Tuesday, August 26, 2014

Cristobal, Rafael, and Sandy.

A little bit more on what I was saying on my Facebook weather page, about the tropical pattern last night.

The pattern looks very October like.... with the deep trough and the cold front along the Gulf Coast. This front is what has caused the convection to flare up along the southern coast.  Rule of thumb, always be aware of frontal bounties  in the Gulf in August. The waters in the Gulf are very warm this time of year.  So even if we don't have great convergence over the Gulf. it does bear watching.

The pattern over the Atlantic has gotten my attention. We have all that October like cool and dry air associated with the trough to the west of Hurricane Cristobal, and a nice southerly flow of the eastern trade wind being pulled north by the front and trough, on Cristobal's east side.
The above image shows how the wind flow is steering Cristobal.
Normally the easterly trade wind flows westward across the Tropical Atlantic into the Caribbean. But as I show on the image the trade winds are being pulled to the north.

Since the trades are not pushing the air into and out of the eastern Caribbean and part of the Atlantic, they are more or less just sitting around and pilling up with nowhere to go. 

Hurricane Cristobal will be moving to the northeast over the next few days. Once he is out of the way  and the trough relaxes, we will see the easterly  trades move back into a normal flow into the Caribbean.

Many times when this happens,  the build of air and all that convergence is redirected back into the western Caribbean as a low amplitude wave of low pressure and convergence, can cause development in the western Caribbean and GOM ( Gulf of Mexico).

The last time this sort of pattern was in place was back in October of 2012 when we had Hurricane Rafael  in the same general position in the Caribbean.  He had a track that was quite similar to what we expect Hurricane Cristobal to have.  Rafael moved east of Bermuda as a hurricane, whereas Cristobal is going to past west of Bermuda, but all in all the tracks will end up much the same.  Back in October of 2012 we also had a deep trough along the east coast ,  helping steer Rafael away from the east coast.  We also had the trade winds bending to the north and away from the western Caribbean.
              The low out over the Atlantic in the above image is Rafael moving north and east.

After Rafael moved north and then northeast out into the north central Atlantic, we had an area of low pressure develop  in the western Caribbean a few days later around the 20th of October ,  south of Jamaica, Haiti, and the Dominican Republic.  This low was caused by the redirection of the trades and convergence into the Caribbean .  In a few days this area of low pressure developed into Tropical and then Hurricane Sandy.  From here she tracked north, thanks to Rafael moving to the northeast and clearing her path. 
                                                                                                                             October 20 2012

       Oct 24, 2012 showing Sandy starting her northward move out of the Caribbean

       October 28, 2012 showing Sandy moving off the East Coast.

A couple of surface charts showing the trough and front positions during that time in Oct of 2012

You can see the two surface charts , with the trough and fronts looking much the same as the charts I've been posting on my weather page quite a bit this year...

Back to Cristobal, he will have a path much like Rafael ending up southeast of the Canadian Maritimes  just as Rafael did.

                                                                      Showing Sandy moving out of the Caribbean and Extratropical Rafael off the Maritimes.

Rafael's Track
Cristobal's Track

The models aren't seeing anything  tropical end of the weekend into the first part of next week..... But they do show some ridging along the Northeast and East Coast of the US, along with lowering pressures in the western Caribbean.



Here is the GFS showing pressures lowering in the western Caribbean as we head into next week. You can see Cristobal is in the same position that Rafael was off the Maritimes.

Pattern recognition is a very important skill when it come to forecasting weather.  I'm not saying we will see a repeat of Sandy, only that the setup is there that lead to her birth.  So we need to keep a close eye  on the Caribbean first part of next week........ with the Tropics , you never know.


Friday, August 8, 2014

Hype, El Nino, Seasonal outlook, and 1992.

I've been talking about El Nino, off and on this year.  Lots of people were predicting a strong El Nino, using words like monster, super, and extraordinarily. 

I didn't fall into that trap. when doing long term seasonal outlooks; it's never wise to go out on a limb unless you're sure. The models and teleconnections have been wrong before. But to be fair, The signals were never all that inductive of a strong El Nino event.

Over the last few years weather event hype has become the big story, or as I call it the big lie, when it comes to weather events. Many websites, and even more than a few of my fellow meteorologist have done a lot of exaggeration.  More and more are becoming snake oil sales people, instead of  discussing the weather in sane dialogue.   Every warning sounds like the apocalypse is upon us. Every storm is going to be extreme,  This storm or that storm is going to bring disaster, Some like "The Weather Channel" are now even naming winter storms.  Many weather reports sounds like it has never been this bad before.  For example, last winter's Polar Vortex, that brought the cold weather.... Many news outlets and weather outlets were using words like unprecedented to describe  a cold wave. But Hey it's winter, it gets cold. Trust me there have been winters much colder that the winter of 2013-2014.  National broadcasters completely over-dramatize their weather reports,  leading to widespread panic. Case in point Hurricanes Iselle and Juiio in the Pacific.   It's no wonder that people are failing to take weather forecast seriously, look what happened last winter in Atlanta.  Global warming is also being over exaggerated.... yes there is evidence that global temperatures are warming.....But what is truly the cause.. nature or humankind...... All I will say is there is a lot of junk science on both sides..... If you want to read what I think... here is a link..

