Issued: 8pm on Thursday, December 21st 2023
Technical Forecast Discussion
Short-Term (Thursday PM 12/21/2023 through Sunday 12/24/2023):
Calm upper-level winds and NVA into the region will support a dominant surface high pressure to set up over the Appalachians throughout the short term. A surface low associated with a deep 500 mb trough to the west is going support warm air advection with southwesterly flow that will bring a warm moist airmass into the region with a warm front over the weekend, pushing daytime highs up into the high 50s and even low 60s for Christmas. With the moisture advection from this airmass, precipitation ahead of the warm front and behind it is expected over the weekend likely through at least Sunday morning.
Long-Term (Monday 12/25/2023 through Wednesday 12/27/2023):
A low-pressure system forming off of the Rockies by Monday is expected to be well into the occlusion stages and closed off all the way up to 250 mb. While the surface low is expected to have formed an occlusion by this point, models show a phase lag between the 850 mb and 500 mb low center, so the system still has some life left in it, but it is expected to be breaking down by this point.
This occlusion is also going to bring widespread chances for showers into the area, as well as a drop in temperature with the cold-core nature of the system closer toward the last half of the week. Rain chances will likely stick around as this low-pressure decays and spins out over the state. The drop in temperature is expected Tuesday night into Wednesday AM with southerly flow behind the occlusion.
Synopsis:
Thursday PM – Friday: Dry conditions with increasing clouds by Friday PM.
Saturday – Christmas Day: Chances for rain over the weekend diminishing to partly cloudy and dry by Christmas AM.
Monday PM – Wednesday: Precipitation returns with cloudy skies, dropping temperatures Tuesday PM.
