ABOUT MODELS, FOR NEWBIES (AND NOT-SO-NEWBIES!)
Written by: Bob Metcalfe
Every so often I frequent a weather message board entitled EasternUSWX.com It's a meeting place for professional meteorologists from the TV, private, and goverment sectors as well students and weather lovers. There are some fantastic posts that come out of there.
I found one this morning that has a ton of value to it. I've actually printed it out for a reference here in our weather center. One of the posters took the time to break down not only Zulu time, but also the approximate release times of all the model runs. It's valuable so that you can get the freshest data. I've literally seen people on that board discuss each 6-hour increment as it comes out!
I've copy and pasted the post below:
Here is a brief guide for all you weather weenies just starting out to when you can find your models....
What time is it?
Weather models are run in UTC, which is Coordinated Universal Time, this can also be referred to as Zulu time (hence the “Z”) which is military time, or GMT, Greenwich Mean Time
“UTC” Coordinated Universal Time = “Z” Zulu = “GMT” Greenwich Mean Time
Weather observations are also reported in this style.
0000z is midnight (@ the Greenwich Meridian)
1200z is noon (@ the Greenwich Meridian)
That’s great, but what time is it here?
Eastern Standard Time (winter) is 5 hours behind UTC
Ex 12z = 7am
00z= 7pm (Remembering that 00z is actually midnight)
During Eastern Daylight Savings (summer) is 4 hours behind the UTC
Ex 12z = 8am
00z = 8pm
LOCAL EDT EST
Midnight 400 500
1 a.m. 500 600
2 a.m. 600 700
3 a.m. 700 800
4 a.m. 800 900
5 a.m. 900 1000
6 a.m. 1000 1100
7 a.m. 1100 1200
8 a.m. 1200 1300
9 a.m. 1300 1400
10 a.m. 1400 1500
11 a.m. 1500 1600
NOON 1600 1700
1 p.m. 1700 1800
2 p.m. 1800 1900
3 p.m. 1900 2000
4 p.m. 2000 2100
5 p.m. 2100 2200
6 p.m. 2200 2300
7 p.m. 2300 2400
8 p.m. 2400 100
9 p.m. 100 200
10 p.m. 200 300
11 p.m. 300 400
LOCAL EDT EST
Ok, now that’s settled, what time can I see each model run?
This depends on the model. It is important to remember with model run timing that the time indicated is actually when the model begins its run for instance 12z starts to run at (Noon Greenwhich mean time) 7 EST. Some models are faster than others.
Here I will outline the NAM, GFS, Euro, UKMET, GGEM and SREF for you.
The following times are for EST.
1.)NAM( North American Mesoscale Model) Model forecasts are produced every six hours at 00, 06, 12 and 18 UTC. Data is available in 6 hour incriments out to 84 hours.
NAM
0z: 8:45pm
6z: 2:45am
12z: 8:45am
18z: 2:45pm
2.)GFS (Global Forecast System) Model Forecasts are also produced every 6 hours. (00, 06, 12, & 18). Like the NAM they are available in 6 hour increments. Unline the NAM, the GFS is a longer range model and goes out to 384 hours.
GFS
0z: 10:30pm
6z: 4:30am
12z: 10:30am
18z: 4:30pm
3.)ECWMF( The Euro) forecasts are a bit more complicated. Some of the data from the Euro is subscription only and will change the times that you can access it for each run. Some sites allow you to access it faster than others. Many people on the board use the WSI subscription Euro, so that’s what we will outline here. The Euro has 2 runs for us here , 0z and 12z. Depending on where you access the ECWMF, will depend whether you can access 6 or 12 hour increments.
Euro (subscription services)
0z: 1:00am
12z: 1:00pm
Euro (Free services)
0z: 1:30am
12z: 1:30pm
4.)UKMET (United Kindgom Meteorological Forecast Model) is issued at 00z, 12z On most sites it is a 72 hour model that is in 6 hour increments through 48 hours, and then 12 hour increments through 72 hours.(you can also get the Ukie out to 144 in 24 hour increments) It is also run at 06z and 18z but only goes out to 60 hours.
UKMET
0z: 11:30pm
12z: 11:30am
5.)GGEM (Global Environmental Multiscale Model) Forecasts are another out of country model. This one we get twice a day 12z and 00z.
GGEM
0z: 11:45pm
12z : 11:45am
6.)SREF(Short Range Ensemble Forecasts) are a set of ensembles that are issued 4 times a day at “off” hours. These are run at 03z, 09z 15z, and 21z and run though hour 87.
