May 19

NYC Area Weather Relaunch

May 19, 2016 Blog Notice

NYC Area Weather will be relaunched on June 1, 2016. The blog will feature a new design, more meteorology-oriented posts, and new features including real-time model guidance and current weather data.

 

 

Apr 07

April 7, 2016 Noon Update: Snow Possible

Brief Update: Snow Possible This Weekend

ne_apcpsfc_f60The return of winter continues into this weekend, as the third snowstorm to affect the Northeast US this month may produce snow in the tri-state area as well.

In a scenario similar to that of last weekend, a powerful vorticity maximum will dig into the region, with forcing for ascent provided via strong cyclonic vorticity advection and low-level convergence. Steep low-level lapse rates are expected, with surface temperatures in the upper 30s but 850-hPa temperatures near -4 degrees Celsius; temperatures are initially expected to support rain, but with the steep lapse rates favoring the development of moderate to heavy precipitation bands, with temperatures in these bands cooling down to the wetbulb, which given the anomalously cold air mass in place will be cold enough to support a potential changeover to heavy wet snow.

The position of the vorticity maximum, surface low pressure and accordingly the precipitation banding is still somewhat uncertain, and will influence the position of the narrow snow axis. Based on the latest model guidance, the position may range from central New Jersey to southeast New York. Any potential snow accumulations will be limited given that the heaviest precipitation should occur during the daytime, with the high sun angle and relatively mild initial surface temperatures the primary limiting factors, although locations especially inland of NYC with colder initial temperatures may record light to moderate snow accumulations under these bands.

More information will be posted on the outlook later tonight or on Friday.

Apr 03

April 3, 2016: Winter Returns for Early April

Forecast Highlights:

ne_ptype_f7Despite a near record warm winter, and a lack of snow events in the Northeast US with the exception of a historic late January blizzard, cold and snow are set to make a comeback this coming week, and parts of the region could end up with their biggest snowstorm of the season in April. As a deep trough sets up near the region, multiple rounds of cold and storminess are expected, most notably tonight when thundersnow and strong wind gusts are possible in parts of the region, followed by additional rain and snow on Monday and a potentially significant rain event later in the week.

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Mar 27

March 27, 2016: Cold Start to April Expected

Forecast Highlights:

e_tmpprs_f192Despite a slight cool down in the last few days, this month remains on track to end up among the top 5 warmest Marches on record in NYC, especially following several days last week with highs in the low 70s. Temperatures are expected to rebound into the upper 50s and 60s again by the midweek period, accompanied by rain and wind, but with remarkable model consistency for a potentially significant early April cold surge, with well below normal temperatures possible around the April 3-5 time frame.

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Mar 20

March 20, 2016: Late Season Snowstorm Expected Tonight

Forecast Highlights:

e_ptype_f35Following the previous blog post, significant changes have occurred in the model guidance forecast for Sunday, with most of the model guidance at some point over the last 2 days having depicted a much weaker low pressure producing little to no snow. With barely 24-30 hours left until the onset of precipitation, discrepancy in the model guidance has actually increased, with some models reverting back to a moderate snowstorm scenario. While at least some snow is expected to affect the area, especially east of NYC, the major snowstorm previously depicted on the model guidance is no longer expected.

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Mar 17

March 17, 2016: Will Spring Start With a Snowstorm?

Forecast Highlights:

e_apcpsfc_f84In a season marked with numerous extremes ranging from 70s in December to NYC’s second biggest snowstorm on record, then back to summer-like warmth in early March, the latest extreme appears to be the potential for a snowstorm to mark the beginning of astronomical spring. Much of the deterministic model guidance depicts a major nor’easter affecting the East Coast; while variability among the models precludes higher confidence in the forecast details, the model guidance nonetheless offers some clues regarding the potential impacts in the region.

