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

- Strong to Severe Thunderstorms Possible on Saturday. Isolated Thunderstorms Possible this Afternoon through Tonight, Mainly North of I-10. Squall Line of Strong to Severe Storms Crosses Our Region on Saturday. Storm Hazards: Damaging Wind Gusts of 40-60 mph, Frequent Lightning & Isolated Tornadoes

- Beneficial Rainfall Tonight through Saturday Night. Rainfall Totals of 0.5-1.5 inches, with Locally Higher Totals of 2-3 Inches Possible

- Moderate Risk of Rip Currents at Area Beaches through Saturday. Breezy Onshore Winds May Result in a High Risk on Sunday

- Small Craft Advisory Conditions from Late Sat Afternoon through Sun Morning

NEAR TERM /THROUGH TONIGHT/

Main Highlights This Period:

- Isolated Thunderstorms Possible this Afternoon through Early this Evening, Mainly Along the I-95 Corridor.

- Hot Temperatures Continue for Inland Northeast and North Central FL Today.

- Moderate Risk of Rip Currents at All Area Beaches.

Early morning surface analysis depicts a decelerating, wavy frontal boundary stretching from west to east across the Interstate 10 corridor. Otherwise, a weak pressure pattern prevails across the southeastern states to the north of this stalling boundary. Aloft...fast zonal flow prevails across the southern tier of the nation, with a 140-knot jet streak positioned at 250 millibars (around 35,000 feet) over the Ozarks and the Tennessee Valley. Meanwhile, a potent shortwave trough was progressing eastward across the Desert Southwest. Latest GOES-East derived Total Precipitable Water imagery indicates that deeper moisture is pooling along and south of the stalling frontal boundary, where PWATs were in the 1.5 -1.75 inch range, while PWATs north of the FL/GA border were mostly in the 1.25 - 1.5 inch range. Mostly mid and high altitude cloudiness prevails over most of our region, with a few hints of lower stratus cloud cover to the north of the stalling front across coastal southeast GA. A few light showers or sprinkles were migrating across our region beneath the mid and high cloud decks, mainly across inland southeast GA. Temperatures at 08Z mostly ranged from the mid 60s to the lower 70s, with dewpoints ranging from the mid and upper 50s across inland southeast GA to the 65-70 range across northeast and north central FL.

The aforementioned potent shortwave trough currently traversing the Desert Southwest will progress eastward within the fast zonal flow pattern, with this feature crossing Texas today and tonight. This shortwave trough and a digging northern stream trough will result in cyclogenesis along the northern Gulf coast later tonight, allowing the stalled boundary near the I-10 corridor to slowly lift northward as a warm front beginning this evening. Gradually strengthening isentropic lift and increasing PWAT values from south to north this afternoon will develop scattered to numerous showers and possibly a few thunderstorms across southeast GA, mainly this afternoon and evening. Isolated to widely scattered showers with perhaps an embedded thunderstorm or two will be possible this afternoon and evening across northeast and north central FL, with activity a littler more likely to materialize along the I-95 corridor late this afternoon, where mesoscale boundary collisions may occur. Breezy northeasterly winds will keep coastal highs around 80 for southeast GA and the lower 80s at the northeast FL beaches. Breaks in the multi-layered cloud cover this morning through early this afternoon will boost highs to the lower 90s for inland locations south of I- 10, and low to mid 80s are forecast elsewhere.

Showers and possibly a few embedded thunderstorms will continue this evening, mainly along the retreating cold front for interior southeast GA. Cyclogenesis to our west and a digging northern stream trough to our north will begin to activate a low level west- southwesterly jet after midnight along the northern Gulf coast. A squall line of strong to possibly severe thunderstorms will materialize towards midnight over the FL panhandle as low pressure glides towards Apalachee Bay and the northeast Gulf towards sunrise. Latest trends in the guidance keep this squall line west of the Suwannee / Alapaha Rivers in the FL Big Bend and interior southeast GA through around sunrise, keeping mainly dry conditions in place over the warm sector for northeast and north central FL. However, model soundings indicate that strengthening 40-50 knot west- southwesterly low level jet based around 850 millibars (around 5,000 feet) will nose into western portions of our area towards sunrise, which will increase the threat for strong to severe storms within the eastward moving squall line beginning as early as the predawn hours on Saturday. Model soundings also indicate increasing CAPE and Helicity values nosing into the Suwannee Valley and interior southeast GA towards sunrise, so we'll have to monitor trends in the high resolution, short-term guidance as to whether the squall line enters our region before or after sunrise on Saturday. Cloud cover and developing warm air advection will keep lows in the 60s almost area wide.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Main Highlights This Period:

- Unsettled weather brings beneficial rain - Isolated strong/severe storms and Saturday - Cooler temperatures return this weekend

As a trough shifts over the SE US, its associated cold front will push through the area on Saturday, clearing south by Sunday. Showers and storms are expected across the area on Saturday, with activity beginning over the far interior counties of SE GA during the early morning hours, shifting southeast towards NE FL by the mid-morning hours, and then north central FL by the afternoon hours, with activity lessening by the evening hours. Strong to isolated severe storms will be possible as the line shifts across the area. Current CAMs suggest locations south of Waycross, GA will have the highest chances for strong to severe storms from the mid-morning to early afternoon hours. Latest SPC outlook has these locations under a 'Slight' Risk for severe storm potential. With any storms that do develop, damaging winds will be the primary hazard, with Hail also being possible and a low tornado risk for locations from Waycross, GA and southward across NE FL. With numerous to widespread showers on Saturday, there's potential for locations along and north of I-10 to receive near an inch of rain through Sunday morning, with locally higher amounts within heavy thunderstorm near 2-3 inches. With the front pushing across throughout the day, a gradient of daytime highs with cooler highs for locations north of the I-10 corridor. Highs will primarily top out in the low to mid 70s, with locations north of Waycross reaching only to the upper 60s as cold air filters in behind the front, while locations south of I-10 in the 80s, with north central FL locations possibly reaching into the lower 90s. Similar pattern in the overnight Lows, with upper 40s across SE GA and in the 50s across NE FL.