09z: 8:40am
15z: 2:40pm
21Z: 8:40pm
03z: 2:40am
Bob,
ReplyDeleteI watch the ECMWF on the penn state e-wall. Do you know when that site updates it?
Typically, its pretty close to the numbers above. Some sites have a slight delay based on their web update protocols, but it should be pretty close to the 1:30A/PM time. Penn State doesn't mess around!
ReplyDeleteBob I just saw the updated ECMWF on the penn state e-wall, but I don't know how to interpret it compared to yesterday's 12z run. Does it still put WNY in a favorable spot to get hit by that snowstorm next week, or is it showing it to be less favorable?
ReplyDeleteThis last run is LESS favorable on snow Tuesday/Wednesday but to me looks MORE favorable by Thursday, with a deeper surface low and better arranged northwest flow for lake effect. Is this going to be our next (or first) "big storm"... nope. I'd say an initial few inches with a little lake effect again on Thursday and continuing into Friday. That's if you solely believe nothing more than the Euro data.
ReplyDeleteIf you look at GFS ensembles, they aren't overly optimistic at this point either. Its about a 50/50 split for a hit. Unfortunately, even those that show us getting snow aren't too bullish on it. The woes of winter 09-10 continue my friend!
Scratch that, I meant to say Monday/Tuesday!
ReplyDeleteby "initial" in initial few inches, are you talking about the few inches from the storm itself on monday into tuesday? If so, does that mean that the ECMWF is still showing us getting at least some snow from the storm, just not a major snow?
ReplyDeleteI'm confused, though. Doesn't today's euro have a decent slug of moisture surging up from Ohio and PA as the low winds up off the atlantic?
ReplyDeleteYes, we could technically get something from the storm, but blockbuster likelihood is low.
ReplyDeleteAs for the moisture, sure there's moisture, but moisture doesn't always mean precipitation. Look at the layer average RH from 1000-500 and you'll see that it is't as great as a quick glance may make it out to be. And you can also have a ton of moisture but if it isn't rising, it isn't doing anyone any good!
Disclaimer: Our thoughts here in the weather office are unanimous in one thought: Don't take models to heart for major storms or their location until the incipient low has traversed the Rocky Mountains. The mountains have a HUGE impact on something called potential vorticity and the location of the energy, etc. That's why we're always so cautious about getting excited until a day or two ahead of time. Plus, it's still the same old winter... so we can't get excited about anything this year!
Come on guys, we have missed every snowstorm this year. Why would this one be any different. We will be spectators once again. If the GFS verifies forget about any snow except for the same OLD boring lake effect with a few inches like Bob said. That is how it will play out. The GFS shows the storm coming right at us from the Ohi Valley and then it AMAZINGLY veers to the east like every storm this pathatic winter so far.
ReplyDeleteBob,
ReplyDeleteCan I just draw your attention to the 18z run of the NAM? I know it's an in between run, and it's just one run...and it doesn't go all the way out. BUT, it's interesting how it sends the swath of snow all the way to Chicago and the MI/IN border by hour 84. If you extrapolate that further out given the general ENE direction of the precip, it would put us square in the middle of that swath probably a day or two later. Also, why is everyone so sure this is going to miss us to the south again? I don't see any huge high in the way this time. I don't think we're going to get a blockbuster storm. But i'd be happy if WNY could get in on a good 4-8 or 6-10 inch snowfall. On top of what we already have on the ground, the snow will start getting pretty deep around here again.
Hi team. It looks like both the GFS and the NAM have taken a jog north from previous runs. Like Bob and the previous poster pointed out, it's just one run, but, don't you think there is something to be said about both models shifting? I just get the feeling that this storm has the potential to give us the most measurable snow of any synoptic system thus far. No, not a blockbuster by any means, but at least a decent plowable snow to get our snowpack ever deeper.
ReplyDeleteI hope so because I have only plowed my driveway three times down in Livingston County! Bring it on.
ReplyDeleteI feel for you folks down in Livingston County. I graduated from SUNY Geneseo and I remember the winters being bitterly cold and windy almost every day on campus, but there was never any deep or significant snow around. It was a big change from living in Batavia my whole life. Unless you live in those favored upslope areas in Livingston county, you folks miss out on a lot of the good lake effect. Just too far inland!
ReplyDeleteThanks to the last poster. Yes, we do miss out down here in Livingston. My brother lives in Wyoming, NY so he always gets hammered by the lake effect. I can always go plow his driveway (which is pretty much straight down) If I need a plowing kick. He runs an automotive repair shop over there so his driveway needs to stay clean!
ReplyDeleteAny new information on the storm for monday, tuesday?
ReplyDelete