Sept 21: Summer-Like, Record Heat For Friday

The poll for the hottest temperature between Wednesday-Friday is now closed. Despite the models showing 90+ degrees, there have been 5 votes, and they are tied between 78-82 degrees and 82-86 degrees, which had 2 votes each. The other vote came for 74-78 degrees, and there were no votes for 86-90 and 90+ degrees.

This heat spell, a heat wave for the Mid Atlantic, is expected to be the most significant since early September, with temperatures likely returning into the 90s for NYC along with humidity. This will add the count of 90+ degree days for the area, and some places may tie or break their records for the most amount of 90+ degree days in a year.


Tomorrow’s Outlook:

Tomorrow will be the first day of the biggest warm up since the early September heat wave. With the warm front well to our northeast and a cold front approaching from the west, 850 mb temperatures will rise into the 16-18c range, leading to high temperatures reaching the mid to upper 80s inland, upper 80s to lower 90s in the immediate NYC area, and with a SW wind, Long Island and S CT will likely reach the mid 80s, with a few lower 80s possible near the coast and upper 80s in western Long Island.

Tomorrow night, as the cold front approaches, scattered thunderstorms, potentially severe, are expected for the western parts of the area. Some storms could reach the eastern parts of the area, but they will likely not be as strong.


Thursday – Saturday: Summer-Like Weather Continues

Thursday: The cold front is expected to bring storms on Wednesday night, however this cold front will not move through, but rather stall to our north, keeping the very warm conditions in place. Yesterday, I raised my forecast highs to the mid-upper 80s in NYC, and I am keeping them at the same level with today’s forecast. Partly cloudy skies are expected, and an isolated shower cannot be ruled out north of NYC. The cold front, however, will have a rather significant impact on places such as Maine, where high temperatures will drop into the 60s.

During Thursday night, the stalled front will start to lift northeast as a warm front, which will bring in warmer temperatures again. Overnight lows will be in the upper 50s to lower 60s inland, and lower to upper 60s for the rest of the area.

Friday: Friday, however, will be the hottest day of this heat spell, and has the potential to bring record heat from Washington DC to NYC. By the late afternoon, the warm front will have moved through, with mostly to partly sunny skies and a SSW wind expected. After I made my update yesterday, the NAM came into range and is hot, with high temperatures near the mid 90s for NYC, and the GFS has trended warmer as well, now showing high temperatures in the upper 80s for NYC, and it tends to be too cool by a few degrees for the daytime high temperatures.

Looking at the above, I have raised my forecast high temperatures, now expecting upper 80s inland, lower to mid 90s for the immediate NYC area, and Long Island/S CT in the mid to potentially upper 80s. With dew points in the 60s, this will lead to a potentially warmer heat index. Due to this, I issued a heat alert for the immediate NYC area (more details on that in the “Weather Alerts” page).

Saturday: With mild temperatures expected for Friday night as the cold front approaches, it is expected to move through during Saturday. High temperatures will be in the upper 70s to mid 80s, with scattered showers and thunderstorms possible.


Sunday And Beyond: Storm Or Cool Down?

As I mentioned yesterday, there is uncertainty on what happens on Sunday. The uncertainty level is actually higher now, with possibilities ranging from a weak coastal low, to a low pressure moving north just inland, to no storm and a significant cool down. At this time, I have highs in the lower to upper 60s for Sunday with mostly cloudy skies in my 5-Day Forecast, but this is a relatively low confidence forecast and can still change.

Tropics: Igor Extra-Tropical, Lisa Active, Matthew To Form Soon

Igor finished its extra-tropical transition earlier today, and has been declared extra-tropical. Igor ended up closer to Newfoundland than originally thought, almost making landfall there, with reports of significant damage coming from there. Igor continued to grow in size up to its final advisory, with tropical storm force winds extending over 500 miles from the center. As a result, despite being far away from Nova Scotia, tropical storm force winds were very close to Nova Scotia.

Tropical Storm Lisa is currently slightly strengthening while slowly drifting, and is expected to intensify into a strong tropical storm, if not a weak hurricane. Afterwards, it will face an increasingly unfavorable environment, and will likely start to weaken. Lisa is currently not a threat to land.

Tropical Disturbance In Caribbean Could Become Major Hurricane

As I mentioned a few days ago, the models took a tropical disturbance in the Caribbean and developed it into a hurricane, with the potential track ranging from the Gulf of Mexico to the Bahamas. This tropical disturbance is currently active in the southeastern part of the Caribbean, and according to the National Hurricane Center, has a 50% chance of becoming a tropical cyclone over the next 2 days.

This tropical disturbance is expected to move west northwest, likely moving close to Nicaragua before turning more northwest, reaching the Yucatan Peninsula. The area where this will be active has not had a single tropical cyclone since Hurricane Felix in 2007, a destructive Category 5 hurricane which struck Nicaragua. Because of the lack of activity there, there are very high SSTs and Tropical Cyclone Heat Potential (TCHP) values. 95L is currently suffering from some wind shear to its north, but this wind shear is expected to weaken. Once it moves away from South America, with open waters and low shear, it could rapidly intensify, and it could become a major hurricane by the time that it reaches Nicaragua. If this becomes a tropical storm or hurricane, it will be named Matthew.

What happens from there, however, is still a question. It is possible that the storm crosses the Yucatan Peninsula and moves into the Gulf of Mexico, as the GGEM has been suggesting, or it follows the typical path of October storms, reaching the Yucatan and recurving northeast, directly affecting Cuba and making landfall in Florida as a hurricane, like the ECMWF is showing. If the GFS verifies, the storm could then go up the East Coast, however this is still uncertain. At this time, the majority of the models take it near or over Nicaragua, stall it between Honduras and Belieze for a few days, then take it north and NE towards Florida. Whether the first or second scenario happens, this storm is going to affect land directly, and if it does become a hurricane, it will not leave for good without directly affecting land.

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