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

- Seasonably Hot Conditions Continue this Week Heat Index 102-108. Possible Heat Advisories this Weekend and Early Next Week

- Moderate Rip Current Risk through Thursday at Area Beaches

- Isolated Afternoon and Evening Thunderstorms through Friday. Scattered TStorms this Weekend & Next Week. Few Strong Storms Possible Each Day, Mainly Along the I-95 Corridor

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Isolated thunderstorms possible in the Suwannee River Valley this evening.

Lingering dry air aloft will limit instability and convective coverage again today as the low level ridge axis sharpens and lifts north into GA. The easterly flow will push the Atlantic sea breeze inland faster this afternoon and likely merge with the Gulf sea breeze along the I-75 corridor and the Suwannee Valley early this evening. While dry air lingers in the mid level, enough moisture brought inland by the sea breeze should triggered isolated thunderstorms following the sea breeze collision.

Ultimately, this will be a hot and dry day as temperatures will rise into the mid 90s once again and heat index readings push into the 102-108 degree range (below Heat Advisory levels). The sea breeze should keep coastal counties a a few degrees cooler, generally in the low 90s.

Tonight, the low-topped showers and isolated thunderstorm activity will diminish as it shifts west toward the Suwannee River this evening. This will be followed by a quiet and mild summer night with temperatures cooling to the low/mid 70s inland and upper 70s at the coast.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/

Main Highlights This Period:

- Isolated to Widely Scattered Thunderstorms each Afternoon and Evening at Inland Locations

- Seasonably Hot and Humid Weather Inland, Near Heat Advisory Along coastal counties Friday

- Potential Heat Advisory Conditions Saturday due to increasing humidity levels

Friday, strong mid/upper level ridging over the 4 corners region will extend ESE into the Gulf coast and northern FL as troughing over the Mid Atlantic remains north of the region. Surface frontal boundary beneath the trough will be nearly stalled across central GA and Coastal Carolinas with weak ENE flow locally becoming more westerly late in the day. The flow will be weak enough for a strong seabreezes circulation to develop and push the Atlantic and Gulf boundaries inland. A decrease in moisture to below normal values will limit chances for T'storms to widely isolated. Light, variable winds will turn ESE behind the Atlantic seabreeze 10-15 mph at the coast.

Highs will rise to the mid 90s along I-95 and mid/upper 90s inland with low 90s along the coast behind the seabreeze, but higher humidity values will push heat indices to near heat advisory values at the coast and just below inland where dewpoints will mix down to the low 70s.

Friday night, inland Thunderstorms will fade a couple hours after sunset. Intermittent mid to high level clouds will scoot over the area overnight with very light winds becoming calm after midnight. Lows will be in the mid 70s inland and the upper 70s along I-95 and St Johns river basin/NE FL coast with near 80 values along the SE GA coast.

Saturday, ribbon of shortwave energy between strong western ridge and a trough over the Mid Atlantic states will dive ESE over the southern Appalachians to the Carolina coast. This will serve to deepen the trough over the east coast as the western ridge shifts eastward into the southern plains, and will allow the previously stalled cold front to move south into SE GA Saturday. Very high PWATS will pool ahead of the southward sinking front with values well above normal above 2.0-2.4 inches over SE GA and near 2.0 inches over NE FL. With WNW flow, Atlantic seabreeze will remain pinned along or just east of I-95 where numerous thunderstorms will develop as strong heating, lift from the seabreeze and front focus storms east of highway 301. Stronger storms will be possible near I- 95 along the seabreeze as strong low level instability and heavy water loading support gusty downburst wind gusts 40-55 mph. Showers and thunderstorms will linger longer through midnight due to the influence of the front.

Highs Saturday will rise to the upper 90s along and west of I-95 with mid 90s at the coast. Higher humidity values will keep inland dewpoints in the low/mid 70s and upper 70s at the coast and peak heat indices 106-110 will create potential heat advisory conditions for NE FL coastal SE GA and the NE FL coast. Lows Saturday night will be similar to Friday morning lows in the mid 70s inland and upper 70s to near 80 along the coast.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

Main Highlights This Period:

- Increasing Chances for Afternoon and Evening Thunderstorms Late this Weekend and Early Next Week

- Potential Heat Advisory Conditions Sunday into Next Week

As the trough deepens over the coastal southeast, the frontal boundary will sink into NE FL Sunday. The front will slowly move into NE FL Monday as upper troughing is sharpened by another upstream shortwave shifting southeast across the OH valley. The front will wash out Tuesday as another front approaches from the north Tuesday night and moves into SE GA Wednesday.

Scattered to numerous showers and Thunderstorms are expected in the afternoon into the mid evening hours Sunday and Monday as the front sinks through the area due to a combination of above normal moisture levels, strong heating, and lift along the front and the Atlantic/Gulf seabreezes.

Afternoon thunderstorms chances will decrease to scattered coverage Tuesday and Wednesday as another front approaches from the north with increasing WSW winds over the area.

Highs during the period will be above normal in the mid to upper 90s Sunday into next week with mid 90s even to the beaches due to West to SW low level flow. Heat index values will rise to heat advisory levels this weekend 106-110 along the coast and near heat advisory levels 104-108 inland.

AVIATION /06Z THURSDAY THROUGH 06Z FRIDAY/

Similar to yesterday, dry air will limit todays potential for TSRA with only a small chance of low topped showers at inland terminals. However, a few low-topped showers may develop into TSRA as sea breezes converge near KGNV this afternoon around 20z-24z. Winds will be light and variable until the sea breeze development this afternoon, which will shift winds east-southeast around 10-15 knots. Predominantly VFR conditions.

MARINE

High pressure will diminish winds over the waters through the end of the week. A frontal boundary will then stall north of the Georgia waters this weekend, with this feature potentially increasing chances for showers and thunderstorms through early next week. Prevailing west winds are expected by Sunday and Monday, with the afternoon sea breeze shifting winds across the near shore waters to southeast during the afternoon hours.

Rip Currents:

Surf heights continue to lower today, however a lower end Moderate risk following the passage of the afternoon sea breeze is expected at all local area breaches. Similar conditions are expected Friday.

FIRE WEATHER

- HIGH DAYTIME DISPERSION VALUES INLAND on SUNDAY

Tropical Storm Bertha will be well to the west Today as Bermuda high pressure stretches across central FL. Light and variable winds will increase behind the Atlantic seabreeze this afternoon as it pushes towards highway 301 through the afternoon, turning winds ESE 10-15 mph with gusts to 20 mph. Widely scattered thunderstorms will form along the inland moving seabreeze boundary along and west of highway 301 where higher moisture aloft will reside. A frontal boundary to the north of the area will sink southwards slowly Friday into the weekend with increasing chances for thunderstorms. Increasing transport winds will support high daytime dispersions across inland areas on Sunday. Min RH values will be 35-40 percent this afternoon over inland Southeast Georgia.

Fog Potential and Other Remarks: Significant fog development is not expected for the next several nights.

PRELIMINARY POINT TEMPS/POPS

AMG 96 75 96 75 / 0 10 10 10 SSI 93 80 93 80 / 0 0 10 0 JAX 96 76 96 77 / 10 0 10 0 SGJ 92 76 92 76 / 0 0 0 0 GNV 96 74 96 75 / 20 20 10 10 OCF 95 74 95 76 / 20 20 10 10

JAX WATCHES/WARNINGS/ADVISORIES

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