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 & Humid Today Heat Index 102 - 108. Heat Advisories Possible this Weekend and Next Week for Portions of Our Area

- Moderate Rip Current Risk Continues at Area Beaches

- Widely Scattered Afternoon/Evening Thunderstorms Today, along I-75 in Northeast FL and west of highway 301 across Inland SE GA

- Scattered to Numerous Afternoon & Evening Thunderstorms this Weekend. Strong to Isolated Severe Storms Possible Each Afternoon Along the I-95 Corridor

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Isolated to Widely Scattered Thunderstorms Late this Afternoon and Evening along the I-75 Corridor in Northeast FL and west of highway 301 in Southeast GA.

Scattered mid to high level clouds are lingering across NE FL from earlier showers and storms near I-75. Calm conditions are common inland while a light southerly breeze is persistent at the coast around 4-8 mph. Another typically muggy overnight has transpired with local dewpoints in the mid 70s inland and upper 70s for the coast with near similar temps in the upper 70s inland and around 80 at the coast and these values will lower a few degrees through sunset. Localized shallow ground fog will form over portions of inland NE FL where storms produced briefly locally heavy downpours.

Today, a strong mid to upper level ridge over the southern Rockies and western TX will extend east southeastward over our area as a trough to the north flattens across the Mid Atlantic states as upstream shortwave energy moves across the Great lakes and Midwest. With lack of upper support, frontal boundary will not make much southward progress today across north GA and the Carolinas while Atlantic surface ridge axis extends into NE FL. The riding will allow for weak ENE flow over the area with light and variable morning winds around 5-10 mph becoming more westerly over inland SE GA this afternoon.

Mostly sunny skies, strong diurnal heating and our weak pressure pattern will generate the daily Seabreeze circulation and push the Atlantic and Gulf boundaries inland. Expecting Precipitable water levels to range 1.4-1.70, mainly below average again today which will limit convective chances and have widely scattered T'storms developing across I-75 in NE FL and between highway 301 and US-221 in SE GA as the Atlantic/Gulf seabreezes merge. Winds will turn east southeasterly behind the Atlantic seabreeze up to 10-15 mph into the I-95 to US-17 corridors including the St Johns river basin with gusts to 20 mph along coastal locations.

Highs will rise to the mid 90s along I-95 and mid/upper 90s inland with low 90s along the coast behind the seabreeze. Dewpoints will initially be in the mid 70s and mix down to the low 70s over inland NE FL and upper 60 over inland SE GA which should keep peak heat index values just below heat advisory criteria 102 to 108. Similar heat indices expected along the coast despite higher dewpoints in the mid/upper 70s as temperatures remain limited off the waters.

Tonight, 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 upper 70s to near 80 along the SE GA coast.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Main Highlights This Period:

- Increasing rainfall chances this weekend

- Potential heat advisory conditions Saturday

Slow southward moving frontal boundary just north of the region on Saturday will slide southward into SE GA on Sunday. This will lead to continued increase in moisture levels aloft into the region with PWATs increasing to 2 inches or more by late Saturday and continuing through Sunday. Scattered to numerous showers and storms(PoP 30-60%) are expected by Saturday afternoon, with main focus along the I-95 and US-301 corridors as the westerly steering flow will interact with the East Coast sea breeze, along with risk of isolated strong to severe storms with gusty winds to 40-60 mph, along with heavy rainfall risk along the I-95 corridor, along with urban flooding risk. Numerous to widespread showers and storms (PoP 50-80%) are expected in the moist Northwest steering flow as focus remains along the I-95/US-301 corridors with interaction once again with the East Coast sea breeze, along with isolated strong to severe storms with gusty winds to 40-60 mph, and once again localized flooding rainfall risk along the I-95 corridor. Expect to remain in a Marginal Risk of Excessive Rainfall this weekend, but the recent dry weather will likely prevent the issuance of any Flood Watches.

