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

- Coastal and Marine Hazards Continue. Minor Tidal Flooding Continues for St Johns River through Monday night,. High Risk for Rip Currents and High Surf (NE FL beaches) through Tuesday. Small Craft Advisories Continue through Tuesday

- Heavy Rainfall and Localized Flood Potential for NE FL Coast. Isolated Thunderstorms Possible this afternoon and tonight, south of I-10. Rainfall amounts 1/2 to 2 with localized amounts up to 3 to 4 for

UPDATE

Showers have spread in across the interior of NE FL from Gainesville northward along highway 301 and westward into the Suwannee Valley as a shortwave extending from the mid MS and TN Valley valley into the Gulf coast lifts Northeastward across the region. High pressure to the NNE centered over the Mid Atlantic coast is wedging a cool and dry air mass southward along the SE U.S. coast with east northeast flow at the surface while flow above the boundary layer veers SE and then WSW in the mid and high levels, helping pump more moisture across north FL and SE GA. The 12Z KJAX sounding shows 1.50 inches of Precipitable Water, which is already above the 75th percentile of early November climatology for atmospheric moisture levels.

The moisture levels will continue to increase above the 90th percentile (1.75 inches) today into this evening as the shortwave shifts ENE across the area. Cooler mid level temps and elevated instability levels of over 1,000J/kg of Most Unstable CAPE will bring a limited risk of embedded isolated T'storms today into this evening mainly along the SE GA coast into NE FL south of I-10, but only impacts will be enhancement of brief heavy downpours. Scattered to numerous showers will lift northward into the afternoon into I-10 and the FL/GA state line, mostly west of Jacksonville, while numerous showers move onshore the SE GA coast due to lift from coastal convergence and inverted troughing over the coastal waters.

Overall rainfall amounts will not be heavy through sunset, under .10 to .25 inches, but additional rainfall tonight of a half inch to one inch is expected along the NE FL and SE GA coast and inland areas of NE FL south of I-10. The high end of guidance still has up to 2-3 inches rainfall potential for where coastal convergent rain bands, thunderstorms train over the same area as low level easterly flow will counteracted by high level westerly flow that may help the bands remain over one location for a longer duration, especially this evening and overnight. Winds will be breezy by midday to afternoon 10-15 mph with gusts 20-25 mph from the ENE.

Highs will be near climatology in the mid 70s in SE GA and upper 70s over NE FL. Lows tonight will be above normal from the clouds and showers in the low to mid 60s over SE GA, mid to upper 60s over inland NE FL and upper 60s to near 70 along the NE FL coast.

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Heavy rainfall and localized flooding possible for coastal NE FL this evening and overnight.

- Minor tidal flooding withing the St Johns River basin continues

- Rough surf and dangerous rip currents continue

Unsettled weather continues today and through tonight amid the prolonged onshore breeziness. Per the latest morning analysis, yesterday's cold front, which pushed into SE GA last evening, is loosely defined this morning and is progged to become more diffuse through the day as it shifts toward NE FL. As that unfolds, an upper shortwave slowly lifting out of the Gulf will gradually move toward the FL peninsula this afternoon, bringing showers to much of NE FL by the afternoon and through the evening with rain chances around 30- 50%. Given the position of the decaying cold front, buoyancy may increase enough to support a few isolated thunderstorms are possible south of I-10 this afternoon and into the evening as temperatures aloft cool with the incoming upper wave.

The primary concern today isn't the thunderstorm potential given it's fairly low, but there is some potential for heavy rainfall given anomalous deep moisture being ushered into FL by the upper wave. For context, the precipitable water (PWAT) is expected to increase to 1.6-1.8" through this evening (mainly south of I-10) which is around the 90th percentile and considerable for this time of year. The concern will be for urban flooding, specifically for north central FL where PWAT values will be near the 90th percentile and along I-95 corridor where convergent banding may develop particularly late this evening and through early Monday. Rainfall totals over the next 24 hours in those aforementioned areas may push 2-3" with locally heavier amounts up to 4", with most of that accumulating after dusk. However, despite recent showery weather, soils aren't quite fully saturated and the ground still has capacity to absorb a bit more, so the decision was made to hold off on Flood Watch headlines.

