Temperatures will be on the rise this week across the southern Plains, AccuWeather meteorologists say. A northward bulge in the jet stream across the center of the nation will usher in above-average warmth to states like Texas, Oklahoma, Louisiana and Arkansas. Daytime highs are projected to soar into the 70s and 80s Fahrenheit by midweek, a noticeable change from the 30s and 40s observed at the start of the weekend. Compared to the historical average for mid-February, the climbing temperatures