Forum Index > Trail Talk > Wouldn't it be fun to be a weather forecaster?
Previous :: Next Topic  
Author Message
gb
Member
Member


Joined: 01 Jul 2010
Posts: 5063 | TRs

gb
  Top

Member
PostSat Feb 23, 2019 7:43 am 
Reply to topic Reply with quote
Like the Weather

party.gif

Here, in a nutshell, is what it currently looks like to the Seattle forecasters - it is worth a read, because it is actually pretty funny. (This is not just one forecaster but involves a discussion among many meteorologists before issuing the morning forecast.)

Quote:
The big headache in the forecast comes with Sunday night and through

the day Monday as snow levels plunge again without much in the way

of recovery. Model solutions have been slightly schizophrenic when

it comes to precip...precip type...how far north it will reach

and...come to think of it...most forecast details. Prior solutions

maintained a somewhat consistent trend with precip remaining

generally well south of the Seattle Metro with the occasionally

trending wetter or drier...but no major deviations. That changed

with the 12Z ECMWF yesterday...apparently advertising the potential

for significant snowfall. Fortunately...the 00Z ECMWF has backed well

away from that solution...making it a significant aberration in the

forecast trend. As such...primary thinking this shift is to return

forecast to a state similar to 24 hours ago...ignoring that 12Z

solution...especially given that 00Z solutions are favoring those

pre-established trends. All that being said...there still is a

prospect for lowland snow during this time period but total

accumulations at this time look to be less than 2 inches for the

entire 24 hour period starting after midnight Sunday night through

midnight Monday night. As it is just coming in at the time of this

writing...the 06Z GFS has any precip being well south of the CWA for

this time period...turning the snowpocalypse advertised in the 12Z

ECMWF from yesterday into a big old nothing burger. The main reason

of pointing that out is to display the wide spectrum of solutions

out there. Until a consistent set of solutions present

themselves...persistence forecasting in the vein of the already

established trend of prior solutions seems to be the safest bet.



Tuesday looks to see a drying trend continue...even though current

ECMWF is in some disagreement...easing on POPs for the first half of

the day then bringing a slug of moisture for the evening and

overnight period. Snow levels would still allow for snow or mixed

precip during this time...but given that the models are struggling

with Monday...not sure if it would be proper to assign much

confidence to Tuesday either.  SMR



.LONG TERM /WEDNESDAY THROUGH SATURDAY/...Models agree on an upper

level low off the coast influencing the weather over W WA

Wednesday...they just disagree on how much moisture will be with

it...the GFS generally dry with some showers possible while the

ECMWF is rather juicy. Opted to split the difference. The good news

is that snow levels recover rather nicely...climbing back above 1000

ft and as such...any precip would be rain. The best part is that

they stay that way for most locations throughout the long term

forecast period...hopefully marking an end to the threat of lowland

snow for this winter season. Fingers crossed. This low pushes

through the area Thursday with rain expected. Getting into

Friday...models once again fall into disagreement...with the GFS

bringing a pretty sizable ridge over the Pacific and thus going for

dry conditions. The ECMWF on the other hand ends up retrograding the

aforementioned low...pushing it back out the Pacific and thus W WA

remains dry as this system reloads so it can bring rain back to the

area late in the weekend. To be honest...this solutions just looks

odd. Opted to lean more toward the GFS...but tipped my hat to the

Euro with weak POPs under 20 percent...just in case.  SMR
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
neek
Member
Member


Joined: 12 Sep 2011
Posts: 550 | TRs
Location: Seattle, WA
neek
  Top

Member
PostSat Feb 23, 2019 9:21 am 
Reply to topic Reply with quote
Ah, chaos. Stupid butterflies. A question I've had for a long time: why don't forecasts come with some indication of confidence? Is it that most people don't know what to do with a statement like "we are 60% sure there's a 40% chance of rain next Tuesday"?
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
Chief Joseph
Member
Member


Joined: 10 Nov 2007
Posts: 4826 | TRs
Location: What Verlot Forgot.
Chief Joseph
  Top

Member
PostSat Feb 23, 2019 10:18 am 
Reply to topic Reply with quote
One could roll some dice and be about as accurate, at least for mountain forecasts more than a day or so out. They were calling for 1-2" of snow here and we got 7-8".

