Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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193 FXUS64 KHUN 191402 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 902 AM CDT Wed Jun 19 2024 ...New NEAR TERM... .NEAR TERM... (Rest of Today) Issued at 902 AM CDT Wed Jun 19 2024 A large area of high pressure continues to be centered off the northeastern seaboard this morning. The western portion of this ridge extends west into the southeastern CONUS. Two boundaries extend southward from a parent low to a storm system moving through southeastern Canada. One is an actual cold front that extends from Wisconsin into central Iowa and western Oklahoma. A weaker boundary is a weak area of convergence extending from Michigan through Indiana and into eastern Arkansas. The strong area of high pressure is forecast in most models to build to the WSW today and towards the Tennessee Valley. This will push the forcing with these features further to the west a bit today. This forcing is mainly producing mid/high cloud cover, but it is thick enough to help dampen the heating today. Do expect some clearing though in our southeastern counties such as Cullman, Marshall, and DeKalb counties later this morning into the afternoon hours. Further west near the AL/MS border, this cloud cover may stay in place or increase some today. Some warm air advection is shown in models today, so that might help push highs everywhere into the 87 to 90 range. However, think some lower 90s could occur in locations that see more sunshine, especially in our southeastern counties. && .SHORT TERM... (Tonight through Friday night) Issued at 355 AM CDT Wed Jun 19 2024 Low temperatures tonight should cool to around 70 as the upper cloud deck slowly thins. With less cloud cover and the upper high heading southward, higher heights/thicknesses and a strong sun should return very warm to hot conditions on Thursday, highs rising into the lower 90s. Thu is also the first day of summer (which starts around 351 PM CDT). Similarly mild conditions Thu night with lows around 70. Friday, the first full day of summer will feel like summer, with highs warming into the low/mid 90s. Corresponding heat index readings should range in the 90s both Thu/Fri. And with high pressure controlling the weather, no precipitation is expected into early Saturday. && .LONG TERM... (Saturday through Tuesday) Issued at 355 AM CDT Wed Jun 19 2024 Guidance from the 0Z suite of global models suggests that a strong mid-level high will be centered across the TN Valley at the beginning of the extended forecast period. However, the subtropical ridge is predicted to retrograde with time this weekend (becoming centered across eastern NM/western TX by 0Z Monday) as a northern stream trough digs east-southeastward along the U.S-Canadian border and into the eastern Great Lakes. Although this evolution will result in a gradual increase in NW flow aloft for the TN Valley, highs will still manage to reach the m-u 90s in the valley on both Saturday and Sunday (u80s in elevated terrain), with heat indices in the 98-102F range as dewpoints creep back up into the u60s-l70s. Due to less of an impact from subsidence, a few afternoon/evening showers and thunderstorms will also return to the southeastern portion of the CWFA Saturday, with a slight increase in spatial coverage for all areas on Sunday. There is reasonably good agreement among the models that a weak cold front (attached to the northern stream trough) will drop southward through the region on Monday, and we have indicated our highest POPs for the extended period on this day. Frontal convection will likely end south of the TN River Monday evening, with the front expected to decelerate and become increasingly oriented in a NW-SE fashion to the west of the forecast area on Monday night/Tuesday. Although a slightly drier airmass may spread into the northeastern portion of the region, there is some uncertainty regarding precisely where the front will lie, and we have kept a low (~20% POP) intact for Tuesday. High temperatures will change little (if at all) in the wake of the front, but may be a couple of degrees cooler due to an increase in cloudiness both days. && .AVIATION... (12Z TAFS) Issued at 610 AM CDT Wed Jun 19 2024 VFR weather continues for the TAF. A flow of high altitude moisture from the tropics will produce broken to overcast conditions today. Otherwise high pressure off of the east coast will bring an ESE flow over the area. Winds around 5kt early should increase into the 10-15kt range from the mid morning through the afternoon, then become light from the ESE tonight. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...KTW SHORT TERM....RSB LONG TERM....70 AVIATION...RSB