April 2018 Discussions & Observations Thread

[bluewave]

22 minutes ago, nzucker said:

Should finish right on average at 69 days...Central Park reached a low of 32F as of 3:51am...32/14 right now, nice and crisp for April 9th.

Will probably be the last freeze barring clearer than expected weather tonight, or an unseasonably late cold airmass. NYC hasn't had regular freezes in late April since the late 1800s.

4-16-14 was interesting in that it was the 12th latest freeze date on record for NYC. The only more modern date close to that was the late freeze on 4-17-80. The PV was really cranking that winter into spring. The cool trough even stayed stuck in the shadow of the PV right through the summer.

[Rtd208]

Current temp is 31 here. Cold April morning. 

[ForestHillWx]

28/20..deep, deep...spring

[nzucker]

3 minutes ago, bluewave said:

4-16-14 was interesting in that it was the 12th latest freeze date on record for NYC. The only more modern date close to that was the late freeze on 4-17-80. The PV was really cranking that winter into spring. The cool trough even stayed stuck in the shadow of the PV right through the summer.

The snowfall on 4-15-14 was also interesting in that it was the latest accumulation since 4-19-83, which hit Long Island hard. 

The PV feature that gave Dobbs Ferry 74" that winter, and a near record cold March with several misses to the south, stayed active into the summer. The troughing re-oriented itself over the Midwest/Lakes, but still delivered the coolest and least humid summer since 2009.

[bluewave]

35 minutes ago, nzucker said:

The snowfall on 4-15-14 was also interesting in that it was the latest accumulation since 4-19-83, which hit Long Island hard. 

The PV feature that gave Dobbs Ferry 74" that winter, and a near record cold March with several misses to the south, stayed active into the summer. The troughing re-oriented itself over the Midwest/Lakes, but still delivered the coolest and least humid summer since 2009.

There have been some interesting patterns in regard to average first and last freeze dates for NYC vs the some interior Northeast stations. While both areas are moving to later fall first freezes, NYC is holding relatively steady in the spring since 1980.

First and last freeze dates since 1980...

NYC

1980....first....Nov 16

2017...first....Nov 24

1980...last....Mar 29

2017...last....Mar 30

BTV

1980...first...Oct 2

2017..first...Oct 12

1980 last...May 11

2017.last...Apr 28

BDL

1980..first...Oct 6

2017..first...Oct 21

1980...last...May 1

2017...last...Apr  19

[nzucker]

34 minutes ago, bluewave said:

There have been some interesting patterns in regard to average first and last freeze dates for NYC vs the some interior Northeast stations. While both areas are moving to later fall first freezes, NYC is holding relatively steady in the spring since 1980.

First and last freeze dates since 1980...

NYC

1980....first....Nov 16

2017...first....Nov 24

1980...last....Mar 29

2017...last....Mar 30

BTV

1980...first...Oct 2

2017..first...Oct 12

1980 last...May 11

2017.last...Apr 28

BDL

1980..first...Oct 6

2017..first...Oct 21

1980...last...May 1

2017...last...Apr  19

This makes sense according to the precepts of climate change...the North is warming faster than places in the mid-Atlantic, and this is expected by most GCM simulations. It is logical as the North depends more on radiational cooling and the health of the cryosphere, both of which are impacted negatively by climate change. As the North warms more quickly than the rest of the country, the discrepancy in changes of frost/freeze dates between places like BTV and NYC will probably grow.

Although I haven't studied this, there is probably more variation possible in places away from the ocean that have later freeze dates. It is easier for BTV and BDL to move up 2 weeks than NYC, which is already a coastal climate with limited radiational cooling that has a relatively early last freeze date.

There is definitely some luck involved here, too. We have had two particularly cold airmasses in early April (2018 and 2016), which falls within the normal window of NYC's last freeze. Most of the heat in April has been in the middle of the month, probably part of the reason BDL has seen a change in its final freeze. The last major cold spells in May were Memorial Day 2013, when parts of New England had a snowstorm, and then May 2010, when Dobbs Ferry had a freeze on 5/10 and a high of 46F on 5/14. Although luck plays a role, the overall trend is warming, and this is evidenced by the revision of the USDA Hardiness Zones Map from 1990 to 2012; most places moved half a zone (5F) warmer in the 20 year period. The tendency towards longer growing seasons should continue nationwide, and particularly in the North. However, there will always be variation due to the weather.

[bluewave]

8 minutes ago, nzucker said:

This makes sense according to the precepts of climate change...the North is warming faster than places in the mid-Atlantic, and this is expected by most GCM simulations. It is logical as the North depends more on radiational cooling and the health of the cryosphere, both of which are impacted negatively by climate change. As the North warms more quickly than the rest of the country, the discrepancy in changes of frost/freeze dates between places like BTV and NYC will probably grow.

Although I haven't studied this, there is probably more variation possible in places away from the ocean that have later freeze dates. It is easier for BTV and BDL to move up 2 weeks than NYC, which is already a coastal climate with limited radiational cooling that has a relatively early last freeze date.

There is definitely some luck involved here, too. We have had two particularly cold airmasses in early April (2018 and 2016), which falls within the normal window of NYC's last freeze. Most of the heat in April has been in the middle of the month, probably part of the reason BDL has seen a change in its final freeze. The last major cold spells in May were Memorial Day 2013, when parts of New England had a snowstorm, and then May 2010, when Dobbs Ferry had a freeze on 5/10 and a high of 46F on 5/14. Although luck plays a role, the overall trend is warming, and this is evidenced by the revision of the USDA Hardiness Zones Map from 1990 to 2012; most places moved half a zone (5F) warmer in the 20 year period. The tendency towards longer growing seasons should continue nationwide, and particularly in the North. However, there will always be variation due to the weather.

