Aug 22 Morning, 2012: Little Changes In Forecast

Forecast Highlights:

– Mainly dry, seasonable conditions through weekend
TROPICS: Keeping an eye on Tropical Storm Isaac


Tuesday, August 21 Observations

Mostly/partly sunny skies continued across the area on Tuesday with temperatures slightly warmer than those of Monday, reaching the upper 70s to lower 80s across the entire area. The coolest high was 78 degrees in New London, CT; the highest temperature was 83 degrees, tied between Teterboro, Newark (NJ) and LaGuardia (NY).

Wednesday – Early Week: Little Changes In Forecast

As with August 20’s update, there is not much to mention in this morning’s discussion other than the generally seasonable conditions lasting through the weekend and into early next week. Isolated showers may still be possible on Wednesday, otherwise a high pressure builds into the region through the weekend staying north of the area, slowly moving offshore by Monday. Through Thursday, partly/mostly sunny skies will continue with highs in the lower to mid 80s from NYC and further north/west, above 85 degrees in parts of the immediate NYC area, with upper 70s to lower 80s in most of Long Island/S CT.

The center of the high pressure is expected to stay north of the area, with more of a south wind expected by Friday through the weekend. Temperatures through Friday and Saturday, temperatures similar to those of the late week are expected to continue. A weak cutoff low may end up southeast of the area by Sunday and Monday, which would result in increased cloud cover especially further south/east along with slightly cooler temperatures. The next cold front is likely to affect the area with a risk of rain around early-mid next week, perhaps focusing around Tuesday.

Tropics: Watching Tropical Storm Isaac

With very little interesting weather in the Northeast region, attention turns to the Caribbean, where Tropical Storm Isaac formed today. There are several coincidences comparing Isaac to last year’s Irene; both of them start with “I” as both are the 9th named storms of their hurricane seasons, they formed in the same region one day apart and both are generally headed in a similar direction in the northern Caribbean. Despite this very similar start, however, the storms are unlikely to have a similar ending. Irene had a more northerly component to its movement and crossed Puerto Rico, staying north of the Caribbean islands and east of the Bahamas while intensifying and recurving at the right angle for an East Coast hurricane. Isaac, however, has more of a westerly component to its movement, and is increasingly likely to track over Hispaniola, which if happens, may disrupt Isaac’s intensification or cause weakening; Hispaniola’s mountains have managed to disrupt tropical cyclones including recent examples of 2006’s Ernesto and 2008’s Gustav, despite expected intensification.

While Isaac is on track to target Florida, it is uncertain if it ends up on the west or east side of Florida; most model guidance takes it just east of Florida, although the ECM has been consistent with a Gulf of Mexico strong hurricane, and the GFS has fluctuated between just west and just east of Florida. The ECM at this time is likely the western outlier, although there is still not enough confidence at this time to know exactly whether Isaac will track west or east of Florida. At this time, I am siding with a track taking it just east of Florida; should it take this track, the possibility is there that some form of Isaac, either a tropical storm or remnants, especially should it move inland over the SE US first, may move through parts of or most of the East Coast, but this is not likely to happen in the form of a hurricane moving up the coast as Irene did. While Isaac is unlikely to have the same type of impact Irene had on the East Coast, it will be watched for the possibility that Isaac may have some impact, more likely indirect in the form of remnants, north of the SE US. At the same time, a western solution taking it west of Florida and into the Gulf of Mexico is also not out of the question, especially should the ridge to Isaac’s north remain strong with Isaac continuing on a west/WNW path. Stay tuned for more information on Isaac with tonight’s update.

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