River Card Posted February 21, 2011 Share Posted February 21, 2011 Cannot find threads regarding spring forecasts but how would you call spring for the upper midwest, Chicago region? Looks like the monthly euro wants normal trending towards a progressively hotter and drier pattern into summer but we all know that model is not to be trusted so now we seek unto you for clarity. Thank you! Link to comment Share on other sites More sharing options...
mnweather Posted February 21, 2011 Share Posted February 21, 2011 How does the NWS know when it is going to rain by Lake Superior and snow inland? What do I have to look at to know myself? Link to comment Share on other sites More sharing options...
isohume Posted February 22, 2011 Share Posted February 22, 2011 How does the NWS know when it is going to rain by Lake Superior and snow inland? What do I have to look at to know myself? Generally temperatures near a coastal region are moderated by the body of water the air is traversing over and mixing with. Water has a higher specific heat content than air, which means it can handle more solar or terrestrial radiation before it sensibly "warms"...the opposite is also true. It takes longer for water to cool and the flux it gives off in the winter is a relative warm flux, thereby enabling a mixed llvl atmos near the coast supporting rain whereas inland areas the warm flux contribution is not enough to prevent snowfall. This coastal effect is larger in the Fall and Spring when temp differences btw the water and overlying airmass are the greatest, hence a greater available heat flux. You can evaluate water temps and the degree or depth of the incoming cold airmass. If enough of a difference is noted, generally 3-5 C or so, and the incoming airmass is not extremely cold or deep...then a mixed sfc layer will most likely develop. If you have access to a program like RAOB, you can adjust the llvl temp profile to account for the modified mixed layer expected. If it turns out the new sfc warm layer is deep enough, you can infer ra over sn in these areas. Link to comment Share on other sites More sharing options...
mnweather Posted February 23, 2011 Share Posted February 23, 2011 Does the GFS have a southern bias? Link to comment Share on other sites More sharing options...
okie333 Posted February 23, 2011 Share Posted February 23, 2011 Does the GFS have a southern bias? Not a pro met, but I can tell you that it doesn't since the July update. Link to comment Share on other sites More sharing options...
dtk Posted February 23, 2011 Share Posted February 23, 2011 Does the GFS have a southern bias? In what sense [general surface low tracks, for example]? We are (finally) starting to do a better job of looking at extratropical surface low track verification. The only example I have seen broken down by cross-track/along-track was the Dec. 26. 2010 event. The GFS mostly had a rightward/eastward bias and was actually pretty good in terms of timing (i.e. the along track error).....i.e. no hint of anything resembling a "southerly bias". The EC was a little slow and had a slight eastward bias (but was generally the best global, despite this notion it was terrible for this storm). The UK was WAY too slow and east (now this is indicative of a 'southward bias' perhaps) and the GGEM was out to lunch (it had mean cross track biases more than 100% larger than any of the other globals). Link to comment Share on other sites More sharing options...
friedmators Posted February 23, 2011 Share Posted February 23, 2011 If you had a billion dollars to throw at weather prediction what would you spend the money on? Supercomputers,satellites,ground stations,etc? Link to comment Share on other sites More sharing options...
isohume Posted February 23, 2011 Share Posted February 23, 2011 If you had a billion dollars to throw at weather prediction what would you spend the money on? Supercomputers,satellites,ground stations,etc? Salaries. Link to comment Share on other sites More sharing options...
dtk Posted February 23, 2011 Share Posted February 23, 2011 If you had a billion dollars to throw at weather prediction what would you spend the money on? Supercomputers,satellites,ground stations,etc? More in-situ data (particularly sondes, ocean/ship based), supercomputing, and more R&D (model and data assimilation algorithm development). Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 23, 2011 Share Posted February 23, 2011 More in-situ data (particularly sondes, ocean/ship based), supercomputing, and more R&D (model and data assimilation algorithm development). What are your thoughts on potential funding for the next 5 years given the current financial/budget situations? It does seem some level of stream lining and potential small scale budget reductions are likely at some point--how will that potentially effect the folks in modeling? Link to comment Share on other sites More sharing options...
