Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/12/17

Area Forecast Discussion
National Weather Service Goodland KS
830 PM MST Sat Nov 11 2017 .UPDATE... Issued at 830 PM MST Sat Nov 11 2017 Difficult forecast regarding coverage and extent of clouds, fog, freezing fog, visibilities and temperatures. At 0330z low clouds extend from near McCook to Colby to north of Tribune with a clear sky to the west. Areas in the clear are below freezing and starting to get dense freezing fog. Right now trended temperature/dewpoint forecast to the RUC which has a pretty good handle on things and for visibility the rap13 and gfslampgrid visibility forecasts. Basically dense fog/freezing fog is expected to expand east/northeast tonight then dissipate a bit across the west toward morning. Models are showing another batch of low visibilities moving south into the area during the mid to late morning hours which may have to be dealt with with some type of advisory. Anyway, dense fog advisory is published and out. && .SHORT TERM...(This evening through Sunday) Issued at 232 PM MST Sat Nov 11 2017 Forecast problem will continue to be the stubborn saturated low level air mass that remains across the area. As has been the case the last week, models have had trouble in resolving the low level thermal and moisture fields. Weak surface low with its associated boundary was located to our southeast. This kept weak north to northeast winds across the forecast area today. This setup kept the saturated low level air mass over the area. Clearing line to the west has been creeping slowly east due to lack of a strong downslope component. At this time it looks like the clearing line barely makes it to the east of the Colorado border. Then the moisture moves back to the west once again. High resolution guidance is consistent in redeveloping stratus and fog but disagrees on how far west to put the next round of fog. At this time am thinking the Nam may be a little too far east with the Hrrr a little better. The general consensus is to develop fog along and east of the Colorado border and move it slowly east through tomorrow morning before dissipating it. Some dense fog looks possible again but models disagree on where. So will not issue an advisory and will let the evening shift take another look at it. Forecast soundings and high resolution guidance would support some patchy drizzle in the eastern third and inserted that into the forecast. The stratus looks like it may last into the afternoon which will wreak havoc on the temperature forecast and probably make for a wide range of high temperatures. All in all the temperatures look near to slightly cooler than todays maxes. .LONG TERM...(Sunday night through Saturday) Issued at 1249 PM MST Sat Nov 11 2017 The extended period (Mon-Sat) looks dry even though a couple cold fronts drop through the area. Sunday night through Tuesday a broad ridge will prevail aloft with southerly flow at the surface resulting in milder temperatures Mon-Tue and max temps 10-15 degrees above normal. A cold front will drop rapidly through the area Tuesday night, associated with a weak short wave aloft moving east across the northern Plains. Timing among the various models is fairly consistent. No precip is expected but max temps Wednesday will return to normal in the 50s. The next system to affect the Central Plains will occur Thu night-Friday. There is a timing difference with GFS guidance bringing the front through Thu evening while the EC is about 12 hours slower. Either way, temps Friday will be about 10 degrees colder. Given the speed of the system, location of better forcing to the north and better moisture displaced southeast of the area, the chance of any significant precipitation with the late week system looks slim. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 400 PM MST Sat Nov 11 2017 Forecast issues for both terminals will be timing and extent of low clouds/br/fg and associated visibilities as low level moisture remains across the area. For KGLD, currently expecting sub ifr conditions to continue through about 08z with visibilities possibly lowering to 1/4sm creating lifr/vlifr conditions. Should see conditions improve to vfr after 09z as northwest winds under 10kts move in and push the low clouds to the east. NAM model continues with high amounts of low level moisture and should it verify keep ifr cigs at the terminal for the entire taf period. For KMCK, currently expecting mvfr/ifr conditions to continue through maybe 16z before moving east of the terminal allowing vfr conditions to return from 17z-00z. Adjustments and updates will likely be needed through the evening. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Dense Fog Advisory until 8 AM MST /9 AM CST/ Sunday for KSZ001>003-013>015-027>029-041-042. CO...Dense Fog Advisory until 8 AM MST Sunday for COZ090>092. NE...Dense Fog Advisory until 8 AM MST /9 AM CST/ Sunday for NEZ079- 080. && $$ UPDATE...99 SHORT TERM...BULLER LONG TERM...DLF AVIATION...99
