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 Severe Storms Possible on Tuesday Afternoon & Evening with Potential for Localized Flooding and Damaging Winds

- Strengthening Northeasterly Winds on Tuesday Night & Wednesday. Small Craft Advisory Conditions Likely Tuesday Night - Wednesday Night. High Risk for Rip Currents at Area Beaches Wednesday through Thursday

NEAR TERM /THROUGH TONIGHT/

Main Highlights This Period:

- A couple of stronger storms possible in north central Florida this afternoon

Precipitation chances are low over southeast Georgia and the northern portions of northeast Florida today as northwesterly flow brings in drier air (PWATs near 1.5"). Along and south of where the front sits (south of Jacksonville), precipitation chances are at about 30-60% this afternoon and evening, higher as you go southward towards north central Florida. Less moisture and increased winds today will limit the localized flooding potential we've seen the past few days and expect tomorrow, but we cannot rule out a few stronger storms producing gusty winds and heavy downpours.

High temperatures will be in the mid 80s for inland southeast Georgia, and upper 80s to low 90s elsewhere. Low temperatures will generally be in the lower to mid 70s with patchy fog possible again early Tuesday morning near north central Florida.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

Main Highlights This Period:

- Strong to Isolated Severe Storms on Tuesday Afternoon and Evening. Main Hazards: Damaging Wind Gusts of 40-60 mph, Frequent Lightning Strikes, and Localized Flooding.

- Heat Index Values of 100-105 Degrees Across Northeast and North Central FL on Tuesday Afternoon.

- Breezy Onshore Winds Develop at Coastal Locations on Tuesday Evening, with Small Craft Advisory Conditions Overspreading Our Local Waters

- Rough, Building Surf and a High Risk of Rip Currents on Wednesday

A potent shortwave trough diving southward from the eastern Great Lakes tonight will drive a strong cold front into the southeastern states by the predawn hours on Tuesday, with this boundary crossing southeast GA on Tuesday evening and then through northeast and north central FL during the predawn hours on Wednesday. This deep trough will develop a 100-knot jet streak based at 250 millibars (around 35,000 feet) near the Carolina coast by Tuesday evening, placing our region within the ascending region of this feature. Breaks in the morning cloud cover will help to destabilize our atmosphere ahead of this cold front, and strengthening high pressure over the Great Lakes in the wake of this front will begin to wedge down the southeastern seaboard during the afternoon hours, creating additional convergence over our area. The Storm Prediction Center has expanded the "Marginal" risk (level 1 of 5) for severe thunderstorm development to include most of our area on Tuesday afternoon and evening. Downburst winds of 40-60 mph, torrential downpours, frequent lighting strikes, and possibly some potential for hail will exist within any strong to isolated severe storms that develop and push southward. A potentially earlier afternoon onset of convective activity should again keep highs in the mid to upper 80s for locations north of Waycross, while temperatures elsewhere soar to the low and mid 90s. Heat indices will rise to the 100-105 degree range for northeast and north central FL before convection arrives later in the afternoon.

Strong to isolated severe storms will remain possible ahead of the southward moving cold front on Tuesday evening across northeast and north central FL, while a cooler and drier air mass advects into southeast GA after midnight, allowing skies to clear from north to south. High pressure will build into the southeastern states towards sunrise, tightening our local pressure gradient and creating breezy northeasterly winds across coastal southeast GA on Tuesday evening, with these breezy conditions spreading to coastal northeast FL towards midnight. Despite a northeast breeze at inland locations, cool air advection will drive lows down to the upper 50s and lower 60s for inland portions of southeast GA, with mid to upper 60s arriving elsewhere inland towards sunrise as the front pushes to near the Interstate 4 corridor in central FL. Breezy onshore winds will keep coastal lows closer to 70.

Deep troughing along the U.S. eastern seaboard will push a cold front into south FL on Wednesday. A few showers and thunderstorms could linger in the immediate wake of this frontal passage for locations south of I-10 early on Wednesday morning, followed by seasonably cool high pressure building into the southeastern states, providing our area with one last gasp of Spring weather. A tight local pressure gradient on Wednesday will only gradually loosen, keeping breezy onshore winds in place along the I-95 corridor through Wednesday night. Despite plenty of sunshine, strong cool air advection will result in highs only reaching the upper 70s to lower 80s. High pressure will then gradually weaken as it builds into the southeastern states on Wednesday night, dropping lows to the mid and upper 50s for inland locations north of I-10, with low to mid 60s elsewhere inland. Breezy onshore winds will continue to keep coastal lows closer to 70.

