040 FXUS64 KMOB 260938 AFDMOB Area Forecast Discussion National Weather Service Mobile AL 438 AM CDT Sun Sep 26 2021 .NEAR TERM UPDATE /Now Through Monday/...An upper level ridge continues to build north over the Southern Plains as it slowly shifts east. Surface high pressure stretching north along the east side of the Mississippi River shifts east in response, becoming centered off the Carolina coast by Monday evening. Southerly flow returns to the Lower Mississippi River Valley and Southeast in response, and moisture begins to return to the region. Through Monday, best moisture return is over the Lower Mississippi River Valley, though guidance is advertising precipitable h20 values around 1.0" beginning to move north across the forecast area by Monday evening. With increasing upper subsidence, temperatures creep upward to a bit above seasonal norms by Monday. Today, temperatures topping out in the low to mid 80s are expected, with mid to upper 80s expected Monday. Am still expecting temperatures to drop into the mid to upper 50s across most of the forecast area by sunrise Sunday, upper 50s to around 60 Sunday night. Low temperatures in the mid to upper 60s expected along the coast. There continues to be a low risk of dangerous rip currents on area beaches, with light winds, low swell and decreasing tidal range. /16 && .SHORT TERM /Monday night Through Tuesday night/...An upper level ridge of high pressure will amplify across the Lower Mississippi Valley region and across the Upper Midwest and northern Plains states Monday night into Tuesday before gradually shifting eastward across the western Great Lakes, Tennessee Valley and north central Gulf Coast region late Tuesday night into early Wednesday morning. A deep layer dry and subsident airmass will remain in place across the majority of our forecast area during the Monday night-Tuesday night period and have kept dry conditions in the forecast across most places during this time frame. The exception could be across portions of southeast MS and far southwest AL where some short range guidance shows a narrow plume of moisture with slightly enhanced PWAT values between 1.3-1.5 inches potentially advecting in from the southwest by Tuesday afternoon. Isolated showers or even an isolated thunderstorm cannot be ruled out over this portion of the area by Tuesday afternoon, and have indicated a slight (~20%) chance POP generally along and southwest of a Richton, MS to Coden/western Dauphin Island, AL line. However, it is entirely possible that this plume of moisture could remain oriented to our west on Tuesday, so POPs were trended a bit lower than the more optimistic NBM and ECMWF guidance. Surface high pressure will shift across the southeastern U.S. and western Atlantic early this week, allowing for a return southeasterly to southerly flow across our area. Surface dewpoints are expected to rise back into the 60s through the short term period, so expect slightly muggier conditions as compared to the past few days. Lows Monday night will range in the lower to mid 60s over most interior areas and in the upper 60s to lower 70s along the immediate coast. Highs Tuesday should warm into the mid to upper 80s over most places. Lows by Tuesday night continue to trend slightly warmer in the mid to upper 60s over interior areas, while continuing to range in the upper 60s to lower 70s along the immediate coast and beaches. /21 && .EXTENDED TERM /Wednesday Through Saturday/...The heat and humidity slowly return as we head deeper into the work week and weekend. Ridging aloft becomes less amplified over the region as a trough digs through the Northeast and a cut off low meanders over the Desert Southwest. Flow aloft quickly transitions from northerly to southerly Wednesday into Thursday as the ridge begins to break down. During the same timeframe, model guidance is hinting at a subtle shortwave pivoting from the TX Coast up into the Mississippi River Valley. Meanwhile, the local area remains on the western periphery of the weakening surface high on Wednesday and Thursday, which allows southerly flow to usher some moisture back into the region. That said, southeast Mississippi is the only portion of the area that may see a decent bump in moisture as PWATs increase to around 1.5 inches with 0.9-1.2 inches for the rest of the area. The combination of the nearby weak shortwave and increasing moisture could be enough to spark isolated showers and storms on Wednesday afternoon across southeast Mississippi and coastal Alabama. Not entirely confident on Thursday afternoon's activity as most of the convection should be west of the area, so POPs were capped around 15% for the same area as previously mentioned. Dry conditions are expected Friday through the weekend. Temperatures will top out in the 80s each afternoon with a few spots hitting 90° across parts of south central Alabama. 07/mb && .MARINE...Surface high pressure over the Lower Mississippi River Valley shifts east to near the Eastern Seaboard into Monday. A light to occasionally moderate offshore flow this weekend shifts to east to southeast early in the coming week in response. Seas generally 2 feet or less during the period. /16 && .PRELIMINARY POINT TEMPS/POPS... Mobile 82 61 86 65 86 68 85 67 / 0 0 0 0 10 10 30 10 Pensacola 83 65 85 70 86 71 86 71 / 0 0 0 0 10 10 20 10 Destin 83 68 84 72 86 72 86 73 / 0 0 0 0 10 10 20 10 Evergreen 86 58 88 64 88 65 89 67 / 0 0 0 0 10 10 10 10 Waynesboro 84 57 86 62 86 65 86 66 / 0 0 0 0 10 10 20 10 Camden 85 58 87 63 87 65 88 66 / 0 0 0 0 10 10 10 10 Crestview 86 57 87 64 88 65 88 67 / 0 0 0 0 10 10 10 10 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at: http://weather.gov/mob