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Morning Roundup: Humid, unsettled weather continues

A near-tropical airmass has settled into the region over the past few days, with high dew points and temperatures in the 80’s creating uncomfortably sticky conditions. This airmass, most notably, was a major factor in the flooding rains and thunderstorms over parts of Northeast New Jersey on Wednesday. While much of the area saw little rain, isolated locations saw totals upwards of one inch, with isolated spots receiving more. Training thunderstorms produced 6.24″ of rainfall in less than 3 hours in Mountainside, NJ.

Today, the airmass will remain warm and humid with a southeasterly flow in the low levels continuing to draw in air off the ocean waters. The best forcing for thunderstorm development will remain back to our west, but a few isolated storms cannot be ruled out. These will, again, be capable of producing extremely heavy rain. The frontal boundary associated with this storm system won’t actually cross the region until Friday afternoon. Here are some highlights from around the meteorological community:

  • Torrential rains produced over 6″ of rain in less than 3 hours in Mountainside, NJ yesterday. Widespread flooding including damage to roads was reported in Mountainside and Scotch Plains. 
  • Thunderstorms with torrential rains will again be possible today, but are expected to generally stay farther west than on Wednesday. The airmass, however, will remain very humid and warm.
  • A frontal boundary associated with the storm system over the Central US will finally approach the area on Friday, with the humid and uncomfortable airmass finally scouring out by Friday evening.
  • Saturday looks likely to be a beautiful day with lower humidity, west winds, and highs in the lower to middle 80’s.

Cold weather continues, storms offshore

For the greater part of the past month, the weather has featured below normal temperatures with occasional precipitation — and much of the same will continue. We’ve experienced two or more “significant” winter weather events, but for now, the pattern looks to continue to feature the aforementioned cold temperatures while significant precipitation events tend to avoid our area. Although this will eventually change when the amplitude of the trough axis over the Northeast US decreases somewhat, we’re not expecting much of a change in the forthcoming work week.

Monday, a system passes to our north with the low pressure center actually tracking through Northern New England. A cold front will approach our area by the afternoon hours and west winds will usher in another cold airmass. The only other noteworthy weather event in the coming week will be a southern stream disturbance which will slide off the Southeast Coast. But forecast models are in good agreement on the fact that the developing surface low will head seaward — well too far south and east of our area for any impacts in terms of sensible weather. Some light precipitation may ultimately graze the area coasts should the track of the storm end up farther north and west of current guidance.

GFS model indicating a low pressure system passing off the coast on Wednesday -- too far south and east for impacts in our area.

GFS model indicating a low pressure system passing off the coast on Wednesday — too far south and east for impacts in our area.

Super Bowl event should be light, but may feature mixed precipitation: In a similar fashion to the parade of clipper systems which we have experienced over the past few weeks, forecast models are indicating a pattern change which will allow for frequent precipitation events emerging from the south and west of our forecast area. The first looks to impact the area during the upcoming weekend — in fact from Saturday into Sunday — and may impact the Super Bowl and associated activities.

That being said, guidance is still very inconsistent with timing and precipitation impacts. The general idea, however, is for a low pressure system to shift front the MS Valley into the Northeast US. What remains uncertain is how quickly it does so, and how much warm air advection pushes north through our area. This will determine when the heaviest precipitation falls, and whether it falls as frozen precipitation or the warm air takes over and results in rain.

Over the next few days we will feature the super bowl forecast for free in each of our daily posts, with updates on the latest information.

Summer Outlook 2013

Below, you will find our 2013 Summer Outlook. We’ve laid out the details and broken down the expected temperatures and precipitation, as well as factors and reasoning involved in the outlook. We encourage your comments, thoughts and feedback!

Factors/Expectations:

1) Neutral ENSO conditions should persist through the upcoming summer with sea surface temperature anomalies (SSTA) not far from normal in the tropical Pacific.

2) The negative Pacific Decadal Oscillation (PDO), or cold eastern Pacific, that we saw through winter has weakened somewhat, but will continue to be slightly negative/cold this summer season.

3) The Atlantic Multidecadal Oscillation (AMO) continues to run slightly positive/warm, with a SSTA profile of warmth near the East Coast, cold in the central Atlantic, and warm in the deep tropics.

4) The strong blocking pattern of negative North Atlantic Oscillation (NAO) and negative Arctic Oscillation (AO) that yielded a very cold late winter/early winter has since dissipated. Both indices have been predominately neutral to slightly positive over the past several weeks, and the historical tendency is for this to continue into the ensuing summer. There may be a one month period of –NAO/AO, but the overall signaling should be near neutral or slightly positive in terms of the NAO/AO blocking indicators.

5) The closest, most similar analog to the present conditions in terms of PDO, NAO, AO, PNA, ENSO, and other factors appears to be 2001. Note that analogs are utilized as tools to identify patterns and obtain clues from the past that may enable us to more accurately forecast the future. No one year is identical in pattern to another year.

6) Palmer Drought Index and Standardized Precipitation Index for the month of May have shown to be excellent foretellers of the June-July-August (JJA) temperature anomalies across the Continental United States (CONUS). The correlation is a strong one, when examining the past 20 years. Areas of drought/dry persistence in May tend to be the breeding grounds for heat in the summer and strong ridging. Likewise, areas of wetness / high soil moisture in the late meteorological spring tend to indicate an ensuing summer of coolness or at least less frequent heat spells.

7) Patterns of strong blocking in the late spring often foretell summers of strong USA heat while patterns devoid of blocking in late spring tend to yield summers of weaker USA heat.

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Clouds, showers expected through Tuesday PM

NAM model showing heavy rain impacting the area Tuesday afternoon and evening along a cold front. Clearing is expected behind the front by Wednesday.

NAM model showing heavy rain impacting the area Tuesday afternoon and evening along a cold front. Clearing is expected behind the front by Wednesday.

Ahead of an approaching cold front, clouds and showers are expected to become more numerous throughout the area beginning late this Monday evening. Despite warm temperatures aloft (thanks to a mid and upper level ridge), southeast winds at the surface will keep the air cooler and damp through most of the area ahead of the approaching front. Low clouds and drizzle are a possibility throughout most of Tuesday. However, there is an isolated chance of some peaks of sun by Tuesday afternoon as winds turn more southerly. This usually occurs directly ahead of the front, so it will be short lived. A period of steady rain is likely Tuesday afternoon and evening as the front crosses the area from west to east, beginning in Western New Jersey and eventually making its way through NYC and Long Island.

Behind the front, winds will quickly shift from southeast to northwest with temperatures dropping accordingly. The new colder airmass will settle into the area by Wednesday with highs in the upper 40’s, but cold northwest winds keeping it chilly. The blustery west-northwest winds are expected to stick around through the end of the week — so enjoy the warm air while it’s still here!

Tonight: Mostly cloudy with a slight chance of drizzle. Lows in the lower to mid 40’s throughout most of the area, a bit warmer near the coast. Southeast winds 10 to 15 miles per hour.

Tuesday: Mostly cloudy with rain likely. The rain may be heavy at times. Highs in the mid to upper 50’s. Southeast winds turning southerly around 20 miles per hour.

Tuesday Night: Mostly cloudy with rain likely early, then clearing. Lows in the upper 30’s to lower 40’s.  Southerly winds turning west-northwest around 20 miles per hour.

Wednesday: Mostly sunny with a slight chance of showers. Cooler, with a high in the upper 40’s. Blustery northwest winds around 20 miles per hour.