The current satellite shows cloud streets in West VA, but no cumulus in PA. I haven't really explored Dr. Jack's cumulus forecast before, but today's forecast matches observations. No cumulus were forecast for PA today and none are in the forecast for tomorrow. I guess the air mass is too dry.
http://www.drjack.info/BLIP/index.html
Does anyone else use these forecasts? Which ones do you like?
Dr. Jack's forecast
Moderator: CHGPA BOD
Re: Dr. Jack's forecast
I use Dr. Jack and the blip maps all the time. I find it to be a pretty reliable forecast, even the forecast for potential clouds. I also find that I can get to the top of lift forecast, rather than the -3 ceiling. I also appreciate that it gives a forecast three days out so that you can try to plan ahead for a good day.
Tom McGowan
Tom McGowan
Dr. Jack's forecast: A Quick Guide
Yes, I too regularly use (and rely on) the Blipmaps. Here are some hints on using it.
Use the Univiewer page to access the maps: http://www.drjack.info/BLIP/univiewer.html
Before you do anything else, go to the lower right corner of the screen and click on the Opacity control's Up arrow to make the Blipmaps more easily readable.
1. There are two different models used, RAP and NAM, and they can occasionally produce quite different forecasts. The NAM covers three days and is somewhat useful as a planning forecast. In very general, unscientific terms I have found that the short-term RAP is the more accurate one on the morning of a flying day. However, these are only forecasts and subject to all the vagaries of forecasting. Be very careful not to use them to justify a decision not to go to the hill. Pick the most optimistic one and use that to justify going flying.
2. As Tom said, I too find that the Boundary Layer (BL) Top Height Thermal Index=0 (TI=0) often describes our max attainable altitude on blue days.
3. To determine whether cumies will form and at what altitude, only use the CU Cloudbase for CU>0 map which graphically depicts where and how high cumies are likely to form. Some pilots make the mistake of only looking at the the CUmulus Cloudbase map which does not assess the likelihood of their forming.
4. The Thermal Updraft Velocity will usually approximate the best two or three thermals found in the course of the day. The average climbs will be less. Keep in mind that the TUV describes the airmass's climb rate; not the glider's. One needs to deduct the glider's sink rate (circa 200 fpm) from it to come up with the supposed glider climb rate.
5. If the two left hand Mouse Click Pop-Ups are enabled ( MiniBLIPSPOT and BLIP SkewT) one can click on a flying site of interest and Blipmap will generate two site-specific forecasts. One is a table of information that is useful because it shows how conditions will change over time. The other is a traditional Skew-T, for those who can read them. To figure out where your flying site is actually located on the map you can click the Basemap tab and then use the Zoom controls to locate it.
6. Dr. Jack provides a two very handy glossaries of the terms used. They can be found at the bottom of the main Blipmap image: BlipMap Links: Parameter Summaries and Parameter Details.
7. One semi-experimental parameter used is the BL Max.Up/Down Motion. This describes large scale convergence activity, and I have seen Davis Straub successfully employ it to predict the occurrence of convergence clouds in Florida and Georgia. I wonder whether this parameter might have some relevance for the Ridgely pilots who routinely experience coastal airmass convergences?
Random observation: Given the same forecast numbers for climbs and cloudbases, the actual conditions experienced in the flats will generally be lower than in the mountains due to terrain influences.
Use the Univiewer page to access the maps: http://www.drjack.info/BLIP/univiewer.html
Before you do anything else, go to the lower right corner of the screen and click on the Opacity control's Up arrow to make the Blipmaps more easily readable.
1. There are two different models used, RAP and NAM, and they can occasionally produce quite different forecasts. The NAM covers three days and is somewhat useful as a planning forecast. In very general, unscientific terms I have found that the short-term RAP is the more accurate one on the morning of a flying day. However, these are only forecasts and subject to all the vagaries of forecasting. Be very careful not to use them to justify a decision not to go to the hill. Pick the most optimistic one and use that to justify going flying.
2. As Tom said, I too find that the Boundary Layer (BL) Top Height Thermal Index=0 (TI=0) often describes our max attainable altitude on blue days.
3. To determine whether cumies will form and at what altitude, only use the CU Cloudbase for CU>0 map which graphically depicts where and how high cumies are likely to form. Some pilots make the mistake of only looking at the the CUmulus Cloudbase map which does not assess the likelihood of their forming.
4. The Thermal Updraft Velocity will usually approximate the best two or three thermals found in the course of the day. The average climbs will be less. Keep in mind that the TUV describes the airmass's climb rate; not the glider's. One needs to deduct the glider's sink rate (circa 200 fpm) from it to come up with the supposed glider climb rate.
5. If the two left hand Mouse Click Pop-Ups are enabled ( MiniBLIPSPOT and BLIP SkewT) one can click on a flying site of interest and Blipmap will generate two site-specific forecasts. One is a table of information that is useful because it shows how conditions will change over time. The other is a traditional Skew-T, for those who can read them. To figure out where your flying site is actually located on the map you can click the Basemap tab and then use the Zoom controls to locate it.
6. Dr. Jack provides a two very handy glossaries of the terms used. They can be found at the bottom of the main Blipmap image: BlipMap Links: Parameter Summaries and Parameter Details.
7. One semi-experimental parameter used is the BL Max.Up/Down Motion. This describes large scale convergence activity, and I have seen Davis Straub successfully employ it to predict the occurrence of convergence clouds in Florida and Georgia. I wonder whether this parameter might have some relevance for the Ridgely pilots who routinely experience coastal airmass convergences?
Random observation: Given the same forecast numbers for climbs and cloudbases, the actual conditions experienced in the flats will generally be lower than in the mountains due to terrain influences.
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Pete Lehmann
Re: Dr. Jack's forecast
Wow! Thanks Pete! Very helpful.