flag levels for the next several days.
There are no hydrological concerns or significant river rises
expected over the next week across the area.