Area Forecast Discussion
Issued by NWS Tulsa, OK
Issued by NWS Tulsa, OK
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398 FXUS64 KTSA 211912 AFDTSA Area Forecast Discussion National Weather Service Tulsa OK 212 PM CDT Sat Sep 21 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Through Tonight) Issued at 212 PM CDT Sat Sep 21 2024 Another abnormally hot and humid day has transpired across much of eastern OK and northwest AR. Latest observations around the region show temperatures have already climbed into the mid-upper 90s in many locations. Heat indices will hover around 105F through the rest of the afternoon. A Heat Advisory remains in effect for much of eastern OK and west-central AR through 6 PM this evening. Upper-level ridging responsible for this unseasonably hot weather from the past few days will begin to breakdown and shift southeastward this evening into tonight as a vigorous upper- trough/low moves over the Rockies and eventually over the Plains by Sunday morning. Preceding this, CAM guidance continues to suggest a few isolated showers and storms (10-20% chance) developing/moving along the flow of the upper-level ridge through sunset this evening, mainly impacting areas of far northeast OK and far northwestern AR. Severe weather is not expected, but any storms that do form may result in locally strong gusty winds and brief heavy rain. Mejia && .LONG TERM... (Tomorrow through Saturday) Issued at 212 PM CDT Sat Sep 21 2024 A pattern shift will commence Sunday as a positively tilted trough ejects off the Rockies and moves over the Central/Southern Plains. In response, a plethora of mid/high clouds will overspread the forecast area from northwest to southeast through the day. At the surface, a modest cold front, with considerably cooler and drier air behind it, will begin to move into the northwest part of the CWA by mid-morning, pushing southeastward through the area by early Monday morning. Isolated to scattered elevated showers and thunderstorms are expected to be ongoing along and ahead of the frontal boundary Sunday morning, mainly affecting far northeast OK, near the KS border. As the front continues to advance southeastward, daytime heating ahead of the front should increase instability in the afternoon (MLCAPE increasing between 1000-1500 J/kg). Given a moist boundary layer underneath 40-50 knots of 0-6km bulk shear, a few strong to marginally severe thunderstorms look probable along and ahead of the front, with the highest threat occurring north of I-40 in OK and into far northwest AR. The primary hazards with any organized storm/cluster of storms will be damaging wind gusts and locally heavy rainfall that may lead to flooding, though small hail will also be possible. Guidance suggests the threat of severe thunderstorms lowers after sunset. Overall rainfall amounts through Monday should generally be less than an inch, though localized heavier amounts may occur. As mentioned in the previous forecast discussion, forecast high temperatures are still somewhat uncertain on Sunday, especially north of I-40, and will be highly dependent on frontal timing/position and rainfall prior to peak heating. Particularly, north of I-44, temperatures may struggle to reach 80 degrees if the front is faster than forecast. Elsewhere, and especially across southeast OK and west-central AR, afternoon temperatures ahead of the front should rise into the low-mid 90s. The front will exit the forecast area by early Monday morning. Significantly cooler temperatures are expected on Monday as thick cloud cover and precipitation lingers behind the front. Showers and thunderstorms should gradually diminish from west-to-east through the day Monday as the upper-level trough shifts east of the area; dry conditions are forecast by Monday evening/night. There is still a lot of uncertainty with regards to the synoptic pattern beyond Monday. Consensus in global models and ensembles indicate a secondary upper-level trough/low developing over the Plains behind the initial trough by midweek, but how it evolves and where it tracks is highly uncertain at this time. At the moment, it appears slightly cooler to near average temperatures and slightly above normal rainfall is favored through the second half of the week and into next weekend. Mejia && .AVIATION... (18Z TAFS) Issued at 1203 PM CDT Sat Sep 21 2024 VFR conditions remain the expectation for much of the forecast period. A few possible exceptions would be a low chance of storms across far NW AR terminals this afternoon, patchy fog across western AR overnight, and additional showers and storms spreading into NE OK late tonight through mid Sunday morning. These scenarios continue to have low chances of impacting flight conditions at any specific terminal. && .PRELIMINARY POINT TEMPS/POPS... TUL 75 87 61 72 / 20 60 80 30 FSM 75 93 70 78 / 0 20 40 60 MLC 74 94 62 77 / 0 20 50 50 BVO 69 83 56 72 / 30 70 70 20 FYV 71 90 64 75 / 10 30 60 70 BYV 71 90 66 73 / 20 50 60 70 MKO 74 91 61 72 / 10 40 70 50 MIO 71 87 59 69 / 20 70 70 40 F10 73 91 60 74 / 10 40 70 40 HHW 73 93 68 79 / 0 10 20 50 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...Heat Advisory until 6 PM CDT this evening for OKZ049-053>057- 059>062-064>068-070>076. AR...Heat Advisory until 6 PM CDT this evening for ARZ019-020-029. && $$ SHORT TERM...67 LONG TERM....67 AVIATION...07