812 FXUS64 KJAN 091813 AAA AFDJAN Area Forecast Discussion...UPDATED National Weather Service Jackson MS 1213 PM CST Wed Jan 9 2019 .UPDATE... Updated for 18Z aviation discussion && .AVIATION... 18Z TAF discussion: Expect VFR conditions through the afternoon & entire forecast period. Expect skies to remain clear across the area, other than a few high clouds departing near HBG & PIB. Otherwise, north- northwesterly winds will be breezy with sustained winds generally between 10-15mph or so & gusts as high as 20-25mph, with some brief gusts up to near 30mph possible. Expect these gusty winds to wind down around 09/23Z - 10/00Z, becoming lighter around 5-10mph through the overnight hours. Another day of great VFR flight categories can be expected tomorrow, with north-northeast winds but generally lighter than today. /DC/ && .DISCUSSION... Expect a nice & cooler day today as cold air advection continues throughout the afternoon. Only a few high clouds are streaming across the south as the cold front from yesterday continues to progress south over the Gulf of Mexico. Due to strong ~1030-1035mb high pressure & drier air building in (i.e. less than a quarter inch PWs & dewpoints falling in the mid-upper 20s), expect a dry & clear afternoon. With cooler thermal profiles (i.e. ~8-10 deg. C colder @ 925mb), highs will be closer to normal in the mid- upper 50s. Due to a strong pressure gradient, winds could be breezy & help the region mix out well. Due to that, went slightly warmer for highs today, especially across the north, even with much cooler boundary layer temperatures. Also dropped dewpoints due to increased mixing. Otherwise, expect a nice afternoon in store. Updates will be out shortly. /DC/ Prior discussion below: Today and tonight: A much cooler morning is ongoing as temperatures are running around 5-15 degrees degrees cooler than 24 hours ago. Dry weather is expected today as surface high pressure filters south into the region behind yesterday's cold front. North winds will be slightly breezy today as the pressure gradient will remain tightened early but should eventually relax later this afternoon and evening. Highs today will top out in the lower 50s across the Highway 82 corridor to the mid and upper 50s across the Highway 84 corridor under plenty of sunshine. With a relaxing pressure gradient overnight and clear skies in place, temperatures will drop into the upper 20s and lower 30s areawide. /28/ Tomorrow through Tuesday: Ridging aloft and at the surface will be in place across the Mississippi River Valley at the start of the period tomorrow. Dry weather will persist through Friday morning before the next storm system brings rain back to the area. Clouds will gradually increase in coverage from the west on Thursday with seasonably cool high temperatures in the mid to upper 40s north of I-20 and low 50s to the south. A southern stream shortwave trough will be ejecting out of the Desert Southwest and into the Southern Plains on Friday morning. An evolving coupled jet structure will help foster upstream precipitation development along the Red River Friday morning into the afternoon hours. This activity will gradually spread east with the leading edge of precipitation encroaching on the ArkLaMiss Delta Friday afternoon. Cloud cover will increase from the west across the area on Friday which will help keep high temperatures cooler in the mid 40s to low 50s with the coolest values over the Delta where wetbulbing effects will be more pronounced. The bulk of the rainfall will move through the area Friday night through Saturday as the main shortwave trough swings through the Lower Mississippi River Valley. Surface cyclogenesis will take place Friday night over eastern Texas with the low deepening as it tracks along the I-20 corridor in the vicinity of the baroclinic zone. A strengthening low level jet will aid in robust isentropic ascent above the surface stable layer. This will also be occuring in the presence of deep layer forcing and respectable Q vector convergence resulting in widespread rainfall. Event total rainfall amounts will range from 0.25-0.5" across the Pine Belt with higher amounts of around 1" further north along the Hwy 82 corridor. The stratiform nature of the rain and lack of higher rainfall rates will preclude any flash flooding concerns. Rain will end from west to east Saturday night and is expected to be clear of the area by sunrise Sunday with the only exception being the potential for a few isolated lingering showers. Blended temperatures heavily towards raw guidance which resulted in daytime highs on Saturday in the low 60s across the Pine Belt and upper 40s along the Hwy 82 corridor. Drier but chilly weather will return behind the cold frontal passage Saturday night with cold air advection continuing through Monday. High temperatures on Sunday and Monday will be in the 40s for much of the area. The airmass will modify by Tuesday as the cold air advection shuts off with highs returning to the 50s. Model guidance starts to diverge by the middle of next week, however conditions are expected to remain dry before the southern stream becomes active again by late week. /TW/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 30 50 31 50 / 0 0 0 0 Meridian 28 50 28 51 / 0 0 0 0 Vicksburg 30 49 37 50 / 0 0 0 0 Hattiesburg 32 53 31 55 / 0 0 0 0 Natchez 30 52 36 52 / 0 0 0 0 Greenville 30 46 34 44 / 0 0 0 0 Greenwood 27 48 31 47 / 0 0 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ DC