General Tropical Discussion Thread

[ticka1]

Interesting run of the EURO being posted across the internet:

http://raleighwx.easternuswx.com/models ... _loop.html

[don]

And the NAM is even more interesting FWI

[Mr. T]

The 0z Euro brings a very weak system into W LA with a continued movement to the W thereafter. This model gives us welcome rainfall at the end of the week as the remnant moisture overspreads the area.

[srainhoutx]

A lot of NWS WFO's are chiming in today. I would not be surpised to see an Invest tagged for this disturbance with all the models hinting at development. Perhaps someone would like to start a new thread/topic. After all, we are here to discuss the weather.

Houston/Galveston:

NAM DEVELOPS A DISTINCT SURFACE LOW PRESSURE AREA IN THE NORTHERN
GULF AND PUSHES IT OFF TO THE WEST TOWARDS THE LA AND UPPER TEXAS
COAST BY THE MIDDLE OF THE WEEK. WILL HAVE TO KEEP AN EYE OUT IF
THIS FEATURE DOES IN FACT DEVELOP AS IT WOULD HAVE AN IMPACT ON
POPS DURING THAT TIME PERIOD. FOR NOW WILL STICK WITH ISOLATED
DEVELOPMENT ASSOCIATED WITH SEABREEZE CIRCULATION MAINLY DURING
THE NEXT SEVERAL AFTERNOONS. OTHERWISE HOT AND HUMID CONDITIONS
WILL BE THE NORM AS HIGH PRESSURE RIDGE REMAINS IN CONTROL ACROSS
THE CENTRAL U.S.


Lake Charles:

LONG TERM...A RATHER LARGE INVERTED TROF OR EASTERLY WAVE WILL
BRING RELIEF AROUND THE MIDDLE OF THE WEEK AS MOISTURE AND CLOUD
COVER WITH ASSOCIATED SCATTERED SHOWERS AND THUNDERSTORMS ALL MOVE
IN FROM THE EAST. THE INCREASED SHOWERS AND THUNDERSTORM ACITIVITY
SHOULD PERSIST THROUGH FRIDAY. HIGH PRESSRE WILL BUILD INTO THE
GULF OVER NEXT WEEKEND WITH ANOTHER PERIOD OF HOT AND DRY CONDITIONS.



New Orleans:

HEADING INTO NEXT WEEK...THE BROAD AREA
OF HIGH PRESSURE WILL SHIFT MORE TOWARD THE CENTRAL GULF OF
MEXICO...AS A WEAK AREA OF LOW PRESSURE DEVELOPS ALONG A WASHED OUT
FRONTAL BOUNDARY OVER SOUTHERN FLORIDA. THIS LOW WILL THEN SLIDE TO
THE WEST BENEATH A STRONG MID-UPPER LEVEL RIDGE CENTERED OVER THE
MID-SOUTH. THIS WEAK AND BROAD AREA OF LOW PRESSURE WILL TRACK
THROUGH THE EASTERN GULF AND INTO THE NORTHERN GULF OF MEXICO BY
WEDNESDAY. WINDS WILL TURN EASTERLY ON MONDAY AND REMAIN SO THROUGH
WEDNESDAY. THESE WINDS SHOULD ALSO INCREASE TO AROUND 10-15 KNOTS
AS THE PRESSURE GRADIENT BETWEEN THE LOW AND A HIGH OVER THE
SOUTHEAST GROWS. AS THE LOW PASSES TO THE WEST AND MOVES TOWARD
TEXAS...WINDS WILL TURN BACK TO THE SOUTHWEST. HOWEVER...A DECENT
GRADIENT BETWEEN THE LOW AND THE OTHER RIDGE OVER THE CENTRAL GULF
WILL KEEP WINDS UP AROUND 10-15 KNOTS THROUGH THE END OF THE
WORKWEEK. SEAS WILL RISE TO AROUND 2 TO 3 FEET DUE TO THESE
PROLONGED 10-15 KNOT WINDS. 32

[srainhoutx]

A small area of disturbed weather is currently traversing the E Caribbean Graveyard. With light shear ahead, as this feature nears the Western Caribbean perhaps some further development. Each day brings more activity. Almost that time IMO.

