Saturday Update

SAT 3/15: Interesting trend in the midday model runs. The SREF and GFS have increased precipitation totals across the Cape and the SREF now has much higher probabilities of accumulating snow across the region.

The GFS also continues the idea of ocean effect contribution lasting into Sunday night as cold northerly winds develop. The Regional Canadian model is also further north with its 12z model run... What was looking like almost a complete miss 24 hours ago is now looking a bit better and closer to the forecast that was put together all week long. We shall see...

Fri 3/14

Score yet another win for the high resolution European computer model. Yet again the model was the first to suggest the potential big weekend storm system would slide far enough south of New England to spare the region any major problems. It took every other global model between 24 and 72 hours to catch up.

Either way, the reason for Sunday's miss is actually directly tied to a storm center expected to impact our weather Friday Night and Saturday. A small low pressure system will slide south of New England Saturday, eventually strengthening on its way out to sea and becoming a more formidable storm center to our east. As it strengthens it will force the trailing storm system to head on a more south and easterly course through the Tennessee Valley and eastward off the Carolinas. Earlier in the week, it appeared as though the first low pressure system would be relatively weak, and would just barely allow cooler air to drain into the Northeast behind it - setting the stage for a stronger storm over the weekend. Now, with this feature deepening more than expected, stealing some of the energy, and tugging cooler air deeper into the Northeast, it will block the follow up storm from heading northeastward. So the big storm blows up out over the ocean and heads into Nova Scotia, well east of us. With that said, does this mean we can now expect a nice weekend Unfortunately, it doesn't look that way.

The Surface Map and National Radar Mosaic show rain blossoming over the Ohio Valley and beginning to head northeastward. In the meantime, a series of frontal zones are draped near New England on Friday, focusing some light rain showers and bringing a mixture of clouds and sun to the region. The growing area of rain in the Ohio Valley is associated with the aforementioned lead storm system.

This shield of wet weather will spill into New England tonight and continue to affect our weather on Saturday as the low pressure area moves off the Jersey shore and passes south of Nantucket. What was looking like a rather meager event early in the week is now a fair precipitation producer, with up to a 1/4 to a 1/3rd of inch of rain possible, with higher totals to our north and west. Not only will the storm deliver some wet weather, it will also organize the frontal zones over the northeast and send them slowly southward (also allowing for the storm to track south of New England) and pushing progressively cooler air into the area - this should lead to a rather raw feel to the weather tonight and Saturday morning as east to northeast winds combine with temperatures in the upper 30s to low 40s.

While most of the rain should be over by early afternoon on Saturday, things may not improve much thereafter. As the storm center slides eastward and out to sea south of New England it will shift winds to the north and continue to drain cooler air southward across New England. With northerly winds increasing and the atmosphere continuing to cool, yet not really drying out in the low levels, it will be tough to scour out the clouds. In fact, we could see the development of ocean effect or ocean enhanced clouds and snow or rain showers as we head into Saturday night and especially Sunday / Sunday night as the temperature differential between the air and ocean increases. In addition, there's still some upper level energy to spin through on Sunday and the developing offshore storm to our south - overall enough mechanisms to hold in cloud cover through the weekend and keep the chance for precipitation in the forecast. In addition to the clouds, north winds could become quite strong later Sunday on the backside of the intensifying ocean storm. Gusts over 40mph are possible Sunday night. Monday should find improving conditions, though some clouds could linger for a time and it will be brisk and chilly.

Our next storm system should arrive during mid-week.