boca_chris wrote:Wow that is a strong ridge.
Yes it is....it is early by I think some of those on the "it's too early to tell" side of the fence may be jumping over soon...
I'd like to see some research on previous years at this time and if there was this much ridging that we are seeing..
Any pro mets want to comment? - I think this is a bit unusual for this time of year...
With all due respect to the posters in this thread, I think it's rather misguided to follow the daily progress of the surface reflection of the bermuda ridge in early April.
I think a couple of points need to be made here:
1. What you are looking at is a surface feature. Surface high, lows, troughs and ridges, cold fronts, etc. are not the primary forces in
steering a TC. They are but a small component of the MEAN steering flow that determines the eventual track of a TC. This layer of mean steering flow is dependent on the strength of the TC, and how vertically deep the vigorous circulation (relatively high vorticity values) extends upward through the atmosphere. CIMSS has some really useful mean layer steering analyses, however I don't know if there's a site on the web that you can actually get global model forecast mean height/wind fields from mean LAYERs - say 850-500MB or 850-300MB, etc.
2. "Past performance does not insure future results". You've seen the disclaimer in investment ads, now you'll see it here. Daily and weekly persistence of the Bermuda ridge has little bearing what will happen in 2 - 6 months down the road, and particularly if you consider that what you will usually be looking at is a 1 or 2-day window inside that 2 - 6 month time frame when a TC will be approaching the whatever the western extent of the ridge happens to be at that time.
So even assuming you have a "monster Bermuda ridge" in place during the bulk of the season, regardless of the strength of that ridge, there will always be breaches, be they transient (troughs in the westerlies) or semi-permanent (the TUTT); deep layer or shallow; and strong or weak. It is the precise timing and strength of these often subtle features that eventually determine whether a system will recurve or continue toward the CONUS/Mexico/Central America/etc. The western extent of the ridge, often times THE pivotal determinant in whether a TC recurves or makes landfall, is continuously in flux. Rarely do we have straight deep layer easterlies here in eastern Florida for 3-5 consecutive days, let alone a week or more.
The same can be said for seasonal analogs - "Past performance does not insure future results". Several meteorological parameters come together to determine seasonal trends in TC formation and landfall potential - as most of you well know, some (e.g. ENSO) are more influential than others. There is variability in each of these parameters, and it would be very rare for all these parameters to come together "just right" for one season to match another. Analogs are rarely identical, and are of much more use in extreme cases, when one or two of the major forecast parameters show a significant deviation form normal. In sum, with few exceptions, no two seasons are that much alike, let alone two consecutive seasons. Show me two that you think were, and I'll show you a boatload of reasons why I think they were not.
(unsolicited lecture)
If I was to give the board some unsolicited advice as far as how to be a "better" or more learned armchair TC watcher, I would start off with these nuggets.
a) Don't look at model prognoses, radar, and remotely sensed data (not only satellite but QS, MI, et. al) to the exclusion of other sources. Look at surface and upper air ANALYSES, look at RAOBs, etc. Often times as a TC gets within 24-36 hours of landfall, RAOBs can be more useful than model data as far as pinpointing a landfall. Example: When Charley was moving NNW over western Cuba on the evening of THU AUG 12, I remarked to a colleague that the 00Z Tampa RAOB was SSW to SW all the way up through the atmosphere, and that it gave me gut feeling that there was no way that the TC would make it as far north as TPA before making landfall.
b) Try and think "3D". I touched on this a couple paragraphs up. When you're looking down at a satellite picture, you're looking through a good 10 miles of vertical depth of troposphere, which is the "space" where weather happens. As you "look down" from above, try and think about what is occurring at the various levels 250MB/35KFT, 500MB/17KFT, 700MB/10KFT, 850MB/4KFT, etc. Then look at analysis and prog charts from these levels - they're out there. Look at the local discussions from the met community (private sector, NHC, NWS FO's) to see what they are analyzing.
c) "All convective masses in the tropics are not 'tropical waves' ". My best scientific guesstimate is that you will see no less than eleventy billion convective blowups over the Atlantic this season. Look and see what is happening in the atmosphere to cause the convection before you assume it's a T-wave. See what kind of vorticity (i.e. spin) if any, is going on at the lower levels. My mantra has always been
"Convection = overrated, vorticity = underrated."
Just my .0000002. Hopefully, my blathering rant has some semblance of coherency.
/unsolicited lecture)
