Marine Weather and Tide Forecast for Jacksonville Beach, FL

NEAR TERM /THROUGH TONIGHT/

Main Highlights This Period:

- High Risk for Rip Currents Continues This Afternoon at Area Beaches.

- Scattered Strong Storms Late this Afternoon through this Evening. Main Hazard Area: Inland Locations Along and West of U.S.-301. Primary Storm Hazards: Wind Gusts of 40-55 mph, Frequent Lightning Strikes, Heavy Downpours and Localized Flooding

Afternoon surface analysis depicts a wavy stationary frontal boundary that extends from coastal New England westward across the Mid- Atlantic states and then southwestward through the Tennessee and lower Mississippi Valleys. Meanwhile, weak low pressure (1013 millibars) over coastal Louisiana was situated along a surface trough that extends southward across the central Gulf. Otherwise, strong Atlantic surface high pressure (1030 millibars) centered near Bermuda was extending its axis westward across our area
Aloft
cutoff troughing was spinning over the eastern half of Texas, while deep-layered ridging off the southeastern seaboard was building westward. Latest GOES-East derived Total Precipitable Water imagery indicates that a deep tropical air mass was in place across our area, with PWATs around or in excess of 2 inches. However, a drier air mass associated with deep ridging that was building westward towards the FL peninsula has dropped PWAT values to the 1.5 - 1.75 inch range for east central and southeast FL. Showers and thunderstorms developing along and north of the Interstate 10 corridor were being steered briskly northward at 15-20 mph, with a few stronger storms developing over inland portions of southeast GA and also along the St. Johns River in the vicinity of Jacksonville. Away from ongoing convection and cloud cover, temperatures at 19Z generally ranged from 85-90 degrees, with dewpoints in the upper 60s inland to mid 70s at coastal locations, where southeasterly winds were gusting upwards of 25 mph at area beaches behind the inland moving Atlantic sea breeze boundary.

Showers and thunderstorms will continue to gradually shift inland this afternoon as the Atlantic sea breeze moves westward, with mesoscale boundary collisions becoming more numerous for locations along and west of U.S. Highway 301 this afternoon and evening. A seasonably warm and humid air mass has allowed surface based CAPE values to rise to around 2,000 j/kg at inland locations, and this instability, combined with abundant tropical moisture, should allow for storms to increase in coverage and intensity as the afternoon progresses. Scattered strong storms will be possible into the late evening hours, mainly for interior southeast GA, as a drier air mass advecting over north central FL potentially limits convective coverage for locations south of I-10. Stronger storms will be capable of producing downburst winds of 40-55 mph, along with frequent lightning strikes and torrential downpours. Convection potentially training from south to north repeatedly over the same locations could result in localized flooding, particularly for urban or normally flood prone, low-lying areas. Convection should diminish in coverage and intensity towards midnight for interior locations, with breezy southeast and then southerly winds prevailing through around midnight at coastal locations.

Convective debris clouds will gradually thin out towards sunrise, with coastal showers and possibly some isolated thunderstorms potentially developing in the deeper tropical air mass that will remain in place over coastal southeast GA. Lows tonight will generally fall to the 70-75 degree range inland and the mid or upper 70s at area beaches.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

- Summer-like pattern continues.

- Afternoon thunderstorms inland Tuesday, along I-95 Wednesday.

- Heat index 95-105 degrees in the afternoons.

Southerly flow on Tuesday will allow hot temperatures and afternoon storms again, with the Atlantic and Gulf sea breezes both developing. With the southerly flow, the two sea breezes will interact in a more central location, with highest storm coverage being west of I-95. High temperatures Tuesday will be in the lower 90s over most of the area, with peak afternoon heat index values around 100 degrees for portions of northeast FL.
Convection may linger a few hours after sunset near the I-75 corridor.

By Wednesday afternoon, steering flow will begin to shift more southwesterly, increasing storm coverage closer to the I-95 corridor that afternoon and evening. With more cloud and storm coverage Wednesday, temperatures will be a few degrees cooler than Tuesday, but still pretty hot in the mid 80s to low 90s.
South/southeasterly winds overnight will keep mild low temperatures, in the mid 70s along the coast.

LONG TERM /THURSDAY THROUGH MONDAY/

- Daily Thunderstorm Chances.

- Slight Risk of Heavy Rainfall During the Upcoming Weekend.

