Oct 7: Forecast For Medium Range Uncertain

Note: The 5-Day Forecast was updated for the entire area tonight.

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After cloud cover cleared today, with mainly sunny skies, temperatures were much warmer than the last few days, with highs in the lower 70s for the immediate NYC area. While tomorrow and Saturday are likely to be warmer, with frost possible for Saturday night, there is a lot of uncertainty for the medium and longer range. In today’s update, I will look at the model trends, the set up, and what we could see during this time frame.

**Note: This is a long discussion mentioning the trends, expected scenarios at this time, and potential trends. For those who do not want to read the discussion, you can check the 5-Day Forecast page.**

Friday – Saturday: Mild, High Confidence

Tomorrow and Saturday will both be mainly sunny, with high temperatures rising into the upper 60s to lower 70s inland and lower to mid 70s for the immediate NYC area. Tomorrow night is expected to bring above average low temperatures, in the upper 40s inland and lower to upper 50s elsewhere. Confidence on this part of the forecast is high, however by Saturday night, uncertainty returns to the forecast.

Saturday Night – Sunday Night: Chilly? Moderate Confidence

By Saturday night, the model differences become a little larger. A trough is expected to be in the Northeast, however its timing and southern extent are still uncertain. Looking back at the trends, at first, the models showed this as a strong trough, then trended towards a weak trough too far to the N/E to have a significant impact, being why I raised my forecast temperatures. The latest trends, however, now have the timing a little slower, with the trough trending slightly further south/west with each run, leading to colder temperatures being shown on the models. The GFS, for example, now has lows in the upper 30s for NE NJ and mid 30s in NW NJ, when previously it barely had lows in the mid 40s for NE NJ and 40 degrees for NW NJ.

The models are still slowly trending, but in this time range, they are usually close to the final solution, and with no major shift likely at this time, I decided to lower the forecast lows for Saturday night into the mid to upper 30s inland with the potential of frost, lower 40s for S CT, lower to mid 40s N/W of NYC, mid 40s in Long Island, and upper 40s to lower 50s in NYC. I am following the cooler solutions, as I am thinking that the cooler solution could be the one that verifies, however there is still some room for slight changes with these temperatures, with the potential for slightly warmer lows than I am expecting.

Due to this trough, however, Sunday’s highs are now expected to be cooler. Throughout the day yesterday, the models trended slightly colder, and now show highs only in the lower 60s for Sunday. While I think that is too cool, considering the models sometimes have a cool bias, I still went ahead and slightly lowered Sunday’s highs to the upper, potentially mid 60s inland and upper 60s to potentially lower 70s for the immediate NYC area. If there is any additional trend with Sunday, it is possible that high temperatures trend a little warmer, and I am thinking at this time that the models could trend a little warmer.

Sunday night is expected to be milder due to an approaching warm air mass, with less uncertainty for this time frame. I currently expect low temperatures to be in the upper 40s to lower 50s inland, and lower to upper 50s elsewhere.

Monday – Tuesday: Some Rain, Warm Or Cold? Low-Moderate Confidence

Yesterday, I mentioned how a warm spell was becoming more likely for Monday. Today’s models, however, took a step back, placing the trough in Canada further south, leading to cooler highs. In some cases, such as the 18z GFS, the storm is completely suppressed, and the area sees a chilly rain with highs in the lower to mid 60s. While I am not following this solution yet, I am keeping an eye on this trend, however at this time I do not expect this south trend to continue much longer, and I would not be surprised if the GFS went a little warmer with its next few runs.

For Monday’s highs, I went slightly lower than yesterday’s forecast, expecting highs in the mid 70s, except for Long Island/S CT in the lower to potentially mid 70s. It is possible that I slightly lower my forecast temperatures if the trend to pull the trough further south continues, however for now I am staying with the milder scenario. Regardless of the temperatures on Monday night, some showers are likely, however any shower should be light, with all models indicating rainfall amounts less than 1/4 inch as this is a weak storm.

For Tuesday, solutions range from a ridge in control and high temperatures in the upper 70s to lower 80s to a chilly rain and highs in the lower to mid 60s. As the models have yet to show any sign of consistency, with the outcome depending on Monday’s storm, I am currently going in between the two solutions, with high temperatures in the lower to mid 70s and a few showers, but this is a low confidence forecast and is subject to change.

Wednesday And Beyond: Potential Storm?

On Wednesday, temperatures are once again uncertain as a trough or a ridge could be in control of the pattern, but looking at the overall pattern, a negative PNA is expected, meaning that a ridge in the west coast is expected. If this does happen, a trough would likely drop east of the ridge, potentially in the central United States. With this set up, it is possible that a coastal storm could develop between Wednesday and Thursday, and on Friday, the trough would move more east towards the region, potentially bringing rain and cooler temperatures according to this scenario.

This is still in the longer range, and can change over the next few days, however the potential for the above scenario is there with the pattern in place. Stay tuned for more details on this time frame over the next few days.

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