07/11/10  11:54 AM

Unlike last summer, this summer has provided the Philadelphia and New York City metropolitan areas with plenty of heat and humidity.  That theme is not likely to end any time soon.

High pressure will continue to build into the northern Mid Atlantic from the Ohio Valley while a weak area of low pressure exits into the Atlantic to the east.  The combination of which is supporting the transport of slightly drier air into the northern Mid Atlantic.  However, the northerly winds are also creating a down sloping influence off the Appellations leading to temperatures to rise into the mid 80′s to lower 90′s throughout the region for highs today.

Through Tuesday morning, high pressure will keep the New York City and Philadelphia metropolitan areas dry.  However with the high pressure system expected to move off the coast, the return of highs in the mid 80′s to lower 90′s and dew points in the 60′s and 70′s will return.  This combination of temperatures and high dew points will make for another round of hot and humid weather conditions for the start of this coming week.

One major change however from last week is that cold front over the Great Lakes will attempt to move through the northern Mid Atlantic starting on Tuesday night and continuing on through next week.  These cold fronts will not succeed in changing the dynamics of the air mass in place, which will be hot, humid, and unstable.  However, the constant interaction of these cold fronts with this air mass will lead to the constant threat of thunderstorms for the region each afternoon.  At this time I think the best threat is over eastern Pennsylvania and the Hudson Valley as these locations will be closer to the mid level disturbances that will spark these thunderstorms.  Otherwise, most locations will be stuck in the loop of hazy, humid, warm mornings with localized dense fog followed by hazy, hot, and humid afternoons.  There may be some relief at the beaches with an occasional sea breeze IF winds remain below 10 mph from the southwest.

For details on your locations conditions, visit the NY NJ PA Weather Local Seven Day Forecast!

05/03/10  4:52 PM

As the cold front exits off the New Jersey coast this evening, a new air mass will follow with much lower humidity and tranquil weather conditions.

As we can see with the water vapor satellite picture this evening, very dry air is behind this departing cold front, which will lead to rapidly clearing skies tonight through tomorrow morning.

Excellent weather conditions are expected through tomorrow afternoon as high pressure moves over the region.  A weak disturbance will pass through the northern Mid Atlantic on Tuesday night with a few isolated showers, otherwise increasing clouds can be expected.  High pressure will remain in control Wednesday through Friday with clear skies, light winds, and high temperatures averaging slightly above normal in the 70′s.

A cold front will follow on Saturday with wide spread showers and thunderstorms.  There is potential for the strongest thunderstorms to produce heavy downpours, frequent lightning, small hail, and dangerous wind gusts.  The cold front will exit by Saturday night with much cooler air to follow.

High pressure will build in on Sunday and Monday with clear skies.  Temperatures on both days will average below normal for the period with highs struggling in the 60′s.

04/26/10  7:27 AM

An area of low pressure over Ohio will slowly move to the east today with another round of moderate to heavy rainfall later this morning through early this evening.  The rain will be heavy at times with another half inch to an inch of rain possible by late tonight.

As the area of low pressure moves off the New Jersey coast tonight, the rain will intensify once again along the immediate coast.  The rain will continue on through Tuesday morning but will taper off towards noon tomorrow.

So, basically we have another 24 to 30 hours of overcast skies, patchy fog, and periods of moderate to heavy rain to contend with to start the week.  Temperatures won’t move much from the 40′s and 50′s as well, but the apparent temperatures will feel like the 40′s under these gloomy conditions.  However, there is some good news!

Once this storm exits, a new pattern will take hold and one that will be very pleasant for many throughout the Philadelphia and New York City metropolitan area!  A strong upper low over eastern Quebec will continue to shift east towards the Canadian Maritimes on Tuesday night and Wednesday, which will put the region in an area of convergence and confluence.  This type of pattern supports high pressure over the Tennessee Valley to intensify, which will provide a cool yet dry northwesterly flow over the region through mid week.  Temperatures will average near normal with highs in the 60′s and lows in the 30′s (mostly over the interior) and 40′s.  Then the real change in the pattern takes hold!

