Forecast Discussion
503 FXUS64 KMEG 211734 AFDMEG Area Forecast Discussion National Weather Service Memphis TN 1234 PM CDT Mon Apr 21 2025 ...New AVIATION... .KEY MESSAGES... Updated at 1234 PM CDT Mon Apr 21 2025 - Significant river flooding will continue across portions of the Mid-South through this week. - Showers and thunderstorms will move through the Mid-South today, with a low chance of strong to severe thunderstorms across northeast Mississippi this afternoon. - Unsettled weather will continue throughout the week with multiple rounds of storms possible, especially later this week. && .DISCUSSION... (Today through Sunday) Issued at 315 AM CDT Mon Apr 21 2025 A line of thunderstorms continues to push through the Mid-South early this morning along a weakening frontal boundary. Over the next few hours, this boundary will eventually become stationary across NE MS, keeping showers and thunderstorms in the forecast for much of day with the remainder of the area drying out. While upper-level support is well to our north, most CAMs are bringing a small instability axis up through NE MS by this afternoon. While the threat is very low, this will introduce a conditional threat for a few strong to severe thunderstorms generally around midday into the afternoon hours. Damaging winds and hail (up to quarter size) are the main concern. Shear will likely remain < 30 kts across all heights, so there does not appear to be a tornado threat. Aforementioned frontal boundary will remain stalled over NE MS Tuesday, keeping a chance of showers and thunderstorms around. Quasi-zonal flow aloft will keep us stuck in an unsettled pattern by midweek and continue into the weekend. North MS will have the highest shower and thunderstorm chances Wednesday, with chances expanding northward at times Thursday and into Friday. Weak shortwave will pass through Friday, likely bringing a higher chance of showers and thunderstorms along with it. By the weekend, there begins to be some spread in ensemble guidance with how quickly we will be able to move out of this unsettled pattern, with the ENS favoring a slightly drier solution and GEFS favoring a slightly wetter solution. Really the biggest forecast note for the second half of the week will be our QPF amounts. While QPF amounts are generally in the 1 to 2 inch range across the area, our soils remain very saturated from the heavier rain earlier in the month. This could introduce a least a small threat for additional flooding across the Mid-South, especially across NE AR, the MO Bootheel, and NW TN. Do I think things will get as bad as they were? No. Do I think this will not help our rivers that are already running high? Yes. Something to keep in mind and watch over the next few days. If QPF amounts increase at all, the concern for flooding will likely increase as well. With the unsettled pattern, expect for high temperatures to remain above average in the 80s for most of the Mid-South. && .AVIATION... (18Z TAFS) Issued at 1234 PM CDT Mon Apr 21 2025 VFR forecast through period at all sites except TUP. High pressure is currently making its way in to the region to the north of a stationary boundary located over northeast Mississippi. Areas north of the boundary are to see high clouds and weak northerly/variable winds with some cumulus below 3 kft this afternoon. A few showers may impact MEM tomorrow, but confidence is low in this scenario at this time. TUP is expected still experience rain showers and drops into MVFR this afternoon before prevailing MVFR CIGs and a lull in rainfall in to the overnight hours. A few thunderstorms have been shown in recent CAM guidance across northern MS along the stationary boundary after 06z. However, timing and coverage are still uncertain. So, the PROB30 has been retained from 06z - 12z to cover this uncertainty. Showers associated with any storms may still be present through the end of the period after 12z. && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$ PUBLIC FORECAST...CMA AVIATION...JAB