LONG TERM /THURSDAY THROUGH MONDAY/

Main Highlights This Period:

- Rough Surf and a High Risk of Rip Currents Continue at Area Beaches on Thursday and Friday.

- Gradual Warm-Up Forecast from Friday through the Weekend with Dry Weather Likely to Continue.

High pressure building southward from the Appalachians on Thursday morning, with this feature gradually weakening as it pivots eastward, pushing offshore of the southeastern seaboard by Friday morning. Ridging aloft will then build over the lower Mississippi Valley on Thursday, with this feature then sliding slowly eastward from Friday through the upcoming weekend. This evolution of the weather pattern will allow for gradually warming temperatures, but a very dry air mass may persist all the way through the weekend, keeping rain chances far below normal for our region. Highs will warm to the low and mid 80s inland on Thursday afternoon and then the upper 80s by Friday, followed by afternoon highs approaching 90 next weekend. Breezy onshore winds through Friday should keep coastal highs in the low to mid 80s, with mid to upper 80s possible by next weekend. The unusually dry air mass will keep inland lows in the upper 50s and lower 60s on Thursday night, with a gradual warm- up through the 60s towards next weekend. A light onshore breeze will keep coastal lows around 70 late in the upcoming week, warming to the low to mid 70s next weekend.

AVIATION /18Z MONDAY THROUGH 18Z TUESDAY/

Models and current observations have been trending precipitation chances downwards area-wide, so have opted to remove the mention of thunder from the Duval sites and GNV this afternoon. Best chance for a storm will be at SGJ, although confidence is not high. MVFR ceilings continue on and off at the Duval sites this afternoon, but overall these conditions will continue to improve with potential brief periods of MVFR. Storm chances increase Tuesday afternoon and evening.

MARINE

A weak cold front will move south of the waters today, and then dissipate. A stronger cold front will move into the area waters on Tuesday, followed by strengthening northeast winds in the wake of this frontal passage, creating Small Craft Advisory conditions from late Tuesday night through at least Thursday morning throughout our local waters. Breezy onshore winds and elevated seas are expected through Thursday night as high pressure gradually weakens over the southeastern states. Otherwise, additional rounds of thunderstorms are forecast today through Tuesday evening with heavy rainfall and gusty winds expected at times.

Rip Currents: Generally low to low end moderate risk for today. Looking at increased risk to moderate and high from Tuesday and into Wednesday and possibly Thursday.

FIRE WEATHER

ELEVATED NIGHTTIME DISPERSION VALUES EXPECTED AT COASTAL - Locations On Tuesday And Wednesday Nights

AREAS OF HIGH DAYTIME DISPERSIONS WEDNESDAY THROUGH FRIDAY AT - Inland Locations

Only isolated to widely scattered showers and thunderstorms are expected this afternoon and evening, mainly for locations south of Interstate 10. Otherwise, breezy northwesterly transport winds will generally yield good daytime dispersion values this afternoon.

Strong to isolated severe thunderstorms will be possible on Tuesday, mainly during the afternoon and evening hours. Very heavy downpours may result in localized flooding. West-northwesterly transport winds on Tuesday morning will shift to northeasterly late in the afternoon for locations along and north of I-10. Breezy northeasterly surface and transport winds will then overspread our region from north to south on Tuesday night, creating elevated nighttime dispersion values for coastal southeast Georgia.

Scattered showers and thunderstorms may linger into the morning hours on Wednesday for locations south of Interstate 10. Meanwhile, a drier and cooler air mass will filter into our region from north to south as breezy northeasterly surface and transport winds overspread our entire area. These breezy winds will yield good to high daytime dispersion values. Breezy conditions will result in elevated nighttime dispersion values for coastal northeast Florida on Wednesday night. Surface and transport winds will shift to east- northeasterly on Thursday and easterly by Friday, with areas of high daytime dispersion values expected inland and good values elsewhere on both days.

FOG POTENTIAL AND OTHER REMARKS: Patchy fog will be possible early on Tuesday morning for inland portions of northeast and north central Florida. Gusty and erratic winds are possible around thunderstorm activity on Tuesday.

PRELIMINARY POINT TEMPS/POPS

AMG 69 87 59 78 / 20 70 70 10 SSI 75 88 70 79 / 10 80 70 10 JAX 72 92 68 79 / 10 90 80 10 SGJ 74 91 70 81 / 0 80 90 30 GNV 72 93 67 82 / 0 80 90 20 OCF 75 91 70 81 / 20 60 90 40

JAX WATCHES/WARNINGS/ADVISORIES

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