April 2024 Weather in the PNW

[DareDuck]

29 minutes ago, the_convergence_zone said:

WA DNR lead meteorologist predicts an average fire season in Washington:

https://tvw.org/video/the-impact-2024-wildfire-outlook-dnr-lead-meteorologist-2024041114/?eventID=2024041114

 

 

 

Don’t know how you can predict that now. Lightning starts, offshore events in the fall, marine influence or lack thereof. All impossible to predict. Not to mention we’re a few weeks into spring. Not saying it will necessarily be a disaster, but this is even harder than predicting winter snowpack in early October. 

[Cascadia_Wx]

Just now, DareDuck said:

Don’t know how you can predict that now. Lightning starts, offshore events in the fall, marine influence or lack thereof. All impossible to predict. Not to mention we’re a few weeks into spring. Not saying it will necessarily be a disaster, but this is even harder than predicting winter snowpack in early October. 

Yeah but it makes the people who want summer to start this week feel better about things.

[TT-SEA]

21 minutes ago, Cascadia_Wx said:

Yeah but it makes the people who want summer to start this week feel better about things.

Feeling down about what other people like?

[Phil]

Holy f***. Jacksonville FL? Their tornado climo is basically the same as ours, if not lesser.

 

[BLI snowman]

1 minute ago, Phil said:

Holy f***. Jacksonville FL? Their tornado climo is basically the same as ours, if not lesser.

 

Tornadoes in FL really aren't that rare. 

[the_convergence_zone]

1 hour ago, Cascadia_Wx said:

All the mocking about spring conditions not being a predictor, but now this is the gospel. Seems legit

That's a bummer that some on this forum would resort to mocking. I'm inclined to value the opinion of a leading expert in PNW wildfire meteorology. 

46 minutes ago, DareDuck said:

Don’t know how you can predict that now. Lightning starts, offshore events in the fall, marine influence or lack thereof. All impossible to predict. Not to mention we’re a few weeks into spring. Not saying it will necessarily be a disaster, but this is even harder than predicting winter snowpack in early October. 

I recommend watching the first half of the video to get the answer. He goes into the various arguments in favor vs. against an active wildfire season. A nuanced take. He seems to have looked at seasonal predictions that show average to above-average precipitation in June and July to counter the lack of snowpack and warm spring (due to the trend toward -ENSO). If those forecasts fail, that would change his outlook, although many on this forum seem to agree that this could be a cooler and wetter summer than some of our recent ones. He's expecting a warm and dry May. However, he notes that the dry conditions in spring will likely reduce the risk of grass fires this year, although the dry fuel from recent wet springs means that the grass fire risk is still somewhat elevated.

He also expresses confidence in their improved ability to put out fire starts before they spread -- so the forecast does include a bit of faith in the firefighting operations that he is partially responsible for. 

 

[Phil]

54 minutes ago, DareDuck said:

Don’t know how you can predict that now. Lightning starts, offshore events in the fall, marine influence or lack thereof. All impossible to predict. Not to mention we’re a few weeks into spring. Not saying it will necessarily be a disaster, but this is even harder than predicting winter snowpack in early October. 

Looks like a simple probabilistic forecast. Which would certainly be low confidence in this case, but “impossible” is a stretch.

In 2019 it was obvious early on that the 4CH would be suppressed with a flatter, more westerly upper level pattern in the PNW. That fire season was almost nonexistent as a result.

In 2021 it was the opposite, when it was clear by April that the 4CH would a massive beast (lots of off-eq convection, very wide ITCZ/HC).

[Phil]

6 minutes ago, BLI snowman said:

Tornadoes in FL really aren't that rare. 

Yeah, they’re actually common, but they’re usually of the skinny/rope variety. Almost all are EF0 or EF1 (this one looks..beefier).

Thats what I meant. Basically the same story here, lots of little spin ups but rare to see EF3+. But even rarer in that part of FL.

[the_convergence_zone]

1 minute ago, Phil said:

Looks like a simple probabilistic forecast. Which would certainly be low confidence in this case, but “impossible” is a stretch.

