353 FXUS64 KSHV 110908 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 408 AM CDT Thu Oct 11 2018 .SHORT TERM.../Today through Friday/ A beautiful, cool morning across the Four State Region in the wake of a strong cold front which moved through our area on Wednesday. Sfc ridging was centered across NW KS into S NE early this morning with the ridge axis extending southward through Central OK into Central TX. This axis will stay to our west through the day, resulting in a slight CAA pattern to near neutral advection today with the ridge axis expected to shift eastward across the Southern/Central Plains into the Lower Miss Valley overnight. Looking aloft, ridging was centered across the Gulf of Mexico in the wake of Michael with nearly zonal west to east flow across the Southern Plains/Lower Miss Valley. By early Friday, we will be watching a clipper like trough moving quickly eastward across the Plains and moving into the Ohio/Tenn Valleys by Friday Evening. This trough will have a cold front associated with it with the front pushing through most of our region by 00z Sat. Mid and high level moisture will be quick to move back into the region from west to east late tonight through the day Friday with low level moisture really not making its return until late Friday Afternoon/Evening across our western and northwestern zones. Having said that, there is enough upper level support in association with the upstream trough for slight chance/chance pops near and to the north of the I-20 Corridor of Northeast Texas and Northern Louisiana on Friday. The atmosphere will need to saturate from the top down, at least until we see low level moisture return out west and this will set the stage for higher rain chances for the upcoming weekend which will be detailed in the extended discussion below. 13 .LONG TERM.../Friday Night through Wednesday Night/ The remnants of Tropical Storm Sergio from the Eastern Pacific will quickly move east-northeast and into West Texas by early Saturday afternoon. As the surface low of Sergio approaches, strong low-level southerly flow will result in a rapid increase of moisture from the Gulf of Mexico across the Southern Plains and Lower Mississippi River Valley. Widespread showers and a few thunderstorms will develop east and northeast of the surface low. Some of this activity may affect Southeast Oklahoma and portions of East Texas before sunrise Saturday morning. However, rain chances will quickly increase from west to east by Saturday afternoon. High rain rates may lead to locally heavy rainfall and isolated flooding, especially along and north of the Interstate 30 corridor. By late Saturday and into early Sunday, Sergio will begin to interact with a strong cold front that will be diving southeast across the Plains ahead of a large positively-tilted trough axis extending from the Great Lakes and into Northwest Mexico. The rain may diminish slightly for a time across the area during the day Sunday, but coverage should increase once again Sunday night and into Monday as the surface cold front quickly moves across the area. Model guidance still shows considerable disagreement, especially with respect to timing and placement of the heavy rain axis. The GFS, in particular, has shown very poor run-to-run consistency. However, the latest run of the GFS has finally started to come on board with the ECMWF for late Sunday and into Monday. The positively-tilted upper trough will be extremely slow to move across the country. While the surface front will move well south of the forecast area, a considerable amount of precip is expected to develop Sunday night along the 850-700 mb frontal boundary, which will still be northwest of the forecast area. Widespread rain will remain in the forecast during the day Monday. The rain may begin to slowly diminish Tuesday but will not end completely until the upper trough finally pushes the elevated front across the region by late Tuesday or very early Wednesday. The greatest risk for locally heavy rainfall and isolated flash flooding in a short period of time should be during the Saturday through Sunday time period. From Sunday through Tuesday, rain rates should be considerably lower and the event will transition more to a long-duration rain event. Storm total rainfall amounts are expected to be between one and three inches, but higher amounts are likely, especially along and north of the Interstate 30 corridor. Considerably cooler air will finally move into the region on Monday, and most locations should remain below 70 degrees for the entire work week. Despite abundant cloud cover, overnight low temperatures for the beginning of next will be quite cool with most locations falling into the low 40s to near 50 degrees F. CN && .PRELIMINARY POINT TEMPS/POPS... SHV 75 53 74 58 / 0 0 20 10 MLU 75 50 75 56 / 0 0 10 10 DEQ 71 49 65 53 / 0 10 40 20 TXK 72 51 68 53 / 0 0 30 10 ELD 73 47 72 54 / 0 0 20 10 TYR 74 55 73 59 / 0 0 30 20 GGG 75 53 73 58 / 0 0 20 20 LFK 77 54 77 61 / 0 0 10 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 13/09