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

- High Risk for Rip Currents at Northeast Florida Beaches. Moderate Risk at Southeast GA Beaches

- Scattered Thunderstorms Inland Late This Afternoon and Evening. Main Hazard Area: Inland Locations Along and West of U.S. 301

- Mainly Afternoon and Evening Thunderstorm Chances Increase Late this Week and During the Upcoming Weekend. Heavy Rainfall and Localized Flooding will be a Concern

- Hot and Humid - Daily Heat Index 95- 105F through Friday

NEAR TERM /THROUGH TONIGHT/

Main Highlights This Period:

- High Risk for Rip Currents Continues Today for NE FL Beaches

- Isolated Strong Storms Late this Afternoon through this Evening. Main Hazard Area: Inland Locations Along and West of U.S.-301 in SE GA. Primary Storm Hazards: Wind Gusts of 40-50 mph, Frequent Lightning Strikes, Heavy Downpours and Localized Flooding

Lingering showers and storms west of US 301 will gradually dissipate as they shift northward early this morning. Persistent deep-layered ridging across the SE seaboard will gradually retreat ESE with flow becoming more southerly. Latest GOES-East derived Total Precipitable Water imagery indicates a drier air mass over central and south FL has shifted into coastal NE FL dropping PWATs into the 1.6-1.8 in. range. This drier airmass will gradually overtake the deep tropical airmass (PWATs 1.9-2.1 in) currently over SE GA and Suwannee Valley. This will result in isolated to widely scattered showers and storms developing along the inland moving sea breezes in NE FL this afternoon into evening. Breezy SE winds with gusts 20-30 mph develop in the wake of the Atlantic sea breeze this afternoon. Better convective coverage remains across inland SE GA where the tropical moisture remains with ample instability. Due to a more southerly flow, the sea breeze merger will be between US 301 and I-75 corridors. A few strong storms will be possible in the late afternoon into early evening for inland SE GA where activity could be enhanced by passing shortwaves aloft and boundary collisions. Stronger storms could produce gusty winds 40-50 mph, heavy downpours, and frequent lightning. Training storms could result in localized flooding, particularly for urban or normally flood prone, low-lying areas. Similar to previous nights, convection will linger into the early morning and gradually dissipate as the activity shifts northward.

Above seasonable temperatures continue with daytime highs in the upper 80s along the coast to low-mid 90s inland and overnight lows in the upper 60s to upper 70s. Peak heat indices this afternoon will range from the mid 90s to around 100.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

- Afternoon and Evening Thunderstorms capable of heavy rain - Heat index 95-105 degrees in the afternoons

The generally steering flow will trend south-southwesterly Wednesday and then more westerly by Thursday. A rich pool of Gulf moisture will be tapped into Wednesday as flow begins to veer, resulting in more numerous showers and thunderstorms to develop along a slightly more dominant Gulf breeze. The highest chances for widespread thunderstorms will be more focused along the I-95 corridor during the late afternoon and early evening hours. As flow turns more westerly under influence from an positive-tilt upper trough dropping in from the north will again focus the best thunderstorm potential along and east of I-95 and into the adjacent Atlantic coastal waters Thursday afternoon.

Aside from a lightning threat, the primary concerns with thunderstorms this week will be the high-rain rates (4-6" per hour) and localized flooding with a tropical-like airmass, especially Thursday as precipitable water pushes to near record levels (for early June). The threat for severe storms is fairly low given modest to weak lapse rates aloft. This isn't a favorable "training" convection set up, so not slam dunk flash flooding event but it is something to be aware of come Thursday.

Given the development of an offshore flow and a pinned Atlantic sea breeze, hot temperatures - in the low 90s - are expected at the beaches in addition to the inland areas both Wednesday and Thursday.