One has to be careful where they get their weather information.

I say enough, just present the facts when it comes to weather and climate events.  

El Nino:

The Odds of a strong El Nino are very slim. A strong El Niño is not favored in any of the ensemble averages for Niño-3.4.  The Tropical Pacific Ocean was primed for an El Nino, and to a lesser extent is still is. 

But The atmosphere hasn't really responded. In fact there has been some cooling taking  place in the central and eastern tropical Pacific Ocean. Right now there is a  slightly below-average ocean heat content. But the temps are above average near the surface. Upper and lower wind remain average over the Pacific, except for the low level wind anomalies over the Eastern Pacific. 

Despite the tropical Pacific Ocean being primed for an El Niño during much of the first half of 2014, the atmosphere above has largely failed to respond, and hence the ocean and atmosphere have not reinforced each other. As of the beginning of August, we still haven’t seen a strong atmospheric response.  As a result, some cooling has now taken place in the central and eastern tropical Pacific Ocean, with most of the key El Nino regions looking to head to neutral values.

At this time, There is a chance for a  weak-to-moderate El Nino during the late fall and early winter. The chance of an El Nino has dropped to about 65%.  The odds now stand at a one in three chance that El Nino won't happen.

Long Range Outlook:
I've said before, long range outlooks are a lot like reading tea leaves....you need skill and more than a little luck, for them to work out.
There are signs that  September could see a couple of bouts of cold air pour out of Canada into the Great Lakes, Midwest, Northeast and Mid Atlantic.  Right now, this looks possible for the 2nd half of September.

This year has seen a lot of swings in temperatures and has been quite active storm wise. I don't really see any change in that pattern as we head into Fall. October should see the seesaw pattern continue, . It's hard to judge precipitation but we might start to dry out a bit, and we could see a bit more warming of temperatures,  as we move into the end of August thru the first part of October.  But any tropical cyclones during that time would throw that idea out the window.  Once we get past October things turn interesting.     

The Global forecast models favor a weak to moderate El Nino by early winter. My thoughts favor  a weak El Nino. The conditions in northern Canada are looking to set up similar to last fall. So we could see things become unsettled and maybe getting more colder than average , for the last part of Fall heading into early Winter.  In fact when this starts to happen things could move quickly. 

When you look at the statistics for El Nino years , there is a  correlation to snowier winters on average for The Northeast and Mid Atlantic. Of course, if you've followed my seasonal outlooks, you know, PNO, NAO and The AO, will have a lot to say about that.

We have been locked in the same general pattern that we saw last winter (ridging in the west and troughing in the east)...this was one of the main reasons for the active severe weather we've seen this Summer. This pattern looks to stay in place as we move through Fall and head into Winter. 

Based on my observations of the general setup, We will most likely see a winter 2014-2015  that will be quite similar to the Winter of 2013-2014. The statistics support the fact that during a weak El Nino the Northeast sees a lot of snow...even more that during a strong El Nino.
These are my first thoughts and the upcoming Winter....So don't take any of this to heart...things could change as we get closer.

The 1992 tropical season:

Even without El Nino forming yet, the pre El Nino conditions in the Pacific, have suppressed the Tropical Atlantic.  1992 was a El Nino year, in which El Nino was fading, so the setup would be very similar.  If you follow my blog, you know I believe in cycles.....
                                               The 1992 Atlantic season storm tracks.

                                            The 1992 Eastern Pacific season storm tracks.

The tropical setup and activity in 1992, in both the Atlantic and Pacific were very similar to this season.

1992 was very active in the Eastern and Central Pacific. As has been the case this year, many of the tropical cyclones came close to the Hawaiian Islands.  One of these was Hurricane Iniki, passed 300 miles south of the Big Island of Hawaii, and ended up making landfall on the Island of Kauai. Kauai is about 296 miles northwest of the Big Island of Hawaii, and is just northwest of Oʻahu . It is the 4th largest island in the Hawaiian chain.  Hurricane Iniki had maximum sustained winds of over 140 miles per hour with gusts as high as 175 miles per hour at landfall, making Iniki the most powerful hurricane to strike the Hawaiian Islands in recent history.

1992  saw a slow start in the Atlantic Basin, the year ended up well below average in tropical cyclone activity. But it did have one surprise, Hurricane Andrew. Andrew was a Catorgry 5 that nearly wiped out southern Florida.

Like this year conditions in the Eastern and Central Atlantic were unfavorable for tropical cyclone development.  Only five named storms would form (one was added later which brought the number to 6), most of those formed closer to the United States. Andrew was a major exception, forming in the Central Atlantic. Andrew quickly intensified into a Category 5 hurricane near the Bahamas. Andrew lost some punch over the island, weakening to a Category 4. But within a day he was once again a Category 5.

He made landfall as Category 5 (one of only two other known storms to hit the US mainland that strong) on Elliott Key and later in Homestead, Florida. Andrew caused unbelievable damage across Southern Florida and later when he again came ashore at Morgan City, Louisiana.

I'm not saying anything like Hurricane Andrew will form this year in the Atlantic Basin......But as history shows, it is possible.... so don't let down your guard this tropical season.
Well that's it hope you liked it.