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Nov 26

Nov 26-27, 2013 Storm Updates

Occasional updates will be posted below on the heavy rain, snow/ice and wind event affecting the region today and tomorrow. Updates will also be posted on Twitter.

Links:

Yesterday’s forecast discussion
Twitter updates
8-Day Forecast


Final storm rain totals in NYC: (Updated 10 PM)

Central Park – 2.49″
LaGuardia – 2.21″
JFK Airport – 1.97″


Blog Updates: (Regional radar from the Pennsylvania State University e-Wall)

 

6:10 PM: Storm Gradually Ending

nerad257As of 6 PM, the area of low pressure stretched from Rhode Island through Boston and Maine. Minimum pressure is near 988 mb, and the low will continue to intensify while tracking NNE and consolidating tonight.

The steady precipitation has mostly moved out, with a final wave of light-moderate precipitation currently moving through. This is falling in the form of snow in NW NJ and SE NY, with rain elsewhere. The precipitation shield in the south end of the system has largely collapsed since early this afternoon, but with isolated rain/snow showers possible through 7-8 PM. The heaviest rain axis with this storm set up over NE NJ into NYC, SE NY and southwest CT, where at least 2 to 3.5 inches of rain fell; elsewhere in the area, towards NW NJ/SE NY, Long Island and the rest of southern CT, at least 1.5 to 2.5 inches of rain fell. This makes it the most significant storm to affect the region since tropical storm Andrea in June, which produced widespread 2-4 inches of rain.

Clearing skies are expected tonight with an increasing northwesterly wind at 15-25 mph, gusting up to 35 mph. Thanksgiving day will be mostly sunny, cold, dry and windy, with highs only in the low 30s inland and mid 30s for the rest of the area. Temperatures will gradually moderate through the rest of the week, with the next chance of rain/snow showers towards the first half of next week.

This is the final storm update for today; the next forecast discussion and 8-day forecast will be posted on Thursday. Additionally, a storm summary for this system including archived radar will be posted by tomorrow as well.

3:25 PM: Second Wave Moving In

nerad256As of 2 PM, the broad area of low pressure was centered near central Massachusetts, with a minimum pressure near 992 mb. The low will continue to intensify and gradually consolidate as it tracks NNE into Canada by this evening.

The last few hours were drier across the area as the cold front shifted east of NYC, but with the second wave of precipitation entering the area. Precipitation is currently rain across the area, but with a changeover to wet snow reported over parts of Pennsylvania and NY state as colder air enters the region from the west. Light to moderate rain will continue through at least 7-8 PM as the mixing line will continue to gradually shift east throughout the afternoon, entering NW NJ and interior SE NY within the next 2 hours where up to 1/2 inch of snow is possible. A changeover to light snow showers may be possible towards NE NJ and NYC by the end of the storm with no accumulations expected, with locations east of NYC unlikely to change over to snow by the end of the storm.

 

11:00 AM: More Rain Today; Interior Back-End Snow

nerad254As of 10 AM, the broad low pressure area extends from North Carolina through SE New York. There are two low pressure centers; one near New York City with a minimum pressure of 996 mb, and another near North Carolina, associated with the southern energy currently phasing with the northern stream. The northern low pressure will continue to track NNE into New England, while the southern low will gradually merge with the northern low as the southern energy catches up.

Heavy rain continued across most of the area last night, with temperatures rising into the upper 50s-low 60s in the late overnight into early morning hours for most of the area; the warm front never got west of central NJ, however, with a sharp temperature gradient setting up as NW NJ and interior SE NY failed to warm up beyond the low 40s. The heaviest rain trained over NYC and northeastern NJ, where rain amounts of 2-3″ have been observed so far, with totals elsewhere generally between 1.5 and 2 inches so far, locally higher. Strong south/SE winds were observed last night in the warm sector, with wind gusts generally in the 40-50 mph range for most, locally up to 55 mph in Long Island.

