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

- Hot and Humid Today - Peak Heat Index Values: 103- 109

- Afternoon & Evening TStorms Area-Wide Through Most of. Scattered to Numerous Thunderstorms this afternoon (2 PM 9 PM). Strong Storms with Gusty Winds, Frequent Lightning Strikes & Heavy Downpours I-95 & I-10 corridor and all of SE GA this afternoon

NEAR TERM /UNTIL 6 AM TUESDAY MORNING/

Main Highlights This Period:

- Hot and Humid with Heat Index Peaking Around 103-108 Degrees

- Scattered to Numerous Afternoon Thunderstorms, A Few Strong to Isolated Severe Storms Possible, with locally heavy rainfall

Prevailing westerly low level flow today will keep the east coast sea breeze pinned at the coast, with the west coast sea breeze dominate. MLCAPE values of about 1500 to about 2200 J/kg today combined with the sea breezes, outflows, and high moisture content (PWAT 1.9 inches) will lead to scattered to numerous showers and storms rest of the day. Given the deep westerly flow, a few clusters of storms may produce strong wind gusts and heavy rainfall at times. Some sounding analogs show possible half inch to 3/4" hail this afternoon. A localized flood threat is possible with rainfall rates of 2+ inches per hour likely in some storms. While it's hot and humid, the early onset of precip and the clouds will limit the upward momentum of heat indices, generally capped near 107.

Most of the convection will wind down by 8 or 9 pm this evening, having moved off into the Atlantic waters or to the northeast of the area. However, there is a piece of energy aloft shown by some of the hi-res guidance with an associated cluster of showers and storms moving into the western zones from about 8 pm to midnight, but overall instability will be on a weakening trend during that time so not anticipating much of a severe threat. Still some chance for a couple of showers after midnight but otherwise mild with lows in the lower to mid 70s. No fog anticipated, but patchy low stratus expected for interior southeast GA by sunrise.

SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/

Main Highlights This Period:

- Locally heavy rainfall possible both afternoons - Potential for isolated strong to severe thunderstorms

Southwest flow continues to bring enhanced moisture across the area Tuesday and Wednesday, with PWATs above 2.0" as a front remains over central Georgia. Highest rainfall and storm chances both days will be along and north of I-10 (closer to the front) and also along I-95 throughout northeast Florida, where sea breezes will interact due to the southwesterly winds. Overall storms will be diurnal in nature, but there may be some lingering activity through the night Tuesday into Wednesday. Best chances for strong storms will be in the afternoons and evenings, with gusty winds and localized flooding being the primary concerns.

Temperatures will be 'cooler' over inland southeast Georgia where we expect more cloud/rain cover, with highs in the 80s. Elsewhere, high temperatures will reach the lower to mid 90s, max heat indices will peak around 100-105 degrees Tuesday afternoon.

LONG TERM /THURSDAY THROUGH MONDAY/

Main Highlights This Period:

- Daily afternoon and evening thunderstorms continue with locally heavy rainfall and isolated strong storms possible

Winds continue to come from the southwest Thursday through the weekend, keeping decent moisture over the area and chances for afternoon and evening storms. For Thursday and Friday, highest coverage will be over Southeast Georgia, closer to the aforementioned front as it dissipates. Inland northeast Florida will see the lowest storm coverage, with precipitation chances at about 20-40% Thursday and Friday.

Late this week, another front will approach from the northwest then stall near the FL/GA state border this weekend, increasing storm chances over much of the area Saturday. Given the extended period of higher rain chances, there may be a concern for localized flooding, especially near I-95 and along and north of I-10. Temperatures will generally be at or just above average during this period.

AVIATION /00Z TUESDAY THROUGH 00Z WEDNESDAY/

Convection has ended at all TAF sites except for a few storms that have redeveloped near KGNV that may linger until 01Z with potential MVFR conds. Otherwise very moist airmass aloft with PWATs over 2 inches that could produce a brief shower from the mid clouds at any time so have kept VCSH at all terminals through the overnight hours. VFR conds are expected early tonight, then MVFR CIGS are expected to develop in the W-SW low level flow in the 06-10Z time frame at all TAF sites with only minimal restrictions to visibility through sunrise, then a slow lifting of CIGS back to VFR by 15-17Z as diurnal heating will trigger another round of showers and storms during the afternoon hours and for now have placed PROB30 for all TAF sites in the 17-24Z time frame for gusty winds to 25 knots, MVFR CIGS and VSBYS, all of which could end up with lower IFR conds along with stronger wind gusts to 35 knots as timing becomes more clear.

MARINE

The region will be between high pressure to the south southeast, and a frontal zone stalling just north of the local waters through most of the upcoming week. This will lead to a predominant southwest to west flow which will become breezy at times, with periods of Small Craft Exercise Caution conditions, mainly over the offshore waters. The offshore flow will continue to push strong storms with gusty winds and frequent lightning into the coastal waters through the period mainly in the afternoon hours. The frontal zone will weaken mid week which will likely limit showers and thunderstorm activity before another frontal boundary drops southward toward the area Friday into Saturday.

Rip Currents:

Generally a low risk of rip currents continues early this week as surf remains only in the 1-2 ft range in the predominant offshore flow. This trend is likely to continue through mid week as well. Some slight increase in east-southeast wind-sea possible Thursday and Friday but still looks relatively weak. This matches fairly well with latest NWPS rip current probability guidance.

FIRE WEATHER

- Patchy high daytime dispersion values this week - Daily showers and thunderstorms expected

A series of frontal boundaries interacting with a warm, moist, and unstable airmass will maintain above-normal chances for showers and thunderstorms through much of the upcoming week and into next weekend. Periods of locally heavy rainfall, frequent lightning, and gusty winds will accompany the stronger storms. Outside of convection, favorable transport winds and mixing heights will at times support patchy high daytime dispersion values. Temperatures are expected to remain near to slightly above seasonal normals throughout the period, accompanied by elevated humidity levels.

FOG POTENTIAL AND OTHER REMARKS: Areas that receive heavier rainfall may also experience patchy late-night and early-morning fog development due to increased low-level moisture and light winds.

PRELIMINARY POINT TEMPS/POPS

AMG 72 85 70 86 / 50 90 80 80 SSI 76 88 75 87 / 50 80 50 70 JAX 74 91 73 90 / 40 80 50 50 SGJ 74 93 74 93 / 50 70 40 50 GNV 74 93 73 92 / 30 50 30 30 OCF 76 92 74 93 / 20 30 20 20

JAX WATCHES/WARNINGS/ADVISORIES

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