Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
338 FXUS62 KJAX 210522 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 122 AM EDT Fri Jun 21 2024 ...New AVIATION... .UPDATE... Issued at 955 PM EDT Thu Jun 20 2024 Late evening surface analysis depicts a gradually organizing, but weak low pressure enter (1014 millibars), labeled as Invest 92-L by the National Hurricane Center. This feature was centered about 300 miles to the east-southeast of Mayport as of 01Z. Thunderstorm activity has been bursting near a poorly defined center of circulation this evening, and the National Hurricane Center has increased the probability for development into a Tropical Depression to 50% on their evening Tropical Weather Outlook. Otherwise, high pressure (1028 millibars) was gradually weakening over the western Atlantic waters as it sinks southward towards Bermuda. Aloft...stout ridging was centered across the Tennessee Valley and the southern Appalachians, with a Tropical Upper Tropospheric Trough (TUTT) being steered quickly westward across the southern portions of the Gulf of Mexico beneath this ridge. A few weak rain bands on the western periphery of Invest 92-L were progressing west-southwestward across the offshore Atlantic waters to the south of St. Augustine. Scattered multi-layered cloudiness continues to progress across northeast and north central FL, with fair skies prevailing across southeast GA. Breezy northeasterly winds prevail at coastal locations, with winds decoupling further inland. Temperatures generally ranged from 75-80 degrees at 02Z, with dewpoints mostly in the 60s inland, ranging to around 70 at coastal locations. All eyes are on Invest 92-L tonight as this feature moves west- northwestward towards our coastline. This system could organize into a Tropical Depression overnight or Friday morning as it traverses the warm Gulf Stream waters, and outer rain bands should begin to move onshore along the northeast FL coast during the predawn hours on Friday. Beneficial rainfall is on its way to the Interstate 95 corridor, with a dry and subsident air mass closer to the ridge axis aloft over inland southeast GA and the Suwannee Valley likely reducing rainfall intensity and coverage as activity works westward after sunrise on Friday. Heavy downpours and a few embedded thunderstorms should overspread coastal southeast GA and locations east of U.S. Highway 17 by sunrise. Multi-layered cloud cover will otherwise gradually increase from east to west during the overnight and predawn hours, with lows falling to the upper 60s across inland southeast GA and remaining in the 70s elsewhere. && .SHORT TERM... (Friday through Saturday night) Issued at 237 PM EDT Thu Jun 20 2024 Area of low pressure with disorganized convection will move west- northwest toward SE GA and NE FL during the overnight hours and then move inland around or just after sunrise Friday morning. There is not much time for the system to get organized, but there is a small chance it can be a depression before it comes ashore. Either way, impacts are the same with rough surf, potential minor beach erosion during high tide, high risk of rip currents. Expecting numerous showers with embedded thunderstorms with this feature, along with elevated winds and gusts particularly I-95 eastward where some wind gusts exceeding 30 mph are possible. Highs Friday will be a little cooler than normal due the clouds and rainfall passing through with highs in the 85 to 90 degree range. High pressure will build to the northeast behind the low pressure area Friday night through Saturday. This pattern will continue the onshore flow pattern, but the gradient will be more relaxed, so so not expecting winds to be as elevated during this time frame. Above average shower chances will continue in the onshore flow. Diurnal heating could lead to a few afternoon storms on Saturday. Lows Friday night will generally be in the lower to mid 70s, except a little warmer near the coast. Temperatures Saturday will trend above normal, with highs ranging from the lower 90s at the coast, to the mid 90s inland. The high will move further away to the east northeast Saturday night, with the flow becoming more from the south/southeast. Lows away from the coast in the mid 70s, upper 70s coast. && .LONG TERM... (Sunday through next Thursday) Issued at 237 PM EDT Thu Jun 20 2024 The high will continue to drift away to the east this period, as a trough moves into the southeastern US and stalls. An increasingly moist southwest flow will become the trend this period. This pattern will produce above normal chances for showers and thunderstorms. Temperatures will be above normal throughout this period. && .AVIATION... (06Z TAFS) Issued at 122 AM EDT Fri Jun 21 2024 MVFR ceilings around 2500ft and heavy showers will move onshore and impact all TAF sites beginning this morning. Isolated thunderstorms and gusty easterly winds will also be present throughout the day. PROB30s are in place for the best chances for time frame of heaviest showers and/or thunderstorm activity. && .MARINE... Issued at 955 PM EDT Thu Jun 20 2024 Weak low pressure situated about 300 miles to the east-southeast of Mayport, Florida late on Thursday evening may organize into a Tropical Depression overnight or early on Friday as it progresses west-northwestward across the Gulf Stream waters, with this feature approaching the northeast Florida coast late on Friday morning or during the early afternoon hours. Bands of gusty showers and embedded thunderstorms will increase in frequency and intensity during the overnight and predawn hours on Friday, with this activity continuing through late Friday afternoon before diminishing in coverage as this weak low pressure center progresses inland. Meanwhile, strong high pressure centered north of Bermuda will gradually weaken as it settles southward this weekend. Small Craft Advisory conditions will continue throughout our local waters tonight and Friday, followed by winds and seas diminishing to Caution levels on Friday night and then below Caution criteria on Saturday. Seas of 5-7 feet near shore and 6-8 feet offshore tonight and Friday will subside to 4-6 feet on Friday night and then 3-5 feet during the weekend. Rounds of showers and thunderstorms will continue to develop over our local waters this weekend and into next week as prevailing winds become southerly ahead of a weakening surface trough that will settle over the southeastern states through midweek. Rip Currents: Breakers of 5-7 feet will continue at the northeast FL beaches on Friday, with 4-6 foot breakers expected at the southeast GA beaches. This rough surf will create a high risk of dangerous rip currents at all area beaches through Friday. A moderate risk is expected during the weekend due to onshore winds and an easterly ocean swell. && .HYDROLOGY... Issued at 955 PM EDT Thu Jun 20 2024 The Weather Prediction Center has a Marginal risk of excessive rainfall from Friday through Saturday, as locally heavy rainfall totals of 2 to 3 inches will be possible along the Interstate 95 corridor as Invest 92-L impacts our region with bands of heavy downpours. Rainfall amounts further inland will likely remain below one inch. Rainfall will be mostly beneficial, but there will be concerns for flooding at urban locations where rain bands train repeatedly tomorrow and again on Saturday. && .PRELIMINARY POINT TEMPS/POPS... AMG 91 74 91 73 / 40 40 80 30 SSI 87 78 87 77 / 80 50 70 50 JAX 88 75 91 74 / 80 60 80 50 SGJ 87 77 89 75 / 80 70 80 60 GNV 91 73 94 72 / 70 60 90 40 OCF 91 74 95 75 / 80 50 90 50 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through late tonight for FLZ124-125-133- 138. High Surf Advisory until 5 PM EDT this afternoon for FLZ124-125- 133-138. GA...High Rip Current Risk through late tonight for GAZ154-166. AM...Small Craft Advisory until 5 PM EDT this afternoon for AMZ450- 452-454-470-472-474. && $$