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 all Local Beaches Today and Friday. Elevated Risk Returns Early Next Week

- Daily Heat Index up to 107 through Sunday

- Daily Afternoon & Evening Thunderstorms. Main Hazards: Locally Heavy Rain, Lightning & Gusty Winds Up to 40-50 mph

UPDATE

In the midst of pooled moisture ahead of trough has provided a near- saturated upper air observation the morning, with measured precipitable water at 2.36" again which is not to far of from the statistical max for mid September (PWAT 2.38"). While there has been some slight cooling the in upper levels, which could support more frequent or excessive lightning, warming in the mid levels has also occurred, leading to weaker lapse rates and potential energy for thunderstorms later on today, mainly during the early afternoon.

The big picture remains the same, with dry northwesterly flow, associated with a shearing/dampening shortwave, making it into interior SE GA by this afternoon limiting thunderstorm activity while elsewhere there is a 30-60% chance of thunderstorms this afternoon and early evening. The primary focus for convection will once again be along the I-95 corridor with a near west-to-east steering flow in place acting the slow the Atlantic sea breeze and St Johns River breeze from advancing inland/westward.

As has been the situation regarding thunderstorm hazards over the last few days, frequent lightning, gusty outflow winds, and localized flooding are the primary concerns. Timing with CAMs has been relatively solid, indicating expanding shower development through 2 PM followed by scattered thunderstorm potential increasing thereafter as mesoscale boundaries and outflows interact.

Rain and thunderstorms will bring some relief in terms of temperature, but expect heat index to move quickly into the 100s by noon today as temperature rises into the low 90s. Drink plenty of water and seek shade during outdoor activities today and, as always, when thunder roars, head indoors.

AVIATION /12Z SUNDAY THROUGH 12Z MONDAY/

VFR conditions will continue through 13z with brief periods of broken MVFR ceilings at inland terminals (KJAX/KGNV/KVQQ) as low level moisture lifts. Surface winds will be light westerly with a sea breeze developing by 18z-20z for SSI, SGJ, and CRG switching winds to the southeast. Westerly steering winds aloft will push isolated to scattered showers and thunderstorms toward the I-95 corridor where stronger storms may develop due to sea breeze and outflow collisions. Localized IFR to LIFR conditions are possible due to heavy rain limiting visibility. Convective activity will fade after sunset with drier air limiting stratus and fog potential tonight for sites along and north of I-10 Monday morning.

MARINE

Offshore winds will continue across the area waters today and on Monday, except for a sea breeze which will shift winds to the southeast and south during the afternoon hours. Another good chance of a couple of strong thunderstorms this afternoon and evening. Strong gusty winds and very heavy rainfall will accompany the stronger storms. On Monday, less thunderstorm activity is expected and likely be limited to northeast Florida nearshore waters. From Tuesday through Thursday, a strong northeast wind surge will bring small craft advisory conditions, rough seas, and numerous showers and a few thunderstorms over the area waters.

Rip Currents: Prevailing offshore winds (except for an afternoon sea breeze) and weak easterly swells will keep a low-end moderate risk of rip currents in effect the next couple of days. By Tuesday, strengthening northeast winds and building surf are expected which will continue into Thursday. This should result in a high rip current risk and dangerous surf at all area beaches during this time period.

FIRE WEATHER

PATCHY TO AREAS OF HIGH DISPERSIONS TUESDAY THROUGH THURSDAY - Afternoons

A trough of low pressure will stretch across the southeastern US this weekend. High pressure will build to the northeast early next week, and strengthen through mid week. As this high builds, an inverted trough will develop east of the area. The gradient between these two features will result in elevated winds Tuesday through Thursday, especially at the coast. An inverted trough will settle overhead late in the week into the weekend. Daily thunderstorm chances are forecast, mainly in the afternoon and evening hours.

PRELIMINARY POINT TEMPS/POPS

AMG 92 73 94 73 / 10 10 0 0 SSI 91 77 92 79 / 20 20 0 0 JAX 92 75 93 75 / 40 20 10 0 SGJ 91 76 91 76 / 40 30 10 10 GNV 92 74 93 74 / 40 20 40 10 OCF 92 75 93 74 / 50 20 50 20

JAX WATCHES/WARNINGS/ADVISORIES

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