Issued: 6pm on Thursday, July 13th 2023
Technical Forecast Discussion
Short Term (Thursday 7-13-2023 through Sunday 7-16-2023)
Currently, a very unsettled pattern remains over the region and will likely persist throughout the entire forecast period. A very broad longwave trough in the upper levels has brought a low-pressure system through the region, and toward the end of the short-term forecast period, another large low pressure will move in from the west. Today severe weather has been the concern with a strengthened low-level jet, bringing the threat of damaging winds, hail, and a couple of isolated tornadoes due to strong wind shear caused by this jet streak. This next low-pressure system is forecast to be a cutoff low and is expected to strengthen the pressure gradient with that trough, leading to enhanced upper-level flow. However, the lower levels of the atmosphere do not appear to be as strong as today’s setup.
Some severe weather is going to be possible on Saturday, with the main threats likely being damaging winds, large hail, and some flash flooding. CAPE values are forecast to be nearing 1,500 J/kg, indicating the threat of these hazards, but wind shear at this time does not look to be supportive of any tornadic development. Model soundings show hodographs that are short and lack low-level curvature, indicating the lack of speed and directional shear. The upper-level pattern is also somewhat meridional, and looking closer to the surface, some cold air advection indicates a frontal passage around sometime Sunday, which is also being supported by PVA into the region with the surface low pressure forming over the midwest region and beginning to move into our coverage area.
Long Term (Monday 7-17-2023 through Thursday 7-20-2023)
Heading into the next week, much of the same pattern will continue for the early part of the week. After this large trough moves off to our east, a more zonal pattern will move in. This will likely bring another low-pressure system to our north and, along with it, another weak cold front. Throughout the long-term forecast, widespread precipitation is expected. The very active pattern for the region is being influenced by a very strong and dominant high-pressure system over the southern central part of the U.S. right now. The strong high-pressure ridge from this system is causing lots of repetitive strong troughing to occur over our area, leading to the continued development of low-pressure systems with frontal passages and subsequently more precipitation. The Climate Prediction Center has the region being normal to slightly above average in temperature over the next 6 to 10 days and slightly above average for precipitation over the same period of time. This pattern does not look to break down until the earliest next weekend, potentially later.