Late week weather takes a hit with backdoor front

As clouds and showers move away from the area this afternoon, we expect some late afternoon and early evening clearing, leading to late-afternoon highs near 60 in some areas. Tomorrow, we expect to have southerly winds ahead of a strong frontal system, in association with a storm system producing severe weather in the Plains, Missouri Valley, and Tennessee Valley, where storms could become quite strong today and especially for tomorrow, with large hail and tornadoes possible.

Although we certainly will not be seeing any severe weather of that sort, the front is strong enough to induce plenty of lift for clouds well out ahead of it. Thus, despite the lack of rain forecast, a decent amount of cloud cover should prevent the area from having high temperatures exceeding 60 degrees tomorrow. Still, though, tomorrow will not be a bad day, with highs in the upper 50s and mostly cloudy skies.

It’s Thursday night through Saturday morning that we are concerned about, with the approach of a backdoor cold front. What happens often this time of year is that when a large storm system forms well to our west, we get counterclockwise flow from that system. If you are far enough east of the low, the winds start to turn easterly (off the ocean) as opposed to southerly.

Today's 12z NAM valid for Friday afternoon shows a prominent backdoor frontal system pushing to our south, leaving us on the cold side of the boundary (NEXLAB).

Today’s 12z NAM valid for Friday afternoon shows a prominent backdoor frontal system pushing to our south, leaving us on the cold side of the boundary. Notice the cold, easterly winds pushing into our area off the Ocean, thanks to higher pressures t our north. Also notice the warmth to our south and southwest. (NEXLAB).

What also happens is that due to the strong ridging out ahead of the cold front, a high pressure system develops to our north. The clockwise flow from the high pressure to our north, which also forces easterly winds to hit our area, perhaps even more-so than the storm system did. It is the boundary where one is influenced by the high pressure to the north (cold, easterly winds) and being far enough southwest to miss this influence, but have southerly winds from the low pressure and cold front where this backdoor cold front develops.

This time of year, backdoor cold fronts are often strong, happen frequently, and push relatively far south (south of us) because the Ocean temperatures in early-spring are still quite cold, especially given the cold winter we have had. Additionally, early-spring also sees more warmth to our southwest, which makes these boundaries stronger.

Because of this front, temperatures should drop into the low 40s on Thursday night and Friday, with plenty of clouds and potentially some rain around. The higher pressures to the north may put a lid on more organized lifting in the atmosphere, so heavy rain is not initially expected, but the boundary will be enough to trigger some showers.

On Friday night and Saturday morning, the cold front to the west will eventually push through, potentially leading to a brief period of moderate to heavy rain, before gradually clearing during the day on Saturday. Although we will be on the cold side of the cold front, the high pressure to the north getting pushed away will help lessen the colder marine influence, and temperatures should not be too cool this weekend — highs in the upper 50s can be expected on both Saturday and Sunday.

However, another storm system with chilly and unsettled weather can be expected early next week. Unfortunately, sustained spring-like warmth is not in the cards anytime soon.

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