The pattern over the past several weeks has been what we call in the meteorology world, a west based negative North Atlantic Oscillation pattern.  This type of pattern keeps a marine influence throughout the Northeast and Mid Atlantic along with a constant threat for slow moving low pressure systems and rain.  However, the negative NAO will shift to the east or become east bases.  This shift is extremely important as the upper level pattern takes a big shift to the east.  This brings a ridge into the East coast, and trust me, we like ridges in the Spring and Summer!

On Thursday and Friday, the upper level ridge will build from the Ohio Valley towards the East coast with the ridge axis moving right over the northern Mid Atlantic on Friday evening.  High pressure at the surface will set up off the Southeast coast, producing an increasingly strong southwesterly flow, which will support impressive warm air advection throughout the northern Mid Atlantic.  Temperatures will warm into the 70′s for highs as a result while humidity will also be on the increase.

By Saturday and Sunday, the ridge axis will be to the east of the region at 500 MB.  This will produce a southwesterly flow at all levels of the atmosphere, but also start to introduce the influence of disturbances approaching from the southwest and moving northeast.  Given the blocking nature in the pattern, this ridge is not going to give way all that much from Saturday on to early next week, which means any cold front that approaches will stall or weaken rapidly while approaching.  We saw this last Spring and Summer as well.  This type of pattern introduces plenty of warm, moist, unstable air into the region ahead of strong disturbances, which spells the threat for strong to severe thunderstorms on the afternoons of Saturday and Sunday.

Now, I don’t expect organized precipitation on Saturday or Sunday so not everyone will see a storm.  However, if a storm does impact your location, it will likely be in the time period between 1 PM and 6 PM when the atmosphere becomes most unstable.

Well, to the late Spring pattern, lets see how long this will ride!

For a detailed seven day forecast, go here!

04/12/10  5:15 PM

High pressure is clearly in control over the northern Mid Atlantic this evening with clear skies and high temperatures rising into the mid to upper 60′s throughout the region.

Tranquil conditions are expected through tonight with light winds and temperatures falling into the mid to upper 30′s over the interior and lower to upper 40′s along the coast.

A weak disturbance, currently over the western Great Lakes, will dive towards the Philadelphia metropolitan area by tomorrow evening with increasing clouds.  Showers are expected on Tuesday night as the disturbances moves towards the southern New Jersey coastal waters.  More isolated showers are expected over the New York City metropolitan area.  Additional weak disturbances will move through the region on Wednesday and Thursday, however most locations can expected dry and cool conditions.

A more impressive disturbance is expected to develop on Thursday night with a warm front slowly moving northeast through the Philadelphia and New York City metropolitan areas on Friday.  This warm front will be capable of periods of heavy rain in the morning followed by a threat of widely scattered showers and thunderstorms through Friday evening.

High pressure will take hold by next weekend with clearing skies and temperatures near normal.  High temperatures will range from the upper 50′s to upper 60′s through the weekend.  Low temperatures will range from the lower 40′s to lower 50′s.

For a detailed seven day forecast, go here!

04/04/10  8:43 AM

Dense fog has developed along the coast and throughout the New York City metropolitan area including Long Island this morning leading to visibility at times below a mile in many locations.  The good news is that once the fog lifts, conditions will improve dramatically.

A weak disturbance is moving through Pennsylvania this morning that will bring much drier air and a westerly wind to the Philadelphia and New York City metropolitan areas by later this morning.  This disturbance will force the fog to lift and lead to another perfect Spring day for the region.

High pressure will hold on through tomorrow with clear skies and warm temperatures in the 70′s and lower 80′s.  The stronger southwesterly flow will override any sea breeze influence with the exception of eastern Long Island where the southwesterly wind will come off the coastal waters south of Long Island.

The next threat for rain will be on Tuesday afternoon as a cold front stalls over the region from the Hudson Valley with increasing clouds and scattered showers.  The cold front will rebound quickly by Tuesday night with clearing skies.  High pressure from the Southeast will build into the northern Mid Atlantic with clear skies and rather warm temperatures once again for Wednesday and Thursday.

A strong cold front is expected on Friday with showers and thunderstorms.  A few of these thunderstorms may be rather severe with strong wind gusts, heavy downpours, large hail, and frequent lightning.