357 FXUS64 KJAN 111539 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 1039 AM CDT Thu Oct 11 2018 .UPDATE... Updated for morning discussion. && .DISCUSSION... Fall has arrived across the ArkLaMiss, at least for now as temperatures this morning dropped into the 50s for the first time since early May. Very pleasant conditions are expected today as temperatures should be in the lower to mid 70s under crystal blue skies. Northerly winds will be a little breezy this afternoon behind yesterday's front but overall conditions should be very nice as we head towards a chamber of commerce type day across the region. /28/ Prior discussion below: Today through tonight: The near term forecast is very straight-forward. Cooler and drier air is advecting southward into the ArkLaMiss region via northerly flow on the back side of weakening Tropical Storm Michael, which is currently moving from Georgia into South Carolina. Given how warm it has been, this air will seem much more fall-like, especially tonight when temperatures drop below 50 for the first time since April at many locations. Much lower dewpoints today and northerly breezes under sunny skies will make for ideal outdoor conditions. /EC/ Late week (Friday) through mid-week next week (Wednesday): The synoptic pattern will consist of remnants of Michael (likely a post-tropical storm moving off the Mid-Atlantic & Atlantic seaboard) while a deeper shortwave trough will be digging into the central Plains. In addition, our area will remain under mostly zonal flow aloft while Tropical Storm Sergio will be making landfall in southwestern Mexico/Baja Peninsula. Due to much drier air (i.e. PWs falling closer to or less than a half inch) & strong surface ridge building through the Plains & mid-Mississippi Valley, expect cooler & much more seasonable fall conditions extending late week into the early weekend. Highs will be near or below normal in most areas in the low-mid 70s while possibly into the lower 80s in the south- southeast Pine Belt & Highway 84 corridor. Due to clouds in the northwest ArkLaMiss Delta, highs could only reach the lower 70s. Friday night could be chilly near or slightly below normal, in the low-mid 50s to possibly upper 40s in the Highway 82 corridor & Golden Triangle region. However, some moisture & clouds could limit overall better radiational cooling. As mid-level ridge builds east across the central Gulf of Mexico, expect increasing low-level thermal temps (i.e. mid-upper teens C. @ 925mb). Expect highs along & south of the I-20 corridor to increase ~5 degrees above normal into the low 80s into late weekend on Sunday. Remnants of Tropical Storm Sergio in the eastern Pacific will gradually be picked up & weaken as it swings through the central Plains & mid-Mississippi Valley. This moisture increase (i.e. 850mb Theta E closer to 330-340K & PWs closer to 1.5-2 inches) will help increase rain chances & clouds into beginning late this weekend & early next week (i.e. late Saturday night through Monday). Global consensus keep most rain & some storm chances along & northwest of the Natchez Trace corridor & especially in the ArklaMiss Delta & Highway 82 corridors. This is out ahead of a trough & front diving down into early next week. Models then seem to struggle exactly how a longwave trough will dig down & if it will phase with a trough over the Desert Southwest into early next week. Due to this, the GFS seems to be prone to higher PoPs into mid-week due to stronger forcing & more continued southwest flow while Euro/Canadian seem to be more in line with less phasing & forcing. Regardless, temperatures will be tough forecast as there could be a sharp temperature gradient. Highs across the ArkLaMiss Delta could struggle to reach the mid 60s or possibly even lower while the rest of the area, especially in the east-southeast, could be into the mid- upper 70s. Due to continued clouds & some continued rain chances, went cooler both Monday-Tuesday in the Delta, especially with such a high standard deviation in ensemble MOS guidance. In addition, PoPs seemed too high & went toward slightly drier, but still some scattered PoPs, into mid-week. These inconsistencies will gradually be ironed out as better consensus is achieved. /DC/ && .AVIATION... 12Z TAF discussion: VFR conditions will prevail through the forecast period. North- northwesterly surface winds will mostly be light, but they will be gusty at times during the heating of the day. /EC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 73 50 76 55 / 0 0 1 3 Meridian 76 49 77 52 / 0 0 1 1 Vicksburg 73 50 76 54 / 0 0 2 4 Hattiesburg 78 52 79 55 / 0 0 0 1 Natchez 73 51 78 57 / 0 0 1 3 Greenville 69 49 71 53 / 0 0 4 4 Greenwood 70 49 72 52 / 0 0 3 3 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ 28