The cold front is currently moving through NYC, with the axis of rain gradually shifting east, shifting the moderate to locally heavy rain into Long Island and Connecticut as locations from NYC and further west see lighter rainfall rates or a temporary break through the early afternoon hours. Meanwhile, temperatures will gradually fall into the upper 30s-low 40s in northern NJ by the mid-late afternoon, and crash into the 40s as well over Long Island and CT with the frontal passage early this afternoon. As the second wave moves through the area in the mid-late afternoon, another round of rain is expected, and along with cold air aloft filtering into the region, a changeover to snow is expected in NW NJ and interior SE NY with less than 1/2 inch expected. Flurries may make it as far east as NYC and northeast NJ by 6 PM, but with no accumulations expected. The storm is expected to end around 5-7 PM as the rain moves out of the region with temperatures falling into the 30s in the evening and 20s overnight with stronger winds developing out of the northwest.

 

2:30 AM: Heavy Rain Continues; NYC Passes 1 Inch

nerad253As of 2 AM, there was a broad low pressure extending from South Carolina into Washington DC, with two centers; one near Washington DC and another near South Carolina, both with a minimum pressure of 998 mb. The broad low pressure area will remain elongated for the duration of its time over the eastern US, with no single well-defined center; the two somewhat separate centers will merge over New England on midday Wednesday as the upper level trough axis moves through.

Since the previous update, interior areas have changed over to rain as well, but barely so, with temperatures stuck near 33 degrees as widespread freezing rain continues over parts of Pennsylvania. The warm front is currently over NYC and Long Island, and continues to push north; this will place most of the area in the warm sector, with temperatures surging into the mid-upper 50s and an increasing SE wind at 15-30 mph sustained, gusting up to 40-50 mph or locally higher east of NYC; a sharp temperature gradient will set up over the area, with interior north/western areas likely remaining in the 30s to low 40s except for a brief spike into the low 50s for a short time later tonight.

As the radar above shows, the heaviest rain is now located over the region, with NYC having recently surpassed 1 inch for the cumulative storm total, making it the 3rd biggest rain event this fall – the 4th highest storm total this fall is barely 0.25 inch – with the total expected to increase as this storm produces the highest rain totals since the remnants of tropical storm Andrea in June. The back end of the initial wave of rain is approaching the area within the next 1-3 hours, but with additional heavy rain from Virginia expected to continue spreading northeast into the area, with coverage area of heavy rain slightly less widespread along with occasional breaks but with parts of the area continuing to see heavy rain until early Wednesday afternoon as the storm lifts out of the region. Storm totals of 1.5 to 3 inches are expected, locally up to 4 inches.

 

10:00 PM: Heavy Rain Enters Area

nerad252As of 9 PM, the low pressure was located near east central Georgia, but with an elongated center stretching into South Carolina. Minimum pressure is approximately 1003 mb, and the low pressure is continuing to track to the northeast/NNE.

As freezing rain continues to fall over central Pennsylvania into NY state, almost all of area has changed over to rain, except for parts of interior NW NJ and SE NY which continue to see freezing rain but with a shrinking coverage area. As the latest regional radar shows to the left, snow is now limited to far western and northern regions as strong mid level warm air advection continues to surge northward, with rain expected to continue for the remainder of the storm except for the possibility of back-end snow showers on Wednesday evening in interior western areas. In the meantime, heavy rain is entering the area, and will continue to fall through early Wednesday morning with 1-2 inches of rain expected. A brief break in the rain is likely around that time, with otherwise continued light-moderate rain, heavy north/east of NYC, through the late afternoon hours.

 

6:25 PM: Freezing Rain Inland, Rain To Intensify Tonight

nerad25As of 6 PM, the low pressure was located approximately over southern Georgia but with an elongated center. Minimum pressure is approximately 1003 mb, and the low pressure is continuing to steadily track to the northeast, changing direction to the NNE tonight.

Over the last 4 hours, temperatures held steady in the mid-upper 30s for most as dew points warmed up to the freezing point, which along with mid level warmth brought a changeover to rain for most except for interior NW NJ and SE NY, which continue to observe freezing rain with sleet in some spots. As mid level warm air advection continues with the low level cold air moderating, these locations are expected to change over to plain rain by 7-9 PM, with temperatures rising overnight into the upper 40s inland and the mid-upper 50s elsewhere with heavy rain developing after 10 PM-12 AM. The heaviest rain will fall tonight into Wednesday morning, with lighter rain for the rest of the day as the elongated low pressure shifts east of the area, with wind gusts peaking in the morning hours as well up to the 40-50 mph range, locally up to 55 mph.

