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Regarding uncertainty for Phillipe and the upcoming rain event:

Do you want to read about the uncertainty for both Philippe and for the rain for the Long Island/ NYC area from the experts at the National Hurricane Center and National Weather Service? Here you go with the first part being about the Long Island/NYC area rain for Friday/Saturday, but the National Weather Service uses a lot of abbreviations. This is why I have been trying to show that there is uncertainty:


Tricky Fri-Fri night with forcing from the incoming upper trof/weak closed low from the west, and low level moisture/ convergence/ WAA with an sfc inverted trough/weak low riding up the coast. ECMWF (Euro) in general is stronger and generating heavier rain with both, but it should be noted that any areas of heavier rain with this combo of systems will likely be more on the mesoscale side, with usual placement and timing errors. At any rate, the entire region should see rain daytime Fri, mainly from NYC metro north/west earlier in the day, then throughout as the day progresses. Best rain chances should then shift more to the east across S CT and Long Island Fri night. With ECMWF slower and a little bit stronger with the upper low and sfc low off the coast on Sat, rain chances could linger into daytime Sat. especially for Long Island and S CT.


Regarding Tropical Storm Philippe, this is a fairly complicated intensity and track forecast. Philippe is in a sheared environment, and currently lacks organization. The system is forecast to move into a slightly drier mid-level airmass in a few days, which may also inhibit the overall convective pattern. Some slight fluctuations in intensity may occur due to the pulsing convective nature of the system during the next few days, with an overall slow weakening trend later this weekend. There remains uncertainty in the intensity forecast and it is possible Philippe maintains its tropical cyclone status as it reaches the northern Leeward Islands, or the system could weaken and open into a trough. The estimated motion is west-northwestward at 4 kt. Philippe is currently being steered by the flow around a weak mid-level ridge and is expected to move west-northwestward over the next couple of days. In the latter part of the forecast period, a weakening and shallow system should turn toward the west-southwest. There is unusually large spread in the model guidance this cycle with the GFS and ECMWF over 1100 miles apart on Day 5. The GFS is stronger and on the right side, of the guidance envelope which has pulled the consensus aids right as well. The ECMWF is weaker and on the left side of the guidance. The track forecast is highly dependent on the intensity forecast, however. The official track forecast is similar to the previous forecast, just slower given the initial slower motion, which is closest to the ECMWF.




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