NEAR TERM...[Today and Tonight]
The large scale pattern continues highly amplified.
This is highlighted by expansive upper ridge from 4 corners Nwd to Wrn Canadian prairies and responsible for record breaking high temps and a deep trough over Ern states with low over Great Lakes and trough axis Swd into Gulf.
Trough axis along or just east of CWA providing for NW steering flow and SEWD trajectory of H5 impulses and MCSs. At surface, low over Great Lakes with quasi-stnry front s then SW across Nrn Gulf states the Nwwd into TX.
During the predawn hours, a shortwave diving SEWD across FL
Panhandle and SW GA providing upper level support for a line of
thunderstorms (part of MCS) currently moving SEWD around 20mph
across SE AL/FL Panhandle and into adjacent waters. Some of these
storms were severe producing very strong winds along with frequent
lightening. Latest radar pix show some weakening of storms as they
spread se into area increasingly much worked over on Fri. Only
exception is right along coast and adjacent waters.
For today into tonight, upper low will sink south while trough
axis retrogrades to the SW in response to building upstream
HI RES guidance shows a couple of vortlobes swinging out of base of trough and across local region later today. Remnants of MCS will continue SE.
In addition, a frontal boundary will drop south into the area and stall across SE AL and the FL Panhandle yielding an increasingly juicy low level as reflected in model PWATS above 2 inches.
This will create a favorable pattern for convection, especially east of the Apalachicola/Chattahoochee Rivers. Some storms may again be strong to severe with wet microbursts yielding damaging winds best bet. With soundings showing uni- directional WSW flow up to H3, high PWATS, grounds already wet from recent rains, and training of echoes possible, locally heavy rain likely and it may generate localized flooding concerns.
Will go with 50-80% W-E POPs today, 40-60% tonight.
Ample clouds will moderate high temps somewhat. Expect high in upper 80s east to low 90s west. However, clouds will be offset by oppressive humidity with heat indices expected to be 95 to 100 degrees. Low tonight in the low to mid 70s.
SHORT TERM [Sunday Through Monday]...
The large scale longwave pattern remains unseasonably amplified
dominated by intense ridging over Wrn states, a deep trough over Ern states with low over OH Valley and axis Swd into Srn portions of Cntrl Gulf of Mex, and a ridge over Wrn Atlc. At surface, low over Canadian Maritimes with cold front Swd down Appalachians then quasi-stnry Swwd across SE AL into TX.
The upper systems continue to retrograde with trough axis shifting Swwd altering local steering flow from WSW to deep SWLY by Sun with good upper diffluence developing invcnty of right entrance region of upper jet.
However strong and resistant upper ridge will prevent significant WWD movement of trough. This will continue to allow any shortwave rounding base of trough to traverse local area. Also, shift in steering flow plus the position of front translates to a deep tropical plume of moisture advecting SW-NE over local region with ample moisture at lowest levels pushing SE-NW.
Also seabreeze that was pinned near coast under previous NW/W steering flow will be reenergized. All this creates a favorable pattern for convection, especially east of the Apalachicola/ Chattahoochee Rivers.
By Mon eve, longwave trough axis extends Swwd to low across the Mid MS Valley, with some drier air moving down base of trough and impacting Wrn most CWA so modestly less favorable for convection. This reflected in model soundings which show PWATs decreasing from around 2 inches at 12z Sun to a still impressive 1.6 inches at 18z Mon. High PWATS continue as under SW steering flow, front only inching Sewd with most of CWA still in juicy warm sector.
For both days, ample multi-layered cloud cover and reduced
insolation will limit instability and chances of strong to severe
Main concern with rich tropical air will be training echoes and/or multiple cells moving only slowly newd producing heavy prolonged rainfall on already wet grounds.
Total Sat-Mon QPF ranges up to 3-4 inches across SE third of our area. This will be aggravated by any seabreeze/outflow mergers so flooding concerns are an issue.
Will go with 30-80% NW-SE POP gradient on Sun, 20-70% NW-SE on Mon.
Cloud cover will lower temps a bit, expect highs upper 80s to around 90 degrees each day, but this will be offset by sultry muggy conditions both days and nights. Expect heat indices in the mid 90s.
LONG TERM [Monday Night through Friday]...
Unseasonably deep trough will be in place over the eastern half of
the country through next week. This will keep moist and deep
southwesterly flow across the forecast area with enhanced rain
chances for most of the week. Periods of more widespread rain will
likely be governed by timing of weak upper/lower level features,
which are difficult to predict this far out.
Therefore, will continue with a general forecast of likely PoPs for the eastern half of area early in the week, with the higher PoPs spreading
west by midweek as the upper level trough slowly retrogrades.
AVIATION [Through 12Z Sunday]...
Expect TSTMS and rain to continue rest of predawn hours that would impact all but possibly VLD with MVFR CIGS/VSBYS and brief IFR conditions and strong winds in any heavier rains.
Conditions will spread E/SE after sunrise with VCTS followed by prevailing TSRA all sites rest of morning then VCTS all aftn into eve.
MVFR VSBYS/CIGS with brief IFR/LIFR conditions possible in any strong storms.
Also gusty with gusts around 20 knots out of the S/SE.
After 02z MVFR cigs in rain possible mainly TLH and VLD.
Southwesterly flow will be on the increase through rest of the
weekend as the Bermuda high strengthens over the western Atlantic
and a frontal boundary approaches the northern Gulf Coast.
Expect exercise caution conditions offshore to continue through most of the weekend.
Brief periods of advisory level winds will be possible late Saturday into Sunday.
Red flag conditions are not expected due to above average relative
humidity values throughout the period.
A wet weather pattern will be in place through the weekend and
into early next week.
South of Dothan, widespread 2 to 4 inch rainfall amounts are anticipated through Monday, with isolated higher amounts.
With no area rivers in flood or action stage, no river flooding is
However, locally heavy rainfall may cause flooding of some urban and/or low-lying areas.
PRELIMINARY POINT TEMPS/POPS...
Tallahassee 90 74 89 72 90 / 70 50 70 40 50
Panama City 87 79 87 76 87 / 60 50 60 30 30
Dothan 92 72 91 70 90 / 50 40 50 20 30
Albany 91 73 90 71 90 / 60 40 60 40 40
Valdosta 89 73 88 73 88 / 80 60 80 60 60
Cross City 88 74 88 74 88 / 70 60 70 50 70
Apalachicola 86 79 86 77 86 / 60 60 60 40 50