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

- Moderate Rip Current Risk at Area Beaches through Wednesday

- Isolated Afternoon Thunderstorms on Today & Wednesday Across Portions of Northeast and North Central FL. Thunderstorm Coverage Increases from Friday through the Weekend

- Heat and Humidity Builds Late this Week through the Weekend. Dangerous Heat Possible Saturday with Heat Index Values of 104-108

- Drought Conditions Persist Across Our Region

NEAR TERM /THROUGH TONIGHT/

Main Highlights This Period:

- Isolated to widely scattered showers and thunderstorms across portions of northeast and north central FL.

- Moderate rip current risk continues at all area beaches as breezy onshore winds develop this afternoon.

Surface high pressure off the mid-Atlantic coast will continue to weaken and shift eastward toward Bermuda as a stalled frontal boundary over South Carolina dissipates into tonight. Meanwhile, an inverted trough shifts westward from the Gulf Stream waters onshore to the east central and northeast FL coast this afternoon into evening. This trough will bring a pocket of deeper moisture (PWATs 1.8-2 in) across northeast and north central FL this afternoon and evening, with isolated to widely scattered showers have shifted onshore mainly to areas south of St. Augustine. The activity will continue to progress inland across the southern St Johns river basin and north-central FL. An isolated thunderstorm could develop this afternoon. A few showers will linger overnight into early Wednesday morning across coastal northeast FL. Around seasonable temperatures continue today with highs in the mid 80s along the coast to the upper 80s to around 90 further inland. Lows tonight will generally range from the upper 60s to mid 70s.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Main Highlights This Period:

- Heat Index Back into the Triple Digits by Thursday

- Gradual Increase In Afternoon Thunderstorm Chances Through the Week

- Moderate Risk for Rip Currents

Low level ridging will move eastward through Wednesday, with onshore flow prevailing over the area. Steering flow will be light and transition to a predominantly southerly direction by Thursday. While some increases in moisture, dry air lingering aloft coupled with marginal lapse rates is expected tamp down the convective coverage along the Atlantic sea breeze as it moves inland each afternoon with generally isolated to scattered showers and thunderstorms. Highest precipitation chances (around 40-50%) will generally be over inland northeast Florida. Temperatures will gradually increase through the week, with highs in the mid to upper 90s by Thursday inland, with even the coast seeing highs around 90 degrees. Maximum afternoon heat indices will approach 100 degrees for some inland locations Thursday as well.

LONG TERM /FRIDAY THROUGH TUESDAY/

Main Highlights This Period:

- Dangerous Heat for Sensitive Groups This Weekend

- Scattered to Numerous Thunderstorms Along the Coastal Counties Friday Onward

Surface winds from the southwest coupled with an approaching front from the north will increase moisture across the area Friday through Monday, enhancing chances for afternoon and evening thunderstorms each day. With the southwesterly winds, precipitation chances will make it all the way to the Atlantic coast, higher coverage Saturday and Sunday.

The primary concern during this period will be the dangerous heat forecast. Highs will approach the mid to upper 90s inland, and low 90s along the immediate east coast, with maximum heat indices approaching 100-105 degrees each afternoon for inland areas. The hottest day will be Saturday, where some select locations will approach Heat Advisory criteria.

AVIATION /18Z TUESDAY THROUGH 18Z WEDNESDAY/

MVFR ceilings have developed across the NE FL TAF sites this afternoon fluctuating between scattered and overcast. Showers have pushed inland south of Jacksonville and will shift westward toward GNV this afternoon. East winds around 10 kts this afternoon subside later tonight. Showers will develop again after 06Z along the NE FL coast potentially affecting SGJ, JAX and CRG in the pre-dawn hours. Lower ceilings will be possible with this activity.

MARINE

A trough moving westward towards the east central Florida coast is expected to develop widely scattered showers and possibly a few thunderstorms to the northeast Florida waters today. This trough will move westward, dissipating over central Florida tonight, with a few showers possibly lingering over the northeast Florida waters. High pressure will weaken off the mid-Atlantic coast as it pushes southeastward towards Bermuda tonight and Wednesday, maintaining a prevailing southeasterly flow across our local waters through Thursday. Evening wind surges will increase speeds to near Caution levels during the evening hours from Wednesday through the weekend. Troughing will then develop over the southeastern states this weekend, creating a prevailing southerly wind and increasing afternoon and evening showers and thunderstorms across our local waters.

Rip Currents: Breezy onshore winds each afternoon will combine with a persistent easterly ocean swell of 7-10 seconds to maintain a moderate rip current risk at all area beaches through Wednesday , especially during the outgoing tide, which will occur during the late afternoon and early evening hours. A lower end moderate risk is expected from Thursday through the weekend at the northeast Florida beaches as the easterly ocean swell diminishes, with a low risk expected at the southeast Georgia beaches.

FIRE WEATHER

High pressure will be in a position to favor the Atlantic sea breeze through Thursday. Expect accompanying sea breeze wind speeds to be in the 8-12 mph range, or around 5-9 at eye level. Temperatures will continue to heat up this week with mid 90s likely this weekend while lowest afternoon humidity be similar to the last few days around 40- 45%. Anticipate the return of more regular bouts of scattered afternoon thunderstorms late this week as moisture begins to increase. Though fine fuels have dried to critical levels during the recent dry stretch, there is no glaring potential of concerning fire weather alignment.

FOG POTENTIAL AND OTHER REMARKS: Patchy inland fog is possible but significant fog development is not expected.

PRELIMINARY POINT TEMPS/POPS

AMG 69 91 73 93 / 0 10 10 20 SSI 76 86 77 89 / 10 10 0 10 JAX 73 90 74 95 / 20 20 0 20 SGJ 75 88 73 91 / 20 20 0 10 GNV 72 93 72 94 / 10 20 20 50 OCF 73 92 73 93 / 10 30 20 50

JAX WATCHES/WARNINGS/ADVISORIES

FL...None. GA...None. MARINE...None.