In 2019 it was obvious early on that the 4CH would be suppressed with a flatter, more westerly upper level pattern in the PNW. That fire season was almost nonexistent as a result.

In 2021 it was the opposite, when it was clear by April that the 4CH would a massive beast (lots of off-eq convection, very wide ITCZ/HC).

Another thing is that if you're going to show up to do an interview about the upcoming wildfire season, the first question is always going to be a request for a forecast. And saying the correct-ish answer of "there are too many unknown factors to say" isn't going to cut it. Listing the reasons for/against is definitely the way to go. 

[Deweydog]

6 minutes ago, Phil said:

Looks like a simple probabilistic forecast. Which would certainly be low confidence in this case, but “impossible” is a stretch.

In 2019 it was obvious early on that the 4CH would be suppressed with a flatter, more westerly upper level pattern in the PNW. That fire season was almost nonexistent as a result.

In 2021 it was the opposite, when it was clear by April that the 4CH would a massive beast (lots of off-eq convection, very wide ITCZ/HC).

ITCZ/HC FTW, IMO.

[MossMan]

Busy morning at work, but I did want to pop in and say I had sprinkles earlier! 

[Phil]

2 minutes ago, Deweydog said:

ITCZ/HC FTW, IMO.

ITCZ = Intertropical Convergence Zone

https://en.m.wikipedia.org/wiki/Intertropical_Convergence_Zone

HC = Hadley Cell

https://en.m.wikipedia.org/wiki/Hadley_cell

[Phishy Wx]

18 minutes ago, BLI snowman said:

Tornadoes in FL really aren't that rare. 

usually not big wedges like that though

[BLI snowman]

4 minutes ago, Phil said:

Yeah, they’re actually common, but they’re usually of the skinny/rope variety. Almost all are EF0 or EF1 (this one looks..beefier).

Thats what I meant. Basically the same story here, lots of little spin ups but rare to see EF3+. But even rarer in that part of FL.

Sure, but tornado dynamics are actually a little more favorable the further north you go in FL. Given the better jet support and shear/helicity that exists in that corridor. Jacksonville is basically GA. 

[BLI snowman]

20 minutes ago, Phishy Wx said:

usually not big wedges like that though

Not typical, but FL has seen some legitimate outbreaks in the past. February 1998 was pretty ugly in the Orlando area. February 2007 as well.  Ninos enhance the southern jet obviously so there's a big correlation there. 

Edited April 11 by BLI snowman

[Phil]

12 minutes ago, BLI snowman said:

Sure, but tornado dynamics are actually a little more favorable the further north you go in FL. Given the better jet support and shear/helicity that exists in that corridor. Jacksonville is basically GA. 

You are correct, but during the spring months there is often low level stability near the Atlantic Coast due to relatively cooler waters. Tornado and overall severe climo attenuates substantially within 30-40 miles of the Atlantic Coast in F/M/A (though in the summer/autumn the equation changes substantially, of course).

There are cases where that added differential heating can favor tornado formation, but for stronger tornadoes that is an inhibiting factor as they’re fueled by airmass and convective dynamics requiring significant boundary layer instability. It’s complicated/non-linear and not fully understood, but the evidence is pretty clear IMO.

[Phil]

Speaking of tornadoes, I noticed @Timmy Supercell is under another watch.

Keep a watchful eye on this collision between the cold front and warm-sector thunderstorm outflow. 80% of the time nothing comes of it, but if something does, it’s a pretty dangerous environment.  

[TT-SEA]

1 hour ago, Phil said:

Looks like a simple probabilistic forecast. Which would certainly be low confidence in this case, but “impossible” is a stretch.

In 2019 it was obvious early on that the 4CH would be suppressed with a flatter, more westerly upper level pattern in the PNW. That fire season was almost nonexistent as a result.

In 2021 it was the opposite, when it was clear by April that the 4CH would a massive beast (lots of off-eq convection, very wide ITCZ/HC).

