May 28, 2012: One More Day of Heat, Humidity

Forecast Highlights:

– Scattered storms, possibly strong, expected on Tuesday
– Cooler pattern develops starting on Thursday
– Additional rain expected on Friday, Saturday


Today’s Observations:

With a large ridge still stuck over the region, another hot and humid day was observed, with the hottest temperatures of the year so far. High temperatures reached the upper 80s to lower 90s from NYC and further north/west, peaking at 92 degrees in Teterboro, NJ, and the upper 70s to mid 80s across most of Long Island and southern CT, which verifies yesterday’s forecast for today. No storm activity was observed across the area, although today wasn’t expected to bring more than isolated activity at most.

Tuesday will be the last hot and humid day as a cold front approaches, resulting in strong/severe storms in Pennsylvania and New York, slowly moving into the area by the late afternoon and overnight hours. Temperatures will then gradually cool down, with highs on Friday struggling to reach the 75 degree mark. Thursday is expected to be drier, although the dry conditions will not be prolonged as another storm approaches for parts of the weekend.

Tuesday’s Outlook:

Partly cloudy skies are expected on Tuesday, increasing by the second half of the day. Hot and humid conditions are expected again, with temperatures reaching the upper 80s to lower 90s from NYC and further north/west, and the upper 70s to mid 80s in Long Island and southern CT. Heat index may approach 95 degrees again in parts of the immediate NYC area.

With the approaching cold front, a line of thunderstorms, some of them strong/severe, is expected to develop over Pennsylvania and New York during the afternoon hours. The line will then move east, affecting the area in the evening and first part of the overnight hours. Although the storms will reach the area, they are expected to weaken by the time they do so, with a risk of locally heavy storms, especially north/west of NYC. If needed, storm updates will be posted tomorrow evening.

Wednesday – Beyond: Cooler Pattern Develops

Over the next day, a strong ridge will spread into Greenland, but unlike the last few times ridging in Greenland attempted to become sustained, this ridge will be firmly established over Greenland over the next week, if not more, making this the first prolonged period of blocking of the entire season and signals a continuation of the pattern change which started in March, when the stubborn progressive pattern began to fall apart. Considering the time of the year, this blocking pattern is unable to result in a cold pattern, although temperatures are expected to end up closer to average, possibly below average at times.

The cold front will move through the region on Wednesday, ending the heat and humidity. Depending on the timing, there is still a risk of isolated storms, locally heavy, in the afternoon along the Interstate 95 corridor, although at this time no widespread storm development is expected. Temperatures will reach the 80s across most of, if not all of the area, with highs in the mid to upper 80s in the immediate NYC area expected. Thursday will be noticeably cooler, with mostly sunny skies and highs peaking in the upper 70s in the immediate NYC area.

By late Friday into the weekend, however, another low pressure will approach from the west, resulting in a return of clouds and rain. The low pressure is expected to approach the region from the Ohio Valley, ending up either in the Great Lakes or the western Northeast. Friday is expected to be mostly dry but with increasing cloud cover and highs ending up again in the 70s. Afterwards, however, the models differ with the timing; there are two main solutions at this time, the ECMWF which quickly brings the rain through on Friday night with partly sunny skies and scattered shower/storm activity for the rest of Saturday and Sunday, and the CMC/UKMET which show a stronger and slower storm, resulting in widespread rain throughout the weekend. Given the CMC’s typical bias of exaggerating storms as well as the lack of consistency with the two models showing the latter solution, I am siding towards the somewhat weaker/progressive GFS/ECM but with slower timing, with shower and storm activity, possibly heavy, expected on Friday night and into Saturday, perhaps Saturday night as well. When the main round of rain ends, partial cloud cover with scattered shower activity is likely, with highs ending up below average, peaking in the upper 60s to mid 70s across most of the area. Temperatures will warm back up into the 80s next week. Stay tuned for more information on the Friday and Saturday storm potential.

6 thoughts on “May 28, 2012: One More Day of Heat, Humidity

  1. Anonymous Reply

    SO is it a most likely bad weather weekend coming up? I trust your forecasts, they are usually better than the big guys but I need to know because we are having a yard sale saturday and sunday but it can’t be in the rain. Any idea yet on the out look for the week ned of the 9th and 10th if this weekend is a washout? Hoping for some good storms later today here in southern westchester, a good chance? Thanks for your grat page and forecasts!

    • NYC Weather Reply

      At this time, it is likely that the worst weather (heavy rain, thunder) will be limited to the first part of Saturday, perhaps lasting through parts of the afternoon but not a full day washout. The rest of Saturday and Sunday shouldn’t be too bad although scattered pop up showers are still possible at times with partly cloudy skies. The weekend of the 9-10th is still too far out to get any clear idea of the outlook.

      Regarding today’s storm activity, I’ll have storm updates posted throughout the afternoon and evening starting at 5 PM.

  2. Anonymous Reply

    I hope that there’s a chance that the timing of the system could speed up and bring most of the rain on Friday with drying by Saturday morning into the rest of the weekend as my agency is having Central Park Challenge in Central Park from 8:30am to 1:00pm. I saw though that no matter what it is expected to dry out during the afternoon hours on Saturday with dry weather expected Saturday night into Sunday.

    • NYC Weather Reply

      There’s still likely going to be rain on Saturday morning, but the afternoon should be better. The second part of that statement though is not a guarantee; with the trough in place, there’s still going to be scattered showers on Saturday afternoon and Sunday in parts of the area, although it won’t be any washout. There is no high pressure coming in behind the cold front.

  3. Anonymous Reply

    There’s gotta be some sort of high pressure building in behind the front responsible for the dry weather on Sunday and really into Monday. With mostly dry conditions for Sunday and especially Monday there’s gotta be some sort of high responsible for that behind the cold front.

    • NYC Weather Reply

      There is going to be a pressure rise, but still it’s not any solid area of high pressure moving in. Due to strong blocking in Greenland, the trough will settle for a while over the region with a low pressure stuck over eastern New England. With that low pressure close to the area, a solid area of high pressure will fail to develop. There will be partial cloud cover and scattered shower activity but no sunny and certainly dry conditions.

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