Scientific Forecaster Discussion
000 FXUS64 KMEG 171129 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 629 AM CDT Wed Jul 17 2019 .UPDATE... See the 12z aviation discussion. && .PREV DISCUSSION... /issued 255 AM CDT Wed Jul 17 2019/ DISCUSSION... Another round of showers and isolated thunderstorms associated with the remnants of Barry is affecting much of North Mississippi at this time. Today should be the last day of increased chances for showers and thunderstorms. The ongoing current convection will continue across much of the day over areas of West Tennessee and Northeast Mississippi. In addition, several CAM models show development of showers and thunderstorms across Southern Missouri that will move southeastward into Northeast Arkansas and the Missouri Bootheel during the afternoon hours. The convection will arrive in the Memphis Metro area during the late afternoon/early evening hours before dying out across Northeast Mississippi just after sunset. Some of these storms could be strong to severe. This convection could also play havoc with high temperatures thus heat indices might not reach Heat Advisory criteria. That being said, a lot will depend on how high the dewpoints climb and the timing of the convection so will keep current Heat Advisory as is. Convection may continue during the overnight hours near the Tennessee River. Otherwise, the Mid-South should begin to dry out as an upper ridge builds over the area. The ridge is not quite as strong as models had been showing several days ago thus can't rule out isolated showers and thunderstorms occurring at any given time Thursday into Friday. Temperatures will climb back into the lower 90s. With the recent rainfall, conditions should be very humid. The combination of the humidity and high temperatures should allow heat index values to reach near or above 105 degrees over much of the area both Thursday and Friday. As a result, a Heat Advisory may be needed for much of the area. The hot and humid conditions will continue into the weekend. Although chances for showers and thunderstorms will begin to increase as the ridge begins to retrograde back to the west and believe it or not moisture from Barry comes back around and into the Southeastern United States. Best chances for rain will occur over Northeast Mississippi. Elsewhere across the CWA, Heat Advisories will likely need to be continued. A cold front will move into the Mid-South Monday into Monday Night. The front will bring relief from the hot and humid conditions, but will also bring an increased chance for showers and thunderstorms. Lingering convection may continue across North Mississippi on Tuesday from the departing front. Otherwise, expect beautiful conditions across the rest of the CWA with highs in the mid 80s and lower humidity. KRM && .AVIATION... /12z TAFs/ Thunderstorms will continue over northeast MS over the next 1-2 hours with more scattered diurnal convection this afternoon. Confidence is lower than previous days that TS will affect forecaster terminals, but VCTS was carried at all sites this afternoon. MVFR/IFR ceilings this morning will gradually improve with VFR conditions expected by mid/late morning outside of convection. Expect storms to dissipate this evening with generally dry weather overnight. If clouds clear out, there may be some patchy fog tonight, but will watch how things evolve before including in the TAF. MJ && .MEG WATCHES/WARNINGS/ADVISORIES... AR...Heat Advisory from noon today to 8 PM CDT this evening for Clay- Craighead-Crittenden-Cross-Greene-Lee AR-Mississippi- Phillips-Poinsett-St. Francis. MO...None. MS...Heat Advisory from noon today to 8 PM CDT this evening for Coahoma-DeSoto-Panola-Quitman-Tallahatchie-Tate-Tunica. TN...Heat Advisory from noon today to 8 PM CDT this evening for Fayette-Shelby-Tipton.