textproduct: Jacksonville

KEY MESSAGES

For the latest NE FL and SE GA Daily Key Messages please visit: https:/www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

- High Risk for Rip Currents at Northeast FL Beaches through Thursday. Moderate Risk of Rip Currents at the Southeast GA Beaches

- Patchy Dense Fog Inland Thursday morning. Main Impact Areas: Inland Southeast GA, Suwannee Valley area

- Scattered to Numerous Afternoon & Evening TStorms Thurs-Tues. Heavy Rainfall Potential on Thurs & Fri for Northeast & North Central FL

NEAR TERM /THROUGH TONIGHT/

Highlights Today and Tonight:

- Waves of showers and embedded thunderstorms with heavy rainfall and gusty winds today and tonight, mainly across Northeast Florida

- Low clouds and patchy dense fog possible inland early this morning

- High Risk of rip currents at Northeast Florida beaches

Deep tropical moisture with PWATs well over 2 inches associated with the remnants of TS Dolly will rotate northward up the FL Peninsula today and tonight as steering flow currently from the East this morning will become more Southeast this afternoon and tonight. This will lead to another day with waves of showers and embedded storms pushing onshore from the Atlantic through the day today and well into the evening hours tonight, before becoming more isolated during the overnight hours. Diurnal heating will help to trigger more heavy downpours and gusty winds from the this activity during the afternoon and early evening hours, mainly over inland areas with best chances for more intense storms along the I-75 corridor of inland NE FL. Max temps will continue near seasonable values with highs in the mid/upper 80s along the Atlantic Coastal areas, near 90F along the I-95/US-17 corridors, and into the lower 90s over inland SE GA/inland NE FL, with peak heat indices in the 100-105F range once again. Early morning low clouds and patchy fog is expected again both mornings towards sunrise, with locally dense fog possible over inland areas, mainly across inland SE GA and the Suwannee Valley, but once again not expecting widespread dense fog.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/

Main Highlights This Period:

- Daily Shower and Thunderstorm Potential: Isolated Strong Storms Possible Inland

Though a gradual shift in the pattern is expected to begin during the short term period, it will overall have little change on the end result for our weather on Friday and into Saturday. Low level high pressure will continue to shift further east/southeast of the region while gradually weakening as well, resulting in more of a southeasterly flow Friday and south to southwest by Saturday.

Friday: A mid level disturbance, originating from persistent troughing offshore over the last several days, drifts northwestward across the area on the western periphery of high pressure ridging. This, combined with the usual sea breeze influence and juicy PWATs as high as 2.3 to 2.5 inches (at least the 90th percentile at KJAX) will result in numerous to widespread showers and t'storms once again on Friday. Instability is generally near to slightly below normal, with more of a "long skinny CAPE" profile per forecast soundings strongly suggesting heavy rain and therefore localized flooding as the primary hazard, especially where training occurs. Though as is common for late summer/early fall, certainly wont rule out some gusty winds with stronger storms, especially with any boundary collisions. Despite an active day, a more southerly component of the flow will allow most areas to rise into the low 90s, except for upper 80s near the immediate coast.

Saturday & Saturday Night: A transition period of sorts, as remnants of the above mentioned upper disturbance linger and PWATs remain above 2 inches while flow shifts more south to southwesterly ahead of an approaching frontal boundary. The ingredients will therefore all be in place for at least scattered to numerous daytime convection, though instead with a more Gulf sea breeze dominant pattern and likely an earlier start to daytime convection. The mainly southwest flow will also allow temps to rise a few more degrees on average across the area, which help further support already sufficient CAPE and therefore isolated strong to localized severe storm potential, especially north and east of the I-75 corridor. The above mentioned front is expected to be approaching or over southern GA by late Saturday Night or early Sunday Morning, which certainly could persist some isolated activity for the Saturday Night period, especially over inland GA.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

Main Highlights This Period:

- Daily Thunderstorms, Isolated Strong Storms Possible Inland.