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
906 PM CST Sat Nov 11 2017 .UPDATE... Issued at 905 PM CST Sat Nov 11 2017 Radar mosaic shows a broad N-S swath of light pcpn across western MO and is starting to edge into central MO currently. Out ahead of this, a batch of heavier pcpn has developed around the UIN-HAE area. Examination of RAP vertical temp profiles and the high potential for evaporational cooling and seeing some higher pockets of reflectivity on radar, there does appear to be a small window of opportunity for sleet to mix in with the rain. It should not be persistent enough to dominate to where a mention is necessary and with relatively warm ground, it should not be a factor on impacts. Temps ranged from the upper 30s in parts of southern IL to lower 50s in central MO. A rather substantial 15-20F dewpoint depression exists. Satellite has cloudy skies areawide. For the most part the previous forecast is on target and made few changes, with pcpn chances, light as they will be wrt QPF, ramping up to at least likely for a 2-3 hour window later tonight. Much of the pcpn that falls will be light rain, but moisture will become more shallow with time and by daybreak Sunday and into much of Sunday morning, enough shallow moisture with weak convergence from a cold front moving thru will justify a switchover to drizzle for a short time before pcpn ends. Persistent clouds thru the day on Sunday nearly everywhere and a cold FROPA will limit any temp rises and should keep most areas in the 40s. TES && .SHORT TERM... (Through Late Sunday Afternoon) Issued at 250 PM CST Sat Nov 11 2017 Thick cirrus will quickly give way to lower clouds this evening in response to broad warm advection ahead of an approaching shortwave from the Plains. Rain is expected to develop this evening in central Missouri where low level moisture convergence is maximized and then spread/expand east toward the Mississippi River by midnight and into Illinois through daybreak on Sunday. DPVA from the approaching shortwave will also aid in synoptic lift across the area. While we are not expecting a signficant amount of precipitation with this system, measurable precipitation will be widespread enough to warrant likely and categorical PoPs tonight. Thickening cloud cover and a southerly wind will keep temperatures from falling too much tonight and have given the nod to a blend of short term model guidance for minimum temperatures Sunday morning. Surface low and cold front, associated with the shortwave, will move across the CWA on Sunday. Have maintained a slower solution, with best chances of rain along and east of the Mississippi River. Light wind, due to the proximity of the surface low, will become northwest during the afternoon in the wake of the surface cold front. Did shave a few degrees off high temperatures for Sunday given thick cloud cover and lingering precipitation. CVKING .LONG TERM... (Sunday Night through Next Saturday) Issued at 250 PM CST Sat Nov 11 2017 Active pattern this week as two upper level trofs will impact the region. The first trof will move into the Upper Plains Tuesday. Associated cold front will drop into the CWA early Wednesday. Ahead of the front decent moisture transport from LLJ and WAA should allow for some widespread showers. Cannot rule out an embedded thunderstorm with the system. The second system moves into the area Thursday night into Friday. As a surface low moves into southern MO a warm front is draped across the CWA before low moves east into IL and pushes associated cold front through the CWA. Models lack agreement with the onset of precip with this system. GFS is more agressive with precip associated with the warm front and the ECMWF keeps the period dry until the cold frontal passage Friday morning. Both models agree with pre frontal precip but are not consistent with timing, The ECMWF seems to lag behind GFS by 12 hours. Temps for the period will be close to seasonal normals with some slightly above normal temps