Area Forecast Discussion
Issued by NWS Memphis, TN
Issued by NWS Memphis, TN
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957 FXUS64 KMEG 250430 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1130 PM CDT Tue Sep 24 2024 ...New AVIATION... .UPDATE... Issued at 828 PM CDT Tue Sep 24 2024 00Z upper air analysis places an upper-level low near Kansas City, MO. Surface analysis shows a cold front extending from southwest Lower Michigan back through portions of the Mid-South near the Tennessee River. Earlier convective activity is now located east of the area over Middle Tennessee and Alabama. Meanwhile, a few rain showers associated with the upper-level low are occurring across portions of southwest Missouri and northern Arkansas. Latest short-term trends indicate a potential for isolated to perhaps scattered rain showers into early Wednesday, especially west of the Mississippi River. Some adjustments will be made to rain chances to reflect trends. Otherwise, the remainder of the forecast is in good shape. CJC && .SYNOPSIS... Issued at 326 PM CDT Tue Sep 24 2024 An unsettled weather pattern will prevail across the Midsouth during the middle and late portions of the week. A deep upper level low pressure system will move into the Midsouth on Wednesday, and move only little through Saturday. This upper low will bring a rainfall into the upcoming weekend, aided by moisture from the remnants of what will likely become Hurricane Helene. High temperatures will prevail in the 70s Wednesday through Saturday. && .DISCUSSION... (This evening through next Monday) Issued at 326 PM CDT Tue Sep 24 2024 Mid-afternoon GOES water vapor imagery showed a closed upper low developing over the MO River Valley. A belt of strong southwest flow aloft was evident southwest of the low, extending from southern AR through the OH River Valley. SPC Mesoanalysis indicated 45 knots of effective bulk shear across northeast MS, coincident with 2500 J/kg of mixed layer CAPE. A Marginal severe threat will continue across the northeast MS into portions of southern west TN into early evening, before CINH increases and upper level divergence zone shifts east into AL. Tropical Storm Helene is forecast to intensify into a major hurricane on Thursday, before making landfall over the FL panhandle Thursday evening. Thereafter, Helene will make a fairly quick path through the Southeast, aided by southerly flow ahead of the synoptic closed low over the Midsouth. Helene`s remnant low will weaken after passing through the southern Appalachians. But the remnant low and tropical moisture will become entrained into the northern side of the synoptic low by Thursday night. PWAT values near 2 inches and the potential for training will result in a Slight Risk for excessive rainfall over west TN and northeast MS late Thursday into early Friday. The synoptic low will weaken and lift into OH Valley on Sunday. Some light wrap-around showers will be possible Sunday and Monday, mainly to the north and east of Memphis. Thereafter, a northern branch trough will drop from the Canadian prairie into the Great Lakes. There remains some spread in global models with respect to the amplitude of this trough and resultant northwest flow across the Midsouth. But at this time, there appears to be a better than even chance of a cold frontal passage around the middle of next week. Autumn-like dewpoints in the 40s and 50s may be on the horizon. PWB && .AVIATION... (06Z TAFS) Issued at 1125 PM CDT Tue Sep 24 2024 Cut off upper-level low expected to drop into the Lower Mississippi on Wednesday. Patchy fog may develop at MKL overnight and produce temporary MVFR conditions at MKL. Otherwise, VFR conditions should prevail through the period at all sites. VCSH possible at sites beginning late tonight and continuing into Wednesday. Potential for VCTS may exist mid to late Wednesday afternoon. However, confidence in coverage remains to low to include in the 6Z TAF set. Light N/NNE winds through the period. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...PWB AVIATION...CJC