647 FXUS64 KBMX 090504 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1204 AM CDT Tue Oct 9 2018 .UPDATE... Aviation Discussion. && .SHORT TERM... Through Tonight. Stronger easterly surface winds in advance of Tropical Cyclone Michael have brought some cooler air into central Alabama this afternoon, although temperatures are still running well above normal. Some banded convection has developed over south Alabama in a zone of weak convergence. This activity will likely dissipate with loss of daytime heating. East winds 5-10 mph overnight will help provide some relief to the warm temperatures, and low clouds will likely form later tonight as Atlantic moisture advects into the region. 58/rose .LONG TERM... Tuesday through Thursday. The weather for central Alabama is looking fairly active for mid week. The quietest and warmest conditions are expected on Tuesday with afternoon/evening isolated to scattered showers and thunderstorms, particularly in the south/southeast as deep layer moisture values increase. These increased dewpoints and PWs will continue from here as two atmospheric features moving into the region will keep rain and thunderstorm chances elevated from a period extending from early Wednesday to late Thursday. A vertically stacked ridge of high pressure will remain off the East Coast and continue easterly to southeasterly flow ahead of an approaching trough axis and frontal boundary moving in from the Great Plains on Wednesday. This front should be positioned somewhere along the Mississippi River by Wednesday afternoon with a large surface anticyclone behind it across the Plains. Between the front/amplified trough to the west and the ridge to our east enters affects from what is forecast to be Hurricane Michael. The latest NHC advisory (as of 4am CDT Monday) has Michael as a high- end Tropical Storm with likely transition to a Hurricane later today. This increase in intensity came as NOAA aircraft reconnaissance found pressure decreases to ~983 mb and maximum sustained winds of 70 mph, just below hurricane status early Monday morning. Despite some lingering wind shear, deep convection around the center of circulation continues to show strengthening and organization on GOES-16 infrared products. Environmental conditions are expected to become even more favorable for intensification over the next 48 hours as the storm moves northward into warm Gulf waters. Though uncertainty still exists as to the rate/magnitude of strengthening, Michael is forecast to be at or near Major Hurricane strength when it reaches the northeastern Gulf of Mexico Tuesday night and into Wednesday. Regardless of classification, effects from Michael are currently forecast to remain primarily in our most southeastern counties from Wednesday through Thursday as heavy rainfall (3-4" with locally higher amounts) and wind gusts 20-30mph are possible. In addition to tropical moisture moving into the region, showers and thunderstorms are also possible across the majority of the forecast area and forcing from the frontal boundary helps enhance lift. This forecast currently places PoPs from 60-70% through early Wednesday afternoon to an increase of 70-90% that evening with focus in the southeast. Will carry high chance PoPs through Thursday morning to account for vicinity effects and areas of rain on the western portion of Michael's circulation. By Friday morning, drier air via frontal passage will have worked in from the west helping to move the remaining tropical moisture off to the east. Have no mentionable rain chances after 12Z Friday at this time. Friday through Sunday. After frontal passage takes place on Friday, much improved weather conditions will move into our forecast area. This front should not only bring drier air, but a much cooler airmass as well. High temperatures are now forecast to be in the lower 70s in the northwest to the low 80s in the southeast on Friday. This temperature distribution will continue through the rest of this forecast period and continue slight decreases. Overnight lows are expected to drop to the low to mid 50s overall, with some in the far northwest seeing upper 40s perhaps. Fog could be an issue on mornings as cold air advection moves over recently saturated soils. Forecasts with regards to Michael will continue to evolve as newer data and guidance become available in future cycles. We'll continue to monitor these changing conditions today as NHC also provides updated forecast and continues NOAA aircraft reconnaissance flights. 40/Sizemore && .AVIATION... 06Z TAF Discussion. Mostly clear skies across the area tonight, with a plume of high clouds just to our east associated with Gulf moisture advecting northward. MVFR cigs will spread across portions of the area due to moist easterly low level flow. Expect these clouds to slowly lift Tuesday morning, but remain at MVFR heights. Another afternoon isolated to scattered showers are possible Tuesday. With uncertainty in coverage, will hold off for now before adding SHRA to the forecast. Winds will remain out of the east to southeast through the period. Through tonight, winds will be 5-8kts, increasing by mid day to around 12kts with gusts to 20kt through the afternoon. 14 && .FIRE WEATHER... An increase in moisture and rain chances through Thursday as we monitor a tropical system that will impact most of the area with generally rain and possibly some stronger winds in the southeast. Best rain chances will be Wednesday afternoon through Thursday morning. Any morning fog will be quite localized and limited to the immediate areas around bodies of water this morning and Tuesday morning. Winds look to increase area wide on Wednesday so fog should be limited at best. Despite the warm and dry conditions, afternoon minimum RH values remain above critical values. No fire weather concerns are expected. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 68 84 71 83 67 / 10 20 40 70 80 Anniston 70 85 71 84 69 / 10 20 40 70 90 Birmingham 71 85 73 84 69 / 20 20 40 70 80 Tuscaloosa 72 87 74 84 69 / 20 20 40 70 70 Calera 70 83 72 82 68 / 20 20 40 80 80 Auburn 70 82 72 82 70 / 20 30 40 80 90 Montgomery 72 86 74 84 71 / 20 30 30 90 80 Troy 71 85 73 84 70 / 20 40 30 90 80 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$