Area Forecast Discussion

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

- Patchy Dense Fog Expected Early This Morning for inland counties.

- High Rip Current Risk & Rough Surf Today through Thursday. Breezy Onshore Winds Overspread Coastal Locations today. Wind Gusts at Area Beaches likely to be around 35 mph Tuesday through Thursday. Small Craft Advisories in effect today through Thursday, with Wind Advisories Possible for Coastal Locations.

- Waves of Showers & Thunderstorms Today, Thursday & Friday, Mainly Along the I-95 Corridor

NEAR TERM /TODAY THROUGH TONIGHT/

Main Highlights This Period:

- Gusty Winds Today from out of the Northeast

- Showers and Thunderstorms This Afternoon

Breezy onshore northeasterly winds will build in from out of the Atlantic and press inland this afternoon as the pressure gradient of high pressure ridging extending in from out of the north tightens, resulting in frequent wind gusts of about 30 mph in addition to diurnal convection developing over the region from out of the east, with more widespread developments occurring over coastal areas and spreading inland through the day. Reduced rain chances expected over inland southeast Georgia. Early morning fog over inland areas today is expected to lift before mid-morning. High temperatures this afternoon will reach up into the lower 90s over inland areas and in the upper 80s for coastal counties. Overnight low temperatures will drop down into the lower to mid 70s for inland areas and in the upper 70s for coastal areas and along the St Johns River. Heat index values for this afternoon will rise to 105 for portions of northeast Florida, remaining below heat advisory levels.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Main Highlights This Period:

- A high rip current risk and rough surf at area beaches. - Breezy northeast winds expected. A Wind Advisory is possible for the coastal areas on Wednesday.

An atypical mid to upper level high pressure system will be over the TN valley on Wednesday. The 500 mb heights over the TN valley area may be record setting for this time of year, close at around 590-600 decameters. Further east, a mid to upper level trough will extend from the Bahamas northeast into the western Atlantic. Both of these systems will retrograde on Wednesday while the surface high pressure ridge along the east coast continues to play a role in maintaining gusty northeast flow for the area. Much drier air will be over the area as noted in prior forecasts, with precipitable water values of below 1.4 inches for most areas with mean layer 1000-500 mb northeast flow noted in guidance. This will result in low precip chances at about 15-25 percent for the forecast area. Most convective activity will be confined to the coastal locations but given the winds aloft may move all the way to the 301 corridor. For winds, sustained northeast winds of about 15-25 mph with gusts around 35 mph, especially for the coast. A wind advisory cannot be ruled out for gusts of near 40 mph.

Wednesday night, mostly clear skies expected as the dry air persists. Northeast flow will slowly decrease, but still remain breezy for the coast at 15-20 mph and gusty. Lows temperatures will fall to the upper 60s to lower 70s, but remain elevated in the mid 70s at the coast due to the onshore flow. Isolated showers may move ashore overnight as well.

For Thursday, the weather pattern will continue to be impacted by the anomalous mid to upper level high over the western TN valley and the approach of the mid/upper level trough. The upper level trough will work through the area late in the day and Thursday night bringing a bit more unsettled pattern to the area and an increase in moisture. A slight decrease in the surface winds is expected, but we still see breezy northeast winds affecting the area. Moisture will gradually increase with the best rain chances at 30-40 percent for the coastal areas and lower chances at 10-20 percent inland northeast FL. It looks like inland southeast GA remains dry. Chances of showers at 20-30 percent will remain possible overnight Thursday night given the moderated onshore flow.

Temperatures continue to be fairly warm with the mid 80s coast and to about 90 further inland. Lows forecast in the mid to upper 60s for inland southeast GA and lower to mid 70s elsewhere.

