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

- Isolated Strong Thunderstorms Today. Hazards: Gusty Winds (40-60 mph), localized flooding & frequent lightning. Main Concern Areas: I-95 corridor and areas north of I-10. Stronger Storm Timing: 3 PM 10 PM

- SUN-MON: Isolated to Scattered Thunderstorms, mainly NE FL. Increasing thunderstorm coverage Tuesday-Friday

- Moderate Afternoon Rip Current Risk Today and Sunday

- Low Chance of Central Atlantic Tropical Cyclone Development Late Week

NEAR TERM /THROUGH TONIGHT/

Highlights through Tonight:

- Potential for strong thunderstorms this afternoon and evening

Lingering upper shortwaves ahead of the weakening frontal boundary will help trigger showers and isolated storms moving inland from the Gulf. Convection will then spread east-northeastward through the day in the general southwest steering flow. Best chances for storms will be along the sea breeze merger near I-95 and SE GA closer to the weakening frontal boundary. A few strong storms may be possible along boundary mergers producing gusty winds and heavy rainfall. Convection will shift off the Atlantic coast later this evening. Temps still expected to reach the lower/middle 90s ahead of convection with peak heat indices around 105F, but still below Heat Advisory criteria. Low temps near normal in the lower to middle 70s inland and upper 70s along the Atlantic Coast.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/

Main Highlights This Period (Sunday and Monday):

- Lower Thunderstorm Chances Sunday, Isolated Strong Storms Possible

- Hotter with Daily Peak Heat Index near 105

Drier air begins to infiltrate across the area from the northwest Sunday as the mid level trough axis across the eastern seaboard weakens and nudges farther to the east. This pattern shift will bring much lower rain chances across southeast GA Sunday (rain chances < 15%) as precipitable water content falls below 1.5 inches, which is below the 25th percentile for this time of year. Higher precipitable water content near 2 inches will focus across northeast Florida Sunday afternoon, mainly south of the Interstate 10 corridor, with morning showers and isolated storms edging inland from the Gulf Coast region under southwest winds, then convective coverage expands eastward into the afternoon toward the Atlantic coast. A few stronger storms will be possible across the St. Johns River basin and toward the Atlantic coast in the afternoon where low level boundaries merge under seasonably cool 500 mb temps of -6.5 to - 7 deg, near the median values for the date.

Monday, models trending a little wetter with the development of another deeper eastern seaboard mid level trough axis, with a return of PWATs back above 2 inches for much of the area under light west- southwest steering flow as a surface front slides southward into central GA. Rain chances nudge up into the 20-40% chance range with a prevailing west coast sea breeze regime and possibly convection ongoing into Monday night across southeast GA with the approach of the surface front and a passing mid level short wave trough. A few strong to isolated severe storms possible as mid level temperatures cool across southeast GA into the -7 to -8 degC range at 500 mb.

High temperatures warm back to above climo values in the mid to upper 90s with heat index values generally topping out near 105 Sunday to 105-109 degF Monday across northeast FL. Near to just slightly at Heat Advisory criteria Monday for northeast FL. Overnight lows will trends in the low/mid 70s.

LONG TERM /TUESDAY THROUGH FRIDAY/

Main Highlights This Period (Tuesday through Saturday):

- More Active Weather Pattern Returns Tuesday

Deeper moisture returns and lingers Tuesday onward as as broad upper troughing establishes across the eastern seaboard with prevailing WSW steering flow across the region and several mid level shortwaves progged to enhance daily thunderstorm activity. This pattern favors a dominant west coast sea breeze regime across FL, sea breeze and outflow mergers toward the late afternoon and evening storms favoring near the I-95, and then late afternoon and early evening storms across southeast GA near meandering surface front.

Above normal temperatures are expected to continue through the week with highs generally in the low 90s Tuesday onward with heat index values generally below local heat advisory criteria at this time.

Tropics Outlook: NHC has a 30% chance of tropical cyclone formation mid to late week across the central Atlantic. Locally, rip current activity could become more enhanced late week depending on the evolution of this system.

AVIATION /18Z SATURDAY THROUGH 18Z SUNDAY/

Line of showers has already pressed through GNV and expect just VCTS/VCSH to linger there through the rest of the afternoon hours. Meanwhile this line will progress to the NE and will need to include a mixture of PROB30/TEMPO groups at remaining terminals, mainly in the 18-22Z time frame for NE FL terminals and 19-23Z for SSI, for the potential of gusty winds to 25-30 knots along with MVFR conds at times. Convection chances still expected to fade after sunset with the usual VFR mid/high clouds overnight, and potential MVFR VSBYS in fog at VQQ from 07-11Z. For Sunday morning, will need to add in at least VCSH for GNV by 12Z and VCTS by 15Z with the early development of convection along the NE Gulf coast, very similar to today.

MARINE

A frontal zone will extend across the Carolinas and into Georgia with a high pressure ridge to the southeast. Rounds of mainly afternoon and evening showers and thunderstorms can be expected each day. Brief southerly wind surges are expected during the late afternoon and evening hours, but winds are expected to remain below Small Craft Exercise Caution levels. The cold front will push into the local waters Sunday night into Monday and then lift back northward as a warm front by mid-week.

Rip Currents: Surf/breakers will remain 1 to 2 feet through early next week in the mainly offshore flow with overall low rip current risk, but brief periods of moderate risk will exist during the afternoon hours as local onshore sea breeze develops each day.

FIRE WEATHER

- Locally High Dispersion Sunday And Monday For Se Ga

Unsettled weather continues today with showers and storms possible along a stalling front and the sea breezes this afternoon. A few storms will be capable of strong wind gusts, locally heavy rainfall and frequent lightning.

West to southwesterly breezes continue today and for the next several days with the exception of the coastal areas where the afternoon Atlantic sea breeze will shift winds east to east- southeast.

A dry northwest flow will bring lower humidity and mostly dry weather to southeast Georgia Sunday with minimum humidity between 30- 40% while scattered to isolated afternoon showers and storms will continue across northeast FL. Monday, continued hot with drier air limiting rain chances further with isolated afternoon limiting and evening showers and storms. Hotter temperatures on Sunday and Monday will increase mixing heights across southeast GA, leading to locally high dispersion each afternoon.

Fog Potential: Significant fog is unlikely, and any strong wind will be associated with nearby thunderstorm activity.

PRELIMINARY POINT TEMPS/POPS

AMG 93 71 97 72 / 50 10 20 10 SSI 90 76 92 77 / 60 30 10 10 JAX 94 74 95 74 / 40 20 20 10 SGJ 93 75 93 75 / 30 20 30 10 GNV 92 73 92 73 / 20 10 30 0 OCF 92 73 92 72 / 30 10 40 10

JAX WATCHES/WARNINGS/ADVISORIES

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