Area Forecast Discussion
Issued by NWS Shreveport, LA
Issued by NWS Shreveport, LA
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894 FXUS64 KSHV 182223 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 523 PM CDT Wed Sep 18 2024 ...New AVIATION... .SHORT TERM... (This evening through Thursday Night) Issued at 205 PM CDT Wed Sep 18 2024 Water vapor imagery this afternoon nicely depicts a longwave trough over the Western half of the CONUS, with a closed low over the Northern Rockies and the Central CA Coast, while downstream of this longwave feature extends a ridge of high pressure from the Southern Plains N/NE into the Great Lakes region and Ontario. A closed area of low pressure then exists downstream of the ridge over the Carolinas and SE. In the lower levels, an expansive area of high pressure extends influence across the NE, the Midwest and towards the Central and Southern Great Plains. Weak troughing continues over the SE, with an area of low pressure off the NC Coast and Delmarva vicinity, with a cold front near the front range of the Rockies associated with an organized cyclone over MT. Quiet conditions are the rule across the Four State region this afternoon provided the influence of high pressure both at the surface and aloft described above. After some patchy morning fog, a nice cumulus field has developed this afternoon. Clouds will continue into the evening before dissipating and possibly yielding the SE advection of some cirrus clouds into the overnight period. Given increasing subsidence aloft and generally better solar insolation, high temps will top off a few degrees warmer than the previous few days for most locations. Patchy fog will then redevelop overnight tonight into early Thursday given limited scouring of low level moisture underneath of the upper level ridge. The overall pattern will feature a slight amplification of the upper level ridge over the Southern Plains and ArkLaTex regions as the aforementioned closed low off the central CA Coast digs SE towards the Great Basin. The increase in subsidence aloft resulting from this will yield partly to mostly sunny skies and another slight increase in afternoon temperatures into the lower 90s. Another round of patchy fog is likely again Thursday night into Friday morning, however, expect coverage to decrease as compared to previous mornings. Kovacik && .LONG TERM... (Friday through next Tuesday) Issued at 205 PM CDT Wed Sep 18 2024 The long term forecast period will feature a continued ridge of high pressure over the Southern Plains and Midwest, with an open wave trough along the Eastern Seaboard and a closed low progressing towards the desert SW from S CA. With the continued upper level ridge influence over the ArkLaTex, afternoon temperatures will remain hot, with Friday afternoon likely to be the hottest day of the week for many given the ridge will likely be at its maximum intensity and have its best influence over the region. By the weekend, the large scale pattern will become more progressive, with the previously mentioned closed low over S CA finally moving into the desert SW, causing a slight eastward shift in the downstream ridge axis. This shift will not be not be enough to cause a marked change in expected weather conditions, with yet another hot afternoon in the low 90s expected under mostly sunny skies. On Sunday, ensemble means and WPC cluster solutions continue to agree upon the NE lift of the desert SW trough towards the Southern and Central Rockies. This is likely to induce sfc cyclogenesis on the leeward side of the Rockies near the OK panhandle or across Eastern CO/Western KS. An associated frontal boundary will then develop to the S of the sfc low and attempt to approach northern zones by the end of the weekend/early next week. Given the projected eastward track of the sfc low, it currently seems reasonable to assume to at least a partial fropa can be anticipated across the area. Currently not seeing a distinct change in the airmass in the NBM guidance at present time, but this will be monitored in future model runs. With the presence of at least a weak boundary in the vicinity, low-end rain chances are likely to materialize near the end of the forecast period. Kovacik && .AVIATION... (00Z TAFS) Issued at 518 PM CDT Wed Sep 18 2024 For the 19/00Z TAF update, light winds will dictate a familiar pattern under surface ridging with MVFR/IFR vis/cigs likely airspace-wide at 19/09-17Z due to low cloud/FG development. VFR vis/cigs are likely before and after this timeframe with light easterly winds returning by the end of the period. /16/ && .PRELIMINARY POINT TEMPS/POPS... SHV 73 92 73 95 / 0 0 0 0 MLU 69 91 68 93 / 0 0 0 0 DEQ 66 93 68 95 / 0 0 0 0 TXK 70 94 71 95 / 0 0 0 0 ELD 66 92 68 94 / 0 0 0 0 TYR 73 95 73 96 / 0 0 0 0 GGG 71 93 72 95 / 0 0 0 0 LFK 73 92 73 94 / 0 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ SHORT TERM...23 LONG TERM....23 AVIATION...16