May 7, 2013: Rain Tomorrow, Weekend Showers

Forecast Highlights:

The stretch of dry conditions will come to an end tonight as an upper level low moves through, producing rain, locally heavy, across the area on Wednesday with scattered showers expected to continue on Thursday, Friday and Saturday. Temperatures will initially remain seasonably mild, leaning on the warm side on Friday, but cooling down early next week with the possibility for inland frost.




Tonight – Friday: Rain Returns

As the upper level low in the Southeast continues to drift NE towards the area, showers will spread in from the southeast after 2-4 AM, with locally heavy rain from NYC and further west in the morning hours. The heavier bands will shift into Long Island, CT and SE NY by the afternoon hours with non-severe thunderstorms possible, as high temperatures peak in the low to mid 60s across most of the area. Rain totals are generally expected to end up around 1/2 inch, locally lower east of NYC and locally up to 1 inch west of NYC.

With the ULL overhead on Thursday, mostly cloudy skies are expected with scattered showers and possible non-severe thunderstorms, with highs peaking in the mid to upper 60s in Long Island/coastal CT and the upper 60s to low 70s for the rest of the area. The ULL will move out on Friday as the next system approaches from the west, although there should be enough breaks in the cloud cover with temperatures aloft warming up enough to allow for a brief warmth surge, with temperatures likely peaking in the mid to upper 70s from NYC and further north/west, perhaps reaching the low 80s in NE NJ in the warmer case scenario. There may be a risk of isolated thunderstorms, especially north/west of NYC focusing later in the day.

Weekend – Next Week: Showers, Then Chilly

As a strong trough digs into the north central US, a cold front will approach the region, with mostly cloudy skies expected. Scattered showers are expected, but with uncertainty regarding how much, with the GFS showing a drier picture with isolated showers and the ECM on the wetter side with occasional light-moderate rain throughout the day. Regardless of this uncertainty, at least some showers are likely across the area, with highs expected to cool back down into the mid 60s to low 70s. According to the latest models, the front mostly clears the area by Sunday with clearing skies and highs in the 60s, although the exact timing of the front is still subject to some changes.

The trough will reach the region by Sunday night into Tuesday, resulting in a surge of cooler than average temperatures as 850mb temperatures fall below 0C across most of the region. Highs on Monday and Tuesday are expected to peak in the upper 50s inland and the low 60s across the rest of the area with mostly sunny skies, while overnight lows are expected to fall into the 40s from NYC and further east/south and the 30s for interior parts of the area, where there may be a risk of frost.

By mid-late next week, the strong ridging in the western US will begin to shift east with a warmth surge likely around the Great Lakes region, but the pattern will still struggle to turn persistently warm for the region. Strong ridging is likely around Atlantic Canada and the western Atlantic ocean, which if the latest models are correct with the overall pattern idea, would lead to a cutoff low forming in the western Atlantic, southeast of the area, which combined with continued weak western US ridging would flatten out the next warmth surge as it reaches the region, preventing temperatures from significantly warming up. This part of the outlook is subject to change as it is over a week away; more information will be posted on the longer range outlook over the next few days.

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