Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/23/19

Area Forecast Discussion
National Weather Service Lincoln IL
924 PM CST Fri Nov 22 2019 .SYNOPSIS... Issued at 234 PM CST Fri Nov 22 2019 An upper level weather disturbance from Kansas will move into central Illinois by late Saturday morning. This will result in areas of light snow from northern Missouri into central Illinois by daybreak, with mainly light rain in southern Illinois. Accumulations of precipitation will be very light with very few, if any impacts to travel Saturday. Dry weather and a clearing sky will be in store for the region later Saturday and Sunday. High temperatures will be on the cool side with readings in the 40s through the weekend. && .UPDATE... Issued at 924 PM CST Fri Nov 22 2019 A short-wave trough pivoting around an upper low centered over Kansas has triggered scattered light precip across central and northern Missouri this evening. Most ob sites have shown light rain thus far: however, the latest ob from KSTL is reporting a rain/snow mix and KDMO is showing unknown precip. With temperatures already below freezing across all but the far SE KILX CWA, think the precip will begin mainly in the form of snow or perhaps a snow/freezing rain mixture. Despite the presence of numerous radar echoes across Missouri, a very dry mid and low- level airmass as evidenced by the 00z KILX upper air sounding will prevent precip from reaching the ground for several more hours. Based on radar trends and latest HRRR forecast, have introduced slight chance PoPs across the far SW around Winchester by 11pm. Have then spread PoPs as far N/NE as a Paris line well after midnight. Am expecting dry weather to prevail along/northeast of I-74. Any precip that occurs late tonight into Saturday morning will be quite light, so overall impacts will be minimal. however, latest ob from KSTL is && .SHORT TERM...(This evening through Saturday) ISSUED AT 234 PM CST Fri Nov 22 2019 An upper level circulation in western Kansas this afternoon will shift toward the mid-MS Valley overnight bringing an increase in clouds and chances for precipitation. The latest low level water vapor satellite loop confirms the lack of low level moisture upstream in the southern Plains, with the moisture focusing on the TN and OH valleys. This means that despite the movement of the upper low into central IL Saturday morning, the precipitation amounts will be on the light side with liquid equivalents less than 0.10" in central IL and possibly up to 0.25" in far southeast IL. A look at the forecast soundings and available energy aloft indicates that precipitation type should start out as light snow in central IL, with all rain south of I-70 toward daybreak. A brief period of freezing rain is possible toward Jacksonville and Winchester around daybreak as we lose ice crystals aloft and the snow changes to rain and surface temperatures hang around 32 degrees. Regardless, with low QPF amounts, any ice accumulation would be mainly to elevated surfaces, and any snow would be a couple of tenths of an inch or less. The trough axis of the upper low is expected to move out of IL by early Saturday afternoon, which will end the precipitation and result in decreasing cloudiness .LONG TERM...(Saturday night through Friday) ISSUED AT 234 PM CST Fri Nov 22 2019 A backing upper level flow from NW to SW by early next week will result in a warming trend with temperatures rising into the lower to middle 50s Monday into Tuesday. A shortwave trough lifting into the upper Midwest Tuesday will bring the next shot at precipitation, mainly in the form of rain Tue into Tue evening. Once again, it appears that the best moisture axis will be south of the region, so rain totals should be on the lower side. High pressure on Wednesday will bring a return to cooler temperatures in the 40s. An upper level ridge building along or just west of the MS Valley toward Thanksgiving will keep us on the cooler side, but also could set-up an extended period of overrunning precipitation for later Thursday through Friday. Precipitation type could be challenging, particularly Thursday night into Friday morning. In addition, there is quite a bit of uncertainty as to where the upper ridge axis will set up, which will impact the placement of the overrunning/warm advection precipitation - which could stay just west of Illinois. For now will need to just go with a chance PoP mention of rain or snow and evaluate this more as we get closer to the event. