Sunny skies will welcome the official arrival of fall at 10:49 a.m. today, but it could be a dark and stormy night in southwestern Connecticut.

The National Weather Service says that, under those bright daytime skies, the temperature will rise to the upper-70s, with a light and variable wind becoming south 12 to 17 mph.

Tonight, however, in a "hazardous weather outlook" the NWS warns that a cold front will begin moving into the region this afternoon and evening, possibly triggering showers and thunderstorms, some with downpours and gusty winds. Nighttime skies will be cloudy and the temperature will dip to the mid-50s.

Tomorrow will be sunny, with a high temperature about 70 degrees. Nighttime will be mostly clear, with a low temperature in the upper-40s.

On Monday, more sunny conditions are in the forecast, with a high temperature in the upper-60s. It will be clear at night with a low temperature about 50 degrees.

Tuesday also should be sunny, with a high temperature near 70 degrees. Nighttime will also be clear as the temperature dips to the mid-50s.

The outlook for Wednesday, according to the weather service, is sunny and temperatures in the low-70s.