I have plenty of respect for people that make their living in agriculture with such big extremes that we have experienced recently. While it was mostly just my annuals, the record hard freeze last November was pretty rough following the extreme warmth and late bloom. I never saw a garden here go from such a beautiful bloom to flattened in just a few hours. We usually have the blooms slowly fade out ahead of the first killing frost or freeze.

[doncat]

18 minutes ago, bluewave said:

I have plenty of respect for people that make their living in agriculture with such big extremes that we have experienced recently. While it was mostly just my annuals, the record hard freeze last November was pretty rough following the extreme warmth and late bloom. I never saw a garden here go from such a beautiful bloom to flattened in just a few hours. We usually have the blooms slowly fade out ahead of the first killing frost or freeze.

The Nov cold snap was coldest so early for my station and others...Also my low of 27° this morning has only been beaten a handful of times for coldest for so late during my 40 years.

[Stormlover74]

Mid 70s Friday and Saturday, will feel extra nice

[bluewave]

26 minutes ago, doncat said:

The Nov cold snap was coldest so early for my station and others...Also my low of 27° this morning has only been beaten a handful of times for coldest for so late during my 40 years.

Quite a clash of air masses coming up over the next week. The SE ridge will flex its muscles as this unusually cold to record cold spring in spots pattern begins to relax. So we get a surge of spring warmth coming up the coast. It could lead to a very wet storm here following the warm up. Models bring a tropical moisture plume north ahead of the storm cutting to our west in about a week.

 

[NewYorkweatherfan]

20 minutes ago, Stormlover74 said:

Mid 70s Friday and Saturday, will feel extra nice

If it only stayed like that all year around I'd be contend!

[winterwx21]

On 4/5/2018 at 6:29 PM, donsutherland1 said:

80 is probably too high. Low 70s are possible.

Maybe I didn't go too far afterall when I suggested 80 degrees back on thursday. I should have stayed with that idea, because now it's looking possible again.

[donsutherland1]

1 hour ago, winterwx21 said:

Maybe I didn't go too far afterall when I suggested 80 degrees back on thursday. I should have stayed with that idea, because now it's looking possible again.

You could be right. I may have been too conservative in the extended range.

[uncle W]

6 hours ago, bluewave said:

There have been some interesting patterns in regard to average first and last freeze dates for NYC vs the some interior Northeast stations. While both areas are moving to later fall first freezes, NYC is holding relatively steady in the spring since 1980.

First and last freeze dates since 1980...

NYC

1980....first....Nov 16

2017...first....Nov 24

1980...last....Mar 29...last freeze was 4/17...

2017...last....Mar 30

BTV

1980...first...Oct 2

2017..first...Oct 12

1980 last...May 11

2017.last...Apr 28

BDL

1980..first...Oct 6

2017..first...Oct 21

1980...last...May 1

2017...last...Apr  19

 

[bluewave]

No wonder the longer range models struggled so much with such a sharp thermal gradient like this.

 

Right side of the back door for Saturday.

 

 

Sunday not so much. 

 

 

[NewYorkweatherfan]

Gfs is warm for this weekend followed by cold. And it's cold the entire run

[MJO812]

56 minutes ago, NewYorkweatherfan said:

Gfs is warm for this weekend followed by cold. And it's cold the entire run

NAO heading towards negative

[MJO812]

Some rain and snow tonight but nothing big

[sferic]

34 minutes ago, Snow88 said:

Some rain and snow tonight but nothing big

Mood Snow on April 10th is still nice !

[tek1972]

Can't stop the warmth . It's coming sooner or later

Sent from my SM-N950U using Tapatalk

[Rtd208]

Wet

[bluewave]

20 minutes ago, Rtd208 said:

Wet

No let up in sight yet for this really wet pattern that began in February. Next Monday looks like it could a real soaker with the deep tropical PWAT plume.

[NewYorkweatherfan]

That radar looks nice to our west. Someone could get a surprise tonight. As the sun goes down the precip is going to move in

[Rtd208]

19 minutes ago, bluewave said:

No let up in sight yet for this really wet pattern that began in February. Next Monday looks like it could a real soaker with the deep tropical PWAT plume.

I know a few met's have been mentioning we could see normal to above normal precipitation over the next several weeks. I wonder if the entire spring/summer could turn out that way.

[SnoSki14]

This would be a really active summer pattern if it continued. Strong air mass clashes between the SE ridge and cold dumping into Midwest.

[RedSky]

Light snow has started after occasional afternoon flurries and 41F

 

[bluewave]

33 minutes ago, Rtd208 said:

I know a few met's have been mentioning we could see normal to above normal precipitation over the next several weeks. I wonder if the entire spring/summer could turn out that way.

3rd wettest 2/1 to 4/9 on record at ISP with 14.64". Also established a new record for days with measurable precip in this time period at 34.

[Rtd208]

2 minutes ago, bluewave said:

3 wettest 2/1 to 4/9 on record at ISP with 14.64". Also established a new record for days with measurable precip in this time period at 34.

A fun month was August 2011, between the heavy rain events then tropical storm Irene, plenty of flooding.

[Rtd208]

2 minutes ago, bluewave said:

If you like cool and wet, then you will really enjoy the new EPS weeklies. Good thing that we will be able to sneak in a few spring days later this week into the weekend.

I am good with it being wet as long as it is not to cool, 60's & 70's would be fine. If the entire summer was wet with temps in the 70's and 80's I would be fine with that, it would probably be on the humid and sticky side as well if precipitation wound up being above normal.

[MJO812]

Euro weeklies show cool weather right through early May.