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 546 PM CST Fri Nov 22 2019 An upper-level disturbance currently over Kansas is spreading clouds and light showers across Missouri late this afternoon. As this system tracks slowly eastward, clouds will be on the increase across central Illinois this evening: however, it appears any light precip will hold off until closer to dawn. Forecast soundings continue to indicate a dry boundary layer, so am expecting ceilings to remain in the VFR category through the entire 00z TAF period. HRRR suggests a band of MVFR ceilings may develop across Missouri later tonight, then spill into far west- central Illinois Saturday morning...but these lower clouds are expected to remain west of the terminals. Have included VCSH at KSPI/KDEC/KCMI as the scattered light precip tracks through the area. Winds will remain light through the entire period. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barnes SYNOPSIS...Miller SHORT TERM...Miller LONG TERM...Miller AVIATION...Barnes
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
922 PM CST Fri Nov 22 2019 .UPDATE... Issued at 919 PM CST Fri Nov 22 2019 Regional radars are showing band of precipitation continuing to move into central and northeast Missouri. Surface reports indicate that a mix of sleet and rain is occurring with this band which is supported by evening upper air analysis which shows that precipitation is moving into a dry atmosphere so wet-bulbing is occurring. Have not received any reports of accumulation given the relatively warm surface temperatures ranging from the middle 30s in Knox County to the middle 40s here at LSX. Will keep likely PoPs going through the night as the latest RAP is showing the upper low currently over Kansas moving east into Missouri which will increase ascent over the region through the night. Forecast soundings do support the mix of rain/sleeting changing to snow over northeast Missouri into west central Illinois with mainly rain with some snow closer to I-70 into tomorrow morning. Snowfall accumulations still look less than 1/2 inch north of I-70. As mentioned in the previous discussion, it is still possible that some dry air will wrap around the upper low later tonight so some light freezing rain/drizzle will be possible over northeast Missouri later tonight with little if any accumulation. Otherwise, lowered temperatures slightly over northeast Missouri and west central Illinois based on current temperatures. Britt && .SHORT TERM... (Through Late Saturday Afternoon) Issued at 312 PM CST Fri Nov 22 2019 The mid-Mississippi Valley is currently situated beneath a weak upper ridge with surface high pressure building in from the northwest. This has resulted in quiet conditions today, though this is likely to change as a broad upper low currently moving out of the Four Corners pushes into the region overnight. The approaching upper low will slowly deepen a surface trough to our southwest, which in turn will help draw the upper portions of yestreday`s cold front back into the region this evening. Isentropic analysis of forecast guidance reveals weak moist upglide along this baroclinic zone overnight, which coupled with weak DCVA associated with the slowly filling upper low, should be enough to generate precip across much of the region. While precip is quite likely tonight and tomorrow morning in southern MO and IL, I`m not certain how far north the precip will extend. The preponderance of ensemble members shows measurable precip extending at least to I-70, with most deterministic forecasts and ensemble means pushing light QPF all the way into NE MO and west central IL. Therefore have continued to increase PoPs across much of the area, with QPF ranging from around 0.1" in our south to 0.01" in our north. Questions also remain with regards to p-type, as sub-freezing surface temps will be creeping into the region through the morning. Thermal profiles should be supportive of snow into tomorrow morning, primarily for areas north of I-70. However, it does appear that we may lose cloud ice toward NE MO as dry air wraps into the upper low, which may result in a brief period of freezing rain. It`s also possible the dry air simply cuts off the precip entirely, so confidence in any fzra is rather low. Therefore have largely stuck with just a rain/snow forecast, with a brief mention of fzra in NE MO. No ice accumulations are expected, and any snow accums are likely to be limited to the north of I-70. Where snow does occur, I would be surprised to see much more than half an inch of snow on grassy and elevated surfaces. BSH .LONG TERM... (Saturday Night through Next Friday) Issued at 312 PM CST Fri Nov 22 2019 Northwest upper level flow will take hold behind the departing low, with a handful of embedded shortwaves forecast to push through