Gloomy Late Spring Blocking Pattern Develops Over the Weekend
Long stretches of nice decent weather have been absent this spring. We now have a strong blocking pattern developing similar to what we saw in early March but minus the big noreasters. Snow lovers would love this weather pattern in the winter. In spring it is a horrible pattern to be in if you want even a couple of nice days back to back Weather models have been signalling a blocking pattern developing in the North Atlantic and today's tele-connection indices show a strong persistent negative North Atlantic Oscillation developing. This creates a blocking high building from the North Atlantic back into Greenland. The downstream results of this are not good. Other than today and Friday, you can say goodbye to warm weather for quite awhile.
The jet stream pattern by next Sunday shifts the jet stream well to the south of normal in the Eastern US. This means more often than not we will be dealing with an onshore. The first high building south for Wednesday & Thursday brings the ocean wind but it is strong enough to pin the remnant Subtropical Alberto moisture to the west. Clouds will be nearby but dry air from New England will allow for some sun from Northern New Jersey & Northeastern Pennsylvania northeast to Southern New England. Areas south of here will be cloudy and cool. Thursday brings a more general overcast with the chance for some rain. Friday becomes the one warm day with temperatures making a run back into the 80s before another front moves through with some late showers and thunderstorms.
Once the onshore flow sets up over the weekend it is not going away according to the GFS at least. The onshore flow could hold on into the first half of next week. With energy to the south there will likely be waves of rain to deal with beginning Saturday and lasting through at least next Tuesday. The wind off the ocean plus the clouds means get used to highs just into the 60s and nights in the 50s. When it is not raining it is just clouds clouds and more clouds. At least you can give the air conditioner a rest. The European model has a slightly more optimistic view of all this. It has a major trough digging southeast out of Canada kicking out the onshore flow early next week but bringing down a rather cool but dry air mass. I would caution that the European model has overdone these troughs in recent weeks so I am a bit skeptical and lean more toward the gloomier GFS idea. Obviously it is only Tuesday but if it is warm weather you like, you have today & Friday and that is just about it...READ MORE ON THE SHORT RANGE FORECAST AT METEOROLOGISTJOECIOFFI.COM