 

2:30 PM: Interior Stays Frozen, Rain Elsewhere

nerad25As of 2 PM, the low pressure was located near extreme SE Alabama. Minimum pressure is approximately 1003 mb, and the low pressure continues to steadily tack to the northeast. The forecast track remains unchanged, continuing to move into Georgia and the Carolinas, then continuing to track NNE into the region tonight and tomorrow roughly along the I-95 corridor and into northern NJ.

Since the last update, most of northern NJ, NYC and western Long Island observed a brief period of light snow/sleet, which has since changed over to rain for most with mid level warm air advection. The rain/snow line is currently positioned near north central NJ into interior SE NY, where light snow/sleet is expected to continue for the short term, changing to rain in the lower elevations and sleet/freezing rain in the higher elevations by the mid afternoon, with the entire area turning to rain by 7-9 PM.

There have been some changes in the anticipated setup since yesterday’s forecast; last minute trends indicate a slightly weaker, further east and more strung out low pressure over the region for tomorrow. Heavy rain is still expected tonight, with rain totals up to 1-2 inches expected by Wednesday morning, with lighter rain possible in the morning with otherwise moderate rain likely to continue through the evening before ending around 4-7 PM from southwest to northeast. The rainfall outlook is for 1.5 to 3 inches of rain, locally higher. Temperatures will spike into the mid-upper 50s tonight, peaking on Wednesday morning before crashing down into the 30s in western NJ and 40s in NYC by the mid afternoon hours. The main uncertainty is with the wind outlook, however; considering that the NAM is likely overdone with the low level jet strength, and an expected inversion, wind gusts are still expected to be strong, around 40-50 mph with locally higher gusts up to 55 mph possible.

 

12:00 PM: Light Snow Enters NJ

1645As of 11 AM, the low pressure was located near far western Florida. Minimum pressure is approximately 1006 mb, and the low pressure is steadily tracking to the northeast. The low is expected to continue tracking northeast into Georgia and the Carolinas today, entering the northeast US region by tonight.

Most of the area has been dry so far, although light snow has been reported in NW NJ and interior SE NY with an initial wave of light snow that affected NY into New England early this morning with light snow accumulations. The precipitation shield from the main storm has entered Pennsylvania and is starting to enter western New Jersey, as the latest radar image above shows, from the Pennsylvania State University e-Wall site. With enough cold in place in the low levels, there are reports of light snow and sleet in western New Jersey. As precipitation spreads NE into the rest of north NJ, SE NY and NYC over the next few hours, precipitation type is likely to start out as brief snow/sleet for most of northern NJ, and rain/sleet further east closer to NE NJ and NYC, with a quick changeover to rain by the mid afternoon for most except for far NW NJ/SE NY.

9 comments

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  1. Anonymous

    Any snowflakes possible for NYC and Long Island later tonight?

    1. NYC Area Weather

      As the main precipitation shield has moved out of the area, it doesn’t appear that snow should fall from NYC and further east tonight.

  2. Anonymous

    But the snow squalls over PA seem to be directly headed for NYC and Long Island. Are they forecast to dissipate or they have a chance of surviving to the coast?

    1. NYC Area Weather

      Most of these are anticipated to dissipate before reaching the area; an isolated snow shower or two can’t be completely ruled out although the highest chance is west and south of NYC.

  3. Anonymous

    Any accumulations expected with those isolated snow showers?

    1. NYC Area Weather

      In locations where snow showers do fall, a dusting may be possible.

  4. Anonymous

    Is a dusting by definition less than 1/2 inch?

    1. NYC Area Weather

      In this case I would say up to 0.1 inch; there isn’t much support for totals that high.

  5. Anonymous

    Thank you! Have a nice evening and Happy Thanksgiving!

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