Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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778 FXUS64 KHUN 121112 AAA AFDHUN Area Forecast Discussion...UPDATED National Weather Service Huntsville AL 612 AM CDT Sun May 12 2024 ...New AVIATION... .NEAR TERM... (Today) Issued at 330 AM CDT Sun May 12 2024 Upper ridging and surface high pressure will continue to keep rain out of the forecast for today. Cloud cover will begin to increase this afternoon as a surface low pressure system moves over the central Plains. Light winds will also become more southeasterly and begin to usher moisture into the Tennessee Valley this evening. As for temperatures, highs this afternoon are expected to reach the upper 70s to around 80 degrees. Overall, no significant weather impacts are anticipated today. Enjoy the day and Happy Mother`s Day! && .SHORT TERM... (Tonight through Tuesday Night) Issued at 330 AM CDT Sun May 12 2024 Upper ridging this weekend will push eastward as an upper trough/cutoff low moves over the Mississippi Valley through the day on Monday. This feature will then continue to progress east over the Ohio Valley through midweek. Meanwhile, a series of shortwaves look to move along the base of this trough (generally over the Deep South and up into our area) Monday night through Tuesday. At the surface, high pressure will be pushed over the eastern seaboard on Monday as a low pressure system over the central Plains traverses the Mississippi Valley and Ohio Valley through midweek. The associated warm front still looks to be to our south by Tuesday morning, but the parent low will then move northeast over the region through the day. Therefore, a portion of our area may be in the warm sector Tuesday afternoon. Overall, anticipating chances for showers to begin to increase area-wide late tonight (20-50% chance). High chances (50-80%) of showers and storms will then comprise most of the day on Monday. Medium to high chances of showers and storms are forecast to continue through Tuesday, with the highest chances Tuesday afternoon (80-100%). Guidance has begun to indicate that instability values will begin to increase Monday night and peak Tuesday afternoon, with instability exceeding 1000 J/kg along with bulk shear around 50 knots. Although, not seeing too much in the way of 0-1 km or 0-3 km SRH at this point. The instability and shear coincides with the trajectory of the aforementioned surface low (with portions of our area in the warm sector Tuesday afternoon). Although, synoptic guidance seems to suggest that the better upper support (more substantial upper shortwaves and upper jet between 60-70 knots) will occur over the northern Gulf coast. Ultimately, we will continue to monitor this system; but, damaging winds, hail, and frequent lightning will all be possible with the storms on Tuesday. SPC has outlooked areas generally southeast of the Tennessee River in a Marginal Risk of severe weather on Tuesday. Additionally, forecast total rainfall at this point ranges between 1-1.5 inches, with locally higher amounts possible. Model PWATs range from 1.3-1.5 inches Tuesday morning through the afternoon, which are between the 75th and 90th percentiles for BMX sounding climatology. Therefore, showers and storms will be efficient rainfall producers and may lead to some minor flooding concerns. WPC has most of our area outlooked in a Marginal Risk of excessive rainfall. Chances for showers and storms will then quickly diminish from southwest to northeast Tuesday night, with low to medium (20-60%) chances Tuesday evening decreasing to low/very low (0-20%) by Tuesday night. As for temperatures, highs will be mild on Monday (upper 60s to lower 70s). It will then be a bit warmer on Tuesday as temperatures top out in the upper 70s to around 80 degrees. Meanwhile, lows tonight will range in the mid 50s to lower 60s. Increasing moisture will result in warmer low temperatures Monday night (in the lower to mid 60s). Lows are then forecast to only drop into the lower 60s Tuesday night. && .LONG TERM... (Wednesday through Saturday) Issued at 330 AM CDT Sun May 12 2024 An upper level low currently over western Colorado will progress eastward, and should be moving over the eastern Ohio River Valley at the start of this period as a weakening trough. The main surface low should be moving over the VA/MD region, while a weaker low and boundary remain over eastern Tennessee. The presence of this front and remaining moisture will help bring isolated to scattered showers and thunderstorms Wed afternoon for the eastern, and much of the central areas. The area of low pressure and moisture should exit further to the east Wed night, and bringing a brief dry period on Thu. Another system nearing the area from the west will bring more shower and thunderstorm chances starting Thu evening over our far western areas, with the activity overspreading the area overnight Thu and on Fri. Have maintained likely (60-70%) rain chances on Fri. Output from some of the medium range guidance, especially the ECMWF/Canadian were hinting that some of the storms Fri afternoon/evening could become strong, with high outflow winds the main threat. Precipitable water amounts at and above 1.5" at this time could lead to locally heavy rain, with localized flooding a possibility. Despite the passage of a frontal boundary early Sat, residual moisture remaining will help continue showers as we close out the week. Clouds and showers on Wed will keep highs in the mid/upper 70s. A return of more sun early Thu and a southerly flow should help push highs into the lower 80s on Thu. Highs around 80 are expected Fri and Sat. Low temperatures in the mid/upper 50s Wed night will moderate into the 60s Thu and Fri nights. && .AVIATION... (12Z TAFS) Issued at 612 AM CDT Sun May 12 2024 No rain is anticipated during the day today and into this evening, but rain chances are expected to increase from the west later tonight. Additionally, MVFR conditions are forecast to develop late tonight into early Monday morning for the MSL terminal. Decreasing CIGs to MVFR will follow for HSV around 12Z as well; however, as this was outside of the forecast period, did not mention in the TAF at this time. Light and variable winds today will become southeasterly through this evening and generally be around 5 knots. Although, winds are expected to begin to increase around 12Z. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...26 SHORT TERM....26 LONG TERM....RSB AVIATION...26