Interesting Long-Range GFS

[wxman57]

I've been monitoring the general pattern out there in the tropics from the S. China Sea to Africa quite closely (as always) and I think that things are about to "break loose" in the Atlantic Basin. Tropial activity has been progressing eastward from the S. China Sea to the eastern Pacific (now) and I believe the Atlantic will get going late this coming week. This is associated with an eastward-moving MJO.

Interestingly, the GFS has been suggesting a quite active perdiod beginning the third week of August. Take a look here:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _276.shtml[url]

Note the 4 tropical stystems indicated. The GFS has been seeing something coming off Africa around the end of next week or next weekend for a few days now. Then all hell breaks loose out there in the tropical Atlantic.

Maybe 91L is just a "decoy" system.

It's that time of year....[/url]

[Guest]

Wxman - thanks for the insight. Being the professional you are - I'm glad you post on our board. Now I have a question wxman - I am trying to learn to read the models - with a heavy emphasis on trying - on the last panel MSLP-1000 500 mb hour - is that the panel that is showing the systems you are talking about?


Patricia

[Scott_inVA]

I've been monitoring the general pattern out there in the tropics from the S. China Sea to Africa quite closely (as always) and I think that things are about to "break loose" in the Atlantic Basin. Tropial activity has been progressing eastward from the S. China Sea to the eastern Pacific (now) and I believe the Atlantic will get going late this coming week. This is associated with an eastward-moving MJO.

Interestingly, the GFS has been suggesting a quite active perdiod beginning the third week of August. Take a look here:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _276.shtml[url]

Note the 4 tropical stystems indicated. The GFS has been seeing something coming off Africa around the end of next week or next weekend for a few days now. Then all hell breaks loose out there in the tropical Atlantic.

Maybe 91L is just a "decoy" system.

It's that time of year....[/url]

Good analysis is always apreciated.

Thoughts on 700mb trof again off shore? http://www.nco.ncep.noaa.gov/pmb/nwprod ... 0_276s.gif

This has been the bane of the GFS all spring.
Scott

[cycloneye]

Agree ticka that wxman57 is helping us in storm2k to understand better all the factors that make the tropics active or not and he is a valuable source of information.About what GFS shows HUMMMMM.

[rainstorm]

that could happen, but models are also indicating very high pressures in the tropical atlantic.

[wxman57]

that could happen, but models are also indicating very high pressures in the tropical atlantic.

If the GFS is correct (no guarantee there), then the pressures in the Atlantic are on their way day down. Note the 1012MB isobar at about 15=20N beyond 10 days out. That's pretty low.

[Anonymous]

I have more info that will support your forecast. I came up with the idea after hours of analysis and research last night.



IWIC Atlantic Tropical Weather Discussion 11:00 PM EDT, August 9, 2003
General Pattern: An upper level trough along the East Coast is producing 40-50 knots of shear between 70W-80W. Dry air and the Saharan Air Layer is in control of much of the central Atlantic.

Gulf of Mexico: An upper level trough over the southeast is enhancing thunderstorm development in the eastern Gulf. These storms aren't tropical in nature. the western Gulf is being dominated by shear and subsidence.

Caribbean Sea: A tropical wave in the central Caribbean is encountering 35 knots of vertical shear being produced by the TUTT. Tropical development isn't expected.

Atlantic Basin: The main area of interest this evening, is INVEST 91L. Latest shortwave infrared satellite imagery reveals a low level circulation near 52W and 27N. Banding features are also evident. This shows that the circulation is well-defined. The LLC is moving west-southwest under the subtropical ridge centered near 60W and 35N. An upper low near 55W and 22N is suppressing thunderstorm development east of the LLC. The upper low is also enhancing upper level winds. The models are in agreement with taking the upper low further south. This may allow conditions to become more favorable for development over the next few days. A general track towards the northern Bahamas is expected. All residents along the East Coast should keep an eye on this disturbance. the UKMET takes a 1012MB low into southern Florida while the BAMD model is showing a track east of NC. It's too early in the game to make a call.

A large tropical wave near 45W is moving westward near 10-15 knots. This wave is gradually become more disorganized and subsidence is preventing thunderstorm development. Conditions for tc development aren't favorable at this time.