--------------
Go placidly amid the noise and waste, and remember what comfort there may be in owning a piece thereof.
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
gb
Member
Member


Joined: 01 Jul 2010
Posts: 5063 | TRs

gb
  Top

Member
PostSat Feb 23, 2019 11:11 am 
Reply to topic Reply with quote
neek wrote:
Ah, chaos. Stupid butterflies. A question I've had for a long time: why don't forecasts come with some indication of confidence? Is it that most people don't know what to do with a statement like "we are 60% sure there's a 40% chance of rain next Tuesday"?

Which is the value of reading the NWS Forecast Discussion. The forecaster that writes the discussion usually makes a statement about reliability at the point in time of the forecast, trends, and differences in various forecasting models.

This looks to be about the most difficult situation for forecast models to resolve because it is so highly unusual, and looks even more difficult in a couple of days, and perhaps going forward, as there is essentially a battle royale between a modified arctic airmass that is driven by a very strange but persistent polar jet and an undercutting warm moist subtropical jet that appears that it will be undercutting the ridge to our west, and eventually portends a likely Pineapple express not far to our south.

This shows the extremely strange Polar/Subtropical jet as forecast for Tuesday morning. What a bizarre loop in the Jetstream.


The local situation of the exact position of low pressure systems off or near the coast and the temperature and depth of any modified Fraser outflow add to the confusion.

It is right to say in this situation that the weather forecasts may only be valid day to day or even not at all.
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
BigBrunyon
Member
Member


Joined: 19 Mar 2015
Posts: 421 | TRs
Location: EASTERN Wa
BigBrunyon
  Top

Member
PostSat Feb 23, 2019 12:51 pm 
Reply to topic Reply with quote
So what's the deal then? Its gonna snow sunday night??

--------------
i'm better at hiking than most everyone!!! and i know it!!!
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
neek
Member
Member


Joined: 12 Sep 2011
Posts: 550 | TRs
Location: Seattle, WA
neek
  Top

Member
PostSat Feb 23, 2019 12:58 pm 
Reply to topic Reply with quote
Chief Joseph wrote:
One could roll some dice and be about as accurate, at least for mountain forecasts more than a day or so out. They were calling for 1-2" of snow here and we got 7-8".

Yeah, one can always find failures, despite the steady increase in forecasting skill since numerical modeling became a reality in the 50s, not to mention step functions in accuracy such as ensemble forecasting in the 90s.  BTW it's usually a dart board in the analogy.  The joke never gets old but of course it's wrong and in fact countless lives have been saved by weather services (when people actually listen).  Thus gb's point that the uncertainty of the next few days does qualify as news in the man-bites-dog sense.

I'm just hoping we don't get another big dump next week.  Enough already!
Back to top
View user's profile Search for posts by this user Send private message Send e-mail Reply to topic Reply with quote
gb
Member
Member


Joined: 01 Jul 2010
Posts: 5063 | TRs

gb
  Top

Member
PostSat Feb 23, 2019 2:07 pm 
Reply to topic Reply with quote
For me the relevance beyond the amazement with this situation comes in evaluating the opportunities for activity. I finally skied day before yesterday after a ridiculously warm December/January and persistent avalanche weakness when colder snow arrived in early February and also back in January. My friend at Alpental tells me that the snow at her place is still really unconsolidated and has sent me a bunch of funny videos of her dog after the big dump. Another friend described skiing with 4' of loose snow on rocks and dirt, and had a whale of a time dealing with Alder......

I don't know about Cougar Mountain, but my guess is all trails have snow coverage including Tiger and in valleys like Darrington and Baker Lake, and in the Eastern Olympics. Ashford still had something like a foot.

With low elevation roads snowed in it is also not realistic to backcountry ski other than the main corridors and ski areas.
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
Malachai Constant
Member
Member


Joined: 13 Jan 2002
Posts: 13951 | TRs
Location: Back Again Like A Bad Penny
Malachai Constant
  Top

Member
PostSat Feb 23, 2019 3:44 pm 
Reply to topic Reply with quote
We live on Squak and skied across early in the storm the snow is consolidated now and crusty. There is over a foot at Forest Rim @1200. Tiger has at least a couple feet on WT3 we went up Section Line Thursday. Cougar has at least a foot at the Radar Peak Parking lot which has not been plowed nor the road. Today we have had rain, snow, gravel, and hail. Mabel a half nice stuck yesterday but has melted higher up the trees are snowy.

