April 24: Storm Update, Long Range Warmth

Today is expected to be a very nice day, with mostly sunny skies and high temperatures reaching the lower 70s in parts of the area. Enjoy the nice conditions today, because the next few days are going to be the opposite.

Tomorrow's Forecast:

Tomorrow is going to be much colder than today. With the clouds and rain in place, temperatures will struggle to warm up, and are expected to remain generally steady throughout the day, in the lower to mid 50s. Meanwhile, due to the warm front to our south, there is going to be a sharp temperature gradient. While Philadelphia should have highs in the upper 50s, Washington DC is expected to have temperatures in the 70s, with parts of Virginia in the 80s.

Widespread rain once again returns to the region tomorrow. With rain starting tonight, heavy rain is expected until tomorrow afternoon, followed by lighter rain as the first wave moves out of the area. Rainfall amounts between 3/4 and 1 inch are expected by this time. South of the warm front, shown as the red line on this map, thunderstorms are expected, with severe thunderstorms in southern and eastern Virginia.

Sunday-Tuesday Storm Update

As with yesterday, the models continued to trend wetter, with the NAM and the GGEM now showing over 2 inches of rain for the area. Yesterday's forecast remains generally the same, though there are a few minor changes.

The rain is still expected to begin tonight, falling heavy at times until tomorrow afternoon. I slightly increased the forecast rain amounts, now expecting 0.9 to 1.3 inch of rain by Sunday afternoon. Lighter rain is then expected for Sunday afternoon and evening. The main difference, however, is that the rest of the models are also showing an additional wave of rain late on Sunday night, as the NAM showed yesterday. As a result, I added moderate rain in the forecast for late Sunday night, with an additional 1/4 to 1/2 inch of rain.

By the time that the rain ends on Tuesday night, at least 1.5 to 2.5 inches of rain are expected. Flooding is possible in parts of the area, especially with the heaviest rain tonight and Sundy morning.

Warm Spell Update

The warm up is still shown on some models, and while there is uncertainty, if the warmer models verify, we could see temperatures in the 80s once again. The 06z GFS kept the cold air mass in place too long, completely suppressing the warm up and keeping high temperatures in the 60s, which at this time is an unlikely scenario. In the previous warm spells, the GFS also generally kept a cold air mass in place longer than the actual result. At this time, I am expecting a generally steady warm up, with temperatures back into the 70s by Friday, reaching the mid to upper 70s by Saturday, though Saturday could end up slightly colder or warmer.