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 at NE FL beaches through Memorial Day

- Scattered to numerous thunderstorms, some will be strong to marginally severe. Daily afternoon thunderstorms expected through next week.

- Daily Heat Index 95-105F through Weekend

- Historic Drought & Elevated Wildfire Danger Continues

NEAR TERM /THROUGH TODAY/

- Hot and Humid; Heat Index Values in the upper 90s. - High Risk for Rip Currents - Scattered strong to marginally severe storms this afternoon. - Localized flooding possible due to slow-moving thunderstorms.

Still quite a bit of convection developing early this morning across the Suwannee Valley and interior areas of southeast GA. This activity is attributed to an embedded shortwave lifting northeastward out of the Gulf and colliding outflow boundaries at the surface. Anticipate shower and isolated storms to dwindle in coverage as it shifts northward, pushing beyond the Altamaha River by sunrise.

Today will be more active in terms of thunderstorm coverage compared to the last couple of days. One notable change will be an anomalous plume of deep moisture over the area, sourced from the Caribbean. Satellited derived PWAT is measuring close to 2.00" currently, which considerably high for this time of year. Secondly, the upper ridge that had kept shortwaves further west over the last two days will flatten out, turning flow aloft more southwesterly and directing another upstream shortwave directly over the forecast area this afternoon.

Those aforementioned factors - moisture and an incoming shortwave - will aid in more successful updrafts along both the Atlantic and Gulf sea breezes as each one makes an inland push this afternoon. Activity will likely ramp up along the Atlantic sea breeze after 3 pm as it interacts with the St Johns River breeze. The following messy combination of outflows and sea breeze will continue to push westward where an eventual merger with the Gulf breeze will occur near or just east of the I-75 corridor.

There's a chance that a few areas may see multiple rounds of heavy rain or training convection through this afternoon which will enhance the potential of minor, short-duration flooding. HiRes ensembles are honing in areas of heavy rain, mainly along the US-301 corridor and southeast GA where there's a reasonable chance (30-50%) of 3"+ over a few hours this evening. For convective threats, the primary concern will be water-loaded updrafts collapsing leading to strong to downbursts, between 40-60 mph.

For this evening and tonight, anticipate outflows to keep convection going through around 10 PM before showers fade completely in the wake region of the departing shortwave. Once convection subsides, conditions will be quiet overnight the airmass "worked over" by the afternoon and evening convection.

Hot and humid conditions continue today before t'storms initiate, with readings in the low 90s and heat index values into the upper 90s. A similar mild and muggy night is expected again tonight with lows in the low/mid 70s.

SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/

- Isolated Strong Storms Possible Inland Sunday Afternoon/Evening - Hot and humid conditions

Ridging over the western Atlantic will continue south-southeasterly flow across the area into early next week. On Sunday, juicy airmass (PWATs 1.8-2.1 in.) will promote numerous showers and storms developing along the inland moving sea breezes in the afternoon into evening. The overall flow will allow for the sea breezes to converge mainly between I-75 and HWY 301 corridors. Some shortwaves aloft move across the area in the upper SW flow and may enhance convection. Strong storms will be possible mainly along boundary collisions. Potential hazards will be wind gusts 40-50 mph, heavy downpours, localized flooding and frequent lightning. Storms will linger into the evening before dissipating. Slightly drier air gradually filters into NE FL on Monday reducing convective coverage to scattered.

Above seasonable temperatures continue with daytime highs in the upper 80s to low 90s. Peak heat indices will be in the mid 90s to around 100. Overnight lows will drop down into the lower 70s for inland areas and in the mid 70s for areas near the shoreline.

LONG TERM /MONDAY THROUGH FRIDAY/

- Hot temperatures Tuesday - Chances of showers and storms each day

The high pressure ridge axis across the southeast states and the western Atlantic will gradually shift southeastward through the week next week. Lingering drier air will lead to scattered showers and storms along the sea breezes on Tuesday. Coverage increases mid to late week with the return of moisture and a decrease in subsidence. Above seasonable temps on Tuesday gradually decrease to below seasonable by the end of the week.

AVIATION /06Z SATURDAY THROUGH 06Z SUNDAY/

Ongoing scattered, nocturnal thunderstorms will remain well inland and aren't expected to impact any TAF terminals through the rest of the early morning hours. Light southeasterly winds will limit fog development and VFR conditions are expected through at least 18z.

A more active thunderstorm day is expected with potential convection impacts to KJAX/KVQQ/KCRG during the middle and late afternoon hours (18z-23z). Thunderstorms today will be capable of significant downpours, gusty outflows and low visibility, possibly resulting in temporary IFR to LIFR restrictions. Thunderstorms are possible at KGNV but will occur late in the day as the Atlantic and Gulf sea breezes merge between 22z-01z. Some convective-remanant stratiform rain may shift eastward back toward the Atlantic coast this evening, though minimal if any visibility impacts are likely with that activity.

Outside of convective winds, easterly winds accompanying the sea breeze will develop this afternoon with gusts up around 15-20 knots.

MARINE

South to southeast winds continue across the local waters through mid week next week with the Bermuda ridge axis lingering north of the local area. Late afternoon and evening nocturnal wind surges are expected daily with periodic Small Craft Exercise Caution conditions. There will be a higher chance of showers and isolated thunderstorm later this evening and through the overnight hours tonight into Sunday morning.

Rip Currents:

As the sea breeze develops, risk for rip currents will edge toward High Risk levels, especially for northeast FL beaches. Surf around 3- 4.5 feet will continue. Due to light onshore winds along the southeast GA beaches, risk will stay at Moderate levels today. The risk today and through Memorial Day will be inherently higher due the holiday increase in beach recreation. Similar expectations are expected on Sunday.

FIRE WEATHER

Increase in showers and storms this weekend will limit daytime dispersions to fair to good. The sea breezes will shift inland each afternoon developing numerous showers and thunderstorms that continue into the evening hours. In the south-southeast flow, the sea breeze merger will likely be between the I-75 and US 301 corridors in the late afternoon into early evening. Isolated strong to severe thunderstorms will be possible later this afternoon into evening with the best chances across southeast Georgia. Potential hazards will be damaging wind gusts, heavy downpours, localized flooding, and frequent lightning. Slightly drier air filters in for early next week lowering storm coverage to scattered. Elevated mixing heights early next week will lead to good to potentially high dispersions.

FOG POTENTIAL AND OTHER REMARKS: Significant fog is not expected into this weekend. Erratic winds during periods of thunderstorms.

PRELIMINARY POINT TEMPS/POPS

AMG 90 68 88 69 / 80 60 90 50 SSI 87 76 87 77 / 30 50 50 30 JAX 92 74 90 75 / 60 50 60 30 SGJ 91 75 90 77 / 30 30 50 20 GNV 93 72 91 73 / 80 60 80 50 OCF 93 73 90 74 / 60 60 80 50

JAX WATCHES/WARNINGS/ADVISORIES

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