April 2019 General Discussions & Observations Thread

[donsutherland1]

A strong coastal storm will bring rain and high winds to parts of eastern Long Island and eastern New England tonight into tomorrow. Some of those areas could see wind gusts in excess of 50 mph. There is a small chance that enough cold air could get involved to bring a little snow to Boston.

Another storm could bring more widespread precipitation to the region on Friday. The potential exists for 1.00" or more precipitation from that storm.

The ENSO Region 1+2 anomaly was -0.20°C and the Region 3.4 anomaly was +1.00°C for the week centered around March 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.30°C and the ENSO Region 3.4 anomaly has averaged +0.96°C. Conditions consistent with El Niño should persist into April in Region 3.4.

The SOI was -8.29 today.

Today's preliminary value of the Arctic Oscillation (AO) was +0.398. The AO has now been positive for 54 consecutive days. The last time the AO was positive for at least that long was during the November 26, 2006 through January 20, 2007 period when the AO was positive for 56 consecutive days. The AO will very likely go negative in the next one or two days.

Since 1950, there have been four prior cases when the AO reached +2.500 or above during the last 10 days of March and then had four or more days with negative values during the first week of April. The mean temperature for the 4/1-10 period in New York City was 51.6° (standard deviation 1.8°). That is about 2 1/2 degrees warmer than climatology for the April 1-10 period (1950-2018). Consequently, it is likely that the April 1-10 period will wind up somewhat warmer than normal even as the period starts on a colder than normal note.

On April 1, the MJO moved into Phase 6 at an amplitude of 0.343 (RMM). The amplitude was higher than the March 31-adjusted figure of 0.417.

Finally through 5 pm today, Atlanta has still not received any snowfall. The window of opportunity to avert record low snowfall (below a trace) is closing. Since 1928-29 when snowfall records were kept, there were only 6 cases when Atlanta received a trace of snow after April 2.

[gravitylover]

7 hours ago, IrishRob17 said:

Welcome to brush fire season, the NYS burn ban went into effect a couple of weeks, as is tradition. https://www.dec.ny.gov/chemical/58519.html

 

It's always at the worst time. I have a monster pile of stuff that needs to be burned and now it's just going to sit until May. Every time this happens the pile grows because I never get to deal with it during the summer. I have lots of rotting brush around the perimeter of the yard 

[Rtd208]

Have had some on and off light rain falling here over the last couple of hours.

Current temp 42

[CIK62]

Next 8 days averaging 53degs., or 4degs. AN.

[IrishRob17]

10 hours ago, gravitylover said:

It's always at the worst time. I have a monster pile of stuff that needs to be burned and now it's just going to sit until May. Every time this happens the pile grows because I never get to deal with it during the summer. I have lots of rotting brush around the perimeter of the yard 

Brush fires have been reduced by 37% since they started this back in 2009. 

[bluewave]

March into May is typically our driest part of the year for relative humidity. I believe the lowest RH value for NYC was around 5% on 3-30-07. The RH today has a shot at dropping lower than forecast guidance. Deep mixing to near 750 mb with 40-50 mph gusts will really dry things our on a warm downslope flow.

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=11&network=NY_ASOS&zstation=NYC&year=2007&emphasis=-99&var=rh&opt=touches&dpi=100&_fmt=png

 

[CIK62]

5 hours ago, bluewave said:

March into May is typically our driest part of the year for relative humidity. I believe the lowest RH value for NYC was around 5% on 3-30-07. The RH today has a shot at dropping lower than forecast guidance. Deep mixing to near 750 mb with 40-50 mph gusts will really dry things our on a warm downslope flow.

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=11&network=NY_ASOS&zstation=NYC&year=2007&emphasis=-99&var=rh&opt=touches&dpi=100&_fmt=png

 

Seems odd that the lowest RH would occur near the date of the most likely day for precipitation around here, namely April 01 @41% chance of >=0.01".

