Issued: 6pm on Thursday, August 22nd 2024
Technical Forecast Discussion
Short-term Forecast (Thursday 08/22/2024 through Saturday 08/24/2024):
Much of the eastern United States remains upstream of a large trough that has managed to dig all the way to the lower South, and thus remains in a strong bubble of high pressure due to upper-level convergence within the Jet at around 1026 mb in the Ohio area. A prominent upper-low currently stationed near New England has been steering this trough to move further off the East Coast, and will continue to do so, cutting off some of the more southerly extent of the trough, and resuming flow through the Midwest off of a steadily building ridge further west. Pressure still remains high, though will drop slightly as the strongest regions of high pressure exit with the trough by Saturday. This pattern will result in the southerly advection of warmer and more moist tropical air, which will increase temperatures to around 90°F on Saturday and dewpoints to around 53°F, as this ridge encroaches further and continues to build. In addition, saturation in the upper levels (400 mb) on Saturday will result in some high clouds. However, chances of precipitation still remain minimal due to the lack of forcing from the still prevalent high pressure.
Long-term Forecast (Sunday 08/25/2024 through Wednesday 08/28/2024):
This pattern will continue to persist as the ridge builds itself further, continuing to increase our temperatures to the low 90s by Sunday. Saturation will reach some of the mid and lower levels (700-600 mb) at this time as well, which will generate some scattered low-level and mid-level clouds. A small surface low pressure may generate near the northern Plains on Monday as a result of a shallower upper-level ridge and travel eastward, though with quite miniscule amounts of 700 mb relative vorticity by Tuesday, it is unclear whether this low will continue to exist as it reaches more of the Midwest. Should it persist, confidence in organization still remains low, and thus quite immature fronts may or may not generate. Confidence in fronts is even lower given the uncommon geographical development of this low pressure, and minimal influence of multiple airmasses to create frontal boundaries. As such, confidence in precipitation remains low, though with a moist airmass located over much of the upper Midwest, some widely scattered showers and thunderstorms cannot be ruled out due to CAPE >1000 J/kg and surface temperatures around 95°F, and surface dewpoints around 60°F. By Wednesday, the ridge will encompass much of the eastern United States, continuing to advect hot, moist air from the south to the Midwest. However, flow will become a bit more zonal by the end of Wednesday, which may serve as a herald to the end of this heatwave.
