The outlook from above A weak upper-level ridge and high pressure at the surface will keep us dry for the day tomorrow. Winds from the south mean the development of fog once again along the coast and in the mountain valleys. A cold front will move through the state Monday with more showers and thunderstorms during the day again. Warm and humid conditions then move in behind the cold front for the middle of the week. An upper-level trough is expected to move in from the northwest late in the week, potentially bringing the risk of showers and storms. Foggy starts continue through Monday Fog will continue to be something to watch out for the next two mornings, especially closer to the coast, in the mountain valleys, and water tributaries. This is all thanks to the Bermuda High off to our east, steering winds from the south, transporting in warm, humid air from the ocean. The fog may not be as dense for the southwest coast on Monday, but it may be more impactful over eastern areas. The winds shift to the west as high pressure slides east and will clear the sky as the morning evolves. The mist should mostly dissipate once the sun comes out, though it may be persistent for a little longer, closer to the coast. Localized flash flood potential Monday afternoon Hope you enjoy the dry weather while you can, because we’ve got more rain on the way for Monday. A cold front will move halfway through the state before dying out later in the afternoon. This will bring more rain showers and thunderstorms with it, mainly in the western half of the state, where the front does move through. Severe weather is not expected at all due to very weak wind shear in the atmosphere. However, a few thunderstorms may produce some heavy downpours. Also, the steering flow aloft will be very weak, so any storms that do form will not be moving very far. With the amount of moisture in the atmosphere, this can lead to issues where a storm just sits over one area for a time, dumping 2-3 inches of rain with isolated locally higher amounts, pending on how juicy the atmosphere becomes. Because of this, some localized flash flooding isn’t out of the picture, especially for areas that tend to flood easily. Dew points rise midweek Tuesday 2 AM (06z) to Thursday 8 PM (00z Friday) - Our cold front will provide a brief respite from the humidity on Tuesday. An upper-level ridge supported by the Bermuda High will keep us mostly dry on Tuesday. Then the humidity builds back in with increasing temperatures. This will make it feel a little warmer than what it will be outside, with some heat indices reaching the low 90s in the far south. The combination of high heat and humidity will also increase the instability. This means that we’ll have to keep an eye out for your normal summertime pop-up showers and thunderstorms through the middle of the week. Any storm that does form will be very weak due to low instability and windshear. Showers and storms possible late week Models are hinting at a return to more rain on Friday as another cold front moves through the region. Because we are almost a week out, there is still quite a bit of uncertainty in the forecast. A model ensemble is where a model is run many times, but the initial conditions are tweaked a little each time to address any small changes in the atmosphere. We then compare each ensemble member with the others to see if there is a trend in the forecast. Most ensemble members currently indicate a better chance of rain on Friday, with cooler conditions expected next weekend following the cold front. However, due to the chaotic nature of the atmosphere, stay tuned as we get closer and get a better idea of the forecast! Temperature outlook through Friday Today's update prepared by Penn State student intern |
Mike Haggett
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