July 2014 - Page 3 of 3 - New York Metro Weather

Heat with afternoon thunderstorms today and Wednesday

July 8, 2014/0 Comments/by Doug Simonian

A warm and muggy airmass has its grip on our area, and combined with a slowly approaching cold front and a disturbance aloft, some showers and thunderstorms will be triggered. For most of the day today, the cold front will still be a bit far to our west, which will generally lead to mostly sunny skies, hot temperatures, and a delay in any thunderstorm activity.

NAM model valid for 2:00pm shows temperatures in the low-to-mid 90s in our area, with 80s along the shores.

850mb temperatures of 18C with sunshine support high temperatures in the low-to-mid 90s, which will generally be commonplace throughout the area. The one exception will be for most of Long Island and the immediate Jersey Shore beaches, where temperatures will stay in the 80s, due southerly winds from the ocean bringing in slightly cooler temperatures.

Initially, the highest 500mb vorticity and core of the trough are still to our west, as evidenced in the image below. The cold front is associated with the low pressure system well to our northwest, and we have a warm, southwesterly flow out ahead of it. However, there is a weak surface pressure trough in the Mid Atlantic — which combined with a weak 500mb vorticity maximum — may act to try and force some convection during the evening.

NAM model showing a weak surface trough and weak area of vorticity, which may help to trigger some thunderstorms. The core of the trough will remain to the west for most of the day, which will delay the thunderstorms somewhat. Additionally, 18C 850mb temperatures will lead to quite the hot afternoon.

As far as the type of thunderstorms that can be expected, some may produce some some strong winds and very heavy rain, due to sufficient wind shear, moderate instability, and very high precipitable water values. Read more

Severe thunderstorms again today, Arthur a ‘Cane

July 3, 2014/0 Comments/by John Homenuk

Severe thunderstorms rocked the NY/NJ area on Wednesday evening, owing to rich tropical moisture and strong atmospheric instability. Behind storms of that nature, typically, the airmass becomes less humid, cooler and drier. Thursday will be atypical in that sense, as tropical moisture will actually increase once again. Rising dew points and humidity values will continue — and temperatures in the 80’s and 90’s are expected again by early afternoon. And, again, an approaching mid level disturbance is expected to aid in the development of strong to severe thunderstorms by afternoon.

Storms will progress from southwest to northeast, initially forming in Pennsylvania and making their way through New Jersey. As was the case on Wednesday dangerous lightning, flash flooding, strong winds and small hail are all possible in strong to severe thunderstorms that do develop. The National Weather Service has issued a Flash Flood Watch for much of the region, and the Storm Prediction Center has placed the area in a Slight Risk for severe thunderstorms through this evening.

Todays Day 1 Outlook from the Storm Prediction Center showing a Slight Risk near our area.

Heat and severe storms Wednesday, Arthur late week

July 2, 2014/0 Comments/by John Homenuk

UPDATE 2:00pm: A severe thunderstorm watch is in effect until 9:00pm this evening. The Storm Prediction Center suggests severe thunderstorms are possible, capable of producing strong winds, small hail, and dangerous lightning. Stay tuned for updates including any severe thunderstorm or flood related warnings. The latest information on the severe thunderstorm watch can be found here.

Heat Advisories were issued by the National Weather Service for much of New Jersey on Wednesday, as heat is expected to build throughout the area once again. Rising dew points are only adding to the issue — as they will create a much muggier, more oppressive airmass than the past few days this week. Heat index values are expected to rise well into the 90’s and possibly come close to 100 in some spots later this afternoon. Any time dew points rise into the mid 70’s while temperatures are in the mid 90’s — the air will be quite heavy.

In addition to the oppressive heat, strong to severe thunderstorms are possible this afternoon. The Storm Prediction Center has placed the area in a “Slight Risk” for severe thunderstorms, indicating a risk of small hail and strong winds. In addition to those threats, heavy rain and frequent lightning would be likely in any thunderstorms that develop. We encourage you to stay tuned throughout the day for updates on the developing thunderstorms and hazardous weather threat. In addition, stay hydrated and avoid prolonged outdoor exposure.

Day 1 Outlook from the SPC showing a Slight Risk throughout the area on Wednesday.

TD1 expected to skirt East Coast on Independence Day

July 1, 2014/0 Comments/by John Homenuk

A developing tropical system is expected to shift northwestward toward the Southeast US coast over the next 24 hours, strengthening from a Tropical Depression into a Tropical Storm at some point during this week. This, almost all forecast models agree upon. What happens thereafter is another story. From Thursday morning forward, there is a considerable amount of spread amongst usually reliable guidance, as the tropical system will shift northeastward along the Mid-Atlantic states of the East Coast. Eventually, an incoming trough and shortwave will kick the tropical system to the north and east, but the timing of this depends highly on the positioning of said feature during the latter half of this week.

This means that our fourth of July forecast is up in the air — and at risk of being spoiled by tropical rains. Adding to the issue is the potential for rain along the front, even if the Tropical Storm is hundreds of miles to our east. We can thank extra lift from the incoming troughing system for this, and many models are picking up on the potential for heavy rain along this band of lift from Thursday Night into Friday. After that, the track of the exact low pressure center would obviously have more significant impacts on our weather.

Forecast track of Tropical Depression 1.

Archive for month: July, 2014