What does this summer look like in terms of 4CH?

[Timmy Supercell]

19 minutes ago, Phil said:

Speaking of tornadoes, I noticed @Timmy Supercell is under another watch.

Keep a watchful eye on this collision between the cold front and warm-sector thunderstorm outflow. 80% of the time nothing comes of it, but if something does, it’s a pretty dangerous environment.  

So far this one is nowhere near as wild as the last one at least on first impression. 

I think the flooding from training storms, and a wind threat from a QLCS are the highlights. I would've opted for a Severe T'storm Watch for most of the areas in the TOR right now. Prove me wrong though!

[Phil]

34 minutes ago, TT-SEA said:

What does this summer look like in terms of 4CH?

The NPAC HC sector is actually very suppressed (and fast) thus far, but at least some of that is the residual niño component.

2021 and 2019 were easy calls because the tropical base state was stagnant in both cases. This year will (in all likelihood) feature a change in the base state over boreal summer/fall. So it’s difficult to know where things will stand once we lose the niño components of heat/mass exchange.

That being said, while very preliminary, the manner in which the background state of circulation is *evolving* appears much closer to transition years such as 2020 and 2010, and far removed from transitions like 1998 (or 2003, in the other direction). And definitely not following the -SPMM dominant Niña EOF we saw in 2017, 2021 or 2022 (or 1975, inversely). Though maybe next year will, if the niña refuses to die again.

[MossMan]

More sprinkles! 

[Phil]

38 minutes ago, Timmy Supercell said:

So far this one is nowhere near as wild as the last one at least on first impression. 

I think the flooding from training storms, and a wind threat from a QLCS are the highlights. I would've opted for a Severe T'storm Watch for most of the areas in the TOR right now. Prove me wrong though!

Yeah lots of precip and crapvection in the warm sector ahead of strongest forcing.

But these high shear/low CAPE setups can overperform unexpectedly, and at the last possible minute. February 2016 and March 2008 looked like nothingburgers out here, but both ended up mixing out the low level inversion and producing QLCS’s with hurricane force winds and spinups.

[TigerWoodsLibido]

66F and mostly sunny.

[AlTahoe]

63F here for our first 60F of the spring. Gonna snow again by Saturday so going to enjoy it while it last. 

[Phishy Wx]

61 and Fair

[Meatyorologist]

2 hours ago, Phil said:

That was the only snow we saw all winter, dude. Also my area was shafted by that clipper, ended up in a dryslot between bands w/ ~ 1” at most. Rare winter when DCA ended up with more snow than us.

I wasn’t alive yet, but I pretty sure I would’ve hated that winter as much as I hated 22/23.

Damn. I'll take your six consecutive days below freezing w/ 1-4" of snowcover and two lows of 11F. If that's so disappointing for you.

Let's just face it man. Your soul would shrivel up and die if you lived out here for even half a decade.

[TT-SEA]

Seems like we are going to have weak troughing remaining in place next week as ridge builds to the north... 18Z GFS showing it as well.   But its really a nice pattern overall with lots of sun and pleasant temps if it works out this way.  A west coast warm finger situation for many days in a row.

[TigerWoodsLibido]

Hope y'all are doing well. Still a road to recovery for me.

[iFred]

4 hours ago, Cascadia_Wx said:

Yeah but it makes the people who want summer to start this week feel better about things.

Take a break man.

[iFred]

24 minutes ago, Meatyorologist said:

Damn. I'll take your six consecutive days below freezing w/ 1-4" of snowcover and two lows of 11F. If that's so disappointing for you.

Let's just face it man. Your soul would shrivel up and die if you lived out here for even half a decade.

Probably wouldn’t even appreciate the low sun angles, inversion season, the fun of a regional wind storm, or warm and clear summer twilight that lingers into a midnight darkness before breaking out into a beautiful shade of blue orange early the next morning.

[Cascadia_Wx]

5 minutes ago, iFred said:

Take a break man.

I can never tell if you’re being serious or not. But feel like I’ve been pretty tame lately compared to even a couple years ago.