Oct. 15 is @23% on the frequency chart.      At any rate, my indoor RH is 23% now {no heat, windows open}, but it has gone lower during any winter indoors-wise.      Some old style hygrometers need to be re-calibrated after a winter of dry indoor air,  due to a 'hysteresis chemical effect' of the sensor.    That is to say, if this kind of sensor has been sitting at under 40% in an apartment  for months, it will not be accurate if suddenly thrust into an 80% RH environment!

[dWave]

Sunny 66, and not much wind at all so far.

[bluewave]

52 minutes ago, CIK62 said:

Seems odd that the lowest RH would occur near the date of the most likely day for precipitation around here, namely April 01 @41% chance of >=0.01".

Oct. 15 is @23% on the frequency chart.      At any rate, my indoor RH is 23% now {no heat, windows open}, but it has gone lower during any winter indoors-wise.      Some old style hygrometers need to be re-calibrated after a winter of dry indoor air,  due to a 'hysteresis chemical effect' of the sensor.    That is to say, if this kind of sensor has been sitting at under 40% in an apartment  for months, it will not be accurate if suddenly thrust into an 80% RH environment!

ThIs is pretty much the only time of the year that we see RH readings below 20%. Caldwell is the first station of the day to report  a RH value below 20%.

Caldwell       FAIR      64  17  16 W31G43   

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=60&network=NY_ASOS&zstation=NYC&var=relh&threshold=20&direction=below&dpi=100&_fmt=png

[psv88]

64

[Rtd208]

Current temp is 64 here. Nice day.

[Brian5671]

winds picking up, torching to 66.  

[Cfa]

66 with winds really ramping up within the last 2 hours. Warmest day of the year so far.

[uofmiami]

63 and had a gust to 42 MPH

[Snowlover11]

63

[FPizz]

67

[dmillz25]

65

[Cfa]

Yikes. Don’t recall seeing a mosquito this large so early on. It hasn’t even been that warm or wet.

It’s bigger than it appears in this photo, holding on for dear life in these winds.

[Rtd208]

Temp up to 66 here now. Pretty windy as well.

[psv88]

Hit 65. Back to the icebox 

[Uniblab]

3 hours ago, Cfa said:

Yikes. Don’t recall seeing a mosquito this large so early on. It hasn’t even been that warm or wet.

It’s bigger than it appears in this photo, holding on for dear life in these winds.

Cranefly. 

[bluewave]

The warmest day for sections for the LI South Shore since November 2nd. ISP reached a high of 66 degrees. It actually felt nice walking outside today with just a sweatshirt or a light jacket. Warm offshore flow days are always a gift this time of year near the South Shore.

[495weatherguy]

4 minutes ago, bluewave said:

The warmest day for sections for the LI South Shore since November 2nd. ISP reached a high of 66 degrees. It actually felt nice walking outside today with just a sweatshirt or a light jacket. Warm offshore flow days are always a gift this time of year near the South Shore.

Today felt great!

[donsutherland1]

The ENSO Region 1+2 anomaly was -0.20°C and the Region 3.4 anomaly was +1.00°C for the week centered around March 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.30°C and the ENSO Region 3.4 anomaly has averaged +0.96°C. Conditions consistent with El Niño should persist into April in Region 3.4.

The SOI was +9.66 today. That is the SOI's highest figure since the SOI reached +11.26 on January 18.

Today's preliminary value of the Arctic Oscillation (AO) was +0.198. The AO has now been positive for 55 consecutive days. The last time the AO was positive for at least that long was during the November 26, 2006 through January 20, 2007 period when the AO was positive for 56 consecutive days. The AO's going negative is now imminent.

Since 1950, there have been four prior cases when the AO reached +2.500 or above during the last 10 days of March and then had four or more days with negative values during the first week of April. The mean temperature for the 4/1-10 period in New York City was 51.6° (standard deviation 1.8°). That is about 2 1/2 degrees warmer than climatology for the April 1-10 period (1950-2018). Consequently, it is likely that the April 1-10 period will wind up somewhat warmer than normal even as the period starts on a colder than normal note.