LONG TERM /FRIDAY THROUGH MONDAY/

Main Highlights This Period:

- Daily chances for showers and thunderstorms with locally heavy rainfall possible - Elevated rip current risk and rough surf for area beaches will continue this period

The mid to upper level trough from the Atlantic will be moving westward across the region early Friday. An associated sfc trough will also be moving through the area and bring with it a more moist and unstable airmass. Mean low level flow becomes more easterly with a weaker pressure gradient and lighter winds are expected to develop. Blended model guidance shows scattered showers and embedded storms for Friday mainly across northeast FL, with the drier air still lingering over parts of southeast GA where only isolated convection is anticipated.

For the weekend and Monday, surface high pressure moves off to the northeast of the area with pressure gradient supporting light southeast low level flow. Given the high moisture forecast in current model output with PWATs of about 2 inches, we are advertising diurnally driven numerous showers and scattered storms helped by the sea breezes and outflow boundaries. POPs are forecast up to the 50-70 percent range, with some locally heavy rainfall possible for inland northeast FL.

Overall, high temperatures will be in the mid 80s to lower 90s and lows in the lower 70s.

AVIATION /06Z TUESDAY THROUGH 06Z WEDNESDAY/

Patchy to areas of fog and lower cloud decks are expected to develop over inland areas overnight and into Tuesday morning, with visibility levels for VQQ and GNV lifting by around 11z to 13z. Gusty northeasterly onshore winds will build today with coastal sites with sustained winds of about 10 to 15 knots with frequent wind gusts of 20 to 30 knots possible with breezy onshore winds will continue through Tuesday night. Daytime convection will build along the coast and extend inland, with a greater likelihood for showers and storms developing over SSI and SGJ, with showers lingering into the night for coastal northeast Florida.

MARINE

Onshore winds will build across area waters today through Thursday as a tightening pressure gradient associated with high pressure to the north builds through midweek with an accompanying frontal passage pushing through from out of the east, bringing small craft advisory conditions, rough seas, and waves of scattered to numerous showers and a few thunderstorms over the area waters through much of the week. Improving conditions are expected by Friday as onshore winds weaken and seas gradually lower.

Rip Currents: Strengthening northeast winds and building surf combine to lead to dangerous surf and a high rip current risk for area beaches during the morning hours this afternoon and continuing through Thursday.

FIRE WEATHER

- PATCHY TO AREAS OF HIGH DISPERSIONS TUESDAY THROUGH THURSDAY AFTERNOONS.

Strong high pressure will build to the northeast as a backdoor cool front moves through today. Much higher winds begin by midday today for the coastal areas with speeds up to 15 to 20 mph, gusting to 30- 35 mph. These elevated winds remain in place for Wednesday and possibly into Thursday, especially at the coast. Scattered showers and a few embedded thunderstorms expected today, and mostly isolated on Wednesday.

The high pressure north of the area will weaken Friday, with another high building to the northeast over the weekend. Strong surface and transport winds will lead to areas of high daytime dispersion for the Tuesday to Thursday time frame.

Fog Potential...Patchy dense fog expected early Tuesday morning inland areas.

TIDES/COASTAL FLOODING

We are a few days past the new moon phase, and tidal water levels are still elevated to about 0.5 to 0.8 ft MHHW. Despite the strengthening onshore flow the next few days, we are currently not expecting much in the way of coastal flooding concerns, with water levels expected to be just shy of 1 foot MHHW through Wednesday. As we get more water piling up and persistent onshore flow, peak water levels may be around 1 foot or a little higher by Thursday and Friday, and so still below advisory levels. These higher levels may be within the St Johns River basin and will be monitored in subsequent observations and forecasts.

PRELIMINARY POINT TEMPS/POPS

JAX WATCHES / WARNINGS / ADVISORIES

FL...High Risk for Rip Currents from 11 AM EDT this morning through late Thursday night for FLZ124-125-138-233-333. GA...High Risk for Rip Currents from 11 AM EDT this morning through late Thursday night for GAZ154-166. MARINE...Small Craft Advisory from 11 AM this morning to 5 AM EDT Thursday for AMZ450-470. Small Craft Advisory from 4 PM this afternoon to 5 AM EDT Thursday for AMZ452-472. Small Craft Advisory from 8 PM this evening to 5 AM EDT Thursday for AMZ454-474.