Monday, May 28, 2012
May 28, 2012: One More Day of Heat, Humidity
- Scattered storms, possibly strong, expected on Tuesday
- Cooler pattern develops starting on Thursday
- Additional rain expected on Friday, Saturday
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.
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.
Posted by NYC Weather at 11:24 PM