[Phil]

38 minutes ago, Meatyorologist said:

Damn. I'll take your six consecutive days below freezing w/ 1-4" of snowcover and two lows of 11F. If that's so disappointing for you.

Let's just face it man. Your soul would shrivel up and die if you lived out here for even half a decade.

What use is cold if it’s not snowing? Thats like ice cream without sugar. Or a wedding without drinks.

Also, DCA doesn’t represent this area well due to UHI+river influence. It’s a very localized microclimate…one of the worst UHI bubbles in all of North America, in fact.

Here’s Dulles, for comparison. Difference in lows can be 20+ degrees in extreme cases. It’s wild.

[Frontal Snowsquall]

25 minutes ago, TigerWoodsLibido said:

Hope y'all are doing well. Still a road to recovery for me.

It’s good to see you posting again Bryan. Were you able to get your ?

[Cascadia_Wx]

12z EPS looks pretty reasonable into the long range at face value, but it seems like whenever temps are shown close to normal with lots of spread like that it will invariably morph into another ridgy pattern. I guess we’ll see.

[Cascadia_Wx]

Up to 65 at PDX. Pretty big overachievement considering this was supposed to be a “cool” day.

63/41 spread here so far.

[Phil]

27 minutes ago, iFred said:

Probably wouldn’t even appreciate the low sun angles, inversion season, the fun of a regional wind storm, or warm and clear summer twilight that lingers into a midnight darkness before breaking out into a beautiful shade of blue orange early the next morning.

I’ve absolutely loved it every time I’ve visited. There’s a vibe I can’t quite put my finger on, but it’s deeper than just the conifers and distant terrain. I love it.

I haven’t spent any substantial amount of time there, so I can’t say how I’d feel after a year, but even if it’s not the best long term climate for me, I’ll wager that I would enjoy it for a time, at least. I’d be fascinated to learn/experience all the microclimates, mesoscale quirks, and different types of weather that I don’t get to experience here. I like learning, and I like trying new things.

For instance, most windstorms here are sunny or have a broken cloud deck. I’d love to experience a windstorm with dark clouds and precip like you get in the PNW, and I’d also be interested to hear how it sounds through the trees there (I assume the acoustics from a softwood forest are very different from a hardwood forest).

[Front Ranger]

5 hours ago, Cascadia_Wx said:

Seems like most spots I’ve looked at are between 0 to +1,  so it’s not like PDX is that much of an outlier.

And those numbers will only be going up the next several days.

PDX is the warmest I see. SLE, SEA, and BLI are all running below average anomalies.

[Cascadia_Wx]

3 minutes ago, Front Ranger said:

PDX is the warmest I see. SLE, SEA, and BLI are all running below average anomalies.

Let’s check back in a couple days.

[Phil]

11 minutes ago, Phil said:

I’ve absolutely loved it every time I’ve visited. There’s a vibe I can’t quite put my finger on, but it’s deeper than just the conifers and distant terrain. I love it.

I haven’t spent any substantial amount of time there, so I can’t say how I’d feel after a year, but even if it’s not the best long term climate for me, I’ll wager that I would enjoy it for a time, at least. I’d be fascinated to learn/experience all the microclimates, mesoscale quirks, and different types of weather that I don’t get to experience here. I like learning, and I like trying new things.

For instance, most windstorms here are sunny or have a broken cloud deck. I’d love to experience a windstorm with dark clouds and precip like you get in the PNW, and I’d also be interested to hear how it sounds through the trees there (I assume the acoustics from a softwood forest are very different from a hardwood forest).

This is random but I’d also like to experience this so called “heavy drizzle” that you guys talk about. I can’t wrap my mind around what the heck that even is.

[Front Ranger]

3 minutes ago, Cascadia_Wx said:

Let’s check back in a couple days.

Ok...that wasn't the point of my post, though. Was just looking at April so far, and PDX is the warm outlier. 

April will be a bit warmer in a couple days, but the second part won't change.