722 FXUS64 KBMX 062048 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 348 PM CDT Thu Jul 6 2023 ...New LONG TERM... .SHORT TERM... (This evening through Friday) Issued at 159 PM CDT THU JUL 6 2023 Broadly cyclonic flow remains in place over the area south of a large trough over the northern CONUS and Canada, while a subtropical ridge is located near the Arizona/New Mexico/Mexico border region and a weaker ridge is over the Gulf. Various convectively generated/enhanced waves are located in this WNW flow. At the surface, a cold front extends southwestward from northern Quebec, becoming stalled across northern Arkansas. A synoptic surface boundary, apparently a pre-frontal trough, has been moving across the northern and eastern counties this morning resulting in showers and a few thunderstorms which remain ongoing across portions of East Alabama. A well-defined MCV is located over northeast Mississippi. PoPs have been raised especially across the northwest half of the area due to this feature as well as PWATs increasing to around 2 inches. This morning's BMX sounding indicated a PWAT of around 1.73 inches with DCAPE around 800 J/kg. However, mid-levels have likely moistened since then, decreasing DCAPE. This factor combined with modest lapse rates aloft suggests the microburst is mainly in the low category today. There could be some pockets of moderate potential in the far eastern counties where DCAPE is a bit higher. Effective bulk shear was around 25kts this morning but mid-level flow has weakened since then. There could still be just enough mid-level flow for some loosely organized multicells especially near the MCV. Expect strong storms with gusty winds and locally heavy rainfall this afternoon, with a very low but non-zero risk of an isolated severe storm. Heat indices will be in the 100 to 104 degree range. Some activity may linger tonight especially south given the moist air mass and continued disturbances aloft. Will have to monitor for any low cloud/fog development. Overall a similar pattern for tomorrow as PWATs remain near 2 inches, except in the far northern counties where some drier air may move in. Another convectively enhanced shortwave from an MCS that was over Oklahoma this morning will move through. Some areas may need higher PoPs in later updates once there is better agreement on timing and location of this and other waves. Will have to watch an area of increased DCAPE that may move over the area. 32/Davis && .LONG TERM... (Friday night through next Wednesday) Issued at 318 PM CDT THU JUL 6 2023 Not much change from the previous forecast and discussion. With troughing developing over the area this weekend through early next week, several shortwaves will provide increased chances for thunderstorms. Difficult to refine timing details and any severe threat this far out within a northwesterly flow pattern. Will leave threats out of the HWO at this time. 14 Previous long-term discussion: (Friday night through Wednesday) Issued at 350 AM CDT THU JUL 6 2023 The upper level pattern begins to change as we go into the weekend. The troughing to our north begins to deepen in response to the amplifying ridge across the Southwestern CONUS. A shortwave is expected to dig through the Mid-MS Valley during the day Saturday, leading to a cluster of thunderstorms that will move southeastward towards the TN Valley and northern portions of Central AL. There's still a good amount of uncertainty on how the downstream thunderstorm development evolves with this shortwave as the impulse itself ejects northeastward into the Ohio Valley by Saturday night. At the least, we could see increased thunderstorm coverage across the northern portions of the area. This dip in the trough marks a transition to a more northwesterly flow regime where the trough remains across the Eastern CONUS and the ridge to our west becomes more amplified Sunday into Monday. Guidance continues to indicate the potential for another shortwave diving southeastward in this pattern, which could lead to the development of an MCS. This could lead to a severe threat at some point Sunday into Monday, but there are still a lot of questions on the timing and evolution of the system as a whole. There could be yet another shortwave Tuesday or Wednesday as we remain in the the northwesterly flow pattern. Therefore, rain chances and thunderstorms chances each day remain higher than typical for this time of year, but the predictability for any severe threat this far in advance is too low to mention for any specific time period. 25/Owen && .AVIATION... (18Z TAFS) Issued at 1245 PM CDT THU JUL 6 2023 One area of showers and storms currently extends from just east of ANB to east of MGM, and should continue to move east of the terminals. Another area of showers and storms is developing over northeast Mississippi and will southeastward through this afternoon along with additional development due to daytime heating. Best chances for TSRA appear to be at TCL, BHM, and EET where TEMPO groups were introduced. Elsewhere, will amend as necessary. Gusty winds will be possible with any storm. Activity should diminish this evening. Some low clouds and fog appear possible overnight with moist conditions and light winds, but will be dependent on which areas receive rain today. 32/Davis && .FIRE WEATHER... Warm and humid conditions will continue through the weekend. Min RHs will be around 60% each afternoon. Generally light westerly winds will persist. Isolated to scattered diurnal thunderstorm activity will also be possible through the weekend, with more widespread coverage on Sunday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 69 91 68 91 / 30 30 10 50 Anniston 70 91 70 91 / 40 30 10 40 Birmingham 71 92 72 93 / 50 40 10 50 Tuscaloosa 71 92 71 93 / 50 50 20 50 Calera 71 91 72 92 / 50 40 20 50 Auburn 71 89 72 90 / 30 40 20 40 Montgomery 72 93 72 93 / 40 50 20 40 Troy 71 92 71 93 / 30 50 20 40 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...32 LONG TERM....14 AVIATION...32