July 17, 2012: Hot, Stormy Tomorrow

Forecast Highlights:

- Hot, humid again tomorrow; scattered afternoon storms, some severe
- Much cooler for Thursday/Friday with scattered showers
- Seasonable, dry weekend expected
- Not as hot long range pattern likely to develop


----------------------------------------------------------

Records set/tied today:


Newark, NJ
100 degrees (tied record: 100 degrees - 1997)

LaGuardia, NY is listed at 97 degrees in some sources and 98 degrees in others. The record in LaGuardia was 98 degrees set in 2006.


----------------------------------------------------------

Today's Observations:

With another surge of warmth moving into the region, the NYC area observed another mostly sunny, hot and humid day, with Newark observing its second 100 degree day of the month. Temperatures peaked in the mid 90s inland, mid to upper 90s in the immediate NYC area, with JFK, Long Island and southern CT cooler, in the upper 80s and lower 90s with onshore winds. Today was the 2nd warmest day of the year for most places from NYC and north/west, behind July 7.

A cold front will slowly move into the region tomorrow, but one more day of heat and humidity, along with scattered storms, is expected before the cooler temperatures make their way into the area. A drier and seasonable ending to the week is expected, with indications pointing to less heat for the longer range.


Tomorrow's Outlook:


Temperatures will fail to drop much overnight in the immediate NYC area, failing to drop much below 80 degrees, if at all for some areas. As a result, with a partly sunny start to the day, temperatures will quickly be able to warm up, already reaching the mid 90s by 11 AM. Unlike today when dew points were in the 60s, however, dew points tomorrow will already be near/above 70 degrees, resulting in much higher heat index values. While temperatures are expected to be in the mid 90s around noon, the heat index is expected to be near/above 100 degrees.

As the cold front approaches the area, with generally favorable parameters, scattered thunderstorms are expected to form across the northern Mid Atlantic especially after 1-2 PM, which will prevent temperatures from warming up much after 12 PM. Some of the storms will be severe, capable of producing strong winds and hail, as well as downpours and perhaps localized flash flooding with precipitable water values above 2 inches. At this time, most of the area is at risk of seeing scattered strong/severe storms, although some of the latest models focus the initial storm development closer to NYC, which may result in places north of NYC seeing less storms tomorrow. An update will be posted on Wednesday morning with updates on the storm risk along with storm updates throughout the day.


Thursday - Friday: Much Cooler, Some Rain


As the previous update mentioned, the outlook for late this week changed from the previous expectation, as the front will be much slower to come through than originally thought. Thursday is still expected to be warm, with highs in the mid to upper 80s, along with scattered thunderstorms, although the more widespread storms will stay south of the area. By Friday, however, a cooler air mass along with cloudy skies and occasional showers are modeled for the area. This is quite a significant change from two days ago, when mostly sunny skies and seasonable temperatures were expected; if the models are correct, high temperatures may end up as low as only the lower 70s on Friday. The latest models complicate the outlook a bit, as perhaps some models may be slightly exaggerating the cool temperatures, although I did revise the forecast to reflect this trend, with highs in the mid 70s inland and upper 70s across the rest of the area. It is not out of the question that the forecast temperatures may have to be lowered some more.


Longer Range: Warmer, But Not As Hot


By the weekend, drier conditions are expected with temperatures warming back up into the lower to mid 80s for most of the area on Saturday with more widespread mid 80s by Sunday. While temperatures will warm up back to average, possibly a bit above average, there won't be a heat wave for the early week with the core of the ridge staying to the west and another trough approaching. As a result, temperatures will likely peak at most in the upper 80s to lower 90s in the early week before another cold front likely moves through. While the pattern for the rest of the month is not expected to be a persistently chilly one, with occasional heat still expected, it is not likely to be as hot as the first 20 days of the month were, with less frequent 90s for highs. Stay tuned for more information on the longer range.