--------------
"You do not laugh when you look at the mountains, or when you look at the sea." Lafcadio Hearn
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
Grannyhiker
Member
Member


Joined: 29 Jul 2006
Posts: 3184 | TRs
Location: Gateway to the Columbia Gorge
Grannyhiker
  Top

Member
PostSun Feb 24, 2019 3:35 pm 
Reply to topic Reply with quote
As with a policeman's lot, a weather forecaster's lot is not a happy one.  Especially here in the NW!

--------------
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view.--E.Abbey
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
gb
Member
Member


Joined: 01 Jul 2010
Posts: 5063 | TRs

gb
  Top

Member
PostMon Feb 25, 2019 7:03 am 
Reply to topic Reply with quote
The value of experience in evaluating forecast model runs:

NWS Monday:

Quote:
So...here is Monday...the highlight of previous discussions for some

time...and models remain consistent in the trend that the passing

system will indeed remain to the south of the CWA today keeping dry

conditions in place for the vast majority of W WA. In reflection

though...this provides a good learning opportunity to keep in mind

the broader trends of model forecasts throughout the run up to an

event and within that context then consider some of the more

dramatic solutions that may arise. Both the GFS and ECMWF show some

precip creeping a little northward this evening...each model

retaining their characteristic nature with the GFS being a bit more

restrained and the ECMWF being a touch overzealous. Opted to split

the two...allowing for some slight chance pops to be present in some

zones...but expecting little or nothing to come out of it. Snow

levels remain near sea level...so anything that does fall will take

the form of snow.



Models agree on continued dry conditions for Tuesday but start to

differ for Wednesday morning very similar to how they differ for

today and this evening. As such...opted to lean toward the GFS

solution and while it too eventually brings in some precip chances

by Wednesday afternoon...these chances look to be minimal with pops

only getting into slight chance range. The upper level low

responsible will finally push to the east through the day Thursday

according to the GFS while the system lingers off the coast into

Thursday night. Once again...opted toward the more progressive GFS

if for not other reason than what could best be classified as event

fatigue.



As already briefly touched upon...snow levels throughout the short

term will have difficulty recovering...not straying too far from sea

level for most locations and certainly remaining below 500 ft

through Thursday. So...any precip that falls...even though odds are

against it..will fall as snow. Afternoon high temperatures will

remain in the lower 40s...so really no chance of anything that does

fall accumulating or hanging around for any amount of time.  SMR
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
Vertec
Member
Member


Joined: 08 Sep 2018
Posts: 66 | TRs

Vertec
  Top

Member
PostTue Feb 26, 2019 7:18 am 
Reply to topic Reply with quote
"Fingers crossed."

Yes it would be great to have that kind of "flexibility" in job performance.  Being able to say "its not my job" to be accurate would be great.

My observation over the last 3-4 ski seasons is most of the major storms (with significant mountain snow accumulation) have been missed in the near term (2-3 days out) forecasts - but were forecasted correctly in the long term (4-6 days out) forecasts.  It seems there is a reluctance for forecasters to believe near term weather models that go against the "it will be warm and never snow again" narrative.  That reluctance hasn't really applied to the the long term models because those models are "accepted" to be more "speculative" - so when they contain a prediction that goes against the narrative no one cares.

--------------
Out There, carrying the self-evident truth I am endowed by my Creator with unalienable rights of self-defended Life, Liberty, and the pursuit of Happiness.
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
gb
Member
Member


Joined: 01 Jul 2010
Posts: 5063 | TRs

gb
  Top

Member
PostThu Mar 07, 2019 6:17 pm 
Reply to topic Reply with quote
Good observations, Vertec. Forecasting snow in Seattle is a crap shoot because the conditions are usually so marginal. Fraser outflow, a system to the south, low level on, or offshore, and convergence zones all wreck havoc. Nearly every snow event in Seattle is a crapshoot and this is widely publicized.


This particular forecaster has a great sense of humor and is fun to read. After referring to this cold weather as a "bad house guest who doesn't know when to leave", he went on to say this in this afternoon's discussion:

Quote:
Temps in the extended actually look to rise with highs Sunday

approaching 50 in many lowland locations. Likewise...snow levels

throughout this period look to remain above 1000 feet. While all of

this seems promising...much the story of this winter has been models

agreeing on an optimistic scenario for days 7 and 8 only to yank

the rug out from many an unsuspecting forecaster and perpetuating

this slog of a winter. Still...with it now being March...one would

hope that spring would indeed be on the doorstep...so there is

reason for cautious optimism. Although...not helping this argument

is that there will not be a whole lot of fluctuation in overnight

lows...maybe a little bit of headway into the mid to upper 30s

Monday night/Tuesday morning...but the remaining days look to be

ranging in the upper 20s to lower 30s still...so the ritual scraping

of frost and preheating the car each morning will likely continue.