The above mentioned cold front looks to make modest progress southward for this time of year, with longer term guidance suggesting the boundary slows and nearly stalls either over northeast or central FL by Monday. Exactly how far south the front makes it will certainly play a role in the long term forecast, though at least Sunday and Monday are expected to be very active for shower and t'storm coverage accordingly as the boundary slowly drops further southward. A northeasterly flow then looks to build in just behind the front towards mid week, though as of now does not look to be on the level of more common fall northeasterly events. Some drier air will likely start to intrude parts of southeast GA further behind the boundary, which will drop rain chances for some of these areas. Temperatures will run generally above normal Sunday before falling closer to normal for Monday - Wednesday.

AVIATION /06Z THURSDAY THROUGH 06Z FRIDAY/

VFR conds at the current time at local terminals will trend downwards to LIFR conds in stratus and MVFR VSBYS at VQQ/GNV from 08- 12Z, while JAX will be on the fringe of this stratus deck but will need to keep a TEMPO group in for this potential through sunrise. For the coastal terminals will generally be VFR with occasional MVFR CIGS in the 1500-2500 ft range and isolated showers (VCSH), with best potential at SGJ through sunrise this morning. East winds will increase by the afternoon hours to 10-13G15-20 knots, with highest winds at the coastal terminals. Shower activity will increase in coverage at all terminals after 15Z, reaching GNV by 18Z with mostly MVFR SHRA activity and isolated TSRA (VCTS) chances, mainly at GNV. Will continue PROB30 groups at all TAF sites, although will need to place TEMPO for lower IFR VSBYS in TSRA activity at GNV from 18-22Z. Rainfall chances will lower after 00Z at terminals, but will likely need to keep at least VCSH at all terminals in addition to mostly MVFR CIGS in the 1500-2500 ft range through the end of the current 06Z TAF period.

MARINE

Onshore east to southeast flow will continue waves of showers and embedded thunderstorms at times through Friday. Prevailing westerly winds are then expected from Saturday through at least Monday morning as a frontal boundary sinks southward towards our region, with this feature maintaining a stormy weather pattern. Stronger high pressure will build down the southeastern seaboard early next week in the wake of this boundary, likely pushing the front over the northeast Florida waters.

Rip Currents: A long period east-southeasterly ocean swell will combine with breezy northeasterly winds to create breakers of 3-4 feet at the northeast FL beaches and 2-3 feet at the southeast GA beaches Today. These conditions will yield a high risk of deadly rip currents at the northeast FL beaches and a higher end moderate risk for the southeast GA beaches. The long period swell will gradually fade tonight and should not linger into Friday, with the afternoon sea breeze creating enough of an onshore breeze to yield a lower end moderate risk on Friday at area beaches. Prevailing offshore winds this weekend should result in a low risk, while developing onshore winds on Labor Day likely resulting in at least a moderate risk.

FIRE WEATHER

AREAS OF LOW DISPERSIONS ALONG THE COAST THIS WEEKEND..

More clouds than sunshine with periods of showers and isolated thunderstorms will continue through the end of the week as easterly onshore flow pattern persists. This will also keep dispersions generally in the poor to fair range at best as flow aloft will remain weak overall. Isolated strong storms with gusty winds will be possible, in addition to a localized flooding threat with plenty of available moisture. Flow direction starts to shift this weekend as the next frontal boundary approaches from the north and likely stalls over the region by early next week. This will support warmer temperatures and more of a summer-like daily shower and t'storm pattern.

Fog Potential: Gusty and erratic winds can be expected in and near thunderstorms with briefly localized flooding rainfall. Late night and early morning patchy fog and low stratus will be possible through at least the next several nights, especially in areas that received more rainfall.

PRELIMINARY POINT TEMPS/POPS

AMG 92 74 91 73 / 50 20 70 10 SSI 87 77 88 77 / 60 40 40 10 JAX 89 75 90 74 / 50 30 60 10 SGJ 87 75 89 75 / 50 30 50 20 GNV 90 74 91 73 / 80 30 80 20 OCF 90 73 91 74 / 90 50 80 20

JAX WATCHES/WARNINGS/ADVISORIES

FL...High Risk for Rip Currents through this evening for FLZ124-125-138- 233-333. GA...None. MARINE...None.