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January 2020 General Discussions & Observations Thread


Rtd208
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2 minutes ago, Allsnow said:

Next weekend continues to look record breaking with the warmth. 

NYC records are 63 and 66 on the 11th/12th and EWR's are 66 and 67, respectively. I still think fog/stratus could keep temps a bit cooler than what it's showing.

This will probably change, but the ECMWF suggests convection along the front Saturday night may tap into a 65KT+ low level jet. Could be some damage on LI if that verifies.

image.thumb.png.512dcc009b7f4633feccf88f390e33da.png

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Just now, purduewx80 said:

NYC records are 63 and 66 on the 11th/12th and EWR's are 66 and 67, respectively. I still think fog/stratus could keep temps a bit cooler than what it's showing.

This will probably change, but the ECMWF suggests convection along the front Saturday night may tap into a 65KT+ low level jet. Could be some damage on LI if that verifies.

image.thumb.png.512dcc009b7f4633feccf88f390e33da.png

I agree. Most of the time these warm ups are dirty in January. We are usually not under clear sky’s like December 2015 or January 2007. 

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Just now, Allsnow said:

I agree. Most of the time these warm ups are dirty in January. We are usually not under clear sky’s like December 2015 or January 2007. 

Yeah, would like to see the front slow down and/or flow a little more westerly to get the 65+ it is showing.

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3 hours ago, bluewave said:

Individual storm details have been very difficult beyond a few days with the firehose Pacific Jet. Too many different shortwaves for the models to correctly resolve further out. The one recent constant has been temperatures verifying warmer than guidance. Yesterday was the 14th day in a row with above normal temperatures.

Data for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.
Date
Avg Temperature Departure 
2019-12-22 2.5
2019-12-23 13.8
2019-12-24 6.5
2019-12-25 4.7
2019-12-26 6.5
2019-12-27 15.7
2019-12-28 12.9
2019-12-29 7.6
2019-12-30 5.3
2019-12-31 6.9
2020-01-01 4.1
2020-01-02 7.7
2020-01-03 13.4
2020-01-04 13.0

Has there ever been research analyzing model accuracy and relationship with state of the Pacific? 

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Models always confuse me when it comes to Long Island. I never really know if Long Island is being depicted as cooler/warmer/wetter/drier/etc. or if it just appears that way because Long Island doesn’t exist on some models.

Made it up to 44 here, a full 4-5 degrees above forecast.

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Is this the SE Ridge finally starting to cry:    HELP ME MOMMY---I  AM BEING CRUSHED---I CAN'T BREATHE!

At least Jan. 2002 is knocked out of !st Place (sorry just kidding) in the analogs, but still holds three slots in the TT.        Taken collectively, the TC''s all gang up to keep us warm and maybe the EPO staunches some of the heat-letting during the next 15 days.      The PNA never recovers on the EURO Weeklies, at any rate, so ridging in the NW never sets up for long.

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In the wake of a frontal passage, today saw readings top out in the lower 40s, along with a gusty wind. Overnight a weak disturbance could touch off some snow showers. A coating of snow is possible in some areas, especially outside New York City.

New York City will very likely have a mean temperature of 40° or above during the first week of the month. Since 1869, there were 23 cases when the first week of January had a mean temperature of 40° or above in New York City. In 17 (74%), January wound up warmer than normal and in 12 (52%), January had a mean temperature of 35° or above. The average monthly temperature for January for all 23 cases was 36.0° (median temperature: 35.6°).

A short-duration fairly sharp cold shot is possible during mid-week. Ahead of the cold shot, a system will likely bring precipitation to the region from Tuesday into Wednesday. Parts of the area could pick up a light snowfall, though most of the region will likely see little or no accumulation. A greater chance for somewhat higher accumulations of snow exists for eastern New England, especially Cape Cod, and perhaps southeast New Jersey.

The light snowfall scenario is consistent with historic experience during very strong AO+ patterns during the first half of January. Based on the forecast strongly positive AO, the probability of a significant (6" or greater snowstorm) for the major cities of the Middle Atlantic region during the first 10 days of January is low. Since 1950, the biggest snowfall for that region when the AO was +2.000 or above during the January 1-15 period occurred during January 14-15, 1954 when Philadelphia received 3.0" snow and New York City picked up 2.0". Boston has had numerous 6" or greater snowstorms during such cases, including one 10" or greater snowstorm. Therefore, the risk of significant snow would likely be greatest over New England assuming this relationship holds (no significant offsetting variables).

Following the brief cold shot, ridging with warmer than normal temperatures will develop and persist through at least mid-month. Beyond that, the progression of the MJO and state of the teleconnections will determine the pattern evolution for the second half of the month.

Despite 500 mb differences in the extended range, there remains strong consensus between the EPS and GEFS that the PNA will remain negative to strongly negative past mid-month. Such a scenario would lead to a continuation of a generally mild pattern beyond mid-month. Transient cold shots would be possible.

A PNA- typically translates in warm anomalies in the Middle Atlantic region. For the January 16-31, 1981-2019 period, the mean temperature for New York City and Philadelphia was 32.2° and 32.1° respectively. When the PNA was negative, those values were 34.2° and 34.1° respectively. The coldest mean temperatures for PNA- periods occurred when the EPO and AO were both negative (New York City: 29.1° and Philadelphia: 28.9°). The warmest occurred when the EPO and AO were both positive (New York City: 37.9° and Philadelphia: 37.5°).

The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was +0.4°C for the week centered around December 25. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.27°C and the ENSO Region 3.4 anomaly has averaged +0.48°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions.

The SOI was +18.52 today. That is the highest SOI figure since August 10, 2019 when the SOI was +20.15.

Today, the preliminary Arctic Oscillation (AO) figure was +3.302.

No significant stratospheric warming event appears likely through January 13, several short periods of warming appear likely to develop in the upper stratosphere and then to approach or reach 5 mb over the next 10 days. Wave 2 activity will remain relatively muted following the first week of the month except in the upper stratosphere where it will trigger the warming principally above 5 mb. Overall, most of the stratosphere is forecast to remain cold on the EPS.

On January 4, the MJO was in Phase 3 at an amplitude of 0.407 (RMM). The January 3-adjusted amplitude was 0.322.

Based on sensitivity analysis applied to the latest guidance, New York City has an implied 79% probability of a warmer than normal January.

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Based on the latest radar and the most recent guidance, snow showers still appear on track to affect the New York City area tonight into perhaps the first part of tomorrow morning. Numerous areas, especially outside the City, could pick up a coating of snow. Even Central Park could pick up a few tenths of an inch of snow if some of the guidance is accurate.

The lack of a significant snowfall fits a strong AO+ pattern in January. Below are the percentages of days on which 2" or more snow fell in New York City during the January 1-31, 1981-2019 period:

All dates (n=1209): 4.1%
AO < 0 (n=617): 4.7%
AO +2.000 or above (n=164): 1.8%
AO +3.000 or above (n=81): 0.0%

The January 5 AO was +3.302.

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1 hour ago, SnowGoose69 said:

Its taking quite some time to reach the ground but someone might get a quick inch

Yeah it really is having a hard time reaching the ground. Radar echoes say I have moderate snow right now, but I don't even have a flurries falling. Too bad some of this decent band is being wasted by the dry air.

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