3/7/2011 Extended Forecast: Flood Threat Increasing Thursday

There is no doubt when analyzing the latest late night model guidance that another significant rainfall event is on the way from late Wednesday and especially on Thursday. At this point, a widespread two to three inches of rain appears likely. Some higher amounts of around four to six inches are possible. The current flood guidance shows that two to three inches of rain is needed in Southern New Jersey for flooding. The guidance also indicates less than an inch of rain is needed for flooding in Northern and Central New Jersey. These values will not recover much by Thursday and just show how vulnerable we will be if the guidance and forecast holds true and there are no sudden shifts with the heaviest rain axis. There still are waterways in Northern and Central New Jersey running above flood stage and these may fall just fall below the flood stage by Wednesday, showing what a critical situation this maybe with additional rainfall. Even in South Jersey, while significant flooding didn’t occur with this latest event, the waterways are swollen and not ready to take on more rain. So the message here is pretty clear cut. Flooding is quite likely Thursday Night and Friday and some of it should be of moderate to major severity.

I have course also see a favorable opportunity for wind, something we have seen a lot of lately. This is going to be a double-barrel low pressure setup. A low center may exist across the Great Lakes with another forming along the Middle Atlantic. This will already cause a pressure gradient. Then I see an area of high pressure setting up shop northeast of Maine which will tighten it even more. High pressure will also build in from the south as the system slowly trends to the north and east of New York City. With a saturated ground, strong to high winds will have the potential to cause a lot of problems. We were able to get wind gusts to 56 MPH in New York City with the previous storm and frequent gusts of around or above 40 MPH in New Jersey. This storm could have higher and more widespread gusts if the solutions proposed come to fruition.

The remainder of the extended forecast doesn’t appear as important as the time frame I have discussed with great detail. A cold front will swing through on Saturday, but this will be much weaker in comparison to the upcoming storm.