Friday, July 26, 2013

Quick Check On The ENSO & Upcoming Winter

ENSO, for those who do not remember, stands for "El Nino/Southern Oscillation." Depending on which phase it is in (hot or cold), will let us know whether we are trending toward an El Nino or La Nina winter. It could also be La Nada, which means neutral. ENSO is one of the most significant factors in formulating seasonal outlooks, especially winter.


The dynamical and statistical models show predominately "La Nina-like" conditions currently in the central Pacific. Further examining of the actual values and taking a mean of those values, however, show mainly La Nada conditions. 

The plumes as of July 1st from the EURO model are trying to show a positive correlation trend begin by August and continue through the fall months. One thing to keep in mind is these plumes change month-by-month and sometimes begin to show different trends, so do not take them verbatim. 

As of now, it is too difficult to tell what the upcoming winter season will feature in terms of ENSO. If I were to look at historical trends dating back to 1950, I would say the upcoming winter season has a good chance of staying around neutral, with some "Nino-like" characteristics. But that will also depend on the PDO and whether or not it can climb out of its negative phase it has been in for quite some time now. 

My 2013-2014 winter outlook can be expected to be released December 1st. Last year, I was with EPAWA when I did the 2012-2013 winter outlook and I had the help of some great Meteorologists, such as Bobby Martrich and Jim Rinaldi, both based out of PA. 

That's all for now. Arrivederci. 

-Frank Paparatto 






Monday, July 15, 2013

6-Day Heat Wave Will Give Way To Prolonged Reprieve

A giant dome of High Pressure situated over the eastern U.S. is going to bring temperatures soaring into the mid to upper 90's in the northeast. Coupled with high humidity levels, this will lead to dangerous and unbearable outdoor conditions. If there has ever been a week to be down the shore, this will by far be the best week to be there. In fact, the last 30 days going back to mid-June have featured above normal temps in the northeastern U.S.


As I stated in my last blog, the Bermuda High is going to stick around for quite awhile and keep our area in a continuous southwesterly flow of gulf warmth streaming into the area. This has indeed been prevalent and has called for frequent days of heat/humidity with occasional days of pop-up rain showers or t-storms. 

The intention of this blog is to bring attention to readers that a pattern change is on the way. The Bermuda High is going to exit stage right which will help upper level trough's entrench themselves over the northeast for the first time in a long time. 

Lets go through a quick look at a couple of models from the 500mb level, starting off with the 12z GFS. 


At 24 hours, this is a clear view of why we are going to be in a 6-day stretch of 90+ degree weather. An area of High Pressure from the tropics has formed over the Ohio Valley region and a "death ridge" has developed over the southeastern U.S. Heat indexes will surpass 100+ degrees and this will surely call for unflattering outdoor conditions. 


As we advance further into the week, at 108 hours, the area of High Pressure has moved east-southeast and a strong upper level low in eastern Canada has helped lower heights over the area and bring temperatures back to normal. One thing also to note: The upper level low in eastern Canada will spawn a cold front, in which we could be dealing with damaging t-storms coming through the northeast. It remains to be seen whether atmospheric conditions are prone for severe weather, but I have a feeling some areas in the northeast by Saturday night into Sunday could be dealing with severe weather. Also notice how a ridge has developed in the western U.S. by this time, allowing northern stream energy to flow downstream into our area which could help spawn off some severe weather. 



By 168 hours, which takes us to early next week, we are still under the influence of a northwesterly flow even though the ridge in the western U.S. has collapsed by this time. 


Looking at the same time frame in the Atlantic Ocean, we can see the Bermuda High is displaced in the central Atlantic and there are positive height anomalies extending into Greenland. The biggest reason for this pattern change is due to the fact that the Bermuda High has finally shifted east. There is now a weakness over the northeast which will allow upper level trough's to get into the area more "fluidly." At the same time, this allows northern stream energy to downstream into the northeast which could call for wetter than normal conditions to get into the northeast by the end of this month. 

The 12z EURO model is in fair agreement of the 12z GFS of this eventual pattern change as evidenced below...


What does this mean? 

1. The heat wave will come to an end Saturday 

2. An MCS may develop Saturday evening into Sunday which could spark severe weather

3. Pattern changes by early next week to average to slightly below average temperatures and potentially wetter than normal conditions. This pattern may persist into early August, until the Bermuda High re-develops again. 

In sum, a break from the heat and humidity is in order. Stay patient and make the best of it for now! 

I'll be back next month with a look at the Hurricane season and when we can expect tropical storms firing up in the Atlantic. 

-Francesco Paparatto 

















Monday, July 1, 2013

A Glimpse Into The Long Range

BLOG SONG: "Play Hard" by David Guetta, Ne-Yo, and Akon

Today marks July 1st and a day I believe is a good time to assess the current weather pattern we are in. One thing we have noticed over the last 10 days is the constant humidity and periods of showers and t-storms that  develop in the afternoon and evening hours. The ultimate reason for this type of weather pattern is driven by a phenomena dubbed the Bermuda High, sometimes called the Azores High depending on its location.


A Bermuda High is a permanent area of High Pressure located near, you guessed it, Bermuda. Mind blowing, I know. A reason why it is "permanent" is due to the fact land temperatures are greater than ocean temperatures during the summer time. This means we are constantly under a south-southwesterly wind flow thanks to the clockwise motion of the winds circulating around the High. In terms of weather, this means hot and humid weather for our area sourced by the Gulf of Mexico. 


This is a graphic I made showing much of the east coast of the U.S. vulnerable for showers and t-storms at least for the next two weeks thanks to the Bermuda High. So if you look how the weather has been the last 10 days, you will enjoy the 1st half of July as well. 

This is also well evidenced by the Euro model:


500mb pattern of the 00z EURO model shows the Bermuda High as well as the Pacific ridge (which has caused temperatures in the west to soar into the 110-130 degree mark). One other thing to keep in mind with the Bermuda High is that it prevents low pressure systems from tracking into the Mid-Atlantic and Northeast states. If a low pressure system does manage to get into the area, it weakens dramatically. Therefore, most of our precipitation is tropical related from the Gulf of Mexico under an unstable air mass, allowing t-storms to develop in the afternoon hours of the day. 


A quick look at the sea surface temperatures shows mid to upper 80's in the Gulf of Mexico, which proves why our weather has been so humid thanks to the clockwise motion of the winds from the Bermuda High. Also notice the SST's beginning to warm up in the southern Atlantic and off the west coast of Africa. This is eventually going to lead to an active period of tropical weather come mid to end of August and through September. 

Personally, this is not my type of weather. But once the Bermuda High shifts east again (which will then re-develop a new High called the Azores High), our pattern will change for a 2-3 week period where drier conditions can be expected. I am thinking that happens the end of July. 

Have a great day and a safe 4th of July! Drink responsibly ;) 

Francesco Paparatto