Wednesday through Friday. Walsh && .AVIATION... (For the 00z TAFs through 00z Sunday Evening) Issued at 548 PM CST Sat Nov 11 2017 CIGs will lower overnight into at least low-end MVFR category at all TAF sites as an area of light rain overspreads the area. There will be a higher likelihood of IFR at COU and especially UIN and have included in those forecasts. The rain may become drizzle towards the end of the event heading into Sunday morning, and if realized, will contribute to VSBY reductions into IFR, but short of that, VSBYs should stay MVFR or better. A cold front will drop thru Sunday morning taking light/variable winds and becoming NW but speeds should remain less than 10kts. A region of low clouds should hold together, especially around UIN, into Sunday afternoon with this core region then dropping southeastward in the wake of the front. With that in mind, could see low CIGs continue at STL metro sites well into Sunday night, but should clear out of UIN and COU shortly after nightfall Sunday evening. SPECIFICS FOR KSTL: Deterioration of CIGs into MVFR by late tonight but rain onset should occur around midnight. Rain intensities should be light and may end as drizzle after sunrise Sunday. Low-end MVFR should continue thru Sunday and into Sunday night with the potential of IFR late Sunday afternoon and evening depending on how it evolves, but this time period will be more favorable for IFR to occur. Some clearing may occur by late Sunday night. TES && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Shreveport LA
958 PM CST Sat Nov 11 2017 .DISCUSSION... The extensive cu field associated with an axis of H850 moisture has now spread E to encompass the remainder of Ncntrl LA this evening, with cigs beginning to lower a bit over Ecntrl TX as theta-e ridging has developed along a 30-35kt Swrly LLJ axis. Meanwhile, the evening water vapor imagery depicts a flat shortwave trough currently traversing the Cntrl Plains, which will shift E into the Midwest/Upper MS Valley by 12Z Sunday. This shortwave will help nudge a weak sfc front (now extending from NW OK into Cntrl KS) SE late tonight and into the region by late Sunday morning. Ahead of the front, H850 theta-e ridging will shift farther ENE into NE TX/SE OK/SW AR overnight, which should help enhance some weak isentropic lift along the 295-300K surfaces over these areas along and S of the attendant W-E H850 trough. The 00Z NAM is in good agreement with the latest HRRR runs suggesting that isolated -SHRA may develop along/N of the I-30 corridor after 06Z, which seems plausible as weak forcing aloft associated with the H700 trough increases late as well over these areas. Thus, have expanded slight chance pops a little farther S across E TX and E across SW AR, but rainfall amounts (if any) should be quite light. The thickening and expansive cu field will also limit the temp fall overnight, with temps expected to remain fairly steady through daybreak across most areas, the exception being the Ern zones where readings may fall another few more degrees. Have raised min temps across the Wrn half of the area to the mid/upper 50s, with only minimal warming expected Sunday as the sfc front slides S through the area during the afternoon and the expansive cloud shield limits insolation. -SHRA may increase a bit Sunday over portions of NE TX/NW LA, but will leave slight chance pops as is (and defer to the mid shift) as isentropic forcing weakens during the afternoon ahead of the H850 trough with QPF amounts again quite light. Zone update already out...grids will be available shortly. 15 && .PREV DISCUSSION... /issued 610 PM CST Sat Nov 11 2017/ AVIATION... For the ArkLaTex, low to mid VFR cigs to continue with some MVFR for TXK where most rain may occur. VCSH will likely keep decent vsby elsewhere by around daybreak as a weak frontal boundary sinks into the area shift winds from S to NE less than 10 KTS by mid to late day. Climb winds attm are light SE then become W 25KTS by 5kft with moisture thick from 5-10kft. FZL is 12kft and air dries significantly so no threat for ice. FL winds keep W 15-35KTS. Rain ends by late on Sunday with dry wx until midweek expected. /24/ && .PRELIMINARY POINT TEMPS/POPS... SHV 55 68 53 69 / 10 20 10 10 MLU 51 69 51 68 / 5 20 10 10 DEQ 54 62 48 64 / 20 20 10 10 TXK 55 63 50 66 / 20 20 10 10 ELD 54 63 48 66 / 10 20 10 10 TYR 58 68 54 69 / 10 20 20 10 GGG 56 68 54 69 / 10 20 10 10 LFK 56 72 56 73 / 5 20 20 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 15/24