Temperatures will remain above normal this weekend with Highs into the middle/upper 90s prior to the onset of convection on Saturday and expect Heat Advisory headlines across all of NE FL/coastal SE GA with peak Heat indices of 107-111F, while inland SE GA should peak out with Heat Indices 103-107F. Higher rainfall chances and storm coverage and cloud cover increases on Sunday, should hold Max Temps into the lower to middle 90s, but any delay in the onset of convection and possibly higher dewpoint temps into the mid/upper 70s may still support Heat Advisory headlines with heat indices of 105- 110F, mostly across NE FL/coastal SE GA, but confidence is lower for Sunday headlines at this time.

LONG TERM /MONDAY THROUGH THURSDAY/

Main Highlights This Period:

- Another frontal boundary will increase rainfall chances in the Wednesday through Friday time frame

- Potential Heat Advisory Conditions continue next week

Rainfall chances decrease early next week as stalled frontal boundary dissipates and drier air mass builds into the region aloft with PWATs falling just below 2 inches. Another slightly stronger frontal boundary will push southward into SE GA by late Wednesday and stall across NE FL on Thursday before dissipating on Friday. This will bring back increased rainfall chances from Wednesday through Friday, with heavy rainfall expected with this frontal boundary, mainly along the I-95/US-301 corridors, with localized flooding possible in urban areas along with isolated strong to severe storms with interaction with the East Coast sea breeze.

Max temps will remain in the lower/middle 90s on Monday, before widespread Max temps into the middle/upper 90s on Tuesday and Wednesday will likely lead to Heat Advisory/Extreme Heat headlines with Heat Indices around 110F both afternoons. Temperatures return closer to normal values on Thursday/Friday with the increased rainfall chances, mainly in the lower/middle 90s with a lower risk of Heat Advisory headlines.

AVIATION /06Z FRIDAY THROUGH 06Z SATURDAY/

VFR conditions will prevail through the period with exception of localized shallow ground fog at VQQ later this early morning from 06- 10Z. After late morning, light east to southeast winds will increase behind the seabreeze around 10 knots along the coastal sites and only around 5 knots inland. Any convection will remain west of the TAF sites this afternoon and chances too low for VCTS near GNV at this time. The period will end with southeasterly winds around 5-8 knots along the coast and variable under 5 knots inland under scattered to broken mid and high level clouds as storms fade west of the terminals.

MARINE

Southerly winds will continue this morning as high pressure ridge axis across the Atlantic northeast of Bermuda stretches southwest across the area waters through Tonight with east southeasterly winds this afternoon from Seabreeze circulation. A stationary frontal boundary extending from the Carolina coast westward across the deep south will begin to drift southward towards the Georgia waters this weekend, pushing the axis of Atlantic high pressure southward. This change in the weather pattern will create a prevailing offshore wind flow this weekend and early next week, with scattered to numerous afternoon and evening thunderstorms expected across our local waters each day. A few stronger storms will be possible during the late afternoon hours, with briefly strong wind gusts, frequent lightning strikes, and torrential downpours possible. Another front will approach the waters next week with offshore southwest winds increasing to near advisory levels midweek.

Rip Currents:

A moderate risk of rip currents is expected today at Northeast FL and Southeast GA beaches due to onshore east southeast winds this afternoon with wave heights 2 to 3 feet. A moderate risk of rip currents will continue on Saturday with southeasterly winds behind the afternoon seabreeze.

FIRE WEATHER

- High Daytime Dispersion Values Inland Sunday

A frontal boundary to the north of the area will sink southwards slowly Today into the weekend with increasing chances for thunderstorms this weekend. Fair to Good dispersions develop on Today and Saturday. Increasing transport winds will support high daytime dispersions across inland areas on Sunday. Min RH values will be in the 35% to 40% range this afternoon over inland locations. This weekend min RHs improve as moisture increases across the area. With the increased moisture, showers and storms will be more likely during the afternoon hours as the Gulf breeze pushes well inland, will the overall flow predominantly from the west this weekend.

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

PRELIMINARY POINT TEMPS/POPS

AMG 98 76 94 74 / 20 20 40 10 SSI 93 80 93 78 / 10 10 50 40 JAX 96 76 98 76 / 0 10 50 40 SGJ 92 75 95 76 / 0 0 50 40 GNV 96 75 97 76 / 10 10 40 40 OCF 96 75 96 76 / 0 10 50 20

JAX WATCHES/WARNINGS/ADVISORIES

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