Forecast Highlights:
Tonight - Thursday: Pattern Continues
A high pressure will stay in the region through Thursday, providing additional mostly clear skies. Chilly temperatures are expected tonight, falling into the mid to upper 40s inland, low to mid 50s in NYC and the upper 40s to low 50s for the rest of the area. Mostly sunny skies will return on Wednesday with highs in the mid to upper 70s again, with similar temperatures on Thursday but with increasing cloud cover.
Friday - Weekend: Rainy Start, Drier Ending
A tropical disturbance is currently located in the Gulf of Mexico, labeled as Invest 91L. This invest will continue to track northeast, reaching Florida on Thursday and then tracking up the coast, bringing widespread tropical moisture and rain up the East Coast, with the rain expected to focus on Friday into early Saturday. Heavy rain is expected with this system, although there are still model differences regarding the exact track and axis of heavy rainfall, with scenarios in NYC ranging from over 3 inches to only scattered showers. Models such as the CMC and ECM show a track close to the coast with widespread heavy rain across the area, over 2 inches, while the GFS shows a significantly drier outcome, with a weak, more disorganized low pressure staying further offshore with two areas of heavy rain over 1-2 inches, in the interior Northeast and off the coast, with a narrow corridor of less than 1/4 inch along I-95. The 0z ECM run last night showed a similar scenario before returning to its older scenario of a track hugging the coast with heavy rainfall.
There is enough confidence to expect heavy rain over 1-2 inches in parts of the region, with the main area of uncertainty regarding the axis of heavy rain and how much falls in the NYC area. At this time, I kept a potential mention of heavy rain in the 5-day forecast with the possibility of over 1 inch of rain in the area, although the outlook is subject to some changes. At this time, the storm is likely to end around early-mid Satuday, with a drier ending to the weekend with temperatures generally in the 70s. Stay tuned for more information on the outlook for Friday through the weekend.
The dry conditions in the late weekend, however, are not likely to last for long; with weak ridging likely centered around central Canada, an upper level low is likely to reach the region for the early-mid week time period, potentially producing additional rain in the region. By this time of the year, blocking patterns and -NAO don't always correlate to significant cold as they would in the winter; at this time, the pattern for next week appears to contain near to slightly cooler than average temperatures, with the low pressure track modeled to stay north of the area but with the trough in place keeping any significant warm air mass suppressed. More information will be posted on next week's outlook as details become clearer.
As far as that early-mid week system next week, when is the bulk of the rain expected to fall and when should it start clearing the area?
ReplyDeleteThe bulk of the rain is currently expected to fall on Monday, although rain can't be ruled out for Tuesday and Wednesday, especially if the upper level low sticks around longer than expected which is a possibility.
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