April 2024

[donsutherland1]

Starting tomorrow, it will turn somewhat cooler with unsettled conditions. Thursday will be the coolest day of the week with the mercury struggling to reach 50°. Another cold shot could arrive during the weekend.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.9°C for the week centered around April 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.10°C and the ENSO Region 3.4 anomaly has averaged +1.15°C. The ongoing basinwide El Niño event is fading. Neutral conditions could develop later in the spring.

The SOI was -12.91 today.

The preliminary Arctic Oscillation (AO) was +2.288 today.

Based on sensitivity analysis applied to the latest guidance, there is an implied 63% probability that New York City will have a warmer than normal April (1991-2020 normal). April will likely finish with a mean temperature near 55.0° (1.3° above normal).

 

[bluewave]

It will be interesting to see if Newark can maintain a high only in the 40s tomorrow. It would be one of the more impressive 48-72 hr afternoon temperature drops during the month of April if they can pull it off. The last 80s to 40s in the afternoon in April over a few days was back in 2018. 
 

 

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&v=tmpf&hours=72&month=apr&dir=cool&how=exact&_r=t&dpi=100&_fmt=png

[jm1220]

31 minutes ago, bluewave said:

It will be interesting to see if Newark can maintain a high only in the 40s tomorrow. It would be one of the more impressive 48-72 hr afternoon temperature drops during the month of April if they can pull it off. The last 80s to 40s in the afternoon in April over a few days was back in 2018. 
 

 

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&v=tmpf&hours=72&month=apr&dir=cool&how=exact&_r=t&dpi=100&_fmt=png

Here comes the gunk.  

[bluewave]

5 hours ago, jm1220 said:

Here comes the gunk.  

Something unusual is going on with the the TPV. It’s becoming consolidated and very strong for late April. The forecast is for it to  approach record low 500mb heights for late April levels near Hudson Bay next week. All the guidance splits a piece off and it heads for Maine day 6-10. If this scenario verifies, interior portions of the Northeast could face a hard freeze. 

 

 

[MJO812]

19 minutes ago, bluewave said:

Something unusual is going on with the the TPV. It’s becoming consolidated and very strong for late April. It’s forecast to approach record low 500mb highs levels near Hudson Bay next week. All the guidance splits a piece off and it heads for Maine day 6-10. If this scenario verifies, interior portions of the Northeast could face a hard freeze. 

 

Did this happen a few years ago when we all saw snow showers in early May with low temps near freezing?

[jm1220]

13 minutes ago, bluewave said:

Something unusual is going on with the the TPV. It’s becoming consolidated and very strong for late April. The forecast is for it to  approach record low 500mb heights for late April levels near Hudson Bay next week. All the guidance splits a piece off and it heads for Maine day 6-10. If this scenario verifies, interior portions of the Northeast could face a hard freeze. 

 

Maddening how in this perma-Nina regime this keeps happening in mid-April and not Feb when it’s wanted. 

[bluewave]

13 minutes ago, MJO812 said:

Did this happen a few years ago when we all snow snow showers in early May with low temps near freezing?

The TPV looks even stronger this time near Hudson Bay maxing out near -5 SD.  It’s forecast to weaken as it heads to Maine. But there will still be a late season possible hard freeze for interior regions. Both events followed a late season -EPO pattern after record warmth prevailed during the winter.

 

[FPizz]

58 minutes ago, MJO812 said:

Did this happen a few years ago when we all saw snow showers in early May with low temps near freezing?

It was mid-May.  I was getting my pool opened, midday, and snow flakes were falling.  

[psv88]

God that would be fucking terrible. Going to Hershey with my family end of April. Would suck to be in the 30s and 40s. 

[uofmiami]

26 minutes ago, psv88 said:

God that would be fucking terrible. Going to Hershey with my family end of April. Would suck to be in the 30s and 40s. 

Good luck, I'm sure it'll be 60s to 70 during the day in Hershey at least.  No worries in Grand Cayman for us thankfully, haha!

[psv88]

6 minutes ago, uofmiami said:

Good luck, I'm sure it'll be 60s to 70 during the day in Hershey at least.  No worries in Grand Cayman for us thankfully, haha!

Kids don’t have passports or else a would have gone to Caribbean. Didn’t feel like going to Florida again, so we are driving down to Asheville, Nc and checking out the blue ridge parkway, then up to Hershey 

[uofmiami]

9 minutes ago, psv88 said:

Kids don’t have passports or else a would have gone to Caribbean. Didn’t feel like going to Florida again, so we are driving down to Asheville, Nc and checking out the blue ridge parkway, then up to Hershey 

There’s always Puerto Rico and US Virgin Island without passports. It’s pretty easy just make an appointment at post office for them this summer.  Regardless, should be a nice trip down to NC and Hershey. Enjoy and hope weather works out. 

