209 FXUS64 KTSA 100939 AFDTSA Area Forecast Discussion National Weather Service Tulsa OK 439 AM CDT Sun Oct 10 2021 .DISCUSSION... Significant severe weather potentials continues to be likely this evening into tonight across Eastern Oklahoma into Northwest Arkansas with all modes of severe weather forecast. Early this morning...an upper level low pressure was ejecting eastward out of the Four Corners region toward the Southern Plains. At the surface...a surface low was centered over the Texas Panhandle with a surface boundary...which will become the dryline...extending southward across far West Texas. Also from the surface low...a slow moving cold front was positioned to the northeast across Central Kansas into Western Iowa. These features both at the surface and aloft will be the main players in a significant severe weather threat this evening/tonight across Eastern Oklahoma and Northwest Arkansas. The chess board has been set. Ahead of the surface boundaries...southerly low level flow was transporting moisture back into the region with low/mid 60s dewpoints common across the CWA this morning. This flow should remain gusty through the day with gusts 15-30 mph helping to keep temperatures well above the seasonal average this afternoon. By late afternoon...the surface low is progged to be across far Southwest Oklahoma/Northern Texas. The dryline should extend to the south in West Texas and the cold front extending northeast through North Central Oklahoma...just west of Osage co...and into Eastern Kansas. Thunderstorm activity is forecast to initiate along these boundaries mid to late afternoon and push east/northeast into Northeast Oklahoma after 21z...spread across the rest of Eastern Oklahoma after 00z and into Northwest Arkansas around 05-06z. This evening and into the overnight hours...the upper low as well as the surface low are progged to lift northeast through Oklahoma and become negatively tilted...reaching Southeast Kansas/Western Missouri by early morning Monday. The cold front will continue to slide east southeast through the CWA with the dryline moving eastward across Southeast Oklahoma before it is overtaken by the cold front. The cold front looks to be making its way through/exiting Northwest Arkansas around/shortly after 12z Monday. At the onset of storm initiation...both surface and elevated instability combined with mid 60s to around 70 deg dewpoints...0-1km SRH of 200-400+ m2/s2 as well as strong low level and deep layer shear will contribute to storms starting off more discrete. Large hail...damaging wind and also a tornado threat are possible. Latest short-term model solutions continue to indicate higher updraft helicity tracks spreading from southwest Oklahoma into Northeast Oklahoma this evening...which will continue the tornado threat into the evening hours. Surface instability looks to weaken late evening and overnight. However...continued strong low level shear values...200-400+ m2/s2 SRH and a 40-60+KT low level jet will continue the severe potentials into far Eastern Oklahoma and Northwest Arkansas. During this time...storms are forecast to become more linear with a transition to more of a damaging wind threat. However...with the high shear/helicity environment...a tornado threat will remain possible...especially with the potential for quick spin ups along the leading line. These conditions will remain possible into the late overnight hours before weakening after 09-10z. Precip should start to taper off from west to east across East Central and Southeast Oklahoma behind the frontal boundary and exit West Central Arkansas by mid morning Monday. Precip across Northeast Oklahoma...underneath/near the surface low should start to taper off early morning Monday and exit far Northwest Arkansas by late morning Monday as the storm system lifts off to the northeast. One other thing of note...is the potential for periods of heavy rainfall through tonight. Precipitable water values in the 1.5 to 2 inch range combined with possible training of storms across Northeast Oklahoma will aid in rainfall amounts of 1-3+ inches by the time precip exits Monday morning. During the height of the precip...rain rates of 1-2 in/hr are possible which will help to increase a localized flash flooding potential. Across the rest of the CWA...high rainfall rates along the front will allow for rainfall amounts of a half inch to locally over 1.5 inches. Looking into the upcoming work week...the front that moves through tonight is forecast to lift back northward through the region Tuesday and increase moisture over the CWA ahead of another low pressure system progged to move out into the Plains Tuesday night/Wednesday. In response...additional shower and thunderstorm chances are forecast through the week. The greater precip chances at this time are forecast Tuesday night into Wednesday as the surface frontal boundary stalls just to the northwest. Severe potentials will also be possible with this activity. Precip chances finally taper off Friday as the front and the upper level trof axis finally move through the region. Temperatures this week look to fall back toward the seasonal average behind tonights front for the first part of the week and then cool again behind the late week front. && .PRELIMINARY POINT TEMPS/POPS... TUL 89 60 80 55 / 20 100 10 0 FSM 90 64 80 56 / 0 90 20 0 MLC 88 59 79 54 / 10 90 0 0 BVO 87 58 76 50 / 50 100 10 0 FYV 86 61 74 50 / 0 100 30 0 BYV 85 62 72 52 / 0 100 40 0 MKO 87 60 76 55 / 10 100 10 0 MIO 86 60 73 52 / 10 100 30 0 F10 88 58 78 54 / 20 90 0 0 HHW 89 61 80 58 / 10 90 0 10 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...18 LONG TERM....20