http://www.ssd.noaa.gov/goes/east/pr/flash-rgb.html

THE CENTRAL AND ERN CARIBBEAN
ARE UNDER THE INFLUENCE OF EXTREMELY DRY AIR EVIDENT IN WATER
VAPOR IMAGERY WITH MOSTLY ELY FLOW ALOFT MAINTAINING FAIR
CONDITIONS. HOWEVER...A WEAK SURFACE TROUGH MOVED ACROSS THE
WINDWARD ISLANDS AND NOW LIES ALONG 16N63W TO 12N63W ENHANCING
SCATTERED SHOWERS/THUNDERSTORMS FROM 12N-14N BETWEEN 59W-65W.
TOTAL PRECIPITABLE WATER IMAGERY INDICATES AN AREA OF ENHANCED
MOISTURE ASSOCIATED WITH THE TROUGH. EXPECT THE MAJORITY OF THE
BASIN TO REMAIN UNDER DRY AIR AND FAIR CONDITIONS WITH
SHOWERS/THUNDERSTORMS TO PERSIST NEAR THE SURFACE TROUGH WHICH
IS FORECAST TO MOVE WWD.


Hi Res VIS Loop...

http://weather.msfc.nasa.gov/cgi-bin/ge ... height=880

[sleetstorm]

A lot of NWS WFO's are chiming in today. I would not be surpised to see an Invest tagged for this disturbance with all the models hinting at development. Perhaps someone would like to start a new thread/topic. After all, we are here to discuss the weather.

Houston/Galveston:

NAM DEVELOPS A DISTINCT SURFACE LOW PRESSURE AREA IN THE NORTHERN
GULF AND PUSHES IT OFF TO THE WEST TOWARDS THE LA AND UPPER TEXAS
COAST BY THE MIDDLE OF THE WEEK. WILL HAVE TO KEEP AN EYE OUT IF
THIS FEATURE DOES IN FACT DEVELOP AS IT WOULD HAVE AN IMPACT ON
POPS DURING THAT TIME PERIOD. FOR NOW WILL STICK WITH ISOLATED
DEVELOPMENT ASSOCIATED WITH SEABREEZE CIRCULATION MAINLY DURING
THE NEXT SEVERAL AFTERNOONS. OTHERWISE HOT AND HUMID CONDITIONS
WILL BE THE NORM AS HIGH PRESSURE RIDGE REMAINS IN CONTROL ACROSS
THE CENTRAL U.S.


Lake Charles:

LONG TERM...A RATHER LARGE INVERTED TROF OR EASTERLY WAVE WILL
BRING RELIEF AROUND THE MIDDLE OF THE WEEK AS MOISTURE AND CLOUD
COVER WITH ASSOCIATED SCATTERED SHOWERS AND THUNDERSTORMS ALL MOVE
IN FROM THE EAST. THE INCREASED SHOWERS AND THUNDERSTORM ACITIVITY
SHOULD PERSIST THROUGH FRIDAY. HIGH PRESSRE WILL BUILD INTO THE
GULF OVER NEXT WEEKEND WITH ANOTHER PERIOD OF HOT AND DRY CONDITIONS.



New Orleans:

HEADING INTO NEXT WEEK...THE BROAD AREA
OF HIGH PRESSURE WILL SHIFT MORE TOWARD THE CENTRAL GULF OF
MEXICO...AS A WEAK AREA OF LOW PRESSURE DEVELOPS ALONG A WASHED OUT
FRONTAL BOUNDARY OVER SOUTHERN FLORIDA. THIS LOW WILL THEN SLIDE TO
THE WEST BENEATH A STRONG MID-UPPER LEVEL RIDGE CENTERED OVER THE
MID-SOUTH. THIS WEAK AND BROAD AREA OF LOW PRESSURE WILL TRACK
THROUGH THE EASTERN GULF AND INTO THE NORTHERN GULF OF MEXICO BY
WEDNESDAY. WINDS WILL TURN EASTERLY ON MONDAY AND REMAIN SO THROUGH
WEDNESDAY. THESE WINDS SHOULD ALSO INCREASE TO AROUND 10-15 KNOTS
AS THE PRESSURE GRADIENT BETWEEN THE LOW AND A HIGH OVER THE
SOUTHEAST GROWS. AS THE LOW PASSES TO THE WEST AND MOVES TOWARD
TEXAS...WINDS WILL TURN BACK TO THE SOUTHWEST. HOWEVER...A DECENT
GRADIENT BETWEEN THE LOW AND THE OTHER RIDGE OVER THE CENTRAL GULF
WILL KEEP WINDS UP AROUND 10-15 KNOTS THROUGH THE END OF THE
WORKWEEK. SEAS WILL RISE TO AROUND 2 TO 3 FEET DUE TO THESE
PROLONGED 10-15 KNOT WINDS. 32

What should I call the title, srainhoutx?