[Stormlover74]

25 minutes ago, psv88 said:

Kids don’t have passports or else a would have gone to Caribbean. Didn’t feel like going to Florida again, so we are driving down to Asheville, Nc and checking out the blue ridge parkway, then up to Hershey 

We did blue ridge parkway in October during peak season. Insane traffic but gorgeous views

[bluewave]

1 hour ago, FPizz said:

It was mid-May.  I was getting my pool opened, midday, and snow flakes were falling.  

That one was in May 2020 but the one last May was equally as extreme for some locations. 

https://www.nrcc.cornell.edu/regional/narrative/narrative.html

Northeast Overview - May 2023

Notable Weather Events
An upper-level low pressure system that had stalled near the region in late April finally meandered away during the first few days of May but continued to bring persistent below-normal temperatures and rounds of precipitation during that time. In fact, a rare May snow event occurred in some higher-elevation locations of West Virginia and southwestern Pennsylvania. The greatest storm snow total reached 20.3 inches in Davis, West Virginia, ranking as West Virginia’s largest May snowstorm and the snowiest May for any West Virginia site on record. Davis saw 10.1 inches of snow on May 3, ranking as the greatest daily snowfall for May for any West Virginia site. Meanwhile, Snowshoe, West Virginia, had its snowiest May since records began in 1975 with 16.0 inches and its snowiest May day with 7.0 inches on May 3. The site’s snow depth of 15 inches on May 4 was the greatest May snow depth on record for any West Virginia site. The event was also notable even at sites that saw less snowfall, such as Donegal, Pennsylvania, which had its snowiest May since records began in 1945 with 0.7 inches of snow. In addition, on May 1, a storm system associated with the upper-level low set record-low sea level pressures for May at least eight sites including Boston, Massachusetts; Williamsport, Pennsylvania; and New York City. Low temperatures on May 18 bottomed out in the 20s and 30s in multiple parts of the Northeast, running as much as 22 degrees F colder than normal. For instance, lows of 30 degrees F in Scranton, Pennsylvania, and 33 degrees F in Providence, Rhode Island, ranked among the 10 coldest low temperatures for May at those sites. After a mild April, some crops were ahead of schedule, leaving them particularly susceptible to the unusually cold temperatures. There was widespread frost/freeze damage to grape vines, particularly in central and eastern New York where early estimated losses of 70 to 100 percent of some grape varietals were reported at some vineyards. Early estimates indicate around a third of Massachusetts’ apple crop was damaged, while preliminary estimates from New Hampshire indicate damages to the state’s apple crop could exceed $1 million. Vermont officials reported severe damage to thousands of acres of crops, while Connecticut officials also have reported significant crop losses. The full extent of damage will take more time to assess. 

 

[BucksCO_PA]

4 hours ago, bluewave said:

It will be interesting to see if Newark can maintain a high only in the 40s tomorrow. It would be one of the more impressive 48-72 hr afternoon temperature drops during the month of April if they can pull it off. The last 80s to 40s in the afternoon in April over a few days was back in 2018. 
 

 

4 hours ago, bluewave said:

It will be interesting to see if Newark can maintain a high only in the 40s tomorrow. It would be one of the more impressive 48-72 hr afternoon temperature drops during the month of April if they can pull it off. The last 80s to 40s in the afternoon in April over a few days was back in 2018. 
 

 

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&v=tmpf&hours=72&month=apr&dir=cool&how=exact&_r=t&dpi=100&_fmt=png

Since you have "exactly" 48hrs as one of the data points the full scope of the 4/16-18 2003 temp drop is missed. Question would be how many others are underrepresented on that list?

4/16/2003, 4:00pm - 87 degrees

4/17/2003, 4:00am - 49 degrees

4/17/2003, 4:00pm - 40 degrees

4/18/2003, 4:00am - 37 degrees

The actual high at Newark on 4/16/2003 was 88 degrees so that's a 51 degree temp drop in less than 36 hrs.

[Brian5671]

rain seems to be moving in quicker than modeled....lot of convection towards Philly

[bluewave]

15 minutes ago, BucksCO_PA said:

Since you have "exactly" 48hrs as one of the data points the full scope of the 4/16-18 2003 temp drop is missed. Question would be how many others are underrepresented on that list?

4/16/2003, 4:00pm - 87 degrees

4/17/2003, 4:00am - 49 degrees

4/17/2003, 4:00pm - 40 degrees

4/18/2003, 4:00am - 37 degrees

The actual high at Newark on 4/16/2003 was 88 degrees so that's a 51 degree temp drop in less than 36 hrs.

There is no underrepresentation since it all depends on what time interval you use. Set it to 24 hrs and the April 2003 drop is the top one. Anytime you have an afternoon within 24-72 hours with a 30°+ difference it’s noteworthy.
 

 

[BucksCO_PA]

1 hour ago, bluewave said:

There is no underrepresentation since it all depends on what time interval you use. Set it to 24 hrs and the April 2003 drop is the top one. Anytime you have an afternoon within 24-72 hours with a 30°+ difference it’s noteworthy.
 

