May 19, 2013: Warmth, Humidity, Storms This Week

Forecast Highlights:

Widespread showers were observed across the area today with temperatures remaining below average, peaking in the upper 50s to low 60s across the area. With the area entering the warm sector, much warmer temperatures can be expected for the early-mid week, back into the 70s and possibly low 80s, along with a risk of scattered thunderstorms on most days, likely ending in time for a drier and cooler Memorial Day Weekend.

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Monday - Thursday: Warmer, Some Storms

A warm front will clear the area tonight with winds shifting towards the SW, which combined with a warmer and more humid air mass surging into the region, will result in much warmer temperatures for the Monday-Thursday time frame. Monday will start out mostly cloudy with isolated afternoon thunderstorms and highs peaking in the mid to upper 70s from NYC and further north/west and the low to mid 70s east of NYC.

The main uncertainty in the forecast is regarding the setup of a frontal boundary in the Tuesday-Thursday time frame. Earlier model runs indicated this boundary will drop to the south on Wednesday before retreating back north, but with today's models showing a variety of scenarios, ranging from the boundary entirely settling to the south with Tues-Thurs in the 60s with rain, a brief cool down on Tues or Weds with temperatures otherwise in the upper 70s-low 80s, or the boundary staying entirely to the north with either Tuesday or Wednesday warming up well into the 80s. At this time, I kept Tuesday's forecast temperatures in the mid 70s to low 80s, while increasing temperatures for Wednesday and Thursday into the mid to upper 70s  for most of the area away from coastal LI and southern CT. Confidence is not very high on this part of the outlook, however, and the temperature outlook is still subject to change.

As of yesterday's update, Tuesday appeared to have an enhanced risk of thunderstorms; the placement of these storms depends on where the frontal boundary sets up, which the latest trends indicate will remain mostly to the north of the area, which would lower the chance of storms affecting the area during the day and evening hours, with scattered storms still possible overnight. Scattered storms are possible again on Wednesday, with an enhanced risk of precipitation on Thursday associated with the next cold front passage.


Memorial Day Weekend Preview: Cooler, Drier

As yesterday's update noted, a trough is expected to return by Memorial Day Weekend, bringing drier conditions, more sunshine, and a return to below average temperatures. The latest models continue to vary with the ending time of the rain, ranging from Thursday night to Saturday, although at this time Friday appears to be a likely time frame for the rain moving out. The temperature outlook is subject to some changes considering it is nearly a week away, although high temperatures are generally likely to end up in the 60s, with overnight lows in the 40s for most of the area away from the coast. Stay tuned for more information on the Memorial Day Weekend outlook.