the region into early next week. Despite this mid level forcing, no precip is anticipated through Monday thanks to a steady supply dry WNW flow in the mid/low levels surface and high pressure building into the region. As the surface high shifts to our east on Sunday afternoon, surface winds will begin to swing around to the south, drawing warmer air back into the region. With that, temps should build into the 50s on Sunday and I expected several locations to top 60 on Monday. On Tuesday, ensemble means continue to show strong agreement on anomalously low upper level heights over the central portion of the country, increasing confidence that a potentially strong cyclone may move through the Midwest. The 12z runs of the operational GFS, Euro, and Canadian show remarkable consensus on low track, timing, and intensity, further bolstering confidence that the mid-Mississippi Valley will be impacted by this storm a few days prior to Thanksgiving. Despite the increasing confidence, we`re still nearly 100 hours away from this event and it would be foolhardy to try and nail down forecast specifics at this time. Small deviations in low characteristics could on one hand result in frozen precip, while on the other hand result in strong storms in our region. The most responsible forecast at this time is to say at cyclone will move through the Midwest on Tuesday, likely bringing precipitation to the mid-Mississippi Valley. As we approach this event and confidence increases, forecast specifics will become more clear. Beyond Tuesday, high pressure is expected to build into the Midwest while yet another low pushes across the southern CONUS. The surface high and upper level height rises should generally keep a lid on precip chances in our region. However, some guidance does push the northern fringes of the precip from the southern CONUS system into our area on Thursday. Given large differences in forecast guidance, confidence in this period is low. BSH && .AVIATION... (For the 00z TAFs through 00z Saturday Evening) Issued at 556 PM CST Fri Nov 22 2019 Precipitation will spread northeast across the area this evening and continue overnight. The best time for precipitation will be late this evening into the early morning hours. The rain will mix with or change over to snow at KCOU and KUIN with some minimal accumulations on grassy accumulations. The precipitation is expected to move out of the area on Saturday morning. Ceilings will drop to MVFR after 06Z and remain that way through tomorrow afternoon before improving to VFR on Saturday afternoon. SPECIFICS FOR KSTL: Rain will move into the terminal around 06Z and continue into mid morning Saturday. The rain may mix with snow at times between 10-15Z, but no accumulation is expected at this time. Ceilings will drop to MVFR after 06Z and remain that way through tomorrow afternoon before improving to VFR on Saturday afternoon. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Pueblo CO
304 PM MST Fri Nov 22 2019 .SHORT TERM...(This evening through Saturday) Issued at 244 PM MST Fri Nov 22 2019 Currently...Upper low was centered over the KS and CO state line this aftn and was slowly edging to the east. Snow has diminished over much of the forecast area as of 230 pm, but a band of snow persisted stretching from southern Pueblo County down into eastern Las Animas County which was well forecast by the HRRR. Temps have remained in the 20s to around 30F across the plains today under thick cloud cover, while the San Luis Valley and Upper Arkansas River Valley warmed into the mid 30s to lower 40s. Tonight...The upper low will continue to slowly move to the east and out of Colorado tonight, with clearing skies later tonight allowing for efficient radiational cooling. The latest HRRR indicates that there will be a band of light snow continuing from southern Pueblo County into eastern Las Animas County, as well as some spotty snow over the mts, until around 7 pm, then things really start to shut down. Therefore, adjusted forecast POP grids to show this with activity essentially ending by midnight. Overnight lows under clearing skies are expected to drop into the teens to single digits for the high valleys, and into the lower 20s for the plains. The rapid cooling tonight may produce some spotty areas of fog across the San Luis Valley as well as the plains, but do not feel these areas will last long enough to warrant a mention in the forecast. Tomorrow...Cool and dry north to northwest flow aloft settles in across the region, producing a pleasant day across the state. Plan on highs in the 40s for the high valleys, and 50s across the plains. Areas that received significant snowfall on Fri will be slow to warm however, and max temps at those locations may fall short a few degrees. Moore .LONG TERM...