Compared to Saturday, Sunday will be quiet with only locations in north central FL possibly seeing an isolated shower during the early hours as the front continues to push south. Cooler temperatures will be in place behind the front as highs will be in the 70s, with lower 70s across SE GA and upper 70s across NE FL. Similar spread of overnight Lows as Saturday for Sunday night.

LONG TERM /MONDAY THROUGH THURSDAY/

Main Highlights This Period:

- Drier weather and gradual warming through midweek - Cooler temperatures past midweek

As High pressure settles over the area, temperatures will steadily warm up into midweek. Highs begin the week in the upper 70s to lower 80s, rising into the upper 80s to lower 90s by Wednesday. Cooler temperatures along the coast as the sea breeze moves in from the Atlantic each afternoon. The next frontal system currently looks to begin to push into the area by Thursday as high pressure shifts eastward midweek. Isolated chances of showers return Wednesday/Thursday afternoon with the approaching front. Cooler temperatures return to the area behind the front.

AVIATION /12Z FRIDAY THROUGH 12Z SATURDAY/

VFR conditions are expected to prevail at the northeast FL terminals through around 19Z. MVFR ceilings of 2,000 - 3,000 feet are then expected to overspread the Duval County terminals and SGJ after 19Z, with showers and possibly a few thunderstorms developing through around 00Z. Confidence was only high enough to include PROB30 groups for MVFR visibilities during heavier showers at SSI and SGJ, and we did not include vicinity thunderstorms at this time. Confidence is currently too low to include anything other than vicinity shower coverage at the Duval County terminals and GNV. VFR conditions are then expected to prevail after 02Z Saturday at the regional terminals.

MARINE

A frontal boundary currently positioned near the Florida and Georgia border will stall across the northeast Florida waters today. Breezy onshore winds will develop this morning across the Georgia waters, with these winds then building southward across the northeast Florida waters this afternoon. Scattered showers and possibly a few thunderstorms will be possible near and north of this stalled front through this evening, mainly over the Georgia waters. The front will then lift northward as a warm front tonight as a wave of low pressure develops along the northern Gulf coast. Southwesterly winds will strengthen on Saturday morning as this developing low pressure center approaches our local waters from the west. Widespread showers and thunderstorms will impact our local waters on Saturday and Saturday evening, with strong to severe storms possible. Stronger storms on Saturday and Saturday evening will be capable of producing strong wind gusts, frequent lightning strikes, and possibly a few waterspouts.

Small Craft Advisory conditions will likely develop late Saturday afternoon or evening in the immediate wake of the cold frontal passage, as winds abruptly shift to northwesterly. The front will shift south of our area on Saturday night, with gusty winds shifting to northerly after midnight. Breezy northeast winds are then expected on Sunday as high pressure builds into the southeastern states, with diminishing winds and seas early next week as the high pressure quickly moves offshore of the southeastern seaboard.

Rip Currents:

Developing northeasterly winds will combine with a persistent 10-11 second east-northeasterly ocean swell to create a high end moderate risk today at all area beaches. Breezy southwesterly winds on Saturday should reduce the risk slightly, but a lower end moderate risk will likely persist at the northeast FL beaches due to the persistent longer period east-northeasterly swell. North- northeasterly winds will then strengthen on Sunday, with building surf likely creating a high risk at area beaches. Winds will then become onshore again early next week, combining with the lingering swell to produce a moderate risk, with a high risk possibly continuing at the northeast FL beaches.

FIRE WEATHER

- High Daytime Dispersions Today And Saturday

- Beneficial Rainfall Expected Into This Weekend

Scattered showers and embedded thunderstorms will continue Today as a cold front lingers over the area. Breezy southwesterly surface and transport winds across northeast Florida will result in high daytime dispersions for inland locations of northeast Florida. Southeast Georgia will have surface and transport winds from the northwest, with poor to fair values for locations north of I-10. A stronger cold front then moves through Saturday into Sunday, leading to widespread showers and thunderstorms forecast on Saturday and Saturday night. Strong southwesterly surface and transport winds ahead of the front will result in very high dispersions on Saturday across northeast Florida. MinRH will drop into the upper 20-30s Sunday and Monday for most inland areas following the frontal passage.

FOG POTENTIAL AND OTHER REMARKS: Isolated strong/severe storms possible Friday and Saturday. Smoke from nearby fires may result in localized visibility reductions, especially during the overnight and early morning hours.

PRELIMINARY POINT TEMPS/POPS

AMG 81 60 69 48 / 70 70 100 20 SSI 80 66 75 55 / 60 50 90 30 JAX 87 67 83 51 / 40 30 90 40 SGJ 83 69 88 57 / 30 20 70 60 GNV 90 67 86 53 / 20 10 80 50 OCF 91 68 87 56 / 10 0 70 60

JAX WATCHES/WARNINGS/ADVISORIES

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