Valentine eve's storm?

[Lowpressure]

Models are trending north on the last run. We down here want it to track south in order to get a winter storm. It is in that vague 4-5 window that models seem to really struggle with lately.

[Fodie77]

I'm keeping my fingers crossed here at Virginia Tech.

[sphinx]

All of the models are predicting a storm on Tuesday. However, the predicted storm tracks vary widely. The 12 UT NOGAPS suppresses the system giving moderate amounts of wintry precipitation to northern North Carolina, Virginia, and southern West Virginia. Most of the other models show a more northerly track with several giving rain to the aforementioned locations and a rain/snow mix to the northern MidAtlantic and snow to southern New England.

The 12 UT ECMWF run should be out shortly ...

[TeeBird]

As someone that is learning how to read these models, I have a question about which time period one to look at on the nws site? The 0 UTC GFS? the 6 UTC GFS? the 12, etc?

I've started trying to educate myself about what these lines mean and I try to not ask 'dumb' questions, so I hope this one doesn't fall in that catagory.

I live in No VA, if that makes any difference

Thanks

[jimvb]

Nothing is "dumb" here. There is a lot of imponderables about these products on the Web. For example, you see the 0 line (precipitation on GFS) or the 540 line (MSLP on GFS) south of your place, so you figure you are going to get snow. If it's north, you get rain. But how do you know when you get freezing rain or snow? Some of the model outputs show precipitation type, but they only go out to somewhat less than a week and they are inconsistent. I used to use the Coolwx site, but they have produced "Entire grid undefined" so many times that I don't consider them dependable. So I find the ncep site mentioned at the beginning of this thread. But it has its problems, too. Already it is 2007 February 8 20:37 UT (Zulu) and they are still presenting the 06Z runs. I have found another one at

http://www.rap.ucar.edu/weather/model/

but I don't know how long that will last.

The general feeling that I get is that the track of this storm is moving north, so that means more rain in the south and a chance for a snowstorm farther north.

[ncupsscweather]

http://weather.unisys.com/gfsx/loop/gfsx_pres_loop.html

[ncupsscweather]

looking at the latest GFS it is showing nothing but rain for north carolina until the 15th of Feb.

[TeeBird]

Thanks for the information. It's been interesting learning as I go - not for any particular reason, but because it is fascinating to see how the forces interact to create our weather.

I find I learn most by just reading, following links, comparing one poster to another, etc. As much as I would like to, I refrain from the "so, am I getting snow....?" type questions. I would rather learn to read what others are reading and then make my own judgement

Things change quickly don't they?

[icicle]

I know it wasnt posted for me, but i'll use that site as well. thanx for posting it.

Nothing is "dumb" here. There is a lot of imponderables about these products on the Web. For example, you see the 0 line (precipitation on GFS) or the 540 line (MSLP on GFS) south of your place, so you figure you are going to get snow. If it's north, you get rain. But how do you know when you get freezing rain or snow? Some of the model outputs show precipitation type, but they only go out to somewhat less than a week and they are inconsistent. I used to use the Coolwx site, but they have produced "Entire grid undefined" so many times that I don't consider them dependable. So I find the ncep site mentioned at the beginning of this thread. But it has its problems, too. Already it is 2007 February 8 20:37 UT (Zulu) and they are still presenting the 06Z runs. I have found another one at

http://www.rap.ucar.edu/weather/model/

but I don't know how long that will last.

The general feeling that I get is that the track of this storm is moving north, so that means more rain in the south and a chance for a snowstorm farther north.

[Stephanie]

As someone that is learning how to read these models, I have a question about which time period one to look at on the nws site? The 0 UTC GFS? the 6 UTC GFS? the 12, etc?

I've started trying to educate myself about what these lines mean and I try to not ask 'dumb' questions, so I hope this one doesn't fall in that catagory.

I live in No VA, if that makes any difference

Thanks

The later the "time" the more recent the forecast.

"0" is midnight Zulu hours, "6" is 6 am, etc.

You also need to look at the forecasted temperatures in the upper levels of the atmosphere to see if we're talking ice or snow. It could be below freezing at the surface, but if it's above freezing in the upper layers, it'll be rain that will be freezing on contact. Then again, the opposite could happen where it's frozen in the upper atmosphere but liquid at the surface if the temperatures were flip-flopped.

