Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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695 FXUS64 KHUN 260141 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 841 PM CDT Sat May 25 2024 ...New NEAR TERM... .NEAR TERM... (Tonight) Issued at 841 PM CDT Sat May 25 2024 Outflow boundaries lifting northeastward have been the driving force behind the sporadic showers and thunderstorms, and the start of the increase in cloud cover this evening. Additional cloud cover will stream in tonight ahead of the Southern Plains system. With light winds in place, low stratus is possible. The convection with this approaching system will reach the region Sunday morning and is expected to generally remain north of the forecast area. Cannot rule out an isolated shower/storm or two, especially in the southern middle TN counties though. Adjusted POPs to accommodate boundary driven convection and hourly temps, otherwise the forecast was on track for tonight. && .SHORT TERM... (Sunday through Tuesday) Issued at 235 PM CDT Sat May 25 2024 Before any mention of severe weather, we must discuss the high temperatures on Sunday! We have a very high chance of seeing our first 90 degree day at several locations. This has been well represented in nearly all of the HIRES models. Unfortunately this will only aid in destabilizing the boundary layer throughout the day tomorrow and prime the environment for overnight storms. After very sunny peak heating hours, CAMS indicate 1500-2000+ J/KG of CAPE lingering into the overnight hours for storms to take advantage of. Our severe threat comes from a surface low pressure system passing just to the NW of us. A broken line of storms will move through the area ahead of an attached cold front Sunday night into Monday morning, bringing all modes of severe weather and warranting a slight risk (2/5) from SPC. As we entered into CAM coverage this morning, models have been very consistent with harsh environmental parameters being present Sunday night. The aformentioned CAPE will support strong updrafts with 50-60+ KTS of bulk shear favoring organized convection and yielding a low but non zero tornado threat. Steep lapse rates from 7-8 C/KM will support a hail threat and the orientation of the line will be very favorable for damaging winds, which will likely prevail as our primary threat. While CAMS have been consistent in showing the line and favorable parameters, they have yet to align on timing. What appears clear right now is that the HIRES models favor a earlier arrival of the line and a faster departure as compared to previously used global models. Current models have the line entering NW AL Sunday night as early as 8 pm but as late as midnight. Current exit times look to be around mid morning on Monday. Timing is one of two aspects we will continue to refine in subsequent forecasts. The second aspect is the potential for scattered storm development ahead of the line. Models have not necessarily picked up on this yet but the environment Sunday afternoon and evening will be supportive of all modes of severe weather should anything develop ahead of the line. After the line exits our area, clear and dry conditions will develop in its wake throughout the day on Monday. These conditions will prevail for the remainder of the short term as high pressure will begin to build in from the NW. Highs will be slightly cooler than Sunday only reaching the mid to high 80s Monday and Tuesday. && .LONG TERM... (Tuesday night through Friday) Issued at 359 AM CDT Sat May 25 2024 Sfc high pressure allows for dry weather to settle over the region through the mid week. Upper level shortwaves will allow a very low chance of showers (10% or less) during this time, however, confidence is low in this occurring. High temperatures during this period are forecast to be in the 80s with overnight lows in the 50s/60s. && .AVIATION... (00Z TAFS) Issued at 649 PM CDT Sat May 25 2024 VFR conditions will prevail through the majority of the TAF period.Fog development is possible and introduced MVFR CIGS ~11-13Z. There is low confidence on when showers and thunderstorms will arrive to the terminals on Sunday so did not include them in this TAF package. Do have confidence however that the best chance for showers/storms will be after this TAF period. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...JMS SHORT TERM....RAD LONG TERM....HC AVIATION...JMS