Thursday, August 30, 2012

Forecast: Good, then bad, then good

The afternoon update is in from the National Weather Service, and it confirms what I wrote this morning about our weatherfor the front end of the Labor Day weekend.

It's going to be really nice, if you don't mind a bit of heat and humidity. But the heat and humidity will be nothing out of the ordinary for late summer in the Carolinas.

The end of the Labor Day weekend looks to go downhill -- as I wrote this morning. The remnants of Tropical Storm Isaac will move northward over the next few days, then curve eastward Saturday and Sunday, crossing Illinois, Indiana and Ohio. As the remnants move eastward, they'll broaden into a large area of unsettled weather over the East.

There'll be a few storms Sunday and probably a lot of storms Monday.

The change in the forecast is for next Tuesday through Thursday, during the heat of the Democratic National Convention. While there are still some major differences in the computer models, the outlook is better than before.

It's possible we'll enjoy clear and rather nice early-September weather, with highs in the middle and upper 80s next Wednesday and Thursday.

Below is a repeat of what I wrote this morning -- with some updates ...


Outlook: Tropical Storm Isaac set the atmosphere in motion, causing moisture to move northward into the Carolinas from the Gulf for the past two days.  That ends today. Isaac is weakening and drifting northwest. As the day progresses, high pressure from the north begins to dominate. There'll be a few storms today, but many areas will stay dry 

High school football: A nice evening -- shirtsleeves weather. Probably no rain.


 Outlook: An easy forecast. High pressure dominates, so it's rain-free and summer-like. Expect an old-fashioned summer day to end August, with mostly sunny skies, quite a bit of humidity, and highs around 90 degrees.

High school football: Another nice evening. Temperatures in the 80s, dropping to the upper 70s.


Outlook: Another nice day, like Friday. But far to the northwest, the remnants of Isaac are making a turn to the east, crossing Illinois and Indiana. By late Saturday, moisture starts creeping back into the Carolinas.

In Charlotte: Several outdoor pre-convention events are planned, and they'll take place under partial sunshine, hot and humid weather, with highs near 90.  The Matthews Alive festival will be steamy, but rain-free.

College football: It should be a nice day, although hot. Any evening games in the mountains face the interruption of a storm.

Mountains and beaches: This is the last day in which I feel safe, saying the weather should be mostly nice in the high country. A few storms will develop there in the afternoon, but for the most part, conditions will be summer-like at both locales.


Outlook: The remnants of Isaac move from Indiana into Ohio, and the atmosphere across the Carolinas becomes a bit more unstable.  That means a few afternoon and evening storms develop. Skies are partly cloudy, with highs in the upper 80s.

DNC and other Charlotte events: The greatest chance of storms will be in the late afternoon and evening. Otherwise, conditions look OK.

Mountains and beaches: Scattered thunderstorms will develop in the mountains in the afternoon.  The beaches should be nice again.


Outlook: Thunderstorm activity probably will be more prevalent than on Sunday, but Labor Day won't be a washout. Most of the showers and storms will come in the afternoon and evening (typical diurnal activity in the Southeast). It'll be warm and humid, with highs in the upper 80s. If you go outdoors, you will sweat.

DNC: Convention organizers scheduled an all-day outdoor festival in uptown.  At some point in the afternoon and evening, festival-goers might need to find shelter. And they'll need to stay hydrated.


The farther out a forecast gets, the lower the confidence level. And that's certainly the case for the rest of the DNC, for Tuesday through next Thursday.

For now, the National Weather Service says we'll see a gradual drying trend Tuesday through Thursday, with temperatures dropping a few degrees by Thursday (mid 80s for highs).

Caution ... There are lots of things that could make this forecast wrong, including some sort of coastal low pressure system that the European computer model expects to develop.  So don't go to the bank with this forecast.

FYI ... As I said this morning, a new tropical depression has formed in the Atlantic, and it probably will become Tropical Storm Leslie by the end of today. Climatology favors Leslie curving northward into the open Atlantic.