A Slight Risk for Severe Thunderstorms Today...
Near Term [Through Today]...
The 12z KTAE sounding reveals a stable layer from the surface up to
around 1300 ft.
Although we have seen some impressive velocities at low levels this morning on the area radars, winds are not completely mixing down, likely due to this shallow stable layer.
Peak gust we have seen measured so far has been 33 knots at Apalachicola.
Nevertheless, as pre-frontal convection to the west organizes and
moves towards the area later today, there remains a slight risk of
severe storms if the stable layer seen in the TAE sounding can
There also may be less of a stable layer across the western half of the area, and several reports of straight line wind damage have been received up in central Alabama.
In fact, we have recently seen velocities greater than 55 knots dip below a thousand feet on EVX radar with convection moving ashore near the Walton/Bay county line.
Low level shear is very strong with 0-1 km shear recently up to 50 knots on the EVX VAD wind profile.
Hodographs are rather straight though, so we think the main threat
would be damaging winds with the tornado threat remaining low
Elsewhere, widespread dense fog continues across the Florida Big bend early this morning and a dense fog advisory continues in effect there, while it has been lifted elsewhere.
We expect visibilities to improve across the Big Bend by 14z as the fog lifts with surface winds increasing ahead of a cold front.
However, the low level cloudiness should linger through the day with little if any sunshine.
Widespread showers and isolated thunderstorms will sweep
through the local region in advance of the front and we feel confident enough to raise PoPs to nearly 100 percent for all zones.
The SPC continues to highlight our CWA in the day one convective outlook for a slight risk of severe thunderstorms with the main concern being damaging winds although an isolated tornado can`t be ruled out.
While low level vertical sheer profiles look impressive, the best dynamics and stronger low level jet should be displaced off to our northeast.
However, the primary limiting factor will be marginal instability at best.
As mentioned, the local region should stay socked in with low level clouds through the day limiting destabilization.
The locally run CAM models show a very low end threat for severe weather for our FA.
However, we included isolated severe thunderstorms in the grids for all zones due to the low-end threat.
We expect fairly widespread 1-inch rainfall amounts with this system before all is said and done tonight.
Despite the clouds and rain, we should see max temps in the mid to upper 70s.
Short Term [Tonight Through Monday]...
The upper level pattern will remain progressive across the region
with one trough exiting east of the area tonight and another reaching the Lower Mississippi Valley by Tuesday evening.
The cold front should exit southeast of the Lower Suwannee by 02-03z.
We have included slight to low chance PoPs roughly along and east of the Aucilla and Withlacoochee Rivers.
High pressure will then build east along the Gulf Coast on Sunday clearing skies.
Temperatures will be cooler behind the front, but remain a few degrees above normal with morning lows in the upper 30s to mid 40s and afternoon highs generally in the mid 60s.
The high will move off the Southeast U.S. coast on Monday with return flow returning increasing moisture off the Gulf of Mexico.
High temps will reach the upper 60s in most areas with lower 70s in the eastern FL Big Bend.
As the next frontal system approaches, rain chances will return to the forecast Monday with likely PoPs far west and chance PoPs elsewhere.
With so little time between fronts, we do expect sufficient instability to become established to mention thunder anywhere except over the marine area on Monday at this time.
Long Term [Monday Night Through Saturday]...
Very little change from our previous fcst over the extended period,
as the mean trough will remain entrenched over the eastern half of
the U.S. throughout the period.
This will allow a series of shortwaves to dig southeastward into our region and reinforce the main trough, which should result in a lengthy period of below climo (but not extreme) temps beginning on Tuesday.
While the first in this series of shortwaves will be very active with
numerous showers and thunderstorms ending by Tuesday morning, the remaining ones are expected to be dry, and only serve to reinforce
the cool to potentially cold temperatures, especially as indicated
by the ECMWF.
LIFR conditions to continue at all sites at least through daybreak.
After that, conditions will only gradually improve as rain moves in from west to east and surface winds increase ahead of a cold front.
As rain and storms move through the area in the late morning and afternoon on Saturday, expect IFR conditions.
Conditions should return to VFR at DHN/ECP around 20z and finally VLD around 23z with west to northwest winds up to 15 knots.
Sea fog is expected to continue over the cooler shelf waters east of Apalachicola through the morning and possibly into the afternoon.
Southerly winds will increase today ahead of an approaching cold front.
At this time, we expect winds and seas to peak mainly at cautionary levels, although a brief period of marginal advisory conditions cannot be ruled out.
Winds will shift to the west behind the front which will enter the western waters this morning an exit east of the area this evening.
Winds will then become northwest overnight possibly reaching cautionary levels once again.
High pressure will build east Sunday through Monday with winds becoming light and veering to onshore by Sunday night.
The next front will cross the waters Monday night into Tuesday morning.
Winds will once again reach cautionary to marginal advisory criteria ahead of and behind this boundary.
A third front will sweep quickly across the waters Tuesday night.
Seas and offshore winds behind this front are likely to reach advisory levels.
After a wet day today, much drier conditions are expected on Sunday
in the wake of a cold front but red flag conditions are not expected.
Rain returns to the region on Monday.
Rainfall totals with today`s frontal system will generally range from about an inch and a half in Walton County to 3/4 of an inch in Dixie with most areas in between around an inch.
Another system on Monday and Monday night is expected to produce roughly a half to 3/4 of an inch.
While these events should cause minor rises on some area rivers, flooding is not expected at this time.
Preliminary Point Temps/PoPs...
Tallahassee 76 42 65 40 69 / 90 10 0 0 40
Panama City 75 46 64 48 67 / 100 0 0 0 60
Dothan 73 41 63 43 67 / 100 0 0 0 50
Albany 75 41 64 40 67 / 100 10 0 0 40
Valdosta 77 44 64 40 69 / 100 20 0 0 30
Cross City 77 46 67 38 72 / 100 30 0 0 30
Apalachicola 75 46 62 47 66 / 90 10 0 0 50
FL...Dense Fog Advisory until 9 AM EST this morning for Coastal
Dixie-Coastal Franklin-Coastal Jefferson-Coastal Taylor-
Coastal Wakulla-Gadsden-Inland Dixie-Inland Franklin-Inland
Jefferson-Inland Taylor-Inland Wakulla-Lafayette-Leon-
GM...Dense Fog Advisory until 4 PM EST this afternoon for Apalachee
Bay-Coastal waters From Ochlockonee River to Apalachicola FL
out to 20 NM-Coastal waters from Suwannee River to Keaton
Beach FL out 20 NM-Waters from Suwannee River to Apalachicola
FL from 20 to 60 NM.