Friday, July 13, 2012

Weekend Thunder To Be Off & On, Hit & Miss

The whole of the weekend won't be a washout but there will be chances of thunderstorms through the coming weekend. Storms could be on the increase as early as tonight as moisture to our southwest this morning lifts northeast and may push some thunderstorm activity through portions of the region tonight and early tomorrow.  The GFS (below) suggests a batch of showers and storms moving through in the pre-dawn hours around the region.  The Euro (not shown) shows those showers and storms tracking a bit to the north and northwest of us but it does also shown the potential for at least some shower and storm activity tonight.

The thunder chances on Saturday are in association with increased humidity pushing northeast thanks to a warm front (more of a humidity boundary since it's been warm the past few days) lifting through the region, shifting our winds to the south and pulling up subtropical moisture from the Southeastern US.  Thunder chances on both Saturday and Sunday will be scattered around, with Saturday's thunder chances shifting from south to north through the day with a disturbance/warm front pushing through the Northeast and Sunday's thunder chances generally more widespread across the region and in association with an atmospheric disturbance pushing in from the west.

The best chances of a lull in the action locally look to be Saturday afternoon into the evening hours. On Sunday, the thunder threat is not only more widespread but could feature some localized heavy rainfall thanks to increased moisture in the atmosphere. We talked about PWAT rates a few days ago (the amount of moisture in the atmosphere and the potential rainfall that could result) and the GFS continues to suggest PWAT rates over two inches in the region on Sunday.  As a result, any thunderstorm that pops up could produce soaking rainfall rates in those locations that get them.

Keep in mind that storms will be scattered -- it won't storm all day Sunday nor storm everywhere -- some places may not get much of any thunderstorm activity this weekend.  Others may have to deal with localized flooding issues.