Area Forecast Discussion
Issued by NWS Memphis, TN
Issued by NWS Memphis, TN
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694 FXUS64 KMEG 051748 AAA AFDMEG Area Forecast Discussion...UPDATED National Weather Service Memphis TN 1248 PM CDT Sun May 5 2024 ...New AVIATION... .UPDATE... Issued at 954 AM CDT Sun May 5 2024 Currently dry conditions across the Mid-South won`t last much longer with showers and thunderstorms increasing from southwest to northeast throughout the day. A shortwave trough is moving across the Southern Plains this morning with large scale forcing for ascent overspreading the region. Lift may be further enhanced as a mesoscale convective vortex (MCV) from overnight convection in the Southern Plains moves across the Arklatex. Temperatures are generally in the low/mid 70s across the CWA with dewpoints in the mid/upper 60s. Ongoing convection over AR will lift northeast this morning, reaching the Memphis area by 2-3 PM with occasional showers and thunderstorms possible throughout the evening and into the early morning hours. Additional diurnal heating will destabilize the boundary layer with MLCAPE of 1000-1500 J/kg this afternoon. Mid-level lapse rates are rather weak at 6.5 C/km and really aren`t expected to steepen this afternoon, generally limiting hail size to marginally severe criteria (1" or less). Deep-layer shear is relatively weak at this time, but will increase this afternoon as a mid-level jet streak approaches the region. This will raise effective bulk shear to 30-35 kts. The combination of these ingredients will likely lead to largely multicellular convection with the potential to produce damaging wind and marginally severe hail. Low-level shear remains rather weak and will keep the tornado potential low. MJ && .SYNOPSIS... Issued at 430 AM CDT Sun May 5 2024 An active pattern is expected across the Mid-South this week with several rounds of showers and thunderstorms beginning mainly this afternoon and continuing into Thursday. A few strong to severe thunderstorms are possible this afternoon with damaging winds and large hail as the threats. Additional severe weather is possible Tuesday and Wednesday. Temperatures will remain above normal through mid-week with highs mainly in the 80s with lows in the 60s and 70s. Cooler temperatures and drier weather is anticipated for next weekend. && .DISCUSSION... (Today through Saturday) Issued at 430 AM CDT Sun May 5 2024 GOES-16 Water Vapor satellite shows a mature MCS located across Texas early this morning. This convective activity is associated with a mid-level shortwave trough moving through the Southern Plains. Meanwhile, mostly clear skies and a nearly saturated boundary layer is resulting in some patchy fog at times mainly across portions of West Tennessee near the Tennessee River. Temperatures as of 3 AM CDT are in the 60s. Strong to severe thunderstorm potential through mid-week is the predominant concern in this morning`s forecast issuance. Short-term models indicate the aforementioned mid-level shortwave will move through the Lower Mississippi Valley today. Shower and thunderstorm chances will gradually increase throughout the day with the best chances occurring this afternoon into tonight. Surface-based CAPE values increasing to between 1500-2000 J/kg and 0-6 km Bulk Shear values between 25 to 30 kts support the potential for a few strong to severe thunderstorms this afternoon with damaging winds as the primary severe weather threat. Poor 700-500 mb lapse rates may mitigate the severe weather threat to an extent. Mid-range models continue to advertise a greater potential for severe thunderstorms Tuesday and especially Wednesday. Showers and thunderstorms are expected to develop upstream across western Missouri and Arkansas Monday night and weaken as they begin to move into the Mid-South towards Tuesday morning. Moderate surface-based instability combined with ample shear and moderately-steep to steep mid-level lapse rates will support strong to severe thunderstorms where redevelopment occurs. Some model differences still remain with the placement of a surface low over the Middle Mississippi Valley on Wednesday. Nonetheless, moderate to strong instability combined with deep layer shear should be more than sufficient for severe thunderstorms on Wednesday as a cold front approaches the Mid- South. Large hail, damaging winds, and tornadoes are possible. Cooler and drier air will filter in to the region by the end of the week with temperatures falling slightly below normal for early May. CJC && .AVIATION... (18Z TAFS) Issued at 1248 PM CDT Sun May 5 2024 Primary forecast concern remains timing of TSRA. At 1745Z, KNQA radar showed widespread -SHRA and embedded TSRA over eastern AR and northwest MS near CKM. This activity will take a couple hours to translate east with the parent shortwave, but additional development will be possible to the east as temperatures warm. Overall, few changes from the earlier TAFs. CAMs and TCF point toward a modest bump in TSRA chances late this evening, as a secondary midlevel trough axis rotates through. Better than even chances exists for IFR/low MVFR toward sunrise, in the wake of this feature. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...CJC AVIATION...PWB