Forecast Archives
Relief from the Humidity!
Wed 7/9: Had enough of the muggy air? You're probably not alone. Dew point readings have been stuck in the upper 60s to lower 70s since Sunday thanks to a deep southerly flow of air riding up the East Coast - tapping air from the Gulf of Mexico and Deep South. Not only does the air feel heavy and sticky outdoors, but without an air conditioner or dehumidifier running inside, this kind of weather can lead to damp, musty and mildewy (is that a word?) conditions in your home. If you run a dehumidifier, you may have noticed that it's been filling awfully quickly the last several days. If you don't, perhaps you've noticed the damp look and feel to your foundation walls. Regardless, relief from the humidity is finally on the way and will be here for the second half of the work week.
The Wednesday surface analysis places a cold front across the eastern Great Lakes. This front marks the leading edge to a cooler, drier, more refreshing air mass that is dropping south and eastward across the Lakes and toward New York and New England. Behind the front, dew point readings are in the 40s and 50s today and it actually feels somewhat cool. In fact, across the Upper Pennisula of Michigan, despite the strong July sunshine highs will only be in the 60s today with gusty west to northwest winds.
Out ahead of the front, in the warm humid air, a solid line of clouds is pressing eastward. Beneath these clouds areas of showers and thunderstorms have been firing over the Appalachians and gradually pressing eastward toward the coastal plain. Here on the Cape, we will be just far enough east to only see a mix of sun and clouds through the day with any showers holding off until tonight. While it will be another precipitation-free day, it will turn rather windy as the pressure gradient tightens ahead of the approaching cold front. Some wind gusts to 30 mph are possible at times, with sustained speeds probably averaging between 15 and 20 mph.
The front crosses the area late tonight / early Thursday morning. Until it does so, the threat for a few quick moving downpours and a rumble of thunder will be in the forecast. Model probabilities for precipitation are fairly high - on the order of 50 to 60 percent - and given the areal coverage of showers Wednesday to our west, it seems like a fair bet that at least some of the Cape will pick up some wet weather tonight. A widespread soaking rain doesn't appear to be in the cards, but a few neighborhoods could see a quick hitting downpour. We're not in desperate need for rain, but it has been a bit dry - despite the humid weather.
Behind the front, winds will shift from the south-southwest to the northwest, signaling the arrival of "cooler" and drier air. The dew point will drop from the upper 60s Thursday morning to the low 60s by Thursday evening and the upper 50s by Friday morning. Interestingly enough, while the incoming air mass is actually cooler than what we are currently seeing, it's always about wind direction here on the Cape. The southwest wind this week has generally capped temperatures in the 78 to 83 range while friends to the west have reached the upper 80s to lower 90s. On Thursday, winds will turn to the northwest and the downsloping nature of the wind and lack of a marine component should allow for temperatures to match or even exceed what we've seen for much of the week. So behind the cold front, it could actually be warmer locally. Readings should end up between 80 and 85 around the area, with the warmest weather possibly out near Chatham as westerly winds run the length of the Cape.
After a nice day on Thursday, even better weather appears likely for Friday. Nearly 100 percent of the possible sunshine is expected as things look right now and with temperatures in the 76 to 80 range and the humidity quite low, it could be a top 10 summer day. Nice weather should continue into the weekend, though a southwest flow will resume and dew points will creep back up.
The next shot at precipitation comes late in the weekend or early next week as a frontal system slides into the region. The GFS computer model continues to stall this boundary out and allow moisture to gather over the region on Monday and Tuesday, producing heavy rains. Amongst the many computer models used to formulate a medium to long range forecast, the GFS is essentially out on its own with this idea, with every other model allowing for a more progressive, traditional frontal passage.
The Wednesday surface analysis places a cold front across the eastern Great Lakes. This front marks the leading edge to a cooler, drier, more refreshing air mass that is dropping south and eastward across the Lakes and toward New York and New England. Behind the front, dew point readings are in the 40s and 50s today and it actually feels somewhat cool. In fact, across the Upper Pennisula of Michigan, despite the strong July sunshine highs will only be in the 60s today with gusty west to northwest winds.
Out ahead of the front, in the warm humid air, a solid line of clouds is pressing eastward. Beneath these clouds areas of showers and thunderstorms have been firing over the Appalachians and gradually pressing eastward toward the coastal plain. Here on the Cape, we will be just far enough east to only see a mix of sun and clouds through the day with any showers holding off until tonight. While it will be another precipitation-free day, it will turn rather windy as the pressure gradient tightens ahead of the approaching cold front. Some wind gusts to 30 mph are possible at times, with sustained speeds probably averaging between 15 and 20 mph.
The front crosses the area late tonight / early Thursday morning. Until it does so, the threat for a few quick moving downpours and a rumble of thunder will be in the forecast. Model probabilities for precipitation are fairly high - on the order of 50 to 60 percent - and given the areal coverage of showers Wednesday to our west, it seems like a fair bet that at least some of the Cape will pick up some wet weather tonight. A widespread soaking rain doesn't appear to be in the cards, but a few neighborhoods could see a quick hitting downpour. We're not in desperate need for rain, but it has been a bit dry - despite the humid weather.
Behind the front, winds will shift from the south-southwest to the northwest, signaling the arrival of "cooler" and drier air. The dew point will drop from the upper 60s Thursday morning to the low 60s by Thursday evening and the upper 50s by Friday morning. Interestingly enough, while the incoming air mass is actually cooler than what we are currently seeing, it's always about wind direction here on the Cape. The southwest wind this week has generally capped temperatures in the 78 to 83 range while friends to the west have reached the upper 80s to lower 90s. On Thursday, winds will turn to the northwest and the downsloping nature of the wind and lack of a marine component should allow for temperatures to match or even exceed what we've seen for much of the week. So behind the cold front, it could actually be warmer locally. Readings should end up between 80 and 85 around the area, with the warmest weather possibly out near Chatham as westerly winds run the length of the Cape.
After a nice day on Thursday, even better weather appears likely for Friday. Nearly 100 percent of the possible sunshine is expected as things look right now and with temperatures in the 76 to 80 range and the humidity quite low, it could be a top 10 summer day. Nice weather should continue into the weekend, though a southwest flow will resume and dew points will creep back up.
The next shot at precipitation comes late in the weekend or early next week as a frontal system slides into the region. The GFS computer model continues to stall this boundary out and allow moisture to gather over the region on Monday and Tuesday, producing heavy rains. Amongst the many computer models used to formulate a medium to long range forecast, the GFS is essentially out on its own with this idea, with every other model allowing for a more progressive, traditional frontal passage.
