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February 2020 General Discussions & Observations Thread

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18 minutes ago, donsutherland1 said:

3.8” at JFK.

MPO hasn’t measured snow since 1988-89. Up to then, its lowest seasonal snowfall was 22.1” during winter 1954-55.

I started going there in 1986 it would be interesting to see what's been going on there since then.  I dont think Scranton is representative of the area since it's in a valley and further away from it than Allentown is.  Hazelton is closer than either but I dont think they measure there?  But since Scranton is the only other official measuring location in the area, do you have any data for them of under 10" snowfall seasons and where they are at so far this season?  Thanks, Don!

 

 

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13 minutes ago, donsutherland1 said:

I don’t know. The factors responsible for the seasonal AO state remain uncertain. The recent extreme North Atlantic storms have played a recent role.

I wonder if the storms are the cause or the effect?

 

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1 hour ago, LibertyBell said:

any idea on whats causing the AO to be so strong?

There has been some research that the IOD could possibly impact the NAO and AO. Maybe the record +IOD from November into December was in some way responsible. Some of our other extremely +AO +NAO events were preceded by strong MJO 2-3 forcing. It could be that the IO standing wave from November into mid-December played a role. But we’ll  probably need a a study to confirm.

https://journals.ametsoc.org/doi/10.1175/JCLI3577.1?mobileUi=0&

The dominant pattern of atmospheric variability in the North Atlantic sector is the North Atlantic Oscillation (NAO). Since the 1970s the NAO has been well characterized by a trend toward its positive phase. Recent atmospheric general circulation model studies have linked this trend to a progressive warming of the Indian Ocean. Unfortunately, a clear mechanism responsible for the change of the NAO could not be given. This study provides further details of the NAO response to Indian Ocean sea surface temperature (SST) anomalies. This is done by conducting experiments with a coupled ocean–atmosphere general circulation model (OAGCM). The authors develop a hypothesis of how the Indian Ocean impacts the NAO.

 

By analyzing model simulations we found that the South Asian jet can act as a waveguide with circumglobal teleconnection in the Northern Hemisphere. The meridional wind pattern, associated with this circumglobal teleconnection, is connected with the North Atlantic Oscillation. A warming/cooling in the Indian Ocean, especially in the western Indian Ocean, produces anomalies in the South Asian jet. The waveguiding effect of the South Asian jet carries the perturbation into the North Atlantic sector and leads to a NAO-like response.

The observed recent positive trend in the NAO has likely contributions from the observed warming in the Indian Ocean. Our analysis—confirmed by the observed trend in the western South Asian jet and the anomaly pattern of the 300-hPa winter meridional wind—indicates that the change of the NAO may be via the circumglobal pattern.

https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-15-0502.1?mobileUi=0

The teleconnection patterns associated with phases 3 and 7 are also important for Atlantic blocking. In agreement with Lin et al. (2009) and Cassou (2008), 10–15 days after MJO phase 3 a positive NAO pattern develops over the Atlantic. We find that Atlantic blocking frequency is more than halved in association with the positive NAO pattern. In contrast, MJO phase 7 is followed by a negative NAO pattern, which coincides with a high-amplitude wavelike flow and an increase in blocking frequency. Atlantic blocking frequency is almost doubled following phase 7, reaching +16.5% relative to climatology. Approximately 14%–15% of all DJF Atlantic blocked days follow phase 7.

 

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the models show a saturated layer trapped under an inversion tomorrow morning so we should see some dense fog. if you squint you can pretend it's snow

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It will be interesting to see how close this gets to the record.

https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.2097

The Braer storm of January 1993 was the deepest ever recorded cyclone outside of the Tropics with a minimum core pressure of 914mbar, but due to its track between Scotland and Iceland it caused little damage and was never intensively examined. Here we present a study of the dynamics of the storm using modern re‐analysis data from the European Centre for Medium‐Range Weather Forecasts (ECMWF) and sensitivity studies with the Weather Research and Forecasting (WRF) model to quantify influences of diabatic heating and Greenland's topography on the track and rapid deepening of the storm.

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Tomorrow will very likely see temperatures top out in the 50s in much of the Middle Atlantic region. However, a brief shot of modified Arctic air will move into the region for Friday and Saturday. The lowest temperatures could fall into the teens in New York City and lower teens and perhaps single digits outside the City.

Afterward, warmer air will quickly return. It is likely that the February 15-21 period will be warmer than normal overall. Any cold shots would likely be of a short duration. The general above normal temperature regime could persist afterward.

Consistent with the pattern and supported by most of the guidance, no significant snowfalls (6" or more) are likely in the major Middle Atlantic cities through at least the first three weeks of February. There is a greater but still fairly low probability for Boston to see such a snowstorm.

The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.2°C for the week centered around February 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°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 -9.03 today.

Today, the preliminary Arctic Oscillation (AO) figure was +3.286.

No significant stratospheric warming is likely through February 20, but the upper stratosphere above 5 mb will likely warm toward mid-February. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS into the third week of February.

On February 11, the MJO was in Phase 5 at an amplitude of 1.204 (RMM). The February 10-adjusted amplitude was 1.540.

Based on sensitivity analysis applied to the latest guidance, there is an implied 86% probability that New York City will have a warmer than normal February and an implied 56% probability that February 2020 will be among the 10 warmest such months on record.

Finally, a sizable majority (>80%) of years during which the AO has been, on average, strongly positive during the first 15 days of February were followed by a warmer than normal March. The preliminary February 1-12 AO average is +2.926. Recent rapid warming in ENSO Region 1+2 has also typically preceded a warmer than normal March and spring in the Middle Atlantic region.

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10 minutes ago, ict1523 said:

I’m not going outside to verify but I hear some pinging on my window a/c unit. Yay?

Enough sleet mixed in here that it is actually sticking a bit to car tops, a small win in this winter

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5 hours ago, forkyfork said:

the models show a saturated layer trapped under an inversion tomorrow morning so we should see some dense fog. if you squint you can pretend it's snow

I've been doing that for a few days here.

 

32.5/30/S2/SN- It's light to moderate white rain really, such a tease :(

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