Wednesday, September 1, 2010

Sept 1: Will Earl Affect NYC Or Not?

Brief Notes:

- Due to a lot of uncertainty with Earl, the poll on whether Earl will directly affect the NYC area or not has been extended until tomorrow afternoon. As of now, the majority is saying Earl will directly affect the NYC area in the poll, but if you haven't voted yet, it's not too late to vote your
thoughts!

- Today is another hot day across the area, with both yesterday and today in the mid to upper 90s. There have even been a few 100s southwest of NYC, which is not something seen frequently in late August and early September.

Briefly taking a look at the days after Earl, which will be discussed in more details over the next few days, below average temperatures are likely for the weekend into Monday, with high temperatures in the lower to upper 70s across the area, but as a high pressure builds in with a warm air mass spreading in, well above normal temperatures will likely return for mid-late next week, with temperatures potentially back into the lower 90s, and a 2-3+ day stretch of 90+ degrees may be possible for parts of the Mid Atlantic in the warmest case scenario. The September Outlook will be posted either tomorrow or Friday, expecting warmer and drier than normal conditions.

Hurricane Earl's Latest Discussion

Earl's Current Observations: Earl is currently a Category 3 hurricane, with sustained winds near 125 mph and minimum pressure near 941 mb, 2 mb lower than NHC's previous update. Earl is moving NW at 17 mph, and is northeast of the Bahamas. Earl is currently slightly intensifying, and could reach Category 4 intensity again tonight.

Earl's Intensity Forecast: As I mentioned in my morning updates, Earl was downgraded to a Category 3 hurricane, however it has since organized itself and slightly intensified. The main problem for Earl, however, is the dry air that previously entered Earl. It has since gotten itself much more organized, but the dry air could have a negative impact on Earl's intensity, being why I still have Earl potentially strengthening into a category 4 hurricane again. It should weaken once it approaches North Carolina, likely to be a category 2 hurricane when it passes east of New Jersey. By the time that Earl is near Cape Cod, interaction with the trough to its west will result in extra-tropical transition, and Earl will almost be an extra-tropical cyclone, if not one already, once near Nova Scotia.

Earl's Track Forecast: Earl's track forecast has a lower confidence rate than the intensity forecast, especially with the models still all over the place with Earl's long range track. Some models did trend west, such as the GGEM, which is mainly east of the area but still west of its previous runs, the 12z GFS, bringing 1 inch of rain to NYC, and the 12z NAM, also keeping it to the east of the NYC area but west of the previous run. On the other hand, the ECMWF, which previously showed a direct hit for North Carolina and Cape Cod, trended east, as well as the UKMET, which yesterday was very close to Long Island. The NOGAPS has Earl making landfall in Long Island for its last few runs, and while the NOGAPS is not a very good model and can be considered an outlier, due to uncertainty with Earl I decided to use the NOGAPS' track as the western end of the uncertainty cone, however at this time such a solution is unlikely.

For the short term, Earl is expected to keep moving NW, then switch to NW once it approaches North Carolina, however afterwards, the uncertainty is on where Earl starts to recurve NE and how strongly it does so. If the trough becomes negatively tilted, it would be able to pull Earl closer to the coast, leading to more of a NNE than NE track and taking Earl closer to the area. If the trough is more neutral than negatively tilted, however, Earl would be able to recurve further northeast. At this time, due to a lot of uncertainty, there are a lot of possibilities, but for now, I am sticking with my forecast track from yesterday, as it is close to the current model consensus, and as Earl is still moving NW and has a history of being west of its forecast, it could be very close to places such as eastern North Carolina and Cape Cod, but a landfall over Nova Scotia still expected, however.

Summary: Earl has a lot of uncertainty in its future, however it is likely to directly affect at least the eastern parts of the area at this time, but the entire coast from North Carolina to Maine needs to closely monitor Earl. The National Hurricane Service already has hurricane watches extending up to Cape May, New Jersey, with a hurricane warning for eastern North Carolina, and the Tropical Storm/Hurricane watches will continue to be extended northwards over the next day as Earl will be closer.

For Earl's impact on the NYC area, I am sticking with my thoughts from yesterday, which can be found in yesterday's post. Tomorrow, I am planning on posting rain and wind maps for Earl, as the models should start becoming more consistent and there should be a better idea on the overall pattern. Stay tuned for more updates to be posted tomorrow morning and afternoon.

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