Welcome to The Weather Report - General Discussion

Ideas on improvement... (8 replies)

Scott Dennstaedt — Tue, 20 Jul 2010 22:14:05 -0400

I have been invited to write and present a paper at the Sixth Symposium on Policy and Socio-Economic Research at the 91st American Meteorological Society (AMS) Annual Meeting in Seattle addressing effective communication of aviation weather information to users (specifically pilots in my case). I am looking for specific ways to improve the current methods used to identify aviation weather hazards and convey information about them, including turbulence, icing, ceiling, visibility and convection. Ideas for improvement may include how weather information is conveyed to a pilot during preflight and while en route.

There's no specific end-user product in mind here. There's a push by the AMS to learn what "users" of aviation weather information need to make the most informed decisions. This will apply to all stakeholders in aviation including forecasters, dispatchers, controllers, airport managers and pilots. The results (I'm not the only person writing a paper) may be used to improve or modify existing products or create new ones.

"Valid Time" Question (1 reply)

David Volkmann — Thu, 10 Jun 2010 09:42:16 -0400

Hi Scott-

I hate advertising my ignorance on an Internet forum but here goes:

When a model forecast (e.g., HPC Day X 12-Hr PoP Fcst) is stamped with a "valid" time (e.g., 0000Z) is the prediction for the period before or after the valid time?

David

Synoptic chart (1 reply)

Tommy Wiklind — Mon, 26 Apr 2010 20:50:36 -0400

Hi Scott,

Today I saw a synoptic chart from south Florida containing a marking I've never encountered before. It seems to be associated with a trough ahead of a cold front. I attach a pdf file of the synoptic chart. There is severe weather ahead of the cold front and I presume the marking on the synoptic chart is indicating this...

Tommy

rap & ADDS exp sites (1 reply)

Orest Skrypuch — Sat, 13 Feb 2010 13:03:28 -0500

Looks like:

weather.aero
rap.ucar.edu

... are down, and have been down for a bit.

What is the scoop?

* Orest

Trip through a cold front with a surprise (1 reply)

Ron Arnott — Mon, 21 Sep 2009 17:04:45 -0400

The surprise was just how much the temperature can drop. Yesterday took off and up through clouds in SoCal toward Sacramento. There were clouds to 5k below me at 12k at first with a comfy 36 degrees F. As I traveled north the clouds started coming up to almost meet me and the temp was falling to 30, 29 etc. There were some whispy clouds on either side of me here and there that were higher but not covering any great area so I thought even if one does wind up in my path no big deal. A little later one did wind up in my path. I check the OAT, 30 F. Ok no big deal right? Well no. Lo and behold as I passed into the cloud immediately I saw moisture begin to run up the windscreen--wet cloud tops AND the temp dropped to 26 F just like that. That was the surprise. The second build up that I needed to pass through also had the moisture and left some tiny little ice on the plane. Again I was sure that these build ups were very limited in scope so no on-going building up of ice was going to happen, but I was enlightened a bit in that for that particular area the temp dropped 4 degrees in seconds. After the last build up experience I noted the temp and it was working fairly fast back up to 30 degrees F.

Scott, how can an air mass have little surprises like that in just a small area?

South of the equator (3 replies)

Tommy Wiklind — Wed, 02 Sep 2009 16:48:45 -0400

Scott,

Do you have any suggestions for information on aviation weather for South America? In particular Brazil, Argentina and Chile.

Thanks,
Tommy

XM Weather: Aviator LT or Aviator? (4 replies)

John Lapham — Tue, 04 Aug 2009 22:28:23 -0400

I am researching the different weather plans, and think I will be OK with the lower cost Aviator LT plan. I thought I would post my reasons why and see if anyone can talk me into the higher priced plan. I fly a Cessna 152, so I can't fly particularly high or fast!

Here is a list of the additional items found in the full Aviator package, and the reason why I don't think it is necessary. Feel free to tell my why I am full of crap! :)

High Resolution Radar
A mosaic of data obtained by the Canadian network of radars, color-coded to indicate storm severity.