dtk Posted February 23, 2011 Share Posted February 23, 2011 What are your thoughts on potential funding for the next 5 years given the current financial/budget situations? It depends on what aspects/programs you are talking about to be honest. We were already having funding issues with certain things (upgrades to supercomputing is a good example), so these issues are only going to get worse. We are already struggling with the fact that we really can't fit much more on our current computing platform (and we're a long ways off from any real upgrade). We're going to have to be creative in terms of the types of things we can do to improve our products. In terms of other things, I am really only knowledgeable about the model development circles (NCEP/EMC), and I think we will be fine in terms of the labor aspects (a good portion of EMC has been moved to the private/contractor realm). I have no clue what the implications are in terms of the much larger NWS/NOAA picture ....some of this is covered in the other thread. I am starting to wonder what is going to happen with some of the really big money projects (next generation satellite platforms/instruments...which have gone through serious delays and budget overages). I do not honestly think any of the talk about radiosonde replacement and/or few observations is going to get any momentum (many years ago we were actually tasked to perform experiments attempting to demonstrate the impact of removing such observations...yeah, not good). In fact, we now have ways to estimate observation impact on reducing short term forecast errors, quantitatively, for any component of the observing system (or even individual observation). If you have specific questions I can try to answer them. In terms of the big picture, I think there are going to be places we suffer just like anyone else (hiring freezes, cuts to big money projects, etc.)....but overall, I think it is pretty easy for us to demonstrate value in saving life/property. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 23, 2011 Share Posted February 23, 2011 It depends on what aspects/programs you are talking about to be honest. We were already having funding issues with certain things (upgrades to supercomputing is a good example), so these issues are only going to get worse. We are already struggling with the fact that we really can't fit much more on our current computing platform (and we're a long ways off from any real upgrade). We're going to have to be creative in terms of the types of things we can do to improve our products. In terms of other things, I am really only knowledgeable about the model development circles (NCEP/EMC), and I think we will be fine in terms of the labor aspects (a good portion of EMC has been moved to the private/contractor realm). I have no clue what the implications are in terms of the much larger NWS/NOAA picture ....some of this is covered in the other thread. I am starting to wonder what is going to happen with some of the really big money projects (next generation satellite platforms/instruments...which have gone through serious delays and budget overages). I do not honestly think any of the talk about radiosonde replacement and/or few observations is going to get any momentum (many years ago we were actually tasked to perform experiments attempting to demonstrate the impact of removing such observations...yeah, not good). In fact, we now have ways to estimate observation impact on reducing short term forecast errors, quantitatively, for any component of the observing system (or even individual observation). If you have specific questions I can try to answer them. In terms of the big picture, I think there are going to be places we suffer just like anyone else (hiring freezes, cuts to big money projects, etc.)....but overall, I think it is pretty easy for us to demonstrate value in saving life/property. There is always this worry--but I don't know if this will ever be viable the way the Canadians do it--not to mention the general lack of services one gets with more automation. It could be attempted but many of the benefits would be seemingly lost. Link to comment Share on other sites More sharing options...
dtk Posted February 23, 2011 Share Posted February 23, 2011 There is always this worry--but I don't know if this will ever be viable the way the Canadians do it--not to mention the general lack of services one gets with more automation. It could be attempted but many of the benefits would be seemingly lost. I largely agree...but that is not going to stop people from trying. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted February 23, 2011 Share Posted February 23, 2011 I largely agree...but that is not going to stop people from trying. Personally some level of automation is great if it can save time--I wonder how much will be tried. Link to comment Share on other sites More sharing options...
Festus Posted February 23, 2011 Share Posted February 23, 2011 Wonderful thread BTW, thanks to all the mets who have been responding. I'll throw a few questions out there. 1. Why does a fresh snow sometimes lead to colder morning lows? I believe fresh snow corresponds to a higher albedo but is/are there another mechanism(s) involved? 2. What makes some windy days more gusty than others (no convection involved, just your standard windy day)? Link to comment Share on other sites More sharing options...
