Jacksonville, Florida

For the latest NE FL and SE GA Daily Key Messages please visit: https:/www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

• Heavy Rainfall and Localized Flood Potential for NE FL Coast. Isolated Thunderstorms Possible this afternoon and evening. Rainfall amounts 1-3 localized amounts up to 4 for Northeast FL
• Lingering coastal flooding continues within the St Johns River, peaking at Minor flood levels.
• Dangerous surf conditions with rough, high breakers and a high risk of rip currents through early this week.

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.

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.

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.

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.

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.

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

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.