The North Atlantic Oscillation will become neutral on the 12th and then positive for a short period of time after that. This will allow an upper trough over central Europe to retrogade eastward. The pathway for upper level cyclones sliding into Africa from Europe will be shutoff. As a result, there is a good chance that the Saharan Air Layer will weaken. Conditions will become slightly more favorable for tropical cyclogenesis in the eastern Atlantic between 12 August & 14 August. Conditions will be prime for development between 15 August & 18 August, when the North Atlantic Oscillation is positive. In addition, the negative (enhancing) phase of the Madden Julian Oscillation is expected to reach the eastern Atlantic between the 15th and 20th. The Global Forecast System is forecasting a strong tropical wave to exit the coast on the 15th. If the SAL does weaken as expected, we could see some tc development. This is a week away and the SAL has never been predicted with accuracy, so a lot can change.

For a basic and general rundown, refer to our tropical weather outlook. These are unofficial products, and are not from the NHC.

Forecaster: Moreland

[Tip]

We seem to be in the midst of an overall golbal pattern change as mentioned in the analysis provided in the previous posts in this thread. Part of this change will be the demise of the persistent east trough that has plagued the coast for weeks. The European model has now had three or four consistent runs building a heat ridge on the east coast, possibily shutting the door for an east coast runner. This will depend on the how far west the extension of the Bermuda HIgh builds. How long this change will last is up for debate as the NAO is forecast by the GFS to tank again later in August possibly signaling the return of the trough.

http://www.sca.uqam.ca/models/ecmwf_ame ... 9panel.gif

[Suzi Q]

Just would like to say thank you to the absolutely invaluable members on here who do such a wonderful job in not only providing models and links, but also explaining them to those of us who are not yet "in the know". This forum has given me so much more info than I could ever gather at this early point in my meteorological education and I am forever grateful. I hope that my own personal studies combined with the info given here will give me a head start when I actually start the met classes, which at this point seem mind boggling.

[Lindaloo]

welcome to the family eb4480.

[Suzi Q]

Found this on skywarn this morning, thought some of us might be interested in it:

GFS DEPICTING A LLVL
INVERTED TROF DEVELOPING ALONG THE WESTERN GULF BY MIDWEEK POSSIBLY
SENDING A DOSE OF TROPICAL MOISTURE OUR WAY FROM THE BAY OF
CAMPECHE. THIS IS THE FIRST RUN I'VE SEEN THAT'S DONE THIS SO WILL
CONTINUE TO WATCH. OTHERWISE...LOOK FOR SCT CONVECTION EACH DAY
(MAINLY THE AFTN/EVNG VARIETY) THROUGH AT LEAST FRIDAY. BERMUDA HIGH
SHOULD WORK ITS WAY BACK TOWARD THE AREA SOMETIME NEXT WEEKEND
ALLOWING RAIN CHANCES TO DECLINE. DAY 10 PROGS SHOW THE PESKY RIDGE
THAT HAS BROUGHT US THE RECENT HOT WX BEGINNING TO REGAIN IT'S
GRIP...

think we could live without the heat for awhile, don't ya'll?

[Guest]

Eb thanks for busting my bubble - I was hoping the hot weather was done and over with - can't bear to think that high pressure is going to be back over us - does it ever stop.

THe hell with tropics - bring on the coldfronts.

[OtherHD]

THe hell with tropics - bring on the coldfronts.

YAY FOR HEAT!!

[Stormsfury]

Today 12z GFS continues the idea of a remarked increase in activity in tropics at LR.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _276.shtml

[ameriwx2003]

SF and the 18Z does so as well. GFS is holding onto a couple of CV systems. Like the original post stated the long range looks to be active. The lid appears ready to come off;):)

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _384.shtml

[cycloneye]

In other words the lull that ticka said it was going to last until labor day will be over these comming 2 weeks .But seriously what MW posted at gopbi about the high pressure dominating scares me here in Puerto Rico because if that is true no fish CV systems this year. :o :o :o :o

[vbhoutex]

THe hell with tropics - bring on the coldfronts.

YAY FOR HEAT!!

DanG!!! If he isn't the snow nazi he is the HEAT NAZI!!!! GEEZ!!!!

[Stormsfury]

THe hell with tropics - bring on the coldfronts.

YAY FOR HEAT!!

DanG!!! If he isn't the snow nazi he is the HEAT NAZI!!!! GEEZ!!!!

I think the thunder got to him yesterday plus the 4 hour power outage.

[Anonymous]

The 18Z is most impressive so far. I don't see any reason why we wouldn't see a surge in activity in the MDR.

[ameriwx2003]

The Long range GFS continues the trend of a burst of tropical activity:):). 91L could just be a hint of what is yet to come:):

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _384.shtml