PM Update: Warmup midweek, unsettled weather ahead

Monday was the first in a set of what will likely be three summery days — with high temperatures in the 80’s and a warm sun. Autumn-like weather has taken its grip on the areas weather over the last week or so with pleasant days and cool nights. But the below normal temperatures will take a hiatus, however brief it may be, during the next few days. A building ridge in the mid levels of the atmosphere will aid in the development of a southwesterly flow, which will yield increasing mid level temperatures and warmer surface temperatures as well.

High temperatures on Tuesday will reach into the upper 80’s, feeling a bit warmer than Monday. Drier winds, as opposed to the onshore flow which has kept things cooler for the past few days, will make the air feel even pleasantly warm. Humidity will begin to increase as well, but won’t become noticeably uncomfortable until Wednesday. This will signal the approach of a frontal boundary later Wednesday, which will eventually bring an end to the warmer and more summery weather.

NAM model forecasting temperatures in the 90's on Wednesday afternoon with approaching thunderstorms. (Temperatures top left, precipitation top right).

NAM model forecasting temperatures in the 90’s on Wednesday afternoon with approaching thunderstorms. (Temperatures top left, precipitation top right).

As the front approaches during the middle part of the week, the weather will become more unsettled. Showers and thunderstorms will first make their appearance on Wednesday afternoon and evening — breaking the heat and bringing periods of heavy rain with lightning and the potential for some gusty winds. These storms will eventually shift east/southeast of the area later on Wednesday into early Thursday as the boundary passes the area.

The weather will turn more pleasant from Thursday through Friday, as the mid level pattern becomes slightly more zonal. A drier northwest flow will temporarily settle in as well, keeping humidity levels down. But perturbations moving along in the mid level flow, on the periphery of the mid level ridge to our south and active northern stream in Canada, will bring more unsettled weather into the area by later Saturday through Labor Day.

The timing of these disturbances, however, remains extremely uncertain. This lowers our confidence on the Labor Day forecast. While it does look unsettled, with a good chance of clouds and showers, the exact timing of these disturbances will obviously have significant impacts on the forecast for the holiday weekend. The strength of them, additionally, will determine where and when the rain falls.

We’ll keep a close eye on forecast models this week as the holiday weekend approaches. For now, enjoy the warm and summery weather of the next few days!