 

it most certainly is underrepresented when you limit to a specific hour that does not capture the full scope of the temp drop

[bluewave]

5 minutes ago, BucksCO_PA said:

it most certainly is underrepresented when you limit to a specific hour that does not capture the full scope of the temp drop

It’s based on hourly reports which is what it was designed to do. 

[snowman19]

This *could* potentially have big stratospheric implications….major tropical volcanic eruption ongoing. If this thing pumps enough sulfate aerosols into the stratosphere, it could conceivably have effects on next winter’s SPV and NAM (AO) state. This needs to be followed closely @Volcanic Winter…
 

[Stormlover74]

2 hours ago, Brian5671 said:

rain seems to be moving in quicker than modeled....lot of convection towards Philly

All moving offshore just light stuff up here 

[snowman19]

30 minutes ago, snowman19 said:

This *could* potentially have big stratospheric implications….major tropical volcanic eruption ongoing. If this thing pumps enough sulfate aerosols into the stratosphere, it could conceivably have effects on next winter’s SPV and NAM (AO) state. This needs to be followed closely @Volcanic Winter…
 

@Volcanic Winter @bluewave Just to add, there is some speculation that this eruption may reach a VEI 6. Wouldn’t that be unprecedented to have 2 VEI 6 eruptions this close together? I know Hunga Tonga was a 6….

[snowman19]

6 minutes ago, bluewave said:

Looks impressive on the satellite.

 

 

It’s getting more impressive by the hour. Sulfate aerosol measurements are continuing to rise and it appears to be reaching the stratosphere 

[donsutherland1]

Periods of rain are likely tonight into tomorrow. A general 0.25"-0.50" rainfall with locally higher amounts is likely.

Tomorrow will be the coolest day of the week with the mercury struggling to reach 50°. Another cold shot could arrive on Saturday.

Overall, generally cooler than normal conditions will likely persist into at least the middle of next week.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was +0.9°C for the week centered around April 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.10°C and the ENSO Region 3.4 anomaly has averaged +1.15°C. The ongoing basinwide El Niño event is fading. Neutral conditions could develop later in the spring.

The SOI was -5.77 today.

The preliminary Arctic Oscillation (AO) was not available today.

Based on sensitivity analysis applied to the latest guidance, there is an implied 69% probability that New York City will have a warmer than normal April (1991-2020 normal). April will likely finish with a mean temperature near 55.0° (1.3° above normal).

 

[bluewave]

Where was this pattern during the winter?

 

 

[Allsnow]

 

[Volcanic Winter]

6 hours ago, snowman19 said:

This *could* potentially have big stratospheric implications….major tropical volcanic eruption ongoing. If this thing pumps enough sulfate aerosols into the stratosphere, it could conceivably have effects on next winter’s SPV and NAM (AO) state. This needs to be followed closely @Volcanic Winter…
 

Thank you Snowman, I’m just getting caught up on this. One of the few days I’m not being a compulsive volcano obsessive something significant happens. Hoping for the safety of everyone impacted by this, I believe there’s a few hundred living on that island?

I’ll post when I’m caught up with accurate info, I tend to avoid speculation. I also don’t like trying to analyze the size of an event while it’s occurring and before all the data is reviewed, it can be deceiving in both directions. 

I’m trying to verify column height, something to the level of a VEI 5 typically has no problem clearing 20km for a sustained period of time and I’m seeing this latest blast was about 17km based on sources I’m looking at now. Also unclear of the duration of that blast, which matters in terms of volume which is ultimately what determines VEI at this level.  The satellite imagery is impressive though, trying to verify. 

In terms of SO2 loading in the stratosphere, we want to see something similar to El Chichon’s ~7 Tg’s for detectable surface impacts. Probably at least 4-5+. 

[Volcanic Winter]

6 hours ago, snowman19 said:

@Volcanic Winter @bluewave Just to add, there is some speculation that this eruption may reach a VEI 6. Wouldn’t that be unprecedented to have 2 VEI 6 eruptions this close together? I know Hunga Tonga was a 6….

IMHO that kind of speculation is very premature. As mentioned it can be deceiving in both directions. 

Smart people were calling HTHH a 3-4 a day after it happened thinking the entire column was steam (it wasn’t, 1.9 cubic kilometers of ash in it which is already well into VEI 5 territory). And hidden underwater was another 6-8 cubic kilometers of ignimbrite (massive pyroclastic flows from caldera collapse). 

Just IMO and I’m not caught up on this one yet. 

To answer your question it would be rare but not even historically without precedent. Six years before Tambora’s VEI 7 in 1815, there was a mystery eruption from a not fully identified volcano that was at least a VEI 6 in 1809. A six and a seven that close together is pretty mind boggling. And remember a 6 could be 10 cubic kilometers like Pinatubo or 99 cubic kilometers, basically a near 7. At VEI 6 level is when the scale sort of breaks in terms of perception. Things just start getting really ridiculous massive. 

[jm1220]

Sad we have to play the volcano Hail Mary for next winter already.  

What have we come to? 

[Stormlover74]

This rain event really fizzled