Area Forecast Discussion
Issued by NWS Huntsville, AL
Issued by NWS Huntsville, AL
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537 FXUS64 KHUN 111144 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 644 AM CDT Tue Jun 11 2024 ...New AVIATION... .NEAR TERM... (Today) Issued at 408 AM CDT Tue Jun 11 2024 Northwesterly flow aloft of 35-45 knots continues across the TN Valley early this morning, enabling scattered high-level clouds to spread southeastward over the region. Although the translucent cirrus layer has had little impact on radiational cooling, a light NNE wind has, with temperatures currently in the m-u 50s where calm flow is observed. Patchy fog will be possible in these locations through 12-13Z. Over the course of the day, mid-level winds will weaken considerably as a trough to our northeast begins to lift out into the western North Atlantic and a deamplifying shortwave ridge spreads eastward in advance of a weak southern stream disturbance that will track through the Red River Valley of OK/TX. In the low-levels, light NNW winds will continue to advect a slightly cooler/drier airmass southward into the region as a surface high translates southeastward from the western Great Lakes into the Upper OH Valley. With abundant sunshine, highs will once again range from the m-u 70s atop the Cumberland Plateau to the lower 80s in the valley. && .SHORT TERM... (Tonight through Thursday night) Issued at 408 AM CDT Tue Jun 11 2024 Latest short term model consensus suggests that the southern stream disturbance (noted above) will spread southeastward into the central Gulf of Mexico over the course of the short term period, as a strong 500-mb subtropical ridge (initially centered across northern Mexico) builds eastward across the southern Plains and southeastern CONUS. Subsidence beneath the expanding mid- level anticyclone will contribute to further drying of profiles aloft, and with only gradual modification of boundary layer dewpoints anticipated (given the projected orientation of broad surface ridge across the region), dry conditions will continue along with a notable warming trend in afternoon high temperatures, which should reach the u80s-l90s by Thursday. && .LONG TERM... (Friday through Monday) Issued at 408 AM CDT Tue Jun 11 2024 The center of the mid-level high is predicted to become centered directly across the TN Valley by Saturday, with the warming trend continuing as mostly sunny skies during the afternoon will support highs in the mid 90s on Friday and mid/upper 90s on Saturday (but roughly 5-10 degrees cooler both days atop the Cumberland Plateau). Unfortunately, it appears as if low-level moisture will begin to pool ahead of a weakening cold front that will drift southward into the TN Valley before stalling on Friday afternoon/evening as the parent surface low ejects northeastward across Quebec, and the increase in dewpoints will result in heat indices in the 95-99F range Friday and 98-102F range Saturday. The 500-mb high will begin to shift east-northeastward into the NC/VA vicinity on Sunday and Monday, allowing for a gradual increase in deep-layer SSE flow across the TN Valley by early next week. Although this configuration will eventually contribute to gradual moistening of the atmospheric column (and a subsequent increase in clouds and showers) this will likely not occur by Sunday, and highs are forecast to reach the m-u 90s, with heat index values in the 100-105F range. We have indicated a low (20-30%) POP for showers and thunderstorms returning to most of the region Sunday night/Monday, and have indicated lower afternoon temps on Monday as a result of this. However, if the subtropical ridge remains more influential (as indicated by several global models), then the hot/dry pattern may continue for several additional days next week. && .AVIATION... (12Z TAFS) Issued at 644 AM CDT Tue Jun 11 2024 No changes to previous aviation forecast reasoning, as VFR conditions will continue, with a few high-level clouds expected at times and a few lower-level Cu possible during the peak of the diurnal warming cycle this aftn. Light NNE sfc winds will back to NNW and increase to 5-10 kts 16Z, before becoming lgt/vrbl late this aftn. Although non-zero, the risk for BR/FG development at the two terminals early Wednesday morning appears rather low attm. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...70/DD SHORT TERM...70/DD LONG TERM...70/DD AVIATION...70/DD