We're getting ready for a big cool down beginning later this afternoon into the evening, and more so Friday into Saturday as a Canadian Air mass moves across the area this afternoon. There will be a chance for a few showers or storms later this evening behind the boundary, but a layer of warm air aloft ahead of the boundary should suppress thunderstorm development this afternoon.
The front has already entered northwestern OK this morning and will approach the I-35 area this morning, passing the Ponca City area around 10AM and then slow for an hour or two before moving southeast. This boundary will more than likely pass the Tulsa area between 1PM and 3PM and then clearing the rest of our viewing area by early evening. The front will stall across the far southeastern part of the state due to the higher terrain and the impact of the shallow air mass. Our temperatures today should top out near 80 to 83 in Tulsa, the mid-80s across southeastern OK, and the lower 70s for areas northwest of Tulsa. As the front moves southward, the temps will start to drop into the 60s this afternoon across areas northwest of Tulsa with gusty north winds at 15 to 25 mph. The air mass will become colder later tonight into Friday morning with temps in the lower to mid-50s. A second upper air wave will approach the area later tomorrow and will bring a re-enforcing shot of colder air to the state Friday afternoon with temps steady or possibly dropping into the lower 50s.
The air mass is expected to be CAPPED this afternoon, which would tend to limit thunderstorm activity along the boundary, but there will be a slight chance of a few storms this afternoon or evening across Eastern OK. The higher likelihood will occur after midnight into pre-dawn Friday with rain and storm activity developing behind the boundary across northern OK. Some of these storms could produce marginally severe hail in a few spots.
Some precipitation is also a possibility Friday night into Saturday morning. As the wave draws closer, a front in the 5K ft. level will be slowly sliding across southern OK. Locations just near this boundary may see some elevated thunderstorms late Friday evening into Saturday morning. The elevated instability could produce some hail, even Saturday morning, but the confidence is low regarding this portion of the forecast. GFS data this morning brings dry air quickly behind the system and offers no precipitation Saturday for northern OK, while the EURO continues to support a chance for some showers with embedded thunder.
Temperatures Saturday will have a chance to stay in the 40s for most of the day with mostly cloudy conditions, but we'll keep the high near 51.
The clouds should clear out Saturday evening allowing for very temps to drop closer to the local dews, meaning our morning lows will be in the upper 30s Sunday morning. RAW nam output indicates temps nearing or slightly below freezing along the OK-Kansas state line for about 2 hours pre-dawn Sunday. Afternoon highs will be in the upper 50s near 60.
The temps should rebound early next week as another stout storm system will arrive around Wednesday with a chance of storms. The pattern late next week would also support the active weather pattern lasting into next weekend.
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