565 FXUS63 KLSX 301649 AFDLSX Area Forecast Discussion...Updated National Weather Service Saint Louis MO 1049 AM CST Sat Nov 30 2019 .UPDATE... Issued at 1034 AM CST Sat Nov 30 2019 Have updated the forecast thru tonight for a few changes. Some areas of fog will be advecting around through mainly northern portions of the CWA. Overall, clouds should continue to erode thru the afternoon and into the evening hours. However, as the low system approaches, clouds will return. The bulk of the precip has moved out of the area. Have kept PoPs for southern portions of the CWA where TSRA over southern MO will move back into these areas briefly late this morning into the afternoon. Have also kept low PoPs across the northern portions of the CWA to account for some potential DZ. The other main change was to add mention of isod to sct showers, and perhaps a thunderstorm, late this afternoon and into the evening hours as the dry line pushes thru the area. There is still some uncertainty regarding if these showers will develop, but there appears to be enuf instability, with a fair amount of forcing, to suggest at least some chance PoPs. Tilly && .SHORT TERM... (Through Late Sunday Afternoon) Issued at 442 AM CST Sat Nov 30 2019 Showers and a few thunderstorms continued to move east across the area early this morning. Most of the rain was concentrated along and east of the Mississippi River at 09Z where the RAP depicted the strongest low level moisture convergence beneath increasing mid level ascent associated with the upper low over Central Plains. Additional showers are developing over western Missouri and northeast Missouri closer to the surface cold front that will move into the CWA through mid morning. Rain chances will be decreasing from west to east during the late morning into the afternoon as both the GFS/NAM is showing a dry slot spreading across the area during the day. Until then, the RAP is depicting 500-1000 J/kg of MUCAPE with deep layer shear in excess of 60kts. This will support a few strong storms capable of producing hail today. Precipitation chances will increase again late tonight into Sunday. This will occur as the aforementioned upper low moves across southern Nebraska and northern Illinois which will provide enough ascent to warrant high chance/likely PoPs across northeast Missouri into west central/south central Illinois. Forecast soundings and NBM ensemble probabilities suggest that precipitation type late tonight into early Sunday along and north of I-70 will likely be a mix of rain and snow. However, it still looks like little if any accumulation is expected. The warm front currently over southern Oklahoma and Arkansas will move north into the CWA which will allow highs to climb into the 50s and 60s per most of the guidance temps. Highs tomorrow will be much colder under the upper low. Britt .LONG TERM... (Sunday Night through Friday) Issued at 442 AM CST Sat Nov 30 2019 Not much change in thinking next week as the GEFS and ECMWF ensemble mean are showing the upper low moving off to the east leaving Missouri and Illinois dry early next week. Both show a dry upper trough dropping out of the Upper Midwest through Missouri and Illinois on Tuesday. The next chance of precipitation will be Thursday night into Friday when a southern stream trough will bring a chance of rain and snow to the area. Temperatures will start out below normal with northwest surface flow behind upper low. Temperatures will then climb back at or above normal the rest of the week, though forecast plumes from the GEFS are showing increasing spread in temperatures starting Wednesday which lowers confidence in the forecast. Britt && .AVIATION... (For the 12z TAFs through 12z Sunday Morning) Issued at 523 AM CST Sat Nov 30 2019 LIFR/IFR ceilings will persist across the forecast area through midday for KCOU and through late afternoon for remainder of TAF sites. In the meantime, scattered showers and isolated storms are possible ahead of cold front that will slide through region, exiting TAF sites by 18z Saturday. By tonight, winds will veer to the west and increase with gusts to near 30kts at times. For KUIN and KCOU, some wrap around clouds and scattered showers will move in after 08z Sunday. SPECIFICS FOR KSTL: LIFR/IFR ceilings will persist across the St. Louis metro area through 23z Saturday, then lift and scatter out by 02z Sunday. In the meantime, scattered showers and isolated storms are possible ahead of cold front that will slide through region, exiting metro area by 18z Saturday. By 08z Sunday, winds will veer to the west and increase with gusts to near 30kts at times. Will see ceilings lower back down to MVFR by 12z Sunday with some scattered showers possible. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX