Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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583 FXUS62 KJAX 281440 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 1040 AM EDT Fri Jun 28 2024 ...New UPDATE... .UPDATE... Issued at 1039 AM EDT Fri Jun 28 2024 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Showers have begun to form and push onshore from the Gulf coast towards I-75 as west to southwest flow continues ahead of a weak frontal boundary draped east to west over northern/central MS/AL/GA/SC. This flow will bring in the Gulf seabreeze inland through the midday hours before creating maximum lift along the slower progressing Atlantic seabreeze confined closer to I-95 early this afternoon with numerous T`storms. Hazards from today`s T`storms include gusty winds 40-50 mph and frequent lightning. In addition, slow storm motions and above normal atmospheric moisture in the column (PWATS from the 12Z sounding at 2.10 inches this morning) in 90th percentile will make for heavy rainfall rates that may lead to some minor flooding concerns over urban locations and low lying areas, especially along the I-95 corridor. Did lower high temperatures a bit based on latest guidance and expect early start to showers and T`storms in addition to mostly cloudy skies anticipated for much of the midday/afternoon period with most inland areas in the 90-93 degree range and upper 80s to around 90 at the beaches. Heat index values should range 102-106 for today prior to T`storms this afternoon. Tonight, leftover T`storm outflow boundaries may push north into SE GA areas closer to the Altamaha river basin in the early evening hours with mostly cloudy skies from mid and high level debris clouds thinning out gradually overnight. Lows will range into the low/mid 70s for inland SE GA, mid 70s over inland NE FL, and the upper 70s along the coast. && .NEAR TERM...Today through tonight... Issued at 335 AM EDT Fri Jun 28 2024 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Relatively similar setup today compared to yesterday with elevated moisture levels with PWATs near 2 inches...close to 20 percent above normal. The flow from 1000-500 mb per guidance is west- southwest about 10 knots. We are already seeing isolated showers moving through inland northeast FL at 3 AM, fairly unusual that they are that far inland, but they should tend to dissipate the farther inland they get. The forecast today again calls for near 60-80 percent chance of rain, with showers and storms most numerous during the midday time frame, and the best low level convergence along the eastern coastal counties. This is where the prevailing west to southwest flow meets up with a slow moving east coast sea breeze. Have included wording for some storms may contain gusty winds and heavy rainfall, which should adequately cover the threat of storms. The highs today will still manage to hit 90 deg or the lower 90s for most areas. The heat indices are noted to reach about about 109 in some spots over the eastern zones. However, the duration of any heat advy criteria looks short, and if the rain comes in midday, then this may hold back the chance of reaching advisory criteria. Tonight, scattered convection is anticipated during the early evening, but should end fairly early. Overnight, may see some start up again of showers west of the I-75 corridor area but can`t rule out isolated showers anywhere over the region given the persistence of PWATs of 2 to 2.1 inches. Given light south-southwest flow and occasional cloudiness tonight, lows will be muggy in the mid 70s again. && .SHORT TERM... (Saturday through Sunday night) Issued at 335 AM EDT Fri Jun 28 2024 Pattern for deep-layer moisture will continue into Saturday and Sunday with stronger diurnal convection expected to develop in conjunction with the afternoon sea breeze, storm outflow boundaries, and areas of collision. Predominant PWAT levels will range between 2 and 2.25 inches through the period, resulting in increased chances for storms with heavy localized rainfall. High temperatures for the weekend will rise into the mid 90s for inland areas and in the upper 80s and lower 90s for areas along the shoreline. Overnight low temperatures will drop down into the mid 70s for inland areas and in the upper 70s and lower 80s along the coast. && .LONG TERM... (Monday through Thursday) Issued at 335 AM EDT Fri Jun 28 2024 A cold front will press down from out of the north after the weekend and then stall in the vicinity of northern Georgia. The drier air mass along with high pressure ridging will result in drier conditions starting by midweek. The pattern of building diurnal convection will carry into this period with convective developments associated with sea breeze boundaries and areas of collision becoming more inhibited later in the week as PWAT and humidity values decrease. Daily high temperatures are expected to experience a warming trend next week with max temps rising into the upper 90s by the latter half of the week. && .AVIATION... (12Z TAFS) Issued at 636 AM EDT Fri Jun 28 2024 Radar shows scattered showers moving inland from the northeast Gulf of Mexico...this should continue to gradually spread eastward during the morning and early afternoon across TAF sites, with greatest coverage, including scattered TSRA, being during the afternoon. At least isolated convection may continue into the evening. VFR conditions expected, except for MVFR CIGs/VSBYs and gusty winds with TSRA. && .MARINE... Issued at 335 AM EDT Fri Jun 28 2024 Little overall change in the pattern through early next week with a ridge axis to the south keeping a south to southwest flow over the area waters. The airmass remains plenty moist to support rounds of showers and storms each day, some of which will produce brief wind gusts in excess of 25-35 kt at times. Winds will be up to 10-15 kt at the most and seas up to around 3 ft. A weak front will approach from the north by Tuesday and stall and dissipate by mid week. Rip Currents: Though offshore flow is seemingly keeping the risk low, a southeast wind-sea with surf around 2 ft and onshore flow briefly in the aftn will just barely maintain a moderate risk of rip currents today and again Saturday. Should be a south to north longshore current prevailing, that may be a bit stronger than would ordinarily be expected. Max threat looks to be in the morning hours and again after about 3-4 pm. && .PRELIMINARY POINT TEMPS/POPS... AMG 93 73 95 75 / 80 40 60 30 SSI 90 76 91 78 / 70 40 70 40 JAX 92 74 93 75 / 80 40 80 30 SGJ 92 74 92 76 / 80 50 80 40 GNV 91 73 92 73 / 80 40 90 30 OCF 92 73 93 75 / 80 40 90 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$