[srainhoutx]

What should I call the title, srainhoutx?

I created a thread for 94L this morning after it was declared an Invest, sleetstorm.

[srainhoutx]

The disturbance in the Central Caribbean is still chugging west bound. What a small compact disturbance it is...

[srainhoutx]

Over the past several days the long range GFS has been suggesting a pattern change. Upper winds are depicted by that model to become much more favorable regarding development across the Atlantic Basin. Infact in model La La Land, 3 storm appear with one forming near the Western Caribbean and implying a threat to the Gulf. We shall see.

00Z GFS at 360 hours...

[srainhoutx]

Another area to watch just SE of the Windwards...

CLOUDINESS AND SHOWERS ASSOCIATED WITH A TROPICAL WAVE LOCATED ABOUT
700 MILES EAST OF THE SOUTHERN WINDWARD ISLANDS IS MOVING WESTWARD
AT ABOUT 10 TO 15 MPH. DEVELOPMENT...IF ANY...WILL BE SLOW TO
OCCUR. THERE IS A LOW CHANCE...10 PERCENT...OF THIS SYSTEM BECOMING
A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

[ticka1]

Last week in September may be interesting somewhere in the Atlantic or Gulf based on my analysis of Euro and GFS ensembles.


I'd have copied and pasted the post, but too many images to shrink and upload, and hotlinked, they'd get chopped in half...

EDIT
Been informed non-Eastern US Wx forum mkembers may not be able to see that link.

Will copy and paste post, sorry if the images get cropped, but I'm not going to save and shrink all of them and then see if I can get them all to upload.

..............

Euro- Day 10- maybe something just beginning near Cape Verde Islands. 500 mb feature NE of Caribbean moving WNW, no surface reflection or 850 mb vort max, but who knows what might happen with that.



Barely a hint of low level reflection of the inverted trough moving into the Gulf, either, but it is something to watch, IMHO.


Not super exciting, but have to watch something.

GFS ensembles, a couple of members see a weak sub 1008 low around where the Euro may be trying to develop a CV storm, and quite a few members see low pressure in the Western Caribbean/BoC, although the action could/looks like to be in the East Pac.

The averaged MSLP and uncertainty point out the CV area the Euro might be seeing at 240 hours.




Mid-Atlantic ridge in ensemble means at 240 mean a generally Westward movement.



Several ensemble members see the CV disturbance at 300 hours.



Still should be coming West...



Nothing definitive, but last week of September looks exciting. Some of the ensembles show recurve of their systems by 360, but if they have stayed South of about 25ºN, they should still be coming West in 15 days.

Don't you mean August Ed? End of September is over 8 weeks away.

[srainhoutx]

It should be August.

[srainhoutx]

HPC Prelim Extended Discussion:

THE ENSEMBLE
GUIDANCE IS BULLISH ON DEVELOPING A LOW AT THE TAIL END OF THIS
FRONTAL BOUNDARY NEAR THE CENTRAL GULF COAST AND SLOWLY
RETROGRADING IT WESTWARD SIMILAR TO HOW THE LOW THAT BECAME
TROPICAL DEPRESSION FIVE DEVELOPED THOUGH ALONG A MORE COASTAL
ROUTE.

[srainhoutx]

After a few weeks of relative calm across the Tropical Atlantic, it appears things are shaping up to a more active period. We have been waiting for a bit of a pattern change and we are beginning to see that happen now. Guidance is suggesting a more active period ahead and that is showing up now in the longer range. Also of note is the MJO. Although La Nina years tend to lead to weaker pulses, we saw with Alex that even a weak MJO pulse can certainly affect disturbances and can aid in development. The ensembles (GFS) are suggesting that MJO is heading toward a more favorable octant 2. Perhaps guidance is sniffing out this and other more favorable conditions as we move ahead toward peak season. (September 12th) While no one wants a storm in our back yard, it is important to be mindful that we still have a long ways to go before we can put Tropical Season 2010 to rest. Stay tuned as they say, things could get rather interesting as we head toward late August/early September.

[srainhoutx]

Sort of surprised no one has mentioned that the GFS, UKMET, and Euro to a certain extent are in agreement of developing another disturbance from the remains of TD 5 next week in the Northern Gulf. HPC has mentioned a potential feedback issue regarding the GFS, but with other guidance like the Canadian are sniffing out something, there may in fact be something to it. We shall see.

[Mr. T]

Sort of surprised no one has mentioned that the