isohume Posted February 24, 2011 Share Posted February 24, 2011 Wonderful thread BTW, thanks to all the mets who have been responding. I'll throw a few questions out there. 1. Why does a fresh snow sometimes lead to colder morning lows? I believe fresh snow corresponds to a higher albedo but is/are there another mechanism(s) involved? 2. What makes some windy days more gusty than others (no convection involved, just your standard windy day)? I. I've seen a study which suggests that higher emissivity of snow relative to grass (higher net radiation loss) and a lower flux turbulence over snow compared to grass (less microscale sfc mixing) leads to higher nocturnal cooling rates of about 2:1 of snow covered areas to grassy areas. Chart showing ideal nocturnal cooling rates on the y-axis and actual measured cooling rates on the x-axis. Notice cooling rates over snow fall off much quicker and start off at a higher rate than grass. Cooling over snow is closer to ideal cooling rates than cooling over grass. Albedo is a daytime phenomenon which measures the ratio of reflected solar radiation to the amount of radiation absorbed. Snow has a very high albedo, about 0.9, and this allows only about 10% of the sun's radiation to be used for sensible heat production...thus colder daytime highs occur with plenty of fresh snow-cover around. II. Gusts are generated by a dynamic response of the wind field to the quick change in sfc pressure (ie: strong 3hr pressure change couplets)...or more often gusts develop as higher winds aloft are mixed down to the surface. As the boundary layer warms during the day, the layer that reaches the dry adiabatic lapse rate will become mixed, or nearly homogeneous. So, in the morning the sfc winds could be around 5 kts with winds at h85 around 25 kts. By afternoon with the higher lapse rates reached and mixing developing in boundary layer...winds will become gusty as winds aloft are mixed to the sfc. The strength of the gusts will depend on whether or not a directional wind shear is present. If the winds are unidirectional in the bl then most of the high winds atop the mixed layer will be brought down. If there is good turning with height...then only a certain percentage of the high winds will make it to the sfc as momentum is lost because the winds have to change direction on the way down. Notice the unidirectional shear through the mixed layer and how it coincides with the dry adiabatic lapse rate in this example. The winds atop the mixed layer are 31 kts, while winds at the sfc are 16 kts. Based on this data alone, I'd infer good momentum mixing to the sfc and gusts reaching the higher end of this potential. The mark in the middle (the 173 @ 26 kts) is the avg gust potential and this is good to use if the winds were showing a moderate directional shear through the mixed layer. Another non-convective mechanism to produce sfc gusts is cold air advection. Cold air sinks...so the deeper and colder the air is behind a given system...the more likely stronger winds aloft will be forced to the sfc. There are other mechanisms to produce non-convective wind gusts I'm not thinking of I'm sure and others may add to this discussion. Link to comment Share on other sites More sharing options...
BadgerWXman Posted February 24, 2011 Share Posted February 24, 2011 If you had a billion dollars to throw at weather prediction what would you spend the money on? Supercomputers,satellites,ground stations,etc? - More radar sites... like at least double what we have now (all dual pol obviously...) - A LOT more ASOS sites - Hiring humans to man the ASOS sites so we could actually know what type of precip is falling and what type of cloud cover is around at night (can you tell I'm a morning met?) Then we could also have the sites report more frequently.. like every 15 minutes or so. That would be sweet. - A LOT more RAOB sites that would send up balloons 4 times daily so we don't have to run 06/18z models off pure surface data The combination of significantly more surface/upper air OBSERVATIONS would definitely greatly increase the accuracy of models, even if they were to be run with the same algorithms as they use now. Obviously, with this much money it would be wise to increase the computing power of all the models. That would allow for higher resolution farther out in the forecast for mid range models and the ability to add more mesoscale algorithms into the mix... Ugh... what a bad idea it was to decide to join this forum today and use this as my first post... now I'll be stuck dreaming all day... Link to comment Share on other sites More sharing options...
DaculaWeather Posted February 24, 2011 Share Posted February 24, 2011 I always wondered why I can update my current conditions on my website every 5 seconds or so and why the NWS can't do the same thing. Not only that, one of the "official" reporting stations here (Brisco Field in Lawrenceville GA) quits updating at night. You go to the NWS page for that area and it could be 10 12 hours old. Just worthless data. Link to comment Share on other sites More sharing options...
SacrydDreamz Posted February 24, 2011 Share Posted February 24, 2011 Wonderful thread BTW, thanks to all the mets who have been responding. I'll throw a few questions out there. 1. Why does a fresh snow sometimes lead to colder morning lows? I believe fresh snow corresponds to a higher albedo but is/are there another mechanism(s) involved? 2. What makes some windy days more gusty than others (no convection involved, just your standard windy day)? You know, I find it interesting that you mentioned fresh snow... and something I've postulated is that with fresh snow one would have more surface area in contact with air particles. With a stale snow pack you will get melt/freeze cycles which lead to a less porous surface. This is all a hypothesis though, but it's an interesting thought experiment. Link to comment Share on other sites More sharing options...
SacrydDreamz Posted February 24, 2011 Share Posted February 24, 2011 If you had a billion dollars to throw at weather prediction what would you spend the money on? Supercomputers,satellites,ground stations,etc? I would hire a committee of people more knowledgeable than myself and have them spend it. The one suggestion I would have is to increase the amount of surface observing sites... a strong mesonet in each state would be nice. More buoys in the Pacific would be helpful as well. Link to comment Share on other sites More sharing options...
Chris L Posted February 24, 2011 Share Posted February 24, 2011 What does everyone make of snowfall reports that were called upon before the six hourly method was in place? Is it consistent or no? Do you think certain storms were undermeasured or overmeasured? Link to comment Share on other sites More sharing options...
