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

- Isolated Thunderstorms Tonight

- Increasing TStorms & Downpours Friday through Next Week. Waves of Heavy Downpours May Increase the Threat for Localized Flooding

- Moderate Risk of Rip Currents Continues at All Area Beaches

- Coastal and Marine Hazards Increasing Next Week. Strengthening Northeast Winds Arrive Monday Night. Gale Conditions Possible on the Atlantic Waters Tuesday through Wednesday. Increasingly Rough Surf will Create Deadly Rip Currents and Beach Erosion. Moderate Tidal Flooding Possible Tuesday through Wednesday

UPDATE

With the local airmass becoming increasing more moist (PWAT now at 2.33 inches from the 18z JAX sounding), rain chances continue to tick up each day now. For Tonight, a weak low level trough will lift north over parts of eastern northeast FL, prompting a chance of showers and a thunderstorm tonight for coastal areas. Widely scattered convection for the inland areas should be waning through the late evening hours though. Still looks like some potential for low stratus and patchy fog late tonight for the inland zones but mainly to the north of I-10. Minor changes to the POPs and sky condition, but otherwise the forecast is on track.

NEAR TERM /UNTIL 6 AM FRIDAY MORNING/

Main Highlights Tonight:

- Isolated Thunderstorms Tonight

Afternoon surface analysis depicts high pressure (1024 millibars) centered to the east of North Carolina's Outer Banks, with this feature extending its axis westward across the Tennessee Valley and the Deep South. Meanwhile, a cold front extends from the Great Lakes states south and westward across the southern Plains and central TX. Aloft...stout ridging remains in place along the southeastern seaboard, with this feature deflecting a potent shortwave trough that was ejecting from the Desert Southwest across the southern Plains states northeastward. Otherwise, a Tropical Upper Tropospheric Trough (TUTT) was spinning westward across Mexico's Yucatan peninsula towards the Bay of Campeche (southwestern Gulf). Latest GOES-East derived Total Precipitable Water imagery indicates that a surge of deep tropical moisture continues to advect northward across our region, with PWATS now generally in the 2 - 2.2 inch range throughout northeast and north central FL, while PWATs across southeast GA mostly in the 1.75 - 1.9 inch range. A healthy cumulus field has developed this afternoon across our area due to this increase in moisture levels, with scattered showers and a few embedded thunderstorms located mostly west of the I-95 corridor as of 19Z. Deepening southeast to southerly low and mid level flow was directing this scattered convection north-northwestward, generally at 15-20 mph. Outside of developing showers and thunderstorms, temperatures at inland locations were mostly in the upper 80s to around 90, while breezy onshore winds were keeping temperatures at coastal locations in the low to mid 80s. Dewpoints ranged from the upper 60s and lower 70s at inland locations to the mid and upper 70s at coastal locations.

Deep-layered ridging positioned along the southeastern seaboard will shift slowly eastward through tonight, with low and mid level flow gradually veering from southeast to southerly. Increasing moisture levels and mesoscale boundary collisions should result in an increasing coverage of convection through early this evening for locations west of the I-95 corridor. Relatively mild temperatures aloft (due to nearby deep-layered ridging) should keep thunderstorm activity isolated to widely scattered in nature, with strong storms not expected at this time. Briefly heavy downpours and occasional lightning strikes are possible with thunderstorms that manage to develop as activity moves fairly briskly north-northwestward. Convection should diminish during the mid to late evening hours, with another round of showers and possibly a few thunderstorms potentially moving northward after midnight from the FL peninsula along the I-95 corridor. Low stratus cloud cover should overspread inland locations during the predawn and early morning hours on Friday, but widespread fog formation appears to be unlikely. Lows tonight will only fall to the low and mid 70s inland, while a light onshore breeze keeps coastal lows in the mid to upper 70s.

SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/

Main Highlights:

- Above normal rain chances, with strong storms containing gusty winds and locally heavy rainfall.

High pressure will be centered to the east northeast this period, as an inverted trough develops over the western Gulf. A persistent onshore flow around this high will bring ample moisture into the region. Convection each day will be initiated in the late morning hours due to diurnal instability, with this activity moving inland through the afternoons on the east coast sea breeze. Numerous showers and thunderstorms can be expected each day.

