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 Heat Risk Through The Weekend. Heat Index Values Rise to the 100-105 Range Inland this Afternoon. Heat Advisory Conditions Possible Saturday Peak Heat Index: 104-108

- Moderate Rip Current Risk at Area Beaches This Afternoon

- Afternoon & Evening TStorms Area-Wide this Weekend into Next Week. Isolated Storms this Afternoon and Evening across North- Central FL. Strong Storms with Gusty Winds, Frequent Lightning Strikes & Heavy Downpours Possible Along the I-95 Corridor beginning Saturday

NEAR TERM /THROUGH TONIGHT/

Main Highlights This Period:

- "HIGH" Heat Risk Today; Heat Index peaking around 100-107 degrees

- Isolated Strong Storm, Capable of Gusty Winds and Heavy Rain Across North-Central FL

Retrogression of low level ridging off the southwest FL coast will promote a light northwesterly flow across the area today. Being as light as it is the steering flow is expected to keep the Atlantic sea breeze totally pinned to the coast today, though it will lead to a slower inland progression. Today's shower and thunderstorm chances will initiate along the sea and river breezes this afternoon, with the best coverage...scattered at best...staying south of I-10 where deeper moisture (PWAT at ~2") will be cornered by the northwesterly flow. Isolated showers and potentially a thunderstorm cannot be ruled out north of I-10 but much drier and warmer air in the mid levels should prohibit deeper updrafts. For areas where stronger isolated thunderstorms may develop, mainly south of I-10, the primary threat will be lightning strikes, locally heavy rain and nuisance flooding.

It'll be slightly hotter today compared to yesterday. The slower sea breeze, a thermal ridging building from the north, and more isolated to scattered shower/t'storms will allow temperatures to ascend well into the 90s this afternoon, with readings in the mid 90s common. Combine the heat with the humidity and it will feel like a sweltering day for those outside for long durations, especially in direct sun. Heat index values will push into the lower 100's this afternoon, sending HeatRisk into the "High" (level 3 of 4) category across much of the area. Heat sensitive groups will be the most susceptible. If possible, avoid strenuous, outdoor activity to the cooler time frame this morning.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Main Highlights This Period:

- Dangerous Heat for Sensitive Groups This Weekend.

- Scattered to numerous thunderstorms Saturday afternoon and evening, a few strong to severe storms possible

- Moderate Risk for Rip Currents at the Northeast FL Beaches.

With a cold front stalled north of the area and high pressure over the Gulf, winds will be from the west-southwest for much of the weekend. The advection of moisture from the Gulf will bring PWATs in the 1.75" to 1.9" range for much of the weekend. With westerly winds, the Gulf breeze will be able to push inland this weekend. Showers and storms are expected to develop as the breezes move inland, with the higher focus between US-301 and the I-95 corridor during the afternoon hours along the mergers of the sea breezes. Potential hazards for any storms that develop this weekend will be locally heavy downpours, frequent lightning, and brief wet downburst wind gusts to 40-50 mph.

Aside from daily showers and storms this weekend, warmer temperatures during the upcoming weekend could bring Heat Advisory conditions. Temperatures in the mid to upper 90s combined with high humidity with dewpoints in the 70s will bring heat index values in the 105F to 110F range during the afternoon hours, with the warmer day this weekend on Saturday. But an early start to convection with the inland push of the the sea breezes could keep temperatures from getting too warm.

LONG TERM /MONDAY THROUGH THURSDAY/

Main Highlights This Period:

- Scattered to numerous afternoon and evening thunderstorms. A few strong to severe thunderstorms possible.

A trough will dig south towards the southeastern US next week as high pressure sits to the southeast. With these two features in place, southwesterly flow will persists into next week, continuing to bring tropical moisture into the area. Expect to see scattered to numerous coverage of convective activity due to elevated moisture levels and diurnal heating as the southwesterly flow will allow for the Gulf breeze to push inland during the afternoon hours.

Temperatures are expected to trend above average through Tuesday, then near average for Wednesday and Thursday.

AVIATION /12Z FRIDAY THROUGH 12Z SATURDAY/

VFR conditions prevail this period. Otherwise, light westerly winds continue with gradually increasing mid level cloud cover ahead of the sea breeze this afternoon. Ridging aloft should suppress shower and thunderstorm activity and confidence of TSRA impacts remains below 30 percent at this time. The best chance of TSRA influence appears to be late this afternoon (after 20z) near KGNV and terminals south along I-75. The sea breeze will shift winds at the coast around 16z-18z but move inland slower than the last couple of days, reaching KJAX around 21z-23z. VFR conditions tonight with a few mid/high clouds, otherwise just the usual patchy MVFR fog possible at VQQ towards sunrise in the 06-10Z time frame.

MARINE

Offshore winds this morning will shift southeasterly behind the afternoon sea breeze. A weakening front will stall north of the waters tonight and dissipate through Sunday as another front pushes into the southeastern US early next week. This will promote nightly southeasterly wind surges to Exercise Caution levels, mainly offshore through at least the middle part of next week. The predominant offshore flow next week will strengthen with the second front and increase chances afternoon thunderstorms are steered into and develop across the coastal waters.

Rip Currents:

Generally low to near moderate risk of rip currents today, mainly during the afternoon with the sea breeze, combined with a moderate onshore but low amplitude swell. A lower end moderate risk may continue this weekend at the northeast FL beaches, mainly during the late afternoon hours as winds become south-southeasterly following the inland movement of the sea breeze.

FIRE WEATHER

- Areas Of High Afternoon Dispersions Sunday

Westerly to southwesterly flow Today will bring the Gulf breeze well inland, with scattered showers and isolated storms developing along the boundary during the afternoon hours. Activity will be focused closer to the I-95 corridor as the southwesterly flow will keep the Atlantic breeze pinned along the east coast. MinRH levels will be at Good levels through the upcoming weekend and into next week. Temperatures will rise into the 90s this weekend. Increasing transport winds on Sunday will bring areas of high dispersions on Sunday. FOG POTENTIAL AND OTHER REMARKS: Significant fog is not expected Tonight. Daily rounds of showers and thunderstorms, mainly in the afternoon and evening hours. A few strong to severe thunderstorms will be possible each day.

CLIMATE

The return of summertime heat later this week and over the weekend will lead to near record temperatures. Less likely to see readings reach record highs but there is potential for record high minimum temperatures to be threatened.

Record High Temperatures:

June 12: KJAX: 99/1998

June 13: KJAX: 100/1977

Record High Minimum Temperatures:

June 11: KJAX: 77/2005 KGNV: 75/2005

June 12: KJAX: 79/1952 KGNV: 76/1963

June 13: KJAX: 79/1880 KGNV: 79/1998

June 14: KJAX: 79/1880 KGNV: 77/1998

June 15: KJAX: 80/1880 KGNV: 78/1998

PRELIMINARY POINT TEMPS/POPS

AMG 94 77 96 76 / 20 20 40 40 SSI 92 79 93 79 / 30 20 30 20 JAX 96 76 96 77 / 30 20 50 30 SGJ 93 77 94 77 / 30 10 30 10 GNV 94 75 95 75 / 40 30 50 20 OCF 92 75 93 76 / 30 20 40 10

JAX WATCHES/WARNINGS/ADVISORIES

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