May 8, 2013: More Showers Through Saturday

Forecast Highlights:

An upper level low continues to slowly track northeast through the region, having produced heavy rain and thunder in parts of the area this morning with as much as 3 inches in Central Park. The ULL will continue to produce showers on Thursday, with another storm system moving in for Friday and Saturday resulting in a brief surge of warmth and additional showers, followed by a strong cool down early next week with the possibility for interior frost.



Tonight – Saturday: Showers Continue

The upper level low, currently located near western Virginia, will continue to slowly track northeast over the next 2 days, and will be directly overhead on Thursday. While a repeat of this morning’s significant rain totals near the immediate NYC area is not expected, an area of showers is likely to develop near eastern NJ overnight while tracking north, spreading into the area by the early-mid morning hours. Some showers may be locally moderate/heavy, but not to the extent seen this morning, with up to 1/4 or locally 1/2 inch expected. Scattered showers and thunderstorms will continue through the afternoon and evening with highs peaking in the mid to upper 60s especially away from the coast.

On Friday, the ULL will move out of the region while another low pressure approaches from the Ohio Valley. The timing of this storm is expected to be too slow to produce much, if any precipitation during the day on Friday, with mostly sunny skies expected along with much warmer temperatures, peaking in the upper 60s to mid 70s in Long Island and southern CT and the upper 70s to low 80s from NYC and further north/west. Scattered thunderstorms are expected overnight, although the stronger storms are expected to stay west of the area.

The cold front is expected to move through on Saturday, with cooler highs back into the lower end of the 70s. The timing of the front varies with the models, with the GFS faster with the timing and the NAM/ECM on the slower end. I sided closer to the ECM with the timing, with cloudy skies and occasional showers/thunderstorms likely on Saturday, clearing overnight.

Sunday – Next Week: Cooling Down

A strong trough will drop into the region by Sunday into early next week with widespread 850mb temperatures below freezing, resulting in a short round of much cooler temperatures. Partly sunny skies are expected for Sunday with mostly sunny skies for Monday and Tuesday. Sunday is still expected to be generally seasonable with highs likely in the mid 60s to low 70s, but with Monday cooling down into the mid to upper 50s inland and the upper 50s to low 60s across the rest of the area. Monday night will be the coldest of this time period, with lows in the 40s from NYC and further east/south and likely in the 30s for most locations north and west of NYC, likely approaching freezing for interior areas where frost may be possible. A moderation in temperatures is expected for Tuesday with highs likely back into the low to mid 60s.

Towards the middle of next week, strong ridging is expected in the central-western Atlantic Ocean, with the weekend cold front slowing down once offshore, possibly splitting into a cutoff low. Meanwhile, strong ridging in the western US will begin to expand east but will be suppressed as it reaches the region, with temperatures still warming up closer to average for the mid-late week period but without significant warmth. Uncertainty increases on the outlook by late next week, although the latest models indicate the possibility for the next rain event around this time frame. Stay tuned for more information on next week’s outlook.

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