Area Forecast Discussion
Issued by NWS Mobile, AL
Issued by NWS Mobile, AL
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239 FXUS64 KMOB 251151 AFDMOB Area Forecast Discussion National Weather Service Mobile AL 650 AM CDT Wed Sep 25 2024 ...New AVIATION... .AVIATION... (12Z TAFS) Issued at 650 AM CDT Wed Sep 25 2024 Isolated showers and storms increase in coverage through the day, mainly over the eastern and central portions of the area. Coverage of showers and storms for tonight is anticipated to be highest over the eastern portion of the area with lesser coverage further west. IFR to MVFR conditions will be possible with the stronger showers and storms. Northerly to northeasterly winds at 5 to 10 knots are expected over interior areas while closer to the coast winds become easterly to southeasterly at 5 to 10 knots. Winds tonight will be easterly to northeasterly at 5 to 10 knots. /29 && .PREV DISCUSSION... /issued 354 AM CDT Wed Sep 25 2024/ ..New NEAR TERM, SHORT TERM, LONG TERM, MARINE... NEAR TERM... (Now through Thursday night) Issued at 354 AM CDT Wed Sep 25 2024 An upper level longwave trough, currently located over the central US is continuing to dig southeastward this morning. Within the next few hours, it will begin to break off from the northern just stream, resulting in an anomalously large upper low that parks itself over the Mississippi River Valley. This low is responsible for two things: 1) helping to send a frontal boundary into the region from the west, and more importantly 2) keeping the core of soon-to-be Hurricane Helene to our east. For today, the front, which is currently located over central Mississippi, will begin moving into our local area. Plenty of forcing due to strong diffluence aloft and convergence along the front, in addition to ample moisture (PWATs around 1.6 to 1.9 inches), will result in scattered to numerous showers and storms across the area, especially in the afternoon. The front should stall somewhere near the I-65 corridor by Wednesday evening, allowing for high rain chances to continue (especially along and east of it) through Wednesday night. Although lapse rates are rather poor, daytime heating should allow for some destabilization to occur. This, paired with favorable deep layer shear due to the close proximity of the upper low could result in the organization of a few strong to marginally severe storms. Gusty to damaging winds seem to the primary threat. Not really anticipating a tornado threat due to very weak low-level shear values and straight-lined hodographs. For Thursday, all eyes point to the Gulf as Helene rapidly strengthens into a major hurricane and sprints toward the Florida Big Bend area. Thankfully for our local area, the core is far enough away for us to be spared from the hurricane force winds and storm surge effects. However, as this system quickly lifts northward, it is expected to grow in size considerably and therefore we will still see some impacts. Hazardous marine conditions (due to strong winds and high waves), dangerously high surf (breakers greater than 10 feet), and life threatening rip currents are expected, especially as we get into the Thursday afternoon through Thursday night timeframe. We will also be monitoring for the potential of, at least, minor coastal flooding along the coastal interface going into Thursday night. As far as rainfall, we are currently anticipating a general 2 to 4 inches (locally higher possible) over south central Alabama and the western Florida Panhandle through this entire period, with lower amounts for southwest Alabama and southeast Mississippi. This rainfall could lead to isolated to scattered instances of flash flooding, especially over urban and poor drainage areas, and some minor river flooding cannot be ruled out. And lastly, wind gusts of around 25 to 35 mph are anticipated across the area (highest near the coast) starting as early as Thursday morning. An occasional gust to near tropical storm force cannot be ruled out. We will continue to monitor the progress of Helene closely, as any shifts to the west will likely bring stronger impacts than what was listed above. /96 SHORT AND EXTENDED TERM... (Friday through Tuesday) Issued at 354 AM CDT Wed Sep 25 2024 Per the latest track for Helene from the National Hurricane Center, the system is expected to have weakened to a depression over northern Georgia by Friday morning. The system becomes absorbed into a rather unusual large upper low which slowly moves from over the lower Mississippi River valley to become centered near the Mississippi/Ohio River confluence by Saturday. The upper low later breaks down leaving an upper trof over the eastern states by Monday. Am anticipating predominately dry conditions for our area on Friday, with dry conditions prevailing through Sunday. There appears to be a small chance for rain over the eastern half of the area on Monday although confidence is low, then dry conditions prevail on Tuesday except for a possible small chance for rain over Okaloosa county Florida. A high risk of rip currents will continue through Friday night, then a moderate risk is expected on Saturday with a low risk for Sunday. A high surf advisory will probably be necessary for Friday, but surf conditions will have subsided by Friday night. /29 MARINE... Issued at 354 AM CDT Wed Sep 25 2024 Based on the latest track for Helene from the National Hurricane Center and the associated wind field (and probabilities of 34+ knots), have added the 20-60 nm portion of the Alabama coastal waters to the Tropical Storm Warning currently in effect for the western Florida Gulf waters. Have also issued a Small Craft Advisory for the remainder of the marine area which will be in effect from 4 am Thursday to 1 pm Friday, by which time both winds and seas will have subsided sufficiently. Winds and seas will be higher near storms. /29 && .PRELIMINARY POINT TEMPS/POPS... Mobile 89 69 81 64 83 66 86 66 / 40 50 40 20 10 0 0 0 Pensacola 87 73 80 68 82 72 85 72 / 60 80 70 30 10 0 0 0 Destin 86 74 81 71 82 73 85 73 / 80 80 80 50 10 0 0 10 Evergreen 87 70 78 64 83 62 86 64 / 70 70 70 50 10 0 0 0 Waynesboro 85 65 82 62 81 62 84 61 / 50 30 30 20 10 0 0 0 Camden 86 68 77 63 80 62 83 62 / 60 60 60 50 10 0 0 0 Crestview 87 72 79 66 83 64 86 66 / 90 80 80 50 10 0 10 0 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...High Rip Current Risk from this evening through late Friday night for ALZ265-266. FL...High Rip Current Risk from this evening through late Friday night for FLZ202-204-206. MS...None. GM...Small Craft Advisory from 4 AM Thursday to 1 PM CDT Friday for GMZ630>636-650. Tropical Storm Warning for GMZ655-670-675. && $$ This product is also available on the web at: www.weather.gov/mob