398 FXUS64 KMEG 060311 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1011 PM CDT Sat May 5 2018 .UPDATE...Several ASOS/AWOS observations across portions of West Tennessee and Northeast Mississippi indicate visibilities dropping rapidly, especially near the Tennessee River. As a result, a Dense Fog Advisory was issued for the remainder of tonight until 9 AM CDT Sunday morning. Will continue to monitor trends and expand the advisory if conditions warrant. CJC && .PREV DISCUSSION... /issued 824 PM CDT Sat May 5 2018/ DISCUSSION...Surface analysis this evening places a weak cold front over portions of Middle Tennessee and Alabama. Regional WSR-88D radar trends have indicated a substantial decrease in the coverage of showers and thunderstorms across the Mid-South this evening as a mid-level trough begins to push east across the Tennessee Valley and the loss of daytime instability. As of 8 PM CDT, temperatures across the forecast area are already in the 60s with temperatures gradually beginning to approach dewpoints. Clear skies, light to nearly calm winds, some radiational cooling and afternoon/early evening rainfall will be conducive for the formation of fog for the remainder of the night into Sunday morning. Will be closely monitoring trends for a potential issuance of a Dense Fog Advisory, especially across portions of West Tennessee and Northeast Mississippi near the Tennessee River. Will update forecast to remove rain chances, move up timing of the development of fog and adjust any other elements as needed to account for the latest trends. Updated grids will be available shortly. CJC PREV DISCUSSION... /issued 625 PM CDT Sat May 5 2018/ UPDATE... Updated to include the 00z aviation discussion. PREV DISCUSSION... /issued 301 PM CDT Sat May 5 2018/ DISCUSSION... Latest radar images show redevelopment of scattered showers and thunderstorms roughly along the Mississippi River thanks to the upper trof that is moving through the region. These showers and thunderstorms will gradually shift south and east into the early evening hours. Expect all convection to be gone by 8-10 PM. Fog may develop after midnight across areas along and east of the Mississippi River. The weather pattern through at least Thursday of next week looks active as the Mid-South will remain in northwest flow aloft. As a result, off and on periods of showers and thunderstorms will occur through period as several shortwaves move through the northwest flow and/or weak cold fronts push southward into the area. It's almost easier to talk about the dry periods since there are fewer to talk about. Expect Sunday morning to be dry across the Mid-South. By the afternoon, thunderstorms will start developing across Northeast Arkansas and the Missouri Bootheel as a shortwave moves into the region. The chances for showers and thunderstorms associated with the shortwave will shift south and east across the rest of the CWA during the evening hours on Sunday. Meanwhile, some redevelopment will occur near the AR/MO and TN/KY border during the evening as a weak cold front begins to push into the area. Chances for showers and thunderstorms associated cold front will shift south during the overnight hours into Monday as the front passes through the area. Drier air will then begin to filter into the area for Monday night as SFC high pressure located over the Great Lakes builds into the area. The dry conditions will continue into Tuesday. However by Tuesday Night, chances for showers and thunderstorms will begin to occur across Eastern Arkansas as another upper trof begins to push into the region. Chances for showers and thunderstorms may increase Wednesday through Thursday as the broad upper trof moves over the area. By Friday, the upper flow becomes more zonal thus expect a dry period to occur into the beginning part of the weekend. Expect highs to be back into the lower to mid 80s for tomorrow. However, temperatures will return to being more seasonable Monday through Wednesday with readings in the mid 70s to lower 80s. By the end of next week, highs will begin climbing into the mid to upper 80s as SFC winds turn around to the southwest. KRM && .AVIATION... /00z TAFs/ The line of storms across north MS will continue to gradually weaken over the next few hours as it shifts south and instability decreases. Generally dry conditions are anticipated overnight with clearing skies. This will allow fog to develop across portions of the Mid-South, namely at KMKL and KTUP. Otherwise, expect light and variable winds, becoming northwesterly by mid-morning. Dry weather will persist through much of the day, but a few afternoon showers and thunderstorms are possible across northwest AR and the MO Bootheel, spreading south during the evening hours. Johnson && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...Dense Fog Advisory until 9 AM CDT Sunday for Alcorn-Prentiss- Tippah-Tishomingo. TN...Dense Fog Advisory until 9 AM CDT Sunday for Benton TN-Carroll- Chester-Crockett-Decatur-Fayette-Gibson-Hardeman-Hardin- Haywood-Henderson-Henry-Madison-McNairy-Obion-Weakley. && $$