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422 FXUS64 KMOB 092143AFDMOBArea Forecast DiscussionNational Weather Service Mobile AL343 PM CST Mon Dec 9 2024...New NEAR TERM, SHORT TERM, LONG TERM, MARINE....NEAR TERM...(Now through Tuesday)Issued at 343 PM CST Mon Dec 9 202409.12Z upper analysis shows the deep south under a west/southwest flow at high levels in the geopotential height fields with short-wave energy passing out of LA and expected to deamplify theremainder of the day as it lifts across central MS/AL. At the surface, we are warm sectored south of a better defined, but quasi-stationary front draped from the Red River Valley of TX/OK to the Mid MS River Valley. A weak surface trough was oriented from southern MS, southwest to across southeast to south-central LA. Along this surface trough, a zone of precipitable water valuesfrom 1.4 to 1.8 inches was aligned and considering the intersecting surface boundary and the mid level impulse passage riding east northeast in the flow aloft provides enough ascent tokeep the local area unsettled. Radar shows a fairly solid area ofrains streaming east northeast mainly along and west of I-65. Little in the way of thunder at present time within the rain band as radar returns are stratiform/low topped considering little to no instability as mid level lapse rates are around 5.5 C/KM and little to no convective available potential energy (CAPE). There is however a bit of instability (Surface Based Cape at 500-1000 J/KG) poking up into the western FL Panhandle which is lending credence of thunder support so will be watching this area. Some ofthe rains moderate to locally heavy, but with higher intensity drought and elevated flash flood guidance, forecasters will hold off on issuance of a larger areal flash flood watch. Feel any flooding issues coming from higher rainfall rates => runoff will be isolated and confined to areas subject to poor drainage. Sincemidnight, several observations primarily over southeast MS andinterior southwest AL already have received 1 to 2 inches. Flow aloft changes little tonight with moisture axis alignednortheast to southwest from the southern Carolinas to off the LAcoast. There is a signal in the latest short range ensembles ofpatchy fog development overnight and have included this in thegridded forecast. There is also indications in the guidance that coverage of precipitation lowers a bit by late evening before trending back up by daybreak and into the day Tuesday as upper trough begins to sharpen over the Plains down into TX causing upper level support/ascent to increase along a southeastward moving cold front. The front approaches the western zones by late in the day Tuesday and will make passage across the I-65 corridor Tuesday night. The better coverage of showers and storms will shift east of I-65 by late Tuesday night/early Wed AM with the frontal passage. May see a mix of thunder within the larger coverage of warm sector showers Tuesday and Tuesday night as a narrow low level H85 jet strengthens combined with 0-6km bulk shear magnitudes increasing to 40 to 60 kts. Instability is mostlyweak considering degree of cloud cover/rain. Parameters appear tobe a bit out of phase amongst solutions but enough will be present for a Marginal Risk of a sub-severe storm or very isolated, brief severe storm here and there with a strong to isolated damaging wind gust threat being the main impact in any ofthose. Still could also see some moderate to locally heavy downpours and potential isolated water issues in areas subject to poor drainage.Temperatures will be mild and well above normal by Decemberstandards with highs Tuesday in the lower to mid 70s interior tomid 70s coast. Lows will also be mild and well above normaltonight in the lower to mid 60s interior to mid 60s coast. Lowstrend colder Tuesday night as cold air advection arrives in the wake of the frontal passage, 37 to 42 northwest of I-65 to mid 40s east of the Interstate, southward to the coast. /10&&.LONG TERM...(Wednesday through Monday) Issued at 343 PM CST Mon Dec 9 2024A large upper trough continues to push across the eastern CONUS tostart the period with a surface cold front marching its waythrough the forecast area early Wednesday morning. Any lingeringshowers and storms will quickly shift east of the area mid to latemorning with dry, cold air working its way into the area. Surfacehigh pressure slides into the region keeping things dry throughFriday in the cold fronts wake. Heading into the weekend, anotherupper trough approaches the region and high pressure shifts east putting us back into a warm air advection regime. Rain chances will be on the increase again as we head into the weekend withisolated to scattered coverage each day, best chances on Saturday.The next upper trough approaches by the beginning of next week which will likely bring another increase in rain chances. Temperatures follow a similar roller coaster with highs in the 50's and lows in the upper 20's and lower 30's through Thursday night. Temperatures warm back to near seasonable norms in the lower to middle 60's over the weekend and lows in the 40's over the interior and 50's nearer the coast. A Low risk of rip currentswill exist Wednesday through Friday. MM/25&&.MARINE...Issued at 343 PM CST Mon Dec 9 2024Short range ensembles indicate elevated probabilities of advectivetype fog over Mobile Bay where warmer, moist southerly flowcharacterized by dewpoints 65-70 degrees is over-riding cooler bay temperatures 54-59 degrees. Have noticed some mixing out/improved visibilities at time of writing but expect restrictions to lower after dark again. Dense fog advisory remainsin effect until 6 AM Tue and could be expanded for the remainderof Mobile Bay. Considering high confidence of increasing northwesterly flow to small craft advisory criteria in the wake ofa strong frontal passage Tue night, small craft advisories have been posted and will continue into Wed for Mobile Bay, out across the open Gulf. Seas markedly higher Tuesday night into Wednesday with highest seas 6, to perhaps 9 feet in the 20 to 60 NM zones considering the northwesterly fetch. We may see a brief window where wind gusts could increase to gale force and will continue tomonitor over the next couple shifts for a possible upgrade to theadvisory. /10&&.PRELIMINARY POINT TEMPS/POPS...Mobile 63 74 43 55 33 56 38 61 / 80 90 90 20 0 0 0 10 Pensacola 66 75 47 57 38 56 43 62 / 90 80 100 40 0 0 0 10 Destin 67 76 50 60 40 57 45 63 / 90 80 100 60 0 0 0 0 Evergreen 61 74 42 53 31 55 33 60 / 80 90 100 20 0 0 0 0 Waynesboro 62 72 38 54 30 54 34 60 / 60 90 60 0 0 0 0 0 Camden 61 70 39 52 30 53 33 59 / 60 90 90 20 0 0 0 0 Crestview 62 77 44 55 30 56 34 62 / 90 80 100 40 0 0 0 0 &&.MOB WATCHES/WARNINGS/ADVISORIES...AL...None.FL...None.MS...None.GM...Dense Fog Advisory until 6 AM CST Tuesday for GMZ630. Small Craft Advisory from midnight Tuesday night to 3 PM CST Wednesday for GMZ630>632. Small Craft Advisory from midnight Tuesday night to midnight CST Wednesday night for GMZ650-655-670-675.&&$$This product is also available on the web at:www.weather.gov/mob
