Area Forecast Discussion
Issued by NWS Shreveport, LA
Issued by NWS Shreveport, LA
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920 FXUS64 KSHV 181818 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 118 PM CDT Sat May 18 2024 ...New UPDATE, AVIATION... .UPDATE... Issued at 111 PM CDT Sat May 18 2024 && .UPDATE... Issued at 1039 AM CDT Sat May 18 2024 A splendid Saturday is unfolding across the region today with abundant sunshine and temperatures already warming into the 80s. Some fair weather cumulus has developed along a weak sfc trough across South Arkansas, but expect this cu to gradually scatter out through this afternoon. Otherwise, high temperatures should top out in the mid and upper 80s to near 90 degrees this afternoon. The current forecast reflects this thinking so no changes are needed at this time. /19/ && .SHORT TERM... (Saturday through Sunday) Issued at 200 AM CDT Sat May 18 2024 Water vapor imagery early this Saturday morning depicts a split- flow pattern in the mid and upper levels of the atmosphere across the CONUS, with the northern stream featuring a belt of strong cyclonic flow from the Pacific Northwest eastward through the Northern Plains, and an upper level trough extending from the Southern Plains eastward through the TN Valley in the southern stream. Near the surface, a weak trough of low pressure is noted across Northern TX extending eastward across central/southern Arkansas and into the TN Valley, while a quasi-stationary boundary remains situated across the Northern Gulf and near the MS/AL/FL panhandle coastlines. A tranquil morning will continue across the Four State Region, aside from areas of fog developing and continuing through about mid-morning as skies scatter, winds remain light, and grounds remain moist. Could see some locations where visibility is reduced to 1/4 mile or less and conditions meet dense fog advisory criteria, however, at present time do not feel this will be widespread enough to warrant issuing an advisory, especially given the uncertainty in how some passing high clouds may affect radiational cooling. In addition to the fog, a few showers, and even a thunderstorm, has developed along the aforementioned sfc trough across AR as of 07z. This activity may continue through daybreak and possibly further into the morning, but will pose no severe threat and will not amount to much in the way of QPF/additional rainfall. The upper level trough will continue to slowly swing across the region through the day today, with the best dynamics being slowly displaced to the east with it through the afternoon and evening. This will result in an overall dry day. Given the presence of the trough through much of the day, along with the residual sfc trough (altho this should weaken thru the day), really cannot completely rule out a shower or two thru the entirety of the day. Skies will be generally partly cloudy, with a nice cumulus field developing this afternoon. The upper level trough will finally exit the area to the east tonight and into early Sunday, giving way to an upper level ridge of high pressure. This will result in increasing subsidence aloft, with skies clearing after sunset and through the night. These conditions, combined with calm winds will give way to another night of fog development, continuing into Sunday morning. Sunday will be dry as high pressure dominates both at the surface and aloft. Ridging aloft will allow temperatures to climb into the low 90s Sunday afternoon (upper 80s to near 90 across SE OK and SW AR). These hot and dry conditions will then carry us into the long term forecast period. Kovacik && .LONG TERM... (Sunday Night through Saturday) Issued at 200 AM CDT Sat May 18 2024 The upper level pattern to begin the long term will feature high pressure both aloft and at the surface. This will result in continued dry conditions Sunday night into Monday, with overnight lows ranging from the low 70s across much of SE TX and NW LA and upper 60s across SE OK and SW AR under clear skies. The ridge will remain firmly in place on Monday, resulting in a rather hot May day with temperatures climbing into the low to mid 90s. The pressure gradient will begin to increase during the late afternoon and evening hours as sfc cyclogenesis gets going across the TX/OK panhandles. This will allow for increasing southerly winds near 10 mph across at least western portions of the area, which may provide at least some relief from the heat. By Tuesday, a shortwave trough, associated with a broad scale trough across much of the Western US, will eject into the Central Plains, which will nudge the ridge over the Four State Region slightly eastward. Sfc ridge influence over the area will also move well east as lee cyclone moves NE into the Central Plains/Midwest. This will allow for some low level cloud cover to advect northward across at least SE TX and possibly W LA during the morning hours. Will still retain enough upper level ridge influence for high temps to remain in the low to mid 90s for most locations. A few showers may begin to encroach upon northern zones late in the day, associated with a trailing cool frontal boundary from the aforementioned sfc cyclone. Winds Tuesday will be breezy 10-15 mph. The upper level ridge will then noticeably dampen on Wednesday as the large scale western US trough expands eastward and low pressure deepens over the Upper MS Valley. The cool frontal boundary from Tuesday is likely to become stationary on Wednesday as the best dynamics/parent low remain displaced far to the north, resulting in convection developing along the boundary and not making much southward/eastward progress. While this will increase rain and thunderstorm chances across the area, rainfall amounts appear generally light and this boundary will provide no relief in terms of scouring out the hot and increasingly muggy airmass. This boundary is then currently progged to move slowly northward as a warm front on Thursday as a shortwave moves across central and east TX, keeping rain and storm chances in the forecast until the shortwave can finally carry the boundary east with into Friday. At this point in time cannot completely rule of the potential for a few severe storms in the Wednesday/Thursday timeframe, but do not think it will be widespread. Currently then seeing little in the way of an airmass change, so Friday may bring the chance for more typical isolated, single-cell convection driven largely by diurnal processes. General ensemble consensus via WPC Cluster Analysis suggests upper level ridge to maintain some influence into next weekend. Currently do not anticipate the need for any heat-related headlines through the long term nor is there any strong signal for widespread severe weather or heavy rainfall/flooding. Kovacik && .AVIATION... (18Z TAFS) Issued at 111 PM CDT Sat May 18 2024 For the ArkLaTex terminals, fair weather cumulus SCT to ocnl BKN this aftn with the upper low east of KMEM now. Prevailing winds are SW at 5 to 10KT and will slack after sunset. L/V or calm overnight with more patchy BR 3-6SM 09-13Z. Upper level high pressure spreading into the MS River Valley will keep us warm to hot and dry into the new work week. Next chance for convection will be along a weak front over AR mid to late work week. /24/ && .PRELIMINARY POINT TEMPS/POPS... SHV 90 70 92 73 / 0 0 0 0 MLU 87 67 90 69 / 10 0 0 0 DEQ 87 63 89 66 / 0 0 0 0 TXK 88 67 92 70 / 0 0 0 0 ELD 87 64 90 68 / 10 0 0 0 TYR 88 69 90 70 / 0 0 0 0 GGG 88 68 91 70 / 0 0 0 0 LFK 89 68 91 69 / 0 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ SHORT TERM...23 LONG TERM....23 AVIATION...24