256 FXUS64 KSHV 191110 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 510 AM CST Wed Dec 19 2018 .AVIATION... Difficult flying conditions this morning and through the TAF period as we are dealing with Dense Fog at ELD and MLU with widespread showers across our NE TX airspace and moving into NW LA and SW AR. Ceilings underneath this canopy of showers are actually improving to near VFR ceilings with some minor MVFR VSBY concerns but believe this will be temporary. For the 12z TAF package, prevailed the 1/4SM and VV001 conditions at the ELD/MLU terminals, bringing ceilings upwards to at least IFR conditions with improving visibilities as the showers settle in. Out west where widespread showers were ongoing, prevailed VFR ceilings with MVFR visibilities, bringing ceilings down to IFR/MVFR conditions later this morning and prevailing these conditions through the overnight hours. There appears to be a break in the precipitation later this afternoon and through the evening and overnight hours spreading from west to east but more showers will be moving into our region from the north and west in response to increasing lift associated with the upper level trough. Began prevailing rain and lower ceilings/vsbys during the overnight hours across all but the ELD/MLU terminals as this precipitation will not have made it into these airports until the end of the TAF period. Winds will be mostly variable today with speeds at or near 10kts except the TYR/GGG terminals where a southeast wind will prevail through much of the day. Those variable winds will continue through the overnight hours before winds begin to shift around to a northwest direction in advance and behind a strong cold front. 13 && .PREV DISCUSSION... /issued 344 AM CST Wed Dec 19 2018/ SHORT TERM.../Today through Thursday/ Short Term concerns are immediate with widespread showers moving into our western half and widespread dense fog covering our eastern half making for a challenging forecast this morning. Visibilities have improved under the rain shield and extrapolating the leading edge of this shield north and east by 12z, we should be losing the dense fog across extreme NE TX and SW AR. For this reason, with this morning package, have trimmed back the Dense Fog Advisory through 9 AM only keeping it in effect for our eastern half where the rain should wait on making it into these areas until closer to expiration time. Upper trough axis this morning per Water Vapor Imagery shows the trough spinning across SW TX with the trough axis extending northward into the Upper/Middle Red River Valley of N TX and OK. Progs have a good handle on this feature slowing its eastward progression during the day as a strengthening upper level jet max along the back side of this trough digs into its base which should slow the trough down. At the surface, an area of low pressure has formed just off the SE TX Coast and as the upper trough moves closer to our region today, the sfc low should move northeast, staying south and east of our region, thus keeping us removed from the best low level moisture return and greater instability. However, given the upper level forcing across our region and the steeper lapse rates that will be moving ovhd today/tonight, will continue to mention the possibility of isolated thunder mainly along and south of the I-20 Corridor but will also include SC AR in this possibility. Late tonight into Thursday, additional forcing aloft will move into our region from the north and west with additional periods of showers across most of our region before we finally see drier air working into our region along the back side of the trough during the day, thus ending the rain across our west. The cold front associated with this trough will be moving into our western zones late tonight and should quickly move from west to east through the remainder of our area Thursday Morning. A very strong post frontal pressure gradient will be in place during the day Thursday such that a Lake Wind Advisory will be necessary for our entire region with northwest wind gusts approaching 35 mph across our western zones. 13 LONG TERM.../Thursday Night through Tuesday Night/ A few showers may still linger across portions of Southern Arkansas and North Central Louisiana Thursday evening behind a departing upper trough. However, any precip that may still be ongoing should exit completely by midnight Friday morning. Wind speeds will also be slow to diminish, and the resulting cold air advection combined with gradually clearing skies should lead to overnight low temperatures Thursday night/Friday morning falling below 40 degrees F areawide. Any near or below freezing temperatures will be confined to the terrain of Southeast Oklahoma and Southwest Arkansas. Similar temperatures can be expected Friday night/Saturday morning. Shortwave ridging embedded within the progressive west-northwest flow aloft will keep dry weather is place and will allow daytime temperatures to warm back into the 60s across much of the area, possibly near 70 degrees F in Deep East Texas. Another shortwave trough will bring a cold front across the area on Sunday. Deep layer moisture will be relatively lacking. However, a few showers will be possible during the daytime hours of Sunday, mainly east of a line from Toledo Bend Reservoir to Farmerville LA. Rain chances will be more widespread on Monday as the old frontal boundary moves back north as a warm front while another shortwave trough traverses the region. Chances for showers and thunderstorms will continue to increase Tuesday as a deep layer moisture increases and a strengthening upper trough moving through the rockies leads to the rapid development of another surface low and Pacific cold front lee of the Rockies. CN && .PRELIMINARY POINT TEMPS/POPS... SHV 52 46 50 39 / 90 70 70 10 MLU 54 47 50 39 / 100 80 90 30 DEQ 53 42 52 34 / 40 80 30 0 TXK 51 45 50 37 / 70 80 60 0 ELD 51 44 48 36 / 80 80 80 20 TYR 55 45 52 39 / 80 70 20 0 GGG 53 45 52 38 / 90 70 20 0 LFK 54 46 53 38 / 100 60 30 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...Dense Fog Advisory until 9 AM CST this morning for ARZ060-061- 070>073. LA...Dense Fog Advisory until 9 AM CST this morning for LAZ001>006- 010>014-017>022. OK...None. TX...None. && $$ 13/13/CN