(Saturday night through Friday) Issued at 244 PM MST Fri Nov 22 2019 Models in general agreement through the extended period, with an upper level low developing to the west and high pressure to the east. There are differences in how the models want to handle the upper low to the west, especially when it comes to ejecting the system into the Desert Southwest. The GFS is quicker, while the ECMWF really hangs the upper low back west, indicating the potential for heavy snowfall over the San Juan Range. Ensembles are actually in good agreement, slightly favoring the ECMWF at this time. Saturday night and Sunday...broad northwesterly flow will prevail across Colorado during this period. Expect dry conditions to be in place across all of southern Colorado. Temperatures on Sunday will be warm, with upper 50s to lower 60s expected across the lower elevations. Monday into Tuesday...a quick moving upper disturbance in the northwest flow will move across Colorado from Monday afternoon through Tuesday afternoon. Expect snow showers to move into the Central Mountains by Monday afternoon, spreading south and east into the Palmer Divide during the evening hours, and finally south across the Plains Tuesday morning. A cold front will arrive Tuesday morning with low pressure developing over the Plains. There could be a period of moderate to heavier snowfall from the Palmer Divide, to near Pueblo Tuesday morning with the front. Snow will come to an end from west to east Tuesday afternoon as the upper system moves into the Central Plains. Highs on Monday will top out in the 50s, while highs will struggle to reach the 40s on Tuesday behind the front. Wednesday into upper level low is forecast to develop over the Pacific Northwest and drop south along the California Coast. This will spread moist southwest flow out of the Desert Southwest and into the Continental Divide beginning late Tuesday night, and persisting into the weekend. This pattern will heavily favor the San Juan Range and southwest facing slopes. From Tuesday night into Friday, 2 to 4 feet of snow will be possible, with hazardous travel conditions expected for Thanksgiving over mountain passes including Wolf Creek. Winds will also be gusty causing areas of blowing snow causing poor visibilities. The rest of the Continental Divide will also see snow, but is less favorable in southwest flow. A foot or two is possible north of Monarch Pass over the Central Mountains. Lesser amounts are expected over the Sangre de Cristo and Wet Mountain Ranges Wednesday and beyond. As for the Plains, dry conditions will likely prevail. There may be the possibility of light showers over the far Eastern Plains on Wednesday, but dry conditions are expected to prevail Thursday into Friday. Wind will likely be the main concern. Models are developing 65 kt winds at 700 mb for a prolonged period, Thursday into Friday, which may be able to mix to the surface. Winds will have to be watched. As far as model differences, the GFS ejects the low across the Desert Southwest by the weekend. The ECMWF is much slower and the heavy snow would likely persist through the weekend with moist southwest flow continuing. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 244 PM MST Fri Nov 22 2019 Upper low is continuing to edge eastward late this aftn, and will push east of CO overnight. Intermittent light snow continued in a few areas, and one persistent band of snow is stretching from southern Pueblo County into eastern Las Animas County. These pockets of light snow will continue until around 02z-03z tonight, then activity will shut off by midnight. Expect VFR conditions across much of the forecast area over the next 24 hrs, including the three main TAF sites of KCOS, KPUB and KALS. there may be some spotty areas of fog tonight as skies clear, producing temporary MVFR conditions, but with the expected NW sfc flow do not think these areas of fog will last long enough to warrant mention. Moore && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MOORE LONG TERM...MOZLEY AVIATION...MOORE
Area Forecast Discussion...UPDATED
National Weather Service Shreveport LA