I live about as far from Canada as you can get (Florida), so I don't see this improving my situational awareness any.

Canadian Weather Warnings
Textual weather warnings for Canada.

See above.

Winds Aloft (at altitude)
Displays wind speed and direction information from the surface up to 42,000 ft. in altitude. Winds Aloft data is provided in 3,000-ft. increments.

It is my understanding that this is forecast winds, not actual winds. I can look at the forecast winds before I depart, and that will give me what I need to know for the next flight.

Lightning
Uses the National Lightning Detection Network (NLDN), the official lightning detection of the U.S. National Weather Service, to identify cloud-to-ground lightning strikes.

This is probably the most useful of all the extra weather products, since lightning is so prevalent in Florida. However, lightning here is always associated with convective activity (aka thunderstorms), that I can avoid the lightning my avoiding the red areas in the Nexrad images. That makes me think that, although the lightning data would be useful, I can get by just as well using the radar data.

AIRMETs
Advises of weather that may be hazardous to single engine, light aircraft and Visual Flight Rule (VFR) pilots.

Like the winds aloft forecast, this is put out far enough in advance that I can get them while on the ground before I depart.

SIGMETs
Advises of potentially hazardous weather, other than convective activity, to all aircraft.

See Airmets for reason I don't feel I need it.

Echo Tops
A radar-derived data product that indicates the highest altitude at which precipitation is falling. The data is provided up to a maximum of 70,000 ft. altitude, in increments of 5,000 feet.

Since I am unlikely to fly all the way up to 70,000 ft , and the fact you can only select this data in 5,000 ft increments, I will only be looking at the echo tops at 5,000 ft and at 10,000 ft. I just don't think there is enough resolution at the altitudes I will be flying at.

Freezing Level
Displays the altitude and location at which 32°F (0°C) conditions first occur.

Freezing level rarely gets down to the altitudes I regularly fly here in south Florida. Also, this can be obtained during pre-flight, and is unlikely to change significantly during a flight.

Severe Weather Storm Tracks
Patented, arrow-like indicators that incorporate NEXRAD radar data and advanced processing to identify the location of strong storms. Information is provided on forecasted storm direction, speed, hail size estimates and wind shear.

Since I do not plan to get anywhere close to any severe storms, this will not be of much use to me. Plus, I can get a feel for the direction and speed of the storms by animating the nexrad images.

Surface Analysis Weather Maps
A display of high ("H") and low ("L") pressure systems at the earth’s surface.

This is something that can potentially be useful, but I can get this information before the flight from the prog charts, etc. I don't see how it is something that I would need in the plane in real time.

Satellite Mosaic
Displays cloud cover over the continental United States and hundreds of miles off its coastline. An advanced formula estimates cloud temperatures at various altitudes across the country and converts them into estimated cloud height. Clouds below 5,000 feet are so close to ground temperatures, they are not shown.

This is something that, at first blush, seems like it would be really useful to have in the cockpit. Unfortunately, they use an IR satellite image, not a visible satellite image. Because of that, it won't show any clouds below 5,000 feet, and you can only look at images in 5,000 ft increments. Just like the echo tops, I will really only be using the 5,000 ft and 10,000 ft images. I don't see it being particularly useful at the altitudes I fly.

AIREPs/PIREPs

There would be useful, but not if that is all I am getting the more expensive package for. Unless they appear while in flight, most of them I will be able to get on the ground before I leave.

SPC Aviation Weather Watches

See above.

So, am I missing something here, or is this stuff a lot more useful than I think it is?

Thanks for your opinions and comments!

FAA Could Close 20 Weather Offices (1 reply)

Thomas Clare — Mon, 08 Jun 2009 11:17:28 -0400

Washington Post: FAA Could Close 20 Weather Offices

Scott --

Would be very interested in your take on this. Seems to be that losing "local" weather knowledge appears to be the trend (much like decentralized computer helpdesks in the corporate environment) -- but am interested if you see this as a significant development. Many thanks, --Tom

GPS Certifications and the Go/No-Go Question (2 replies)

Jason Moeller — Sat, 09 May 2009 23:23:46 -0400

Okay, it is has been awhile, but I think it is about time I post something on the new site. I have a question. It isn’t a metrological question, but it does pertain to flying IFR. I posed this question at my local flight school and it is causing quite the stir, so I am posting it here too.