Most of the activity will dissipate during the overnight hours Friday night, due to a lack of heating, but could linger through the night Saturday night as a frontal boundary begins to develop toward area from trough over Gulf.

Temperatures will trend above average this period.

LONG TERM /SUNDAY THROUGH THURSDAY/

Main Highlights This Period:

- Strong northeast flow pattern Tuesday through Wednesday, with potential for Minor to Moderate Tidal Flooding, Deadly Surf, and Gusty Coastal Conditions.

- Potential for rounds of heavy rainfall, and a few strong to severe thunderstorms can not be ruled out

During the first part of this period, high pressure will remain to the northeast, as the front extending from the Gulf trough stretches east across region. This boundary will then be near or over the region then through at least the middle of next week, with waves of energy moving east along it.

In the Tuesday to Wednesday time frame models are depicting a low to develop to the east northeast on the front, as stronger high pressure builds to the north. The gradient between these features will lead to a surge of winds from the northeast. The winds may become high enough to warrant wind advisories along the coast.

Current model timing pushes the front just south of the area late next week, as the high pressure builds in from the north northwest.

Daily rounds of showers with embedded thunderstorms forecast this period. The potential for strong to severe storms will exist, along with a high chance for heavy rainfall each day.

Above average temperatures can be expected for the first part of this period, then below average.

AVIATION /00Z FRIDAY THROUGH 00Z SATURDAY/

VFR clouds for most part this evening, but isolated to widely scattered showers or a thunderstorm expected through about 04z/05z, mainly for the northeast FL TAFs. Overnight, there may be few more low clouds at MVFR developing in the prevailing southeast boundary layer flow but chances are relatively low at this time. A few showers will be possible from 09z-14z Friday along the coast mainly near CRG, SGJ, and maybe at SSI. A few showers and a thunderstorm will then redevelop again between 14z and 18z, become scattered to numerous after 18z. For most part will stay with PROB30 groups Friday for this forecast package, but subsequent TAFs may need updating to TEMPO groups.

MARINE

High pressure ridge over the western Atlantic through the weekend will bring breezy southeast winds over local waters while a surge of tropical moisture promotes increasing showers and thunderstorms. As a frontal boundary enters the southeast states and briefly stalls through Monday, rain and thunderstorms steadily builds. By early next week, strong high pressure will build over the eastern U.S. and Mid Atlantic states and wedge down the east coast, pushing the cold front through the local waters by Monday night. This will bring a sharp surge of northeast winds and building seas, making Small Craft Advisory conditions likely on Monday night, with wind gusts potentially reaching Gale Force through mid week.

Rip Currents: A combination of long period east swells near 1-2 ft, onshore flow, and prior surf conditions suggest a low-end moderate risk of rip currents through Friday.

FIRE WEATHER

This will be a wet and stormy period.

High pressure will be centered to the east northeast through Friday. An inverted trough of low pressure will develop over the Gulf Saturday, with a frontal boundary extending east from it across the local area this week into next week. Rounds of showers with embedded thunderstorms will move east along this boundary. An area of low pressure is expected to develop on this boundary to the northeast of the region, as high pressure builds to the north northwest. Elevated winds will surge down the coast Tuesday and Wednesday between the high and the low.

Fog Potential...Patchy inland fog Tonight. Gusty and erratic winds in and near thunderstorms. Locally heavy rainfall with localized flooding possible each day this period.

EQUIPMENT

The KVAX Doppler Radar in Valdosta GA near Moody AFB remains out of service until further notice. Please utilize KTLH (Tallahassee), KJGX (Robins AFB), or KJAX (Jacksonville) during the outage period.

PRELIMINARY POINT TEMPS/POPS

AMG 71 90 72 87 / 20 60 30 70 SSI 75 86 75 84 / 20 40 50 60 JAX 74 88 73 86 / 20 60 40 70 SGJ 77 87 75 86 / 30 60 70 70 GNV 73 89 72 88 / 30 70 50 80 OCF 74 90 74 89 / 30 70 50 70

JAX WATCHES/WARNINGS/ADVISORIES

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