Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/23/24


Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1031 PM CDT Sun Sep 22 2024 .KEY MESSAGES... - Off and on showers will continue through Tuesday. Storm total rainfall will be greatest along and south of the I-72 corridor where 1 to 2 inches will occur. && .UPDATE... Issued at 730 PM CDT Sun Sep 22 2024 Latest surface map shows the cold front approaching a Shelbyville to Paris line. Rainfall this evening has been fairly scattered, though a larger area of light rain is moving toward the western CWA, and the most recent HRRR run shows it making it to about Peoria before fading out. Thunder has been non-existent in our CWA as of late, and the threat steadily diminishes as the front gets further southeast. For the most part, lingering showers should be over before midnight, with additional showers moving northeast toward a Jacksonville-Effingham line toward daybreak. Recent forecast updates were to update the rain trends into early tomorrow, and significantly dial back the thunder chances this evening. Temperatures appear to be on track at this time. Geelhart && .SHORT TERM...(Tonight through Monday) Issued at 314 PM CDT Sun Sep 22 2024 19z/2pm surface analysis shows a cold front between the Illinois River and the I-55 corridor. Scattered showers are beginning to re-develop ahead of the boundary...particularly east of I-55. Think areal coverage will continue to increase over the next couple of hours, resulting in 60-70 PoPs across the E/SE KILX CWA through the remainder of the afternoon and into the early evening. The front will settle southeastward tonight, eventually stalling just north of the Ohio River overnight. With forcing shifting to the south and slightly drier air advecting into the region behind the departing cold front, think early evening showers will come to an end and mostly dry weather can be anticipated overnight. Low temperatures will range from the middle 50s northwest of the Illinois River...to the middle 60s south of I-70. The front will remain stalled across the Ohio River Valley on Monday as a short-wave trough evident on latest water vapor imagery over Colorado approaches from the west. Showers and a few thunderstorms will develop in the vicinity of the boundary...with the best rain chances during the day remaining focused south of I-70. As the wave gets closer and a weak surface low develops and tracks along the front, increased synoptic lift will bring another round of light to moderate rain to much of central Illinois Monday night. Barnes .LONG TERM...(Tuesday through Next Sunday) Issued at 314 PM CDT Sun Sep 22 2024 Showers will be ongoing Tuesday morning, but will shift eastward and come to an end from west to east during the afternoon. Storm total rainfall from yesterday through Tuesday will be greatest along/south of I-72 where amounts of 1 to 2 inches will be common. After a period of dry weather Tuesday night into Wednesday, the forecast for later in the period becomes a bit more complex as a short-wave trough currently over northern Alberta digs southeastward and cuts off over the Mississippi River Valley by mid to late week. The exact evolution of this process remains unclear as synoptic model solutions vary. Another complicating factor will be the presence of a potential tropical system most models are forecasting to track northward through the Gulf of Mexico by Thursday/Friday. This system will likely shunt the upper low N/NW as it approaches the Gulf Coast...potentially bringing an extended period of scattered showers to portions of the Midwest Thursday through the upcoming weekend. Some solutions even suggest tropical moisture may be entrained by the upper low, although this does not seem particularly plausible. End result is a low confidence forecast featuring low chance PoPs for the end of the week into next weekend. Barnes && .AVIATION... (For the 06z TAFs through 06z Monday Night) Issued at 1031 PM CDT Sun Sep 22 2024 Aside from VFR conditions at KSPI late evening, much of central Illinois had ceilings below 2000 feet. A small area of IFR ceilings has been pushing southeast from KBMI-KCMI, with latest HREF guidance suggesting this will remain the case through about 10-11Z. While some improvement is expected around KPIA by mid morning Monday, the MVFR conditions should prevail over much of the area through the day. Periods of showers will track northeast and may reduce visibility temporarily to a few miles, most likely during the morning. Geelhart && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Springfield MO