On April 2, the MJO moved into Phase 7 at an amplitude of 0.247 (RMM). The amplitude was lower than the April 1-adjusted figure of 0.341.

It is now likely that Baltimore, Bridgeport, Islip, New York City, Newark, Philadelphia, Richmond, and Washington, DC have seen their last measurable snowfall of the winter 2018-19 season. Snowfall amounts for those cities were: Baltimore: 18.3"; Bridgeport: 24.6" (highest since 35.1" in 2015-2016); Islip: 12.8"; New York City: 20.5" (lowest since 7.4" in 2011-2012); Newark: 22.0" (lowest since 8.8" in 2011-2012); Philadelphia: 17.1"; Richmond: 13.1" (highest since 15.1" in 2015-2016); and, Washington, DC: 16.9" (highest since 22.2" in 2015-2016).

In addition, based on historical climatology, observed ongoing warming, and the latest ensemble guidance, it is likely that the 32° temperature on March 18 will wind up becoming New York City's (Central Park) last freeze of the season.

Atlanta remains on track to receive no snowfall for the first time on record. The existing record is a trace of snow, which occurred during 24 winters. Snowfall records go back to winter 1928-29.

However, it remains likely that an area extending across northern New York State, northern Vermont, northern New Hampshire, and much of Maine could still see additional accumulating snow. With 1.5" snow today, Caribou reached 155.6", which makes winter 2018-2019 that city's 4th snowiest winter on record.

Finally, on April 2, Arctic sea ice extent was 12,235,128 square kilometers. The previous daily record low figure was 13,444,757 square kilometers, which was set in 2016. The previous earliest date by which Arctic sea ice extent reached the April 2, 2019 figure was April 9.

[gravitylover]

16 hours ago, IrishRob17 said:

Brush fires have been reduced by 37% since they started this back in 2009. 

It shows, just look at all of the deadfall (fuel) piled up in the woods everywhere around the region. When something gets going, if it's a windy day like today it's going to be a total shitstorm.

[CIK62]

Next 8 days averaging 54degs., or about 5degs. AN.

[JerseyWx]

7 minutes ago, bluewave said:

Here comes the return to a wetter pattern again with the developing Greenland block. 

 

The drier pattern in March just couldn't last.

[MJO812]

25 minutes ago, bluewave said:

This 5+ SD AO drop is one of the greatest on record for the month of April. It looks like a perfect reversal of the near record 5+SD rise in early February. It results in a wet pattern with active storm track for our area in April.

 

 

It would be nice to get some snow with this.

[Gravity Wave]

If it means a cool April I'm all in. Any real heat before late May is unacceptable.

[Gravity Wave]

2 hours ago, bluewave said:

The first 80 degree reading of the spring may be late for NYC. The mean first date since 2010 has been 4-16.

NYC first 80 of spring since 2010

Minimum	04-07 (2010)		09-14 (2012)		140
Mean	04-16		10-03		169
Maximum	05-10 (2014)		10-19 (2016)		183
2018	04-13 (2018)	82	10-10 (2018)	80	179
2017	04-11 (2017)	80	10-10 (2017)	81	181
2016	04-18 (2016)	82	10-19 (2016)	85	183
2015	04-18 (2015)	80	09-29 (2015)	83	163
2014	05-10 (2014)	83	09-28 (2014)	84	140
2013	04-09 (2013)	82	10-04 (2013)	86	177
2012	04-16 (2012)	88	09-14 (2012)	80	150
2011	04-11 (2011)	81	10-10 (2011)	81	181
2010	04-07 (2010)	92	09-25 (2010)	89	170

 

If the GFS is right we should break the recent pattern of having an 80+ reading before 4/20.