SMR
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
Mountainfisherman
Member
Member


Joined: 26 May 2010
Posts: 47 | TRs

Mountainfisherman
  Top

Member
PostFri Mar 08, 2019 6:09 am 
Reply to topic Reply with quote
Back to the original question-yeah I think it would be fun to a weather forecaster and I appreciate a little levity in the forecast discussion.  I would like to have the expertise to analyze  the data they are assessing on a short term, long term basis as well as analyzing climate change.  As for accuracy, I sometimes think people want the exact number of raindrops, snowflakes falling in a specific spot-I think in general accuracy is excellent for 3 to 7 days out if you take into account the Forecast Discussion and apply some common sense and a little local knowledge if happen to have it.
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
gb
Member
Member


Joined: 01 Jul 2010
Posts: 5063 | TRs

gb
  Top

Member
PostThu Mar 28, 2019 9:25 am 
Reply to topic Reply with quote
Pretty tough right now to have anything in the way of a reliable forecast. Probably not very wet, but other than that, make a guess, win a prize.

NWS Discussion this morning:

Quote:
SYNOPSIS...The front that brought pockets of light rain to the

area overnight is dissipating over northern portions of Western

Washington early this morning. An upper level trough will give a

few mainly afternoon and evening showers to the area through

Friday and perhaps into Saturday, mainly over the mountains. A

system may bring a chance of rain to the area Monday into Tuesday.

Temperatures will likely remain near or slightly above normal for

the next several days.



SHORT TERM /TODAY THROUGH SATURDAY/...The front that moved

north through the area overnight is now over the northern fourth

of the state and is dissipating as it moves toward British

Columbia. Rainfall with this front was much spottier and lighter

than what was anticipated a couple of days ago. As this front

moves northward, the area will come under the influence of a

slightly unstable but not overly moist air mass that is rotating

around an upper low centered near 43N 132W. Most of the showers

and thunderstorms associated with this upper low will remain well

offshore.



Short term models continue to have difficulty in this split flow

regime we are seeing, especially Friday into Saturday. The ECMWF,

put more emphasis on the southeastward movement of the blocking

high aloft now over far NW British Columbia. Winds aloft over the

area in the ECMWF model world are E to SE, 500 mb height rise to

around 564 DAM, and the air mass is rather stable. The ECMWF world

would result in, at most, only isolated mountain PM showers

Friday into Saturday.



The GFS/Canadian GEM model world has a completely different view

of the world -or the Pacific NW anyway. The southern stream upper

low over the SW Oregon offshore waters lifts northward to off the

mouth of the Columbia River by Friday night. With more ample

moisture, increased instability, and more diffluent upper level

southerly flow, rather widespread convection is seen over the

mountains, mainly during the PM hours, that possibly shift into

the lowlands as they rotate around the offshore circulation.



Either solution is plausible. So the forecast at this time

follows the middle road. A slight chance of late afternoon and

evening thunderstorms was maintained for the south portions of the

area today and for the southern portion of the Cascades on

Friday. Highs both days will be in the 50s to lower 60s and lows

will be in the mid 30s to mid 40s.



The forecast for Saturday will either be partly cloudy with no

shower activity per the ECMWF or quite showery per the GFS. Models

are sticking to their guns and are not converging on a solution.

The middle ground may not be a good forecast - but with either

solution being plausible in this split flow regime is the best way

to go for now. The forecast will be for partly cloudy conditions,

a rather low chance of mainly PM mountain showers, and

temperatures in the upper 50s to mid 60s for daytime highs will be

maintained into Saturday. Albrecht
Back to top
View user's profile Search for posts by this user Send private message Reply to topic Reply with quote
  Display:     All times are GMT - 8 Hours
Forum Index > Trail Talk > Wouldn't it be fun to be a weather forecaster?
  Happy Birthday wamtngal, Hikes With Kids, BearQueen, dougurry!
Jump to:   
Search this topic:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
   Use Disclaimer Powered by phpBB Privacy Policy