LONG TERM /FRIDAY THROUGH MONDAY/

- Increasing Thunderstorm Chances, Carrying a Risk for Flooding

A wet pattern amid a very moist tropical-like airmass will continue through the weekend. The primary threat will be heavy rain and high rainfall rates through the weekend as high-grade Gulf moisture continues to feed diurnal convection. To the north a late-season cold front will begin to sink southward and stall near, but likely to the north of, the Altamaha River in southeast GA and be a second focus for afternoon convection in addition to the sea breeze Friday.

Forecast confidence in the pattern takes a nose dive this weekend. Current expectation is that during the overnight hours Friday into Saturday, a weak low will loosely organize along the stalled front and continue rain chances through most of the night, before it moves off the coast sometime Saturday. On the backside of the low, northeasterly flow should push the stalled front into the forecast area where it'll be parked through Sunday but possibly Monday. This will keep skies mostly cloudy, temperatures a bit cooler than normal, and ignite waves of showers and thunderstorms through the weekend.

Though uncommon for the beginning of meteorological summer, there's some potential for the front to shift further south ushering in a drier airmass and much cooler temperatures early next week. While cooler conditions are expected due to the cloud cover and damp conditions, the forecast still leans toward the stalled frontal scenario, not one where it clears the area to the south. Thus, sensible weather favors highs in the low to mid 80s with daily chances for rain/storms.

AVIATION /12Z TUESDAY THROUGH 12Z WEDNESDAY/

VFR conditions expected for most of the day through the evening, with gusty southeasterly winds filling in this afternoon as the Atlantic sea breeze pushes inland. Overall, precipitation/thunder chances are low near the coastal sites, with best chances for a storm being at GNV and VQQ later this afternoon into the evening.

MARINE

A stalled frontal boundary stretching across the Mid-Atlantic states and into the lower Mississippi Valleys will lift slowly northward today as Atlantic high pressure centered near Bermuda remains over the southeastern seaboard. Breezy southeast to southerly winds will continue through midweek across our local waters, with exercise Caution levels prevailing during the afternoon and evening hours as wind speeds surge to just below Small Craft Advisory levels. High pressure positioned off the southeastern seaboard will gradually weaken and retreat through the week as a cold front shifts southward towards our local waters during the upcoming weekend. Scattered showers and thunderstorms will tend to develop during the overnight and morning hours on today and Wednesday, with activity then increasing in coverage through the upcoming weekend.

Rip Currents:

Breezy SSE winds and breakers of 2-4 feet will maintain a high risk at NE FL beaches this afternoon and evening. A higher end moderate risk prevails at the southeast GA beaches today. High/Moderate risk continues into Wednesday.

FIRE WEATHER

- Areas Of High Inland Dispersion Inland Today And Wednesday

A summery pattern, dominated by the Bermuda high pressure, continues through mid week. General winds will favor a southerly direction today, allowing the Gulf and Atlantic sea to each make a push toward the US 301 corridor. That'll be the "sweet spot" for isolated to widely scattered thunderstorms this afternoon and early evening as the two sea breezes merge. Outside of thunderstorm outflow influences, winds will be southerly inland to south-southeasterly at the coast through the early afternoon around 6-12 mph with gusts around 15 mph inland and up to 20 mph along the immediate coast. Given the breezy conditions, areas of high dispersion are expected this afternoon and likely again Wednesday afternoon. Increasing thunderstorm activity is expected Wednesday and into the weekend as a general winds turn southwesterly, tapping into a tropical-like airmass in the Gulf.

FOG POTENTIAL AND OTHER REMARKS: Significant fog is not expected into early next week but patchy morning fog will be possible in areas where heavy rain fell during the previous afternoon. Erratic winds during periods of thunderstorms.

PRELIMINARY POINT TEMPS/POPS

AMG 90 70 88 70 / 40 40 50 20 SSI 88 77 88 75 / 10 20 50 30 JAX 92 75 93 74 / 30 20 60 30 SGJ 90 76 91 75 / 10 10 50 50 GNV 94 73 92 72 / 30 50 40 40 OCF 92 74 90 73 / 40 70 40 60

JAX WATCHES/WARNINGS/ADVISORIES

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