PatternChangeAfter a beautiful weekend, the workweek will start with an abrupt change. Any rain at this point would be a dramatic change considering that has had seven days in the 90s and only one day of measurable rain (that shows up on record) for Baltimore’s BWI. Yup! It was last Saturday, the 12th, when 0.47″ fell at the airport. I know over 2 inches fell in many spots along with flooding that day.  A similar set up fell two days earlier. But still, it’s been quiet a warm and dry month. That is about change thanks to a cooler, more active wind flow this week. The wind will shift from the north to eventually from the east off of the Atlantic Ocean. Once it starts, it will stay that way for much of the rest of the month.   The wild card is Low Pressure off of the east coast that could get thrown into the Mid Atlantic by next weekend. But short and simply put,  the heat is done. Temperatures will trend below normal with more chances of rain over the next week.

Note: Fall officially begins with the Autumnal Equinox on Wednesday morning at 4:21 AM

Screen Shot2015-09-20 19_07_01Two things to focus on here. First will be the system swinging through on Monday. There may be showers around for the morning, but rain should fill in during the afternoon and evening. Temperatures will stay in the 60s, and feel chilly. Secondly, the weather pattern will adjust in response to a non-tropical Low lingering off of the coast and High Pressure arriving from central Canada. That will push a persistent easterly wind during the week. It may not mean rain every day, but at least a cool, damp feel like Seattle will try to develop. Our rain chances will increase up the the weekend, then another dry spell will finish the month. I am purposely not showing rain forecast maps yet (other than this one) since I think the models are not handling the system well. While it appears that we may stay on the northern edge away from most of the rain, the trend lately has been for a shift of weather systems to the north. That could adjust the cut off line and really impact plans next weekend. So instead, I am showing the wind pattern is in the second slider. But I will do my best to stay ahead of any trends and share them with you all week.

Two sliders showing the developing pattern

Monday Radar Simulation

Reminder: There may be rain showers in the morning. I am starting the slider in the afternoon to show the development and movement of the widespread rain. Most of central Maryland will stay under 0.50″ of rain, with heavier amounts in the mountains.

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Pattern Change

Temperature Outlook

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Pressure and Wind Flow

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The main point here is that this week will NOT be hot and dry. It will not be a washout either. But it will certainly be dominated by cooler and more damp weather. One main player will be how that storm off the coast organizes and moves. I don’t believe it is being handled well, so it is possible it could bring us more rain for the end of the week. Then again, it could be a dud.  Watching that all week will be paramount to individual daily forecasts, after our Monday rain passes by.

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