I don’t think I was the only one who enjoyed the warmth Monday. Temperatures stayed in the mid to upper 50’s through the early afternoon hours before the cold settled back into the Valley.
But why so warm? Sunday was a dreary day, but the temperature was rising steadily in the afternoon and even into the overnight hours. The simple answer is that we had a warm front pass through the region. When the warm front is to our south, winds (if present) come from the east. After the warm front passes to the north of us, the wind shifts to the southeast, south, or southwest. The slight wind shift makes all the difference in our temperature.
Looking back on data from the wee hours of Monday morning, the Charlottesville-Albemarle Airport shows the effect of a wind shift. From 4pm to 11pm Sunday evening, the temperature stayed in the lower 40’s with a calm wind. At 11:54 pm, the winds were out of the southeast at 10 mph and the temperature was 54 degrees. This all changed within an hour – all because of a wind shift!
The quick temperature increase signifies the frontal passage. Throughout Monday morning, the temperature continued to rise into the 60’s. Monday remained warm until sunset, when the cool air could move back into the Valley via west northwest winds.
So we’re back to the cold and our typical January. I know everyone is very interested about the potential winter storm at the end of the week. We still have 3 days to go before the event, but I will say that computer models are divided with the outcomes. Some bring significant snowfall to the area, some keep the snow suppressed to the south. I’ll have a deeper discussion of the storm and model data tomorrow.