SacrydDreamz Posted February 24, 2011 Share Posted February 24, 2011 What does everyone make of snowfall reports that were called upon before the six hourly method was in place? Is it consistent or no? Do you think certain storms were undermeasured or overmeasured? Hard to say with regard to the historical storms... and as far as consistency is concerned, I'm not sure we have that with the six hour measurements... Link to comment Share on other sites More sharing options...
isohume Posted February 24, 2011 Share Posted February 24, 2011 I always wondered why I can update my current conditions on my website every 5 seconds or so and why the NWS can't do the same thing. Not only that, one of the "official" reporting stations here (Brisco Field in Lawrenceville GA) quits updating at night. You go to the NWS page for that area and it could be 10 12 hours old. Just worthless data. It has to do with a limited bandwidth. The NWS can't justify streaming feeds to the ASOS sites for negligible public usage. If the FAA wants to do this that's fine. They own the systems. In fact, I don't know of any site that allows a 5-sec update of ASOS data. If you can't wait for the hourlys or SPECIs then I suggest you dial into the ATIS network. Who knows why KLZU shuts down at night? There could be a myriad of reasons. KLZU is part of the AWOS network and is not maintained by the FAA. If you really want to know, I'd contact Gwinnet County as they are the owners of that particular AWOS. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted February 24, 2011 Share Posted February 24, 2011 When looking at wintry mix events...what do you look for in determining if the p-type is sleet or freezing rain? Link to comment Share on other sites More sharing options...
AtticaFanatica Posted February 24, 2011 Share Posted February 24, 2011 When looking at wintry mix events...what do you look for in determining if the p-type is sleet or freezing rain? Hopefully soon, you'll be able to look at polarimetric radar variables Link to comment Share on other sites More sharing options...
LocoAko Posted February 25, 2011 Share Posted February 25, 2011 Hopefully soon, you'll be able to look at polarimetric radar variables Link to comment Share on other sites More sharing options...
isohume Posted February 25, 2011 Share Posted February 25, 2011 When looking at wintry mix events...what do you look for in determining if the p-type is sleet or freezing rain? A couple popular approaches in determining wintry p-type are: The Top Down Approach and Partial Thickness Nomograms. There are too many details to discuss here and I've been accused of going over people's heads on another forum on this subject, so here are a couple good links which give the overall ideas of each procedure. Top Down http://mesonet.agron...wMicrofinal.ppt Partial Thicknesses http://www4.ncsu.edu.../storage/trend/ Link to comment Share on other sites More sharing options...
DaculaWeather Posted February 25, 2011 Share Posted February 25, 2011 It has to do with a limited bandwidth. The NWS can't justify streaming feeds to the ASOS sites for negligible public usage. If the FAA wants to do this that's fine. They own the systems. In fact, I don't know of any site that allows a 5-sec update of ASOS data. If you can't wait for the hourlys or SPECIs then I suggest you dial into the ATIS network. Who knows why KLZU shuts down at night? There could be a myriad of reasons. KLZU is part of the AWOS network and is not maintained by the FAA. If you really want to know, I'd contact Gwinnet County as they are the owners of that particular AWOS. But I question why they call it an "official" station if you can't get any data from it for 10 hours a day? The data my site sends every 5 seconds is a text file that's less than 400 bytes, and requires very little bandwidth. Even if they only updated every minute, it would sure beat every hour. Link to comment Share on other sites More sharing options...
isohume Posted February 25, 2011 Share Posted February 25, 2011 But I question why they call it an "official" station if you can't get any data from it for 10 hours a day? The data my site sends every 5 seconds is a text file that's less than 400 bytes, and requires very little bandwidth. Even if they only updated every minute, it would sure beat every hour. It's listed because it's the closest ob site to Lawrenceville and I didn't see the word "official" on the NWS website unless I was on the wrong page. As far as the datastream...that's the FAA domain. In the case of KLZU specifically it's in the hands of the county like I already stated. Besides...I've never heard any complaints from the public that the obs aren't updating quick enough. There is no justifiable need for the NWS to provide an obs stream. Link to comment Share on other sites More sharing options...
dtk Posted February 25, 2011 Share Posted February 25, 2011 - A LOT more RAOB sites that would send up balloons 4 times daily so we don't have to run 06/18z models off pure surface data Never mind all of the aircraft, satellite (direct brightness temperature, derived products such as AMVs), wind profiler, gps radio occultation (refractivity profiles), and so on ;-). Link to comment Share on other sites More sharing options...
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