I HAVE learned something while I've been a member here!

[sphinx]

With respect to which GFS simulation to look at. The 00UT run comes out around midnight EDT, the 06 UT run at 6 AM EDT, and 12 UT run at 12 PM, and the 18 UT run at 6 PM.

If a storm is 5-9 days away, I give relatively equal weight to each of the simulations. --> You need to look at all 4 runs- kind of a poor man's ensemble. You should also look at the NCEP ensemble mean solution, the 00 UT GGEM run, the 00 and 12 UT ECWMF runs, and the DGEX. I usually give the most weight to the model that is most consistent from run to run but I also consider how realistic the predicted solutions are. For example, if a simulation predicts a foot of snow on Richmond, the model is probably wrong (at least at the 5-9 day time frame).

Storms usually come into focus between days 3 and 5 (wimpy storms may never come into focus). At this point I look at trends from run to run. I may only look at the last two simulations.

[fci]

Thanks for the information. It's been interesting learning as I go - not for any particular reason, but because it is fascinating to see how the forces interact to create our weather.

I find I learn most by just reading, following links, comparing one poster to another, etc. As much as I would like to, I refrain from the "so, am I getting snow....?" type questions. I would rather learn to read what others are reading and then make my own judgement

Things change quickly don't they?

I rarely post here since I live in South Florida where there is no winter; however, don't ever feel that you have a dumb question!

S2K is a wonderful site to learn about Weather be it Winter type or Tropical (where we wake up down here).

I encourage you to read, read and read and ask for help if you need to decipher things that Pro Mets and other experienced weather-folk may post.

You have come to right place to learn.
When someone posts a link to an explanation about a weather subject, by all means; read it and learn and ask questions if you don't understand.
Most will help you and those that may not choose to won't and a few might be impatient but they are few and far between.

This site contains a wealth of knowledge and amazing insights into weather.

Enjoy!

[ncupsscweather]

You know this really bite's I was hopeing to see some wintry weather here where I live in the Carolina's but now the GFS and NAM have backed off on it and just calling for it to be rain with highs in the 50's. Maybe a couple thunderstorms though atleast I might get some fun out of it instead of just plain rain, I sure hope so. I did see somthing in the GFS of snow on the 15th of Feb but the NAM isn't calling for it. Come to think of it though this year hasn't been the best year for the models they seem to not agree with anything like the storm here awhile back in Ohio they didn't forecast anything about it until like 12 to 24 hours before it hit.

[Windspeed]

The Euro, which had been persistently northern, shifted way south with Friday's 0z run, moving the heavy snow band through the southern Appalachians and mid-Atlantic.

Friday 06z GFS run is similar to the 0z Euro, shifting way south:

Still Image
36 hr precip
Storm Animation

[Pi Master]

Come on, I want some snow for my birthday/Valentine's Day!

[Fodie77]

12z GFS looks incredible for us here in VA

Two important things to note:
1) Southern shift in track from 06z run holds
and
2) Total QPF's are massive

http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_132l.gif 60 hr precip/QPF

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_108l.gif southern track of storm

[cpdaman]

ok time to update this thread

Euro, DGEX, and UKMET have gotten keen to the idea of a major snowstorm hitting the Mid-Atlantic and New England area with the GFS jumping on board late this morning


the snow from the virginia's through new jersey is still on schedule only thing is the strorm may dump heavier amounts further east and including southern new england

[sphinx]

I'd love to be a forecaster today. Still so much uncertainty. The most reliable model, the 00 UT operational ECMWF, is showing a heavy rain event for the MidAtlantic and a snowstorm for the northeast. However,
even ECMWF ensembles beg to differ showing a more southerly track (see HPCC discussion). Most models are showing heavy snow for much of the MidAtlantic. If the storm turns into a monster, rain/freezing rain/ and/or sleet are likely to mix in at many locations. Total precipitation amounts exceeding 1.25 inches are possible. What looked like a 12 hour event a few days ago could last for 24 hours in some locations.

[wxman57]

Yep, looking more and more like a major east-coast snow storm from VA-MD north through Boston. Maybe 10-20 inches and very windy Tue/Wed. And this may only be the first of several storms.

[Stephanie]

It also looks like it's starting later than before. It looks like more of a Valentine's Day storm than a Valentine's Day Eve storm.