The FAA publishes Technical Standard Orders (TSO) on just about everything. Two TSOs that pertain to IFR GPSs is TSO-c129 and c146. TSO-c129 is your old school avionics where you need to have a current GPS database, RAIM, and an appropriate backup. The backup is usually a current (within the past 30 days) VOR check or whatever is appropriate for the route to be flown, still with me?

TSO-c146 governs WAAS. This TSO is known as the “Stand Alone” TSO certification because it does not require any backup. If your database is good, so are you. The handy reference for this is in the AIM Chapter 1, section 1-1-20 (c) 6-7.

Now obviously, if you have a VOR in the aircraft, you should check it. At the very least you want to know its working correctly, right? BUT if you have a GPS that is certified under TSO-c146 (Garmin 430w) and your VOR check is expired, and you need to make that IFR trip, do you go? Is it legal? Safe?

I’ve tried to present this as unbiased as possible and I will not reveal my thoughts until I have read some other replies. This isn’t talked about anywhere either. I searched the AOPA site and a couple of others, but with no luck. It is an important question and it divides my flight school presently. Thanks.

Weather Product Release Times (1 reply)

Thomas Clare — Sat, 18 Apr 2009 20:24:08 -0400

Scott --

Your in-person flight training and online weather courses have trained me well to always focus on the "issue" and "valid" times for every weather product that I review, and I feel that I have incorporated that habit into my flight planning routine. I also do a pretty good job of making sure that I am always looking at the latest available "run" of a forecast model. But one thing that continues to challenge me is remembering when the most frequently used products are issued throughout the day -- i.e. the Zulu-time hours that TAFs, prog charts, Airmets, etc. are issued. Are there any memory tricks or mnemonic devices that you teach to remember these issue times, or is it straight memorization?

Really enjoying the new website.

-- Tom

Cold air, vertical mixing, gusty winds (2 replies)

Michael Heir — Sun, 18 Oct 2009 10:33:32 -0400

Scott,

I had plans to fly tomorrow, but looks like we're going to be having a strong, gusty (25-30kt) direct crosswind at our destination... so I'll be driving 3.5 hrs instead of flying 40mins (each way....)

In 2 aviation area forecast discussions (one in MD and one in NJ), they refer to cold air advection, which will allow strong winds aloft to "mix down" to the surface Also, what do they mean by using the word "decouple" (see below)? Perhaps this would be a good workshop topic to talk about what causes winds aloft to mix down to the surface, and perhaps how a SkewT diagram may help to predict such conditions. They even mentioned the soundings in the area forecast discussion.

Here is some of the area forecast discussion I read:

This one is from NWS Mount Holly, NJ (kphi) issued @ 4:02PM 4/11/09:

Colder and much drier air works in tonight as the pressure gradient 
tightens. This combination will promote enough vertical mixing to 
hold up the wind through the night. Some terminals may be able to 
decouple some at times, but we will indicate sustained winds of at 
least 10 knots everywhere. For Sunday, plenty of dry air is expected 
as high pressure gradually builds into our area. A lingering 
pressure gradient coupled with a colder air mass will team up with 
daytime heating Sunday, allowing for more efficient vertical mixing. 
This will produce a gusty wind and based on forecast soundings, we 
went with gusts up to 30 knots starting around 13-14z.

Also, from the same discussion in the Short Term section, they even said this:

Forecast soundings indicate deep 
boundary layer mixing, up to 800mb, with nearly adiabatic 
temperature profiles. Winds will increase to about 15 to 20 knots 
everywhere.

This next one is from NWS Baltimore/Washington (KWLX) issued @ 2:45PM 4/11/09:

North-northwest winds will gust to 25 kts through sunset as cold air advection will 
help mix down higher winds to the surface.