Area Forecast Discussion
Issued by NWS Mobile, AL
Issued by NWS Mobile, AL
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973 FXUS64 KMOB 240938 AFDMOB Area Forecast Discussion National Weather Service Mobile AL 438 AM CDT Tue Sep 24 2024 ...New NEAR TERM, SHORT TERM, LONG TERM, MARINE... .NEAR TERM... (Now through tonight) Issued at 438 AM CDT Tue Sep 24 2024 A longwave trof over the central states continues to amplify while advancing to roughly along the lower/mid Mississippi River valley to the Great Lakes through tonight. An associated surface low well off to the north brings a weak trailing frontal boundary from the southern/central Plains into central Mississippi and northern Louisiana by the end of the period. A modest surface ridge oriented along the northern Gulf coast weakens today and retreats from the area tonight as the front approaches. A light southerly flow is established today over the area then looks to become light and variable tonight. Have kept mention of precipitation out of the forecast for today (although can`t rule out a stray shower or storm), then will have slight chance to chance pops developing overnight in response to the approaching frontal boundary and also some peripheral response to Potential Tropical Cyclone Nine (PTC9) expected to emerge in the south central Gulf by late in the night. Please see the National Hurricane Center for more information on PTC9. Highs today will be in the lower 90s except for around 90 at the coast. Lows tonight range from the upper 60s well inland to the lower/mid 70s at the coast. A low risk of rip currents is expected through tonight. /29 && .SHORT TERM... (Wednesday through Thursday night) Issued at 438 AM CDT Tue Sep 24 2024 An upper level longwave trough is expected to dig southeastward on Wednesday before breaking off from the northern jet stream on Thursday. This results in an anomalously large upper low that essentially 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 Potential Tropical Cyclone 9 (PTC9) to our east. For Wednesday, the front will begin moving into our local area from the west. Plenty of forcing due to strong diffluence aloft and convergence along the front, in addition to ample moisture, will result in numerous to widespread showers and storms across the area, especially in the afternoon. The front should stall somewhere near the I-65 corridor by Thursday evening, allowing for high rain chances to continue (especially along and east of it) through Wednesday night. By Thursday, all eyes point to the Gulf as PTC9 strengthens and begins it`s sprint to the north-northeast. Models have come into very good agreement over the past 24 hours, with a good majority of the operational models and their ensembles tightly clustered on a landfall in the Florida Big Bend area sometime late Thursday. Rapid strengthening is also anticipated, resulting in a likely landfall as a major hurricane in that area. Thankfully for our local area, the center should be far enough away for us to be spared from the hurricane force winds. 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 5 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, tropical storm force winds are possible primarily for the eastern half of our CWA starting as early as Thursday morning. Probabilities currently sit at 10-20 percent over portions of south central Alabama, the western Florida Panhandle, and along the immediate Alabama coast, with lower probabilities elsewhere. We will continue to monitor the progress of PTC9 closely, as any shifts to the west will likely bring stronger impacts. /96 && .LONG TERM... (Friday through Monday) Issued at 438 AM CDT Tue Sep 24 2024 Per the latest track from the National Hurricane Center on PTC9, the system is anticipated to be over northern Georgia/Carolinas by Friday and soon becomes absorbed into a rather anomalous large upper low centered over the lower Mississippi River valley. The large upper low lumbers to over the Mississippi/Ohio River confluence by Sunday then breaks down to an open trof over the eastern states by Monday. Drier air is anticipated to be in place over the area on Friday, then steadily improves over the eastern portion of the area Saturday into Sunday. Have continued with a dry forecast for Friday and Saturday, then slight chance pops return to east of I-65 for Sunday afternoon. This improvement in deep layer moisture proves short-lived however, with drier air later flowing into the area by Monday, so have gone with a dry forecast for Monday. /29 && .MARINE... Issued at 438 AM CDT Tue Sep 24 2024 Based on the latest track from the National Hurricane Center on PTC9, prob34 values are sufficient to trigger Tropical Storm Conditions Possible wording in the open Gulf waters and Choctawhatchee Bay during Thursday into Thursday night. Please see the National Hurricane Center for more information. Depending on subsequent updates to the track for PTC9 and if expansion of a Tropical Storm Watch into our area remains not necessary, may need to include a Small Craft Advisory for much of the marine area beginning late Wednesday night which continues until seas subside Friday morning. Winds and seas will be higher near storms. /29 && .PRELIMINARY POINT TEMPS/POPS... Mobile 91 70 88 70 81 65 84 66 / 0 10 70 70 50 10 0 0 Pensacola 89 74 86 73 81 69 83 72 / 0 30 80 80 80 20 0 0 Destin 89 75 85 74 82 72 83 72 / 10 40 80 80 80 30 0 0 Evergreen 93 69 86 70 80 66 84 62 / 0 20 80 80 80 40 10 0 Waynesboro 92 69 86 67 80 63 83 61 / 10 30 60 50 50 20 10 0 Camden 91 68 86 68 78 65 80 62 / 0 20 80 70 70 40 10 0 Crestview 92 70 86 71 80 66 84 63 / 10 30 80 80 90 30 10 0 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at: www.weather.gov/mob