Area Forecast Discussion
Issued by NWS Memphis, TN
Issued by NWS Memphis, TN
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141 FXUS64 KMEG 060421 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1121 PM CDT Sun May 5 2024 ...New AVIATION... .SYNOPSIS... Issued at 232 PM CDT Sun May 5 2024 Showers and thunderstorms will affect the Mid-South through tonight with more isolated activity on Monday. A few strong to severe storms possible. Another round of storms will be possible late Monday night and Tuesday with a stronger system forecast to affect the region Wednesday. Cooler and drier conditions are expected Friday into the weekend. && .DISCUSSION... (This evening through next Saturday) Issued at 232 PM CDT Sun May 5 2024 A shortwave trough is moving across the Ozarks this afternoon, enhancing large-scale forcing for ascent across the region. A northwest-southeast oriented band of showers and thunderstorms will continue to lift poleward across the area through 00z (7 pm), with more scattered convection in its wake this evening and overnight. A few strong to severe thunderstorms are possible with this activity, with the primary concern being damaging wind. Hodographs lengthen tonight as the low-level flow increases, but the nocturnal boundary layer is likely to become capped, resulting in mostly elevated storms within a few hours of sunset. Lingering showers are expected tomorrow morning, mainly east of the MS River followed by a midday lull as shortwave ridging develops over the region. However, there is a potential for isolated showers or thunderstorms late tomorrow afternoon as the next approaching waves interacts with residual moisture and warm surface temperatures. Convection will develop upstream over KS/OK Monday afternoon ahead of a cold front. Storms are expected to grow upscale into a linear MCS, weakening early Tuesday morning as they approach the Mid- South. The Day 2 SPC Outlook extended the marginal risk east to account for this activity, but confidence is low that it will maintain its intensity into the Mid-South. Nonetheless, a few strong storms appear to be possible late Monday night. The upper- level shortwave axis will swing across the area early Tuesday but broad west- southwest flow aloft will likely maintain at least weak synoptic forcing associated with embedded perturbations within the mean flow. Diurnal destabilization is anticipated after morning convection which should lead to additional development during the afternoon. Multicellular convection looks to be the primary mode, resulting in a damaging wind threat. A more robust system looks to affect the region Wednesday. A Rex Block develops over the western CONUS with a broad trough over the Plains. A strengthening subtropical jet will develop over the Lower MS Valley, enhancing winds aloft (and deep-layer shear). This jet will also enhance lift within the left exit region, perhaps coupling with the right entrance region of the polar jet over the northern OH Valley. The amount of synoptic forcing for Wednesday will partially depend on the timing of any shortwave troughs rotating around the base of the main trough. The global ensembles maintain fairly strong agreement on the evolution of this pattern with the best lift during the afternoon and evening. Parameter space is concerning regarding the severe weather potential with the joint probability of at least 1500 J/kg of SBCAPE and 40 kts of deep-layer shear at or above 70% along and north of I-40 with decreasing probability to the south south (weaker shear). The CSU machine leaning probabilities for severe weather are ominous and the Craven-Wiedenfeld Aggregate Severe Parameter (CWASP) is well into the 70s (and even 80s in some areas). The big question is whether or not the large scale forcing and diurnal heating will be sufficient to break the mid-level capping inversion. Stay tuned. Rain chances linger through Thursday but drier conditions will advect into the region behind the departing trough as we approach the weekend. The weakening Rex Block will maintain a trough over the eastern CONUS. The NAEFS mean 500 mb heights are in the 10th percentile this weekend, implying below normal temperatures across the Mid-South. This is reflected in the current forecast with highs in the mid 70s and lows in the low/mid 50s. Generally dry weather is anticipated Friday and Saturday, but we`ll have to keep an eye on the potential trough on Sunday. MJ && .AVIATION... (06Z TAFS) Issued at 1113 PM CDT Sun May 5 2024 A shortwave is shifting across the Middle Mississippi River Valley. Persistent showers and thunderstorms are approaching MEM and will likely remain in the airspace for the next 2-3 hours. Storms should be weakening as they approach MKL between 08-80z. Cigs are expected to lower to IFR levels behind the line with additional thunderstorm development possible through the night. We should see a bit of a break in the morning before additional convection develops tomorrow afternoon. Prevailing winds will remain from the south to southwest generally 5-10kt through the TAF cycle, although brief gusts are possible in association with any thunderstorms. Showers and thunderstorms should taper off after sunset. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...MJ AVIATION...JDS