A very humid day is in store for southern New England with dew points running into the 70s and temperatures nearing 90F. To our west a cold front is slowly moving towards the region. Itís this front which will eventually clear the coast and allow cooler and drier air to push out the humidity this weekend.
Along the coast of Florida Georgia, tropical storm Arthur is slowly gaining strength and will move along the east coast clipping the outer banks of North Carolina, but remaining far enough off our coast to only be a minor player in our weather. All the models agree this storm will not directly impact most of the eastern seaboard, but areas from North Carolina to Virginia could see tropical storm or even hurricane conditions.
High pressure builds into the region Saturday and Sunday for a pair of great days with warm and dry condition perfect for outdoor activities. Warmer and more humid air returns to the region next week.
I know how important the weather is the next 4 days to everyone. So many events, some of them planned for a year or more and now we have to contend with possible showers and storms from a cold front and the rain shield from Arthur.
The big picture has us contending with showers and storms form the west first and then the rain from Arthur second. Letís discuss the cold front first. Our cold front is now in the Ohio Valley and moving slowly east. The front will force showers and storms to develop just ahead of it today, tomorrow and again on Friday. Today the storms are quite far to our west. The radar image forecasting the position of the showers around 8PM this evening shows most of them are forecast for the western and central parts of southern New England. There is a severe thunderstorm watch posted as of noon for the western part of Massachusetts.
The map below shows potentially how much rain could fall from late tonight through late Friday night.
Tomorrow, as the front pushes closer this line will once again form and this time it will be much closer to the coast. Therefore the chance of showers for Thursday increases during the day and probably peaks somewhere in the 2PM to 11PM time frame.
Remember, showers are moving east and south so those of you further west will see them earliest in the time window. There will be hazy sun and very warm conditions in the morning.
Thursday July 3rd 6PM to 11PM
Hereís the tough part of the forecast. The radar image below shows the projected position of the shower/thunderstorm line Thursday afternoon. Notice eastern Massachusetts is in the clear, but there are numerous showers to the west. As the evening goes on the shower area will push towards the coast, but at the same time be diminishing temporarily. There can be a window for activities Thursday evening before the showers move in, but a difference in the current projection of a few hours changes this.
July 4th 8AM to 3PM
This is when the showers and storms from the cold front will be most prevalent. Currently, confidence is high for some showers the first half of the day. This means parades, beach parties and other outdoor events might be subjected to showers and some could be heavy. If you donít want any risk of rain, move things to Saturday or Sunday if possible. Is there a chance the area moves in and out faster or slower, absolutely, but this is the best forecast right now.
July 4th 4PM to 11PM
The map below shows a forecast radar for 8PM on July 4th. If this is correct the Pops concert isn't going to happen and all events in eastern Massachusetts will be cancelled. If the system speeds up a bit, then the back edge of the rain could make it to Boston earlier, but we will have to see how the trends go the next 24 hours.
Arthurís rain and wind
Late at night on July 4th Arthur is forecast to make its closest pass to New England. The rain shield will likely stay off the coast, but could clip Cape Cod, Nantucket and Marthaís Vineyard. As the storm passes it will pull in drier air and set us up for a very nice Saturday. If the storm intensifies a lot then the rain could push west and cover more of southern New England. Seas are going to be rough and if you are heading to the beach this weekend be aware of strong rip tides.
The weekend itself is going to be mainly sunny and much drier in terms of humidity. Temperatures will be in the 70s Saturday, but warm back into the lower 80s by Sunday More humidity is in store for next week so prepare yourselves.
We have lots more information to go over all day today and again tomorrow. The forecast is going to change so check back frequently and follow my updates on Twitter @growingwisdom
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