The Weekly Weather Take

Rather than a washout, its been a sticky weekend.  Dewpoints have been in the mid to upper 60's.   The last two Sunday's have been fall like but today will be a summer like day.  Temperatures will climb into the upper 70's and dewpoints will remain in the mid 60's.  The question most people want to know is when will the humidity break?  Unfortunately the uncomfortable conditions will remain in the region until Friday.  By the weekend temperatures will be in the lower 60's so relief is on the way.  So what is causing this summer like pattern?

500 mb Vorticity (mid level of atmosphere)

A upper level low pressure area has dropped out of the pattern.  In a low pressure area winds blow counter clockwise.  That means that our wind direction is from the south and with a southerly wind comes moist tropical air.   A stalled frontal boundary remains just offshore.  Originally it looked like that boundary would be onshore and that's why the forecasts for this weekend turned out to be incorrect.  Its going to take awhile for this disturbance to move.  It's called a "cut off" low pressure center because it has become "cut off" from the rest of the pattern.  The atmosphere behaves (is) as a fluid and moves in wave like patterns.  These waves are not able to push this system out.  Eventually (Friday) this will get kicked out but the forecast is tricky in regard to timing.

Here is the rainfall forecast for the next 3 days, courtesy of the Hydrometeorological Prediction Center (HPC)

This is good news for us, but not so much for New York and Pennsylvania who are still recovering from Hurricane Irene and Tropical Storm Lee.  

Tomorrow is going to be a nice summer like day.  There is a slight chance of showers early.  Fog will be an issue for the commute but after it burns off temperatures will soar to the low 80's.  Tuesday morning will also be foggy.  Tuesday will be mostly cloudy but the sun will peak out and some area's will have a decent afternoon.  By Wednesday rain will approach the region as the upper level low begins to move east.  Timing is up in the air as the models are not in agreement.  In the long range forecast some early season cold weather is likely 10-14 days out or so.

Tropics Discussion

Two Tropical Storms are currently active in the Atlantic Ocean Basin.  These are the 15th and 16th Tropical cyclones.  However, there have been only 3 Hurricanes.  One of these two (Philippe) may become the 4th Hurricane but both systems ultimately will head out to sea.  I expect an active October so the Hurricane numbers will pick up.