646 PM CDT Sun Sep 22 2024 .KEY MESSAGES... - Marginal (1 of 5) Risk for severe thunderstorms today and Monday afternoon and evening. Main hazards will be damaging wind gusts up to 60 mph, small hail, and brief heavy downpours. - Multiple rounds of widespread showers and thunderstorms are expected through Monday night (40-85% chance). Most locations will see an additional 0.50 to 2 inches of rainfall through Monday, with a flooding threat across the eastern Ozarks from localized higher amounts of 3 to 6 inches. - Much cooler temperatures will occur this week with highs in the 70s. - Rainfall chances (30-50%) are increasing for late in the week however confidence remains low with the track of the system. && .SHORT TERM /THROUGH MONDAY NIGHT/... Issued at 230 PM CDT Sun Sep 22 2024 Current Conditions and Synoptic Pattern: Water vapor and upper air analysis showed an upper level disturbance spinning across Colorado and Nebraska. Broad southwest flow aloft was occuring across our area with a moist and unstable airmass in place. The 12Z KSGF sounding measured a PW value of 1.7in and 1000j/kg of MU CAPE. Most of the area was dry early this afternoon however we were watching a few features. One being a weak boundary that was diffuse but could be seen on satellite imagery from roughly Branson to Eminence. A few showers and storms were beginning to develop along this boundary as convective temps have been reached. The actual cold front (with temps in the 60s behind it) was still just northwest of the CWA from roughly Kansas City to Eureka, Kansas. Several breaks in the clouds have allowed for temps to climb into the low 80s across the area. This afternoon through this evening: Latest high res guidance suggests that the highest chance of thunderstorms this afternoon will occur along the weak boundary to the southeast of Springfield. 2000j/kg of ML CAPE and 30kts of effective shear will allow for a few organized storms which may produce some downbursts to 60mph. Heavy rainfall rates will occur with the strongest storms given the high PW values. More uncertain is development along the actual front as it moves into the area. Would expect at least a few showers and storms to develop along the front this afternoon and evening and have kept pops in the 20-40% range. It is possible that many areas remain dry through early evening. Tonight: Strong lift will occur both from an increasing low level jet nosing into the area along with upper level jet interactions. The cold front will also be moving through the area. An area of showers and thunderstorms will likely move from northeast Oklahoma into southwest Missouri generally after 9pm, lasting through the overnight hours. Forecast soundings from the RAP suggest MU CAPE values around 1300j/kg and PW values around 1.8in therefore thunderstorms with heavy rainfall rates will likely occur. Monday: An area of showers and storms will likely continue through most of the day as lift will remain present. A weak surface low looks to move up the front during the afternoon. If enough instability can develop across south central Missouri then a few severe thunderstorms would develop. Confidence remains low with respect to any severe potential however we will need to watch the area along the Missouri/Arkansas border for a wind and hail threat. Northerly winds, clouds and rain looks to keep temperatures much cooler than previous days and have gone closer to the 25th percentile with highs in the lower to middle 60s north of Springfield to around 70 elsewhere. Rainfall will slowly end Monday night as the trough starts to move east. Rainfall Amounts: Overall rainfall amounts have been too high for today thus far (forecast versus observed). However it does appear that rainfall tonight and Monday will be heavier for areas south of I-44 and east of Highway 65. There remains a high spread in total qpf from the HREF with the Joplin area between 0.2-0.9in, Springfield area between 0.9-2 inches and West Plains/Alton areas between 2.3-4.8 inches. Localized flash flooding will be possible across the eastern Ozarks where the rainfall will linger the longest. && .LONG TERM /TUESDAY THROUGH SUNDAY/... Issued at 230 PM CDT Sun Sep 22 2024 Confidence decreases as we head through the week due to the track of a couple of upper level features. One feature is an upper low that will drop south into the northern plains Tuesday. Ensemble clusters still have varying differences on the track of this low. If the low tracks over us then we will likely remain cloudy and very cool (highs in the low 70s) Tuesday and Wednesday. The other key feature will be the development of a tropical cyclone in the Gulf of Mexico this week. Ensembles generally take this feature into the southeast US with some potential that it gets entangled with the upper low over our area and moves west. If this occurs then our rainfall chances will increase towards the end of the week. While confidence in this scenario is low, rain chances have now increased into the 30-50% range Thursday through Saturday, especially across the eastern Ozarks. Confidence is high however that temperatures will remain below average this week with highs likely remaining in the 70s. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 642 PM CDT Sun Sep 22 2024 VFR ceilings for the next few hours before rain returns early Monday morning. Rain may be heavy at times, reducing visibilities and dropping ceilings into MVFR. Showers and thunderstorms will prevail for most of the day on Monday. Winds will remain northerly through the period. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Burchfield LONG TERM...Burchfield AVIATION...Soria