Forecast Discussion
000 FXUS64 KMEG 110439 AAA AFDMEG Area Forecast Discussion...UPDATED National Weather Service Memphis TN 1139 PM CDT Fri Jul 10 2020 .UPDATE... Updated for 06Z Aviation Forecast Discussion below. && .PREV DISCUSSION... /issued 900 PM CDT Fri Jul 10 2020/ DISCUSSION...00Z upper air analysis and evening GOES-16 Satellite trends indicate an upper level ridge axis centered over the Southwest United States with the Lower Mississippi Valley remaining on the eastern periphery of this ridge axis. Rain free conditions persist into this evening with temperatures as of 8 PM CDT in the upper 70s to middle 80s. Rain free weather is expected to persist into the remainder of the night with the current forecast on track. CJC PREV DISCUSSION... /issued 353 PM CDT Fri Jul 10 2020/ DISCUSSION... A hot and dry afternoon across the Mid-South for the first time in awhile. Latest GOES east visible imagery shows a mature MCS near the ArkLaTex, with associated high cirrus spilling into the Mid-South from the west. Temperatures range from the upper 80s across the north to lower 90s further south. Heat index values have remained at 100 or below for much of the day. Northwest winds have advected in a slightly drier airmass across the north, characterized by upper 60s dewpoints. This drier airmass will allow areas across west Tennessee and northeast Mississippi to fall into the mid to upper 60s overnight. Further west, including the Memphis Metro, lows will likely stay in the lower 70s. By late tonight, a MCS is forecast to develop over Missouri and track SSE into the Lower Mississippi Valley by late tomorrow morning. CAMs are still struggling with the exact location of this system as it translates downstream in to our area. Nonetheless, have latched onto the HRRR`s general location and timing of the system for this package. It appears that an MCV or remnant outflow will move into northeast Arkansas as early as 11AM tomorrow and push through the area through the afternoon hours. The instability mass field will vary greatly tomorrow afternoon, as drier air will still reside over portions of west TN and NE MS. However, along and west of the MS River, a hefty amount of CAPE will exist. Values may exceed 3000 J/kg of SBCAPE. Storm mode will be outflow dominant clusters, as only 20 kts of shear will be on hand. If an organized cold pool can maintain, a more widespread risk of damaging winds can be expected. The Mid-South will remain in northwest flow again tomorrow night. The 18Z HRRR depicts another MCS lining up behind the afternoon convection tomorrow evening. This system will also have the ability to produce instances of damaging winds, if it materializes and pushes through our area. All models suggest this solution, but timing will still need to be sorted out for this period. Nonetheless, will add the mention of strong to severe thunderstorms to the HWO for both Saturday and Sunday. The forecast is still on track for a July heatwave next week. The expansive ridge out west will begin to build into the region early next week. Right now, Monday looks to remain the coolest day with highs only in the lower 90s. However, the ridge axis will become nearly centered over the Lower Mississippi Valley by midweek. Preliminary blended guidance suggests highs in the upper 90s to possibly 100F Wednesday through Friday next week. The combination of highs in the upper 90s and dewpoints in the low to mid 70s, will yield heat index values in excess of 105F. Heat advisories will likely be needed for several days. Guidance trends will need to be watched for Excessive Heat. Some weakening of the ridge is possible by next weekend, which could break the streak of excessive heat. Stay tuned. AC3 && .AVIATION... 06Z TAFs Few changes expected for the overnight periods, with light winds scattered cirrus. For the outer periods of the TAF, 00Z model consensus points toward a later than currently forecast arrival of TSRA chances to after 09Z Sunday at MEM. Timing of convective complexes embedded in northwest flow is typically tricky, and will bear watching through the day Saturday. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$