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

- Daily Afternoon & Evening Thunderstorms. Highest coverage over north central Florida this weekend. Strong Gusty Winds, Frequent Lightning, and Localized Flooding are main

- High Risk of Rip Currents Northeast FL Beaches Today, Moderate

- Risk Southeast GA Beaches

- Moderate Risk this Weekend

- Hot Holiday Weekend Potential Max Heat Indices: 105-109F

NEAR TERM /THROUGH TONIGHT/

Main Highlights Today and Tonight:

- Higher chances of afternoon thunderstorms focused over Northeast Florida generally west of I-95 toward the Highway 301 and I-75 corridors - Elevated Rip Current Risk at Area Beaches Today

A bit of a transition day today as deep layer mean flow begins to shift to more south and southwest but only 5-10 kt with some increased moisture in the low to mid levels. The high pressure ridge axis is starting to rebuild to our south today with very light boundary layer flow to start the morning. Aloft, weak vort lobe is across southeast GA and temps aloft today are still warm, but may cool slightly by the afternoon and evening.

Given a weak pressure gradient on July 4th, the east coast sea breeze will be slightly delayed, migrating inland toward Highway 301 by late afternoon. This will favor a sea breeze collision across interior sections of SE GA and NE FL. Scattered showers and thunderstorms will develop by early to mid-afternoon, becoming numerous across inland NE FL and North Central FLparticularly along and south of the I-10 corridor where sea breeze and outflow interactions will maximize convergence and where precipitable water values are about 2 inches. Highest chances are noted to be across Marion, Putnam, and Alachua counties. Did shift some slightly higher rain chances into southeast GA today as well, but probably staying isolated coverage there. Slow storm motions and abundant moisture will support torrential rainfall and a localized flooding threat, while stronger storms may also produce frequent cloud-to-ground lightning and gusty, erratic winds. Convective activity will gradually diminish after sunset, though isolated to scattered showers and storms will linger during the mid to late evening hours across the interior.

For temps today, highs are forecast in the mid to upper 90s and the available low level moisture will result in heat indices climbing to about 102 to 107, so at this time looks to be shy of a widespread heat advisory. Lows tonight only in the lower to mid 70s most areas, but upper 70s coast. Patchy light fog is possible inland areas this morning and possibly again late tonight.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/

Main Highlights This Period:

- Afternoon thunderstorms focused over inland Northeast Florida. - Elevated Rip Current Risk at Area Beaches Sunday

Prevailing flow will be from out of the southwest through the end of the weekend and into the beginning of next week resulting in scattered to numerous showers and storms building into the afternoon and evening, with increased moisture levels over Florida resulting in an increased likelihood for stronger developments over north central Florida and for areas south of the I-10 corridor. High temperatures for the end of the weekend and into the beginning of next week will be in the mid to upper 90s for inland areas and in the upper 80s and lower 90s for areas nearer to the coast. Overnight low temperatures will drop down into the mid 70s for inland areas and in the upper 70s for areas along the shoreline and near the St Johns River. Heat index values will rise up to over 100 with a potential for Heat Advisory conditions on Sunday and Monday.

LONG TERM /TUESDAY THROUGH FRIDAY/

Main Highlights This Period:

- Storm Chances Continue thru Next Week - Above Average Temperatures with High Heat Index Values

The daytime sea breeze will be pinned closer to the coast through midweek as prevailing flow continues to be mainly out the south and southwest while high pressure ridging extends over the Florida peninsula from out of the east. Daily bouts of convection will continue through the extended period with PWAT values over over the forecast area vary between 1.5 and 2.3 inches, with convection potentially becoming less widespread going into midweek as the high pressure ridging from the east enhances over the region and shifts northward. Temperatures will remain above average through the end of next week with daily max temps rising into the mid 90s. Heat index values will rise up to over 100 into midweek next week with a potential for Heat Advisory conditions through the period.

AVIATION /12Z SATURDAY THROUGH 12Z SUNDAY/

Deep moisture trickling in from the southeast this morning and has made it stronger push based on latest satellite estimates. Primary TSRA concerns this afternoon remains focused across Northeast FL, generally west of the I-95 corridor. After considering the satellite trends, upgraded TSRA potential at KVQQ and KJAX this afternoon. High confidence of slow-moving +TSRA at KGNV between 19z-23z. Otherwise, no significant changes to the previous forecast with mainly VFR conditions outside of convective potential and lowest cloud bases around 3 kft at the coast and 5 kft inland. Winds will be very light initially and then increase close to 10-12 knots with the Atlantic sea breeze. Per usual, in the vicinity of +TSRA erratic wind gusts up to 30+ knots is possible. This evening as convection settles, "blow back" showers from residual TSRA may lead to -SHRA along the I-95 corridor.

MARINE

High pressure builds across central and south Florida this weekend into early next week with a transition to south to southwest flow over the local waters and higher afternoon and evening thunderstorm chances over the local waters. Nightly wind surges return with near exercise caution levels developing by Sunday night.

Rip Currents:

At 06z, local buoys show about 2 ft with dominant period 7-8 seconds. NWPS rip current probabilities are lower today than yesterday. Generally looks like moderate risk today, but given the 7- 8 second periods, 2 ft surf, increased beachgoers attendance, and NWPS max rip current probabilities still elevated and collaboration with NWS MLB, will go with another high risk for northeast FL beaches. The highest risk of rip currents will be centered around inlets, piers, any prominent sandbar and sloughs, and near the early morning low tide and the late afternoon low tide. Similarly, looks like a moderate to locally high risk for Sunday.

FIRE WEATHER

Scattered showers and storms will build in this afternoon with the majority of the convection occurring over north central Florida and for areas along and south of the I-10 corridor. Onshore easterly winds will build with daytime heating allowing the breezy diurnal sea breeze to reach further inland, becoming light and variable overnight.

Persistent south-to-southwesterly flow will persist Monday through Wednesday, supporting daily rounds of scattered afternoon and evening thunderstorms. In addition, higher daytime dispersion values are expected by early next week as southwest transport winds increase.

Fog Potential and other remarks: Patchy fog development expected over inland areas overnight and then dispersing before mid-morning. Any stronger thunderstorms will be capable of producing frequent lightning, torrential rainfall, and erratic wind gusts during the afternoon and evening.

HYDROLOGY

Satilla River at Atkinson will remain in Minor Flood through the Sunday and is forecast to lower into action stage Sunday evening.

PRELIMINARY POINT TEMPS/POPS

AMG 97 75 97 76 / 10 10 30 20 SSI 91 79 95 79 / 10 10 30 10 JAX 95 76 97 77 / 20 10 50 10 SGJ 92 77 94 76 / 20 10 60 20 GNV 95 75 94 74 / 50 30 60 10 OCF 94 75 92 75 / 60 30 50 10

JAX WATCHES/WARNINGS/ADVISORIES

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