Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Jan 11 2024 08:17:38 FOUS30 KWBC 110817 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 316 AM EST Thu Jan 11 2024 Day 1 Valid 12Z Thu Jan 11 2024 - 12Z Fri Jan 12 2024 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-MISSISSIPPI VALLEY THROUGH ARKANSAS TO THE ARKLATEX... The wave associated with the upcoming synoptic evolution across much of the eastern and central CONUS today is currently tracking through California and will progressive move east-southeast into the southern plains by this evening. Large scale ascent within a well-defined mid and upper difluent pattern will aid in a rapidly developing area of convection in-of northeast TX into the the Lower to Mid-Mississippi Valley. The process begins between 21-00z as the digging upper trough begins to tilt more neutral to negative as it traverses the southern plains over TX/OK. The area downstream of the mean trough will enter an area of enhanced low-level moisture advection in conjunction with a rapidly intensifying 850mb jet ramping to 50-60kts. Rich, Gulf air will be pulled poleward through the Lower Mississippi Valley and Arklatex, eventually making headway into the southern tier of the Midwest by the end of the period. Surface low will spawn in-of central OK and begin intensifying as the upper pattern allows with instability fields gaining momentum on the eastern flank of the low. Showers and isolated storms will begin firing in east TX, LA, and AR by the early evening hrs, continuing to expand in coverage and magnitude by the end of the period. Deterministic guidance remains steadfast with the coverage and totals within the time frame of 00-12z Friday with all guidance keen on 1 to locally as high as 2-2.5" within a short time after cell initiation with the max generally over northern and central AR where cell mergers take place. NBM thunder probabilities have really climbed over the past succession of runs with a large area of 50-65% now showing up in the 12-hr probability fields, indicative of the increasing convective risks abound within this setup. MUCAPE on the order of 800-1200 J/kg will be found across the Arklatex into AR after nightfall, coincident with the combo of positive theta-E advection and falling height pattern within the amplifying 500mb trough. PWAT anomalies will blossom to 1-2 deviations above normal, an environmental favor for some low-end potential for flash flood concerns, especially within any urban corridors or terrain (Ozarks) where convection is prominent. The MRGL risk was maintained across much of Arkansas up into the Mid-Mississippi areas of southeast MO and far western KY, as well as bisecting the Arklatex. A small extension back southwest was made in coordination with ensemble mean trends of cell initiation potential to the east of the DFW metro. Kleebauer Day 2 The Day 2 outlook will be updated by 0830Z. Day 3 The Day 3 outlook will be updated by 0830Z. Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5e7iX-LlHV7yB-Ij4PlmJwnX-nz2G3ozaIPwUDnIGe2D= geMwaX_XnCDSxPnBoOnM-GeQaw_2kHTCHctj0Ewkxc1NM_E$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5e7iX-LlHV7yB-Ij4PlmJwnX-nz2G3ozaIPwUDnIGe2D= geMwaX_XnCDSxPnBoOnM-GeQaw_2kHTCHctj0Ewkxyy_sKk$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5e7iX-LlHV7yB-Ij4PlmJwnX-nz2G3ozaIPwUDnIGe2D= geMwaX_XnCDSxPnBoOnM-GeQaw_2kHTCHctj0EwkfFGnYhU$=20 $$ =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .