Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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894 FXUS62 KJAX 092309 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 709 PM EDT Thu May 9 2024 ...New AVIATION... .NEAR TERM... (through Tonight) Issued at 335 PM EDT Thu May 9 2024 Strong to severe thunderstorms associated with the southeastward moving MCS will continue to impact southeast GA through late afternoon, with activity expected to cross the FL/GA border in the 5 PM - 7 PM time frame. This MCS will continue racing southeastward early evening hours, with weakening likely as the line pushes across the Interstate 10 corridor towards sunset as it encounters the drier and more stable air mass that remains in place across north central FL. Damaging straight line wind gusts of 50-70 mph will be the primary threat for locations north of I-10, but a few isolated incidents of hail and tornadoes cannot be ruled out across southeast GA through late afternoon. The Storm Prediction Center has maintained an Enhanced Risk (level 3 out of 5) for severe thunderstorms across southeast GA, where a 10% probability of downburst wind gusts in excess of 74 mph exists, in addition to 5% probabilities for tornadoes along with enhanced probabilities for large hail. A Slight Risk was maintained for locations along and south of I-10 into the early evening hours. The longwave trough will continue to dig southeastward across the Tennessee and Ohio Valleys tonight, with strengthening westerly flow to the south of this feature propelling another shortwave trough and associated MCS across the Deep South during the overnight and predawn hours. The prior weakening MCS will push across north central and coastal northeast FL during the early to mid evening hours, with a break in between MCSs expected through the overnight hours. Short-term, high resolution guidance is in relatively good agreement in positioning this next MCS and associated strong to severe thunderstorm threat at the doorstep of the Ocmulgee/Alapaha/Suwannee Rivers around sunrise on Friday, with this activity then sweeping eastward across our area through the morning hours. Breezy west- southwesterly boundary layer flow in advance of this upstream MCS is expected to advect a stratus layer across the Suwannee Valley and inland southeast GA overnight, with these low clouds possibly crossing the I-95 corridor around sunrise. Cloud cover and warm air advection downstream of the approaching cold front should keep lows in the 70-75 degree range overnight. && .SHORT TERM... (Friday through Saturday night) Issued at 335 PM EDT Thu May 9 2024 Upper shortwave trough and associated MCS will move across the region Friday morning bringing strong to severe thunderstorms to the Ocmulgee/Alapaha/Suwannee River basins around sunrise on Friday. This activity will then sweep eastward across our area through the late-morning hours before shifting offshore. There remains uncertainty with the next round of potentially severe weather. If the morning MCS clears the area early enough, the airmass may be able to recover ahead of the approaching cold front from the northwest Friday afternoon into evening. Storms will redevelop ahead of the front but the severity of them will be determined by the airmass recovery. Regardless, damaging straight- line winds will be the main threat along with the potential for hail and isolated tornadoes. The cold front and associated convection is expected to exit to the south Friday evening with a drier airmass clearing the skies in its wake. Sunny skies and around normal temperatures in the 80s are anticipated for Saturday with lows dipping into the upper 50s and 60s. && .LONG TERM... (Sunday through next Thursday) Issued at 335 PM EDT Thu May 9 2024 Warm and dry conditions on Sunday quickly give way to a wet and unsettled pattern for next week as upper shortwaves parade across the region. A wave of low pressure will move eastward across the northern Gulf lifting a stationary front across southern FL up the peninsula Monday into Tuesday as a warm front. As the warm front lifts across the region, a moist and unstable airmass will become established which will support an increasing thunderstorm potential throughout next week. High temperatures will generally be around normal in the 80s and then trend upward on Wednesday. && .AVIATION... (00Z TAFS) Issued at 709 PM EDT Thu May 9 2024 Difficult TAF forecast for this package given the uncertainty in thunderstorm activity timing Friday. For now, have placed VCTS beginning in the morning, with PROB30 groups in the afternoon hours for the TAF sites. Tonight, low ceilings will move in affecting all the sites around 07-09Z, clearing near sunrise. Showers and isolated thunderstorms will linger this evening for a few more hours near SSI especially. && .MARINE... Issued at 335 PM EDT Thu May 9 2024 A squall line of strong to severe thunderstorms will traverse the Georgia waters during the mid to late afternoon hours today, with this line reaching the northeast Florida waters during the late afternoon and early evening hours. This squall line is expected to weaken after sunset as it approaches the waters from St. Augustine southward. Strong to severe thunderstorms will be capable of producing damaging wind gusts, hail, and frequent lightning strikes. Outside of thunderstorm activity, seas of 3-5 feet will prevail both near shore and offshore through tonight. Otherwise, a cold front will enter the southeastern states tonight and will progress southeastward across our local waters on Friday afternoon and evening. Additional rounds of strong to severe thunderstorms will be possible after sunrise and again during the afternoon hours ahead of this front. Winds will shift to northwesterly in the wake of the frontal passage on Friday night and Saturday morning, with weak high pressure the expected to build eastward from the Ozarks on Saturday night, reaching the coastal Carolina region by Monday afternoon. This weather pattern will result in onshore wind development on Sunday afternoon, with onshore winds then strengthening on Monday night ahead of an approaching warm front. Showers and thunderstorms will overspread our local waters by late Monday night as this warm front lifts northeastward across our area. Rip Currents: Gusty offshore winds should result in a low risk at all area beaches on Friday and Saturday. && .PRELIMINARY POINT TEMPS/POPS... AMG 70 82 60 81 / 40 90 10 0 SSI 72 83 64 80 / 30 90 20 0 JAX 72 86 64 84 / 40 80 30 0 SGJ 73 90 67 83 / 40 70 30 10 GNV 73 88 64 87 / 20 60 30 10 OCF 73 89 68 89 / 10 40 30 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$