The Weekend Gets Warmer

We're closing in on the Autumnal Equinox (that's the first day of autumn, by the way), and we've already observed some fall-ish weather. A progressive cold front at the end of last week played a big part in scooping up some cooler Canadian air and sending it our way. In addition to the cooler temps, the front wiped out any humidity in the region, adding to the seasonal feel. It's this time of year that we get large temperature variability throughout the day. Have you noticed how much our temps have ranged in one day? Lately, we've been foggy in the mornings with lows in the low to mid 50s. With some help from the sun, though, it's not difficult to end up with a high in the mid 70s. This time of year, it's not out of the question to see daily temperature ranges of 30°.

Many of you are probably welcoming the autumn weather, but if you're more of a summer person and aren't ready to give up the 80s just yet, don't worry. A trough over New England is in the process of lifting, and a broad ridge is making its way over the Rockies. As this pattern steers the jet stream to our north, the space below it will fill in with warmer weather. This will close off our wind flow from the north and turn it to a more southerly direction. It's possible that this will also pull in some significant surface moisture, but we may not see "humid" conditions until early next week. Dewpoints may peak on Sunday, being pushed along by a cold front advancing from the northwest. This may bring some thunderstorms during this period, but much can change in the coming days.

GFS depiction of surface pressure and temperatures at a few hundred feet AGL tomorrow evening. Note the advancement of warmer temperatures.

Speaking of the cold front, it looks like fall temperatures will return next week after the front ushers in another dash of cool temperatures. In the meantime, high pressure should become more dominant as the ridge arrives from the west. This should keep cloud development relatively low, but as today showed, the sun can generate large gains in temperature even when cloud cover is healthy. It won't be long before autumn weather settles in for good, so use this weekend to get outdoors and enjoy the pleasant conditions.

Tonight: A few clouds with a low of 55°. Winds becoming calm.
Friday: Mostly sunny with a high near 81°. Winds picking up later in the day to 5 mph from the east.
Friday night: Low around 61°. Light winds and mostly clear.

Thanks for reading!
- Caleb Chevalier