Cold Front Arrives Sunday, Rain Chances Accompany The Front. Much Colder Next Week, Frost/Freeze Expected

Lead Forecaster Daniel Crawley

Good Friday afternoon to everyone, classic fall-like weather continues to dominate over the United States for the middle of October. The tropics are quiet right now and there are no expectations of tropical troubles for the US in the foreseeable future.

Our attention this time of the year starts to shift more toward the Northern Latitudes as the transition to the cold season continues. We talked a few days ago about the jet stream showing signs of high amplitude, that is definitely on-going as a huge trough is delivering some colder air into the country from Canada…

This trough will continue to dig to the southeast as we go through the weekend and it will drag a cold front through the Carolinas late Sunday night and early Monday. A few showers will slide in from the west on Sunday but this feature will work with limited amounts of moisture…

NAM 3km Future Radar (Thru Sun 8 pm)

Rainfall amounts are going to be light for those who received a few showers and there’s a chance others will miss out all together. Not exactly the best news as we continue to dry out here in the fall season…

WPC Precipitation (Thru Mon 8 pm)

First Widespread Frost/Freeze Next Week

The big story with this frontal departure will be the much colder air coming into the Eastern United States and will stay around for a few days. A full-on double blocking regime will take over by mid week and will deliver the coldest air of the fall season to this point.

If you watch the video below, you can see where the flow is straight northwest out of the Polar Regions. This will be the first “Cross-Polar” type setup this fall season. The result is going to be temperatures well below normal…

500 mb height anomalies

The brunt of the cold air moves in by Tuesday morning, where all of us will see our first widespread frost of the season, especially if the winds go calm.

850mb temp anomalies (Tues 8 am)

With the double-blocking pattern in place the cold air will not be transient in nature. It will have to sit around and wait for the pattern to relax. By Wednesday morning the cold air is centered across the Southeast. Wednesday morning will likely be the coldest of the three. A hard freeze is possible for some, and a sure bet for the mountains.

850 mb temp anomalies (Wed 8 am)

It may not be until sometime next weekend before this double-block relaxes enough to where zonal flow and Pacific origin airmass returns to the Eastern US.

Key Messages…

  1. A few rain showers are possible on Sunday due to a cold front passage.
  2. Much colder air returns to the region late Monday and Monday Night.
  3. Widespread Frost and Freeze opportunities will exist Tues, Wed, Thurs mornings…
  4. This will likely end the growing season for a significant portion of the coverage area…

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