Wednesday, October 09, 2013

Forecast for Thursday, October 10, 2013

With an area of high pressure now positioned over New England and a coastal storm approaching from the South, the onshore flow has begun. Winds have turned gusty and are from the northeast. Already, some media reports are indicating tidal flooding is occurring in Atlantic City. The coastal storm will be a slow mover and the high will be nearly stationary for several days. This means the onshore flow will be in place for a prolonged period of time and the pressure gradient will tighten for several days. 

Rain is already beginning to impact the southern half of our region. Throughout the evening, the rain shield will slowly lift northward. Otherwise, some drizzle may develop. The exception will be in the Poconos, where there were actually some breaks in the clouds today.  However, skies should become overcast here too this evening. The Poconos may not see measurable rainfall until sometime on Thursday.

It will be breezy inland throughout the night into the overnight hours. At the coast, it will be windy where wind gusts could easily reach 40 MPH, especially along the southeastern part of the New Jersey Coast and along the Delaware Beaches.

Thursday and Friday will feature overcast skies, with periods of rain and drizzle. It will be windy, even inland. Gusts above 30 MPH are possible inland with gusts perhaps exceeding 50 MPH in Eastern New Jersey and in Delaware. With the leaves still on the trees, some spotty power outages cannot be ruled out.  We will have to watch the wind speeds carefully because the gradient may tighten a bit more than the models expect. This will depend on how far north the low moves before retreating later this weekend and if the low pressure system deepens a bit more than the models currently suggest. The persistent northeast wind will result in coastal flooding along the beachfront. Widespread minor tidal flooding is anticipated with some pockets of moderate tidal flooding. Some tidal flooding is also possible along the Delaware Bay. 

I am concerned the computer models are a bit too high on the maximum temperatures for Thursday and Friday. There is a possibility Philadelphia does not reach 60 degrees for a high on Thursday.  For Thursday, the 1200 UTC NAM has 67 and the GFS has 61.

High pressure will slowly build south again and this will push the coastal system back to the south. However, this may not occur until sometime during the weekend and it will be a slow process. As a result, drizzle and showers may linger along with gusty winds. A cold front will move through on Monday. Another frontal system may swing through later on Wednesday into Thursday.