Southwest winds will allow for hot temperatures to reach the Atlantic coast on Thursday, along with high rain and storm chances across northeast Florida as the Gulf sea breeze dominates. Westerly flow continues into Friday, bringing PWATs above 2.0 inches and keeping storm chances high over eastern portions of the region.

A front will approach towards the end of the week, and stall over Georgia through early next week, increasing storm chances each day area-wide. High precipitation chances this weekend will lead to below normal temperatures to end May.

Given several days of impressive moisture, there will be a concern for localized flooding, especially over urban and poor drainage areas this weekend.

AVIATION /18Z MONDAY THROUGH 18Z TUESDAY/

Scattered showers and isolated thunderstorms will continue pushing inland from the coastal terminals this afternoon, with VFR conditions expected to prevail through at least 10Z Tuesday at SSI and SGJ. Vicinity thunderstorms at JAX and CRG will continue through around 22Z, but confidence was only high enough to indicate a TEMPO group for heavier showers at JAX, with MVFR visibilities expected during heavier downpours. Confidence was high enough at VQQ and now GNV to indicate prevailing vicinity thunderstorms and a TEMPO group for brief wind gusts up to 30 knots and IFR visibilities during heavier downpours after 20Z.
Convection could linger past 00Z at GNV. VFR conditions should then prevail at the regional terminals after 03Z, with MVFR ceilings and potential showers expected to develop near the SSI terminal towards sunrise on Tuesday. Periods of MVFR ceilings of 1,500 - 2,000 feet will then be possible after 14Z Tuesday at the regional terminals. Outside of convection, southeasterly surface winds will remain sustained at 10-15 knots at the inland terminals and around 15 knots and gusty at the coastal terminals through around 03Z, followed by winds shifting to southeast to southerly and diminishing to 5-10 knots towards 04Z. Southerly surface winds will then quickly increase to 10-15 knots and gusty at the regional terminals after 13Z Tuesday.

MARINE

A stalled frontal boundary stretching across the Mid-Atlantic states and the Ohio, Tennessee and lower Mississippi Valleys will lift slowly northward tonight and Tuesday as Atlantic high pressure centered near Bermuda expands westward towards the southeastern seaboard. Breezy southeast to southerly winds will continue through midweek across our local waters, with Caution conditions prevailing during the afternoon and evening hours as wind speeds surge to just below Small Craft Advisory levels.
High pressure positioned off the southeastern seaboard will weaken later this week as a cold front shifts southward towards our local waters during the upcoming weekend. Scattered showers and thunderstorms will tend to develop during the overnight and morning hours on Tuesday and Wednesday, with activity then increasing in coverage and frequency from Friday through the upcoming weekend.

Moderate to High Risk Expected on Tuesday and Wednesday Rip Currents:

Gusty southeasterly winds and breakers of 2-4 feet will maintain a high risk at all area beaches this afternoon and evening. A higher end moderate risk is currently forecast on Tuesday and Wednesday at the southeast GA beaches as prevailing winds shift slightly to south- southeasterly, while a high risk likely continues through at least Tuesday evening for the northeast FL beaches.

FIRE WEATHER

- Areas Of High Inland Dispersion Inland on Tuesday.

A ridge of high pressure over Bermuda will extend its ridge axis across the area resulting in a summer like pattern through the week. Afternoon and evening thunderstorms will develop with the Gulf and Atlantic sea breezes each day. The Atlantic sea breeze will be dominant Tuesday, with speeds around 10-15 mph and gusts up to 20 mph. Areas of high dispersion are expected inland over the next few days as breezy southerly transport flow continues amid the hot, unstable afternoon airmass. High nighttime dispersion is expected through mid-week along the Atlantic coast.

FOG POTENTIAL AND OTHER REMARKS: Significant fog is not expected into early next week but patchy morning fog will be possible in areas where heavy rain fell during the previous afternoon.
Erratic winds during periods of thunderstorms.

PRELIMINARY POINT TEMPS/POPS
AMG 71 89 69 87 / 70 50 50 60 SSI 76 88 76 88 / 20 20 30 60 JAX 74 91 75 92 / 20 30 40 60 SGJ 76 89 76 91 / 10 20 20 50 GNV 72 93 72 91 / 60 40 70 40 OCF 73 91 73 89 / 60 50 70 50

JAX WATCHES/WARNINGS/ADVISORIES
FL...High Risk for Rip Currents until 2 AM EDT Tuesday for FLZ124-125- 138-233-333.
GA...High Risk for Rip Currents until 2 AM EDT Tuesday for GAZ154-166.
MARINE...None.