942 PM CST Fri Nov 22 2019 .UPDATE... Cold front has finally exited to the southeast of the forecast area, but scattered elevated convection persists along the 850 mb front over Northern Louisiana. The HRRR has a pretty good handle on the ongoing precip and indicates all of the rain will exit the area by 08z or 09z Saturday morning. Therefore, PoPs grids were updated to reflect latest radar trends and based heavily on the HRRR. Overall, this resulted in trimming PoPs from west to east and removing PoPs completely at 09z. Otherwise, only minor changes were made to temperatures and dewpoints based on latest observations. Updated text products will be sent shortly. CN && .PREV DISCUSSION... /issued 611 PM CST Fri Nov 22 2019/ AVIATION... For the 23/00z TAFs, scattered convection will continue to affect portions of the area mainly southeast of a line form KJSO to KELD for the first few hours of the period. KLFK, KSHV, and KMLU will be the TAF sites most likely to be affected. Most of the showers and isolated thunderstorms should move south and east of all terminals shortly after 23/06z, but patchy drizzle and low clouds will persist into the mid morning hours. Ceilings and visibilities will be somewhat variable, but in general, IFR/LIFR conditions should prevail until around 23/15z. Beyond then, northwesterly surface winds will usher dry air into the region and skies should gradually clear from west to east after 23/18z. CN PREV DISCUSSION... /issued 310 PM CST Fri Nov 22 2019/ SHORT TERM.../Tonight through Sunday/ Temperatures continue to fall into upper 40s and lower 50s with northwest winds in wake of a cold front, currently located east of a line from Many Louisiana to Coushatta Louisiana to El Dorado Arkansas. This boundary will continue to slowly move eastward and out of the region by early evening. Showers and isolated thunderstorms continue to develop along and ahead of the frontal boundary, but it appears that the region will miss any severe weather. Light rain and or patchy drizzle will continue post- frontal as additional activity will develop along the eastward moving 850mb front, which is currently located along a line from Tyler Texas to Hope Arkansas. Another weak disturbance behind both boundaries may also result in lingering patchy drizzle through early Saturday morning before the weather and clouds move out by late Saturday morning/early Saturday afternoon. Much cooler and drier conditions to move into the region as Saturday morning temps will range from the mid 30s north of Interstate 30 to the mid 40s across Northeast and Central Louisiana. Highs on Saturday will generally be in the 50s to near 60 degrees which is slightly below normal for this time of the year. Dry conditions to continue on Sunday as High Pressure moves over the region. Sunday morning lows will fall into the 30s areawide with afternoon highs in the low to mid 60s. /20/ LONG TERM.../Sunday Night through Friday Night/ Sunday into Sunday Night will be a transition period across the Southern Plains/Lower Miss Valley as WNW flow aloft becomes southwesterly as our next weather maker in the form of an upper trough takes up residence across the Intermountain West. In the lower levels, expect to see a strong warm air advection regime commence across our region with high temperatures in the 70s both on Monday and Tuesday areawide. Did not introduce pops until late Monday Night into Tuesday but pops will be on the low end chance variety ahead of our next cold front which is poised to move into our region from the northwest Tuesday Night. Pretty good model consensus on the timing of this frontal boundary pushing through our region but that is where the consensus ends as the GFS is quick to reintroduce overrunning rainfall with southwesterly flow aloft continuing despite the cooler, postfrontal conditions in place beyond Tue Night. The precipitation forecast for the middle and later half of next week will become strongly dependent on the strength of Gulf of Mexico ridging aloft and the degree of amplitude with the next trough digging into the southwest CONUS next week. If our region remains more under the influence of the upper ridge across the Gulf (ECMWF) then the timing of the rainfall may await returning low level moisture by late next week compared to the upper ridge axis shifted east of our region (GFS) and our region more under the influence of southwest flow aloft and greater rain chances as early as Wed of next week. These parameters are impossible to determine so far out in the forecast future so for now, have split the difference between the much wetter GFS and the much drier ECMWF in the Wed thru Fri timeframe next week. Thanks for the coordination efforts today FWD, TSA, LZK...prelims to follow...13. && .PRELIMINARY POINT TEMPS/POPS... SHV 43 58 39 64 / 10 0 0 0 MLU 46 61 39 64 / 70 0 0 0 DEQ 37 54 34 62 / 10 0 0 0 TXK 39 55 36 63 / 10 0 0 0 ELD 41 56 36 63 / 20 0 0 0 TYR 39 57 38 66 / 0 0 0 0 GGG 41 58 37 65 / 10 0 0 0 LFK 43 62 40 66 / 10 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 09/15