Weekend warmup will feature unsettled weather

Much has been made of the cold and snowy weather this week, and rightfully so. Temperatures fell into the teens and 20’s on Wednesday night after snow on Tuesday, and high temperatures Wednesday afternoon barely scraped into the upper 30’s. Those temperatures are more typical for overnight lows this time of year. But there is another story line in the weather pattern, and it is one that will certainly keep appearing until there is a large scale change: the pattern is progressive. In the mid and upper levels, the pattern shows no signs of slowing down, meaning any airmass that settles into the area (no matter how anomalous) won’t meander around for long.

Not surprisingly, the very cold air which moved through the area early this week is well out of the picture. Temperatures will warm into the upper 50’s on Friday and the warming trend will continue through the weekend. Along with the warmup, unfortunately, will come some unsettled weather. As a mid level ridge builds over the Central and Eastern US, multiple disturbances will ride eastward through the Mid Atlantic states. The result, in terms of sensible weather, will be increased potential for clouds and showers on both Saturday and Sunday — but not a washout.

NAM model showing multiple disturbances moving into the Mid Atlantic states this weekend. Image courtesy weatherbell.

Beyond the unsettled weather this weekend, the big story will become a frontal system which will approach the area early on Monday. Initially warm weather from Sunday into Monday will give way to increasing winds, a chance of rain, and cooler temperatures which will funnel in behind the front. Temperatures will return to near or below seasonal averages by the early to middle part of next week.

ISON Outburst: The much anticipated Comet ISON experienced an outburst on Thursday, with amateur observations indicating a magnitude increase of almost 2. Gas emissions have also increased by a factor over 5. This is more than likely due to the comets nucleus interacting with increased heat from the sun. ISON’s tail also seems to be feeling the impact of solar wind, with a disconnection event and increasingly impressive tail structure observed in the latest imagery.

It remains to be seen if the outburst will continue, or if it is a sign of ISON’s nucleus being disrupted and eventually breaking up. Such facts will likely not be known for a few days (it is very difficult to image a nucleus, especially as small as ISON’s, when it is outbursting). Regardless, all eyes will be peeled to ISON over the next few nights as it nears the final countdown to perihelion on November 28. If it survives, it likely will put on quite a show after it grazes the sun.