Otherwise, like the last several days, the wedged surface high to the north will promote breezy onshore winds, leading to dangerous surf zone conditions and continue elevated tides within the St Johns River and it's tributaries. Winds will be strongest at the beaches with gusts around 20-25 mph with winds decreasing away from the coast. Cloud cover and rain showers will keep afternoon high readings in the mid to upper 70s for the area followed by gradual cooling into the 60s overnight tonight.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

Main Highlights This Period:

- Slight Risk of Flooding NE FL Coast due to Excessive Rainfall Mon

Breezy onshore winds will continue on into the beginning of the week with showers and embedded thunderstorms developing over the forecast area, with the strongest developments occurring over northeast Florida and for areas east of the I-75 corridor. SPC indicates that heavy rainfall capable of producing upwards of 2 to 3 inches may be possible over northeast Florida, with the heaviest rainfall developing along the coast in association with elevated PWAT values. Prevailing flow will become more out of the southeast on Tuesday. Daily high temperatures for the beginning of the week will be in the upper 70s and lower 80s. Overnight low temperatures will drop down into the lower to mid 60s over inland areas and in the upper 60s and lower 70s for areas along the coast.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Main Highlights This Period:

- Thunderstorm potential returns next week.

- Diminishing onshore flow and improving coastal and surf zone conditions.

Prevailing flow will shift to become more southerly by midweek as high pressure moves off to the northeast, with showers and storms building over the forecast area ahead of an advancing cold front pressing in from out of the west, with drier air and more stable conditions settling across the southeastern US by the end of the week. High temperatures will trend above average through the end of the week with overnight low temperatures trending to be nearer the seasonal average by the end of the week.

AVIATION /12Z SUNDAY THROUGH 12Z MONDAY/

Generally, MVFR to VFR conditions continue at NE FL terminals early this morning while IFR and MVFR stratus prevails across SE GA. Light showers streaming westward off the Atlantic may bring occasional visibility reductions in visibility at St Simons Island through 14z. Showers and isolated embedded thunderstorms will expand across NE FL through this morning and afternoon as influence from approaching shortwave energy increases. Bouts of showers are likely to persist overnight and beyond the TAF period, especially along the I-95 corridor, which may lead to periods of MVFR or IFR restrictions. East-northeasterly winds continue and will increase to 10-15 knots during the mid morning hours and continue through the late afternoon. Tonight, winds will decrease a few knots and become less gusty inland while backing toward the NNE as weak inverted trough develops along the coast.

MARINE

Strong high pressure wedged along the coast will continue elevated seas and small craft advisory conditions through at least Monday evening. Though winds will decrease through Tuesday, lingering elevated seas will remain through the middle of the week. High pressure will remain to the north but with a weaker influence through the second half of the week resulting in lighter winds and lowering seas. Bouts of showers and heavy downpours will be possible through the middle of the upcoming week, especially Monday and Tuesday as coastal troughing develops.

Rip Currents / High Surf:

Dangerous surf zone conditions continue with a High rip current risk at all area beaches through Monday and elevated to high surf for the entire coast. The highest breakers, around 6-8 feet will be from Ponte Vedra south through Tuesday.

FIRE WEATHER

A weakening cold front sinking southward will lead to breezy east- northeasterly winds through the weekend, especially at the coast with gusts up to 30 mph possible. Waves of showers will move through the area today and increase in coverage today and into Monday. Isolated afternoon thunderstorms possible today, primarily for areas south of I-10 corridor. Despite breezy surface and transport winds, overcast skies will keep mixing heights low and maintain fair to good daytime dispersions. Winds will begin to shift easterly next week then southerly by midweek as speeds diminish.

FOG POTENTIAL AND OTHER WEATHER REMARKS: Significant fog formation is not expected through Monday. Locally heavy rain is possible across NE FL this afternoon and through Monday.

TIDES/COASTAL FLOODING

Tidal levels continue to trend downward after each successive cycle. While elevated tides are expected to continue within the St Johns River basin and its tributaries, water levels are likely to remain in the 1.5-2.0 feet MHHW (mean higher high water), or at "Minor" levels. The previous Coastal Flood Warning for the middle St Johns River has been downgraded to an Advisory. Elevated tides are likely to continue through Monday and possibly until Wednesday. As winds decrease this upcoming week, natural flow direction will allow tides to lower gradually.

PRELIMINARY POINT TEMPS/POPS

AMG 75 62 79 63 / 50 20 10 0 SSI 76 66 76 66 / 70 60 50 30 JAX 78 66 77 67 / 40 50 60 40 SGJ 78 68 76 69 / 30 50 70 40 GNV 80 67 80 67 / 30 40 60 10 OCF 80 68 80 68 / 40 50 40 10

JAX WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 7 PM EST Monday for FLZ038-125- 132-137-225-325-633. High Risk for Rip Currents through Tuesday evening for FLZ124-125- 138-233-333. High Surf Advisory until 7 PM EST Monday for FLZ138-333. High Surf Advisory from 1 PM this afternoon to 7 PM EST Monday for FLZ233. GA...High Risk for Rip Currents through Tuesday evening for GAZ154-166. MARINE...Small Craft Advisory until 7 AM EST Monday for AMZ450. Small Craft Advisory until 11 PM EST Tuesday for AMZ452-454- 470-472-474.