Clouds are on the increase across the region today, as the southern branch of the upper level jet is pulling moisture off the Pacific Ocean. This moist upper level flow will continue today through the upcoming week. At the same time, the lower levels of the atmosphere will be gradually moistening as winds turn southerly across the Southern Plains and Lower Mississippi Valley. Most of this week will be very cloudy, with not much chance of enjoying too many hours of sunshine. Three weak upper level short wave features will ride through the fast westerly flow aloft, over this slowly moistening air mass in place across the Four States. This will generate some light rain mainly south of the area, across southeastern Oklahoma, and Arkansas into western Tennessee on Sunday, Monday, and Tuesday. The best chance for a few sprinkles north of the Missouri and Arkansas state line will be on Tuesday, but the rain will be sparse and light; amounting to only a few hundredths of an inch in a few spots. A better chance of rain will occur on Wednesday into Thursday, as a deep upper level low pressure system drives northeast out of the Desert Southwest into the Central Plains. As this system shifts east on Wednesday, the strengthening pressure gradient ahead of the lower level low pressure center will draw increasingly warm and moist air north across the relatively cooler air in place across the Four States. This warm frontal lift will result in a lengthy period of light to moderate rain, from around noon on Wednesday, through late Thursday afternoon. A brief period of drier northwest flow may allow for a day with more sun than clouds on Friday, before another deep low pressure system builds into the Four States Saturday into Sunday; bringing more substantial rain to the region. A common theme concerning temperatures this week is mild air, compliments of the active southern stream upper level jet which will pull warmer air into the region off the Pacific and Gulf of Mexico. Highs will be mostly in the 50s through much of the week, with lows mainly in the upper 30s and 40s; which is a few degrees above normal maximum and minimum temperatures for early December.