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Mar 12

March 12, 2016: Anomalous Early March Pattern

Post Highlights:

rtma_max_3.9Following a relatively lackluster winter, meteorological spring quickly showed up with temperatures having soared into the 70s and 80s across the region earlier this week, especially during Wednesday and Thursday, March 9-10. The same time period also witnessed severe flooding in the southern United States, unusual cold and rain in Mexico, and much-needed rainfall in California. This post consists of a meteorological analysis of the synoptic-scale evolution of the pattern that ultimately concluded with the highly anomalous pattern over North America this past week.

 

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Feb 24

Feb 24, 2016: Severe Weather in February

Forecast Highlights:

2.25_0230The winter of extremes continues to live up to its name, with a rare February severe weather outbreak currently ongoing across the East Coast. With a warm front having moved through earlier this evening, temperatures are surging into the upper 50s and low 60s, with sufficient lifting and elevated instability to maintain a narrow but intense squall line over the region. The squall line will move through the area later tonight, capable of producing heavy rainfall and damaging wind gusts over 50 to 60 mph.

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Feb 23

Feb 23, 2016 Update: Snow/Ice to Rain, T-Storms Tomorrow

8:25 AM: Snow/Sleet turn to Rain, Thunderstorms Tonight and Tomorrow

In a somewhat similar scenario to last week, light snow is expected to develop inland of NYC this afternoon, before transitioning to ice followed by rain and thunderstorms with temperatures surging into the 50s.

refd1000m_f11

11z HRRR hour 11, valid at 2200 UTC (5pm EST) tonight, depicting widespread sleet and freezing rain over northern NJ with snow farther inland.

A two-part system is currently affecting the East Coast, with the first round of precipitation associated with mid-level isentropic lift and warm air advection. Precipitation is expected to develop in the tri-state area towards 12-2 PM, becoming moderate at times, before mostly tapering off by 10 PM to 12 AM. Unlike last week, however, the antecedent air mass is not very cold at all; 850 hPa temperatures linger just below freezing, with surface temperatures in the 20s and low 30s with a northeasterly wind. Given a slightly below freezing surface wetbulb temperature, precipitation type is likely to fall as snow over northern New Jersey north of I-80 into southern Connecticut, especially in the higher elevations, before quickly changing to sleet and rain by 3-5 PM. By that time, less than 1/2 to 1 inch of snow is expected for most locations. A longer period of snow is likely towards interior southeast New York and Connecticut, where 1 to 2 inches of snow are possible.

refd1000m_f48

0z NMM hour 48, valid at 0000 UTC Thursday (7pm EST Wednesday evening), depicting an approaching squall line over western Pennsylvania in the warm sector of the 988 hPa low over Ohio.

Mainly overcast skies with areas of drizzle will linger tonight as the warm front remains stationed just offshore, while a deeper surface cyclone approaches from the west towards Kentucky and Ohio, forcing the warm front to progress north later by Wednesday afternoon. Inland of the front, a light surface northeasterly wind will maintain the low-level cold air mass, with temperatures lingering in the upper 30s to low 40s with occasional periods of rain. The warm front is currently forecast to move through towards 10 PM to 12 AM on Wednesday evening, with temperatures surging into the mid to upper 50s accompanied by a strong southerly wind, gusting up to 40-50 mph near and east of NYC. High resolution models indicate a narrow squall line accompanying the cold frontal passage on Thursday morning, with model soundings suggesting elevated instability with CAPE approaching 750 to 1000 J/kg along with a strong low-level jet over 60 knots. Even though the latest SPC severe weather forecast keeps the risk south of the area, the aforementioned conditions do likely support a risk of heavy thunderstorms accompanied by strong wind gusts over 50 mph, which would be capable of producing localized wind damage.

Feb 15

Feb 15, 2016: Snow Transitions To Ice, Rain Tonight

Forecast Highlights:

refd1000m_f14Just one day after record breaking cold across parts of the region, a quick turnaround is currently underway with an amplifying trough approaching the region bringing strong warm air advection through tomorrow. Widespread snow has developed across the area this afternoon, and is expected to change over to freezing rain and rain tonight into Tuesday morning, accompanied by a surge in temperatures into the 50s. Drier conditions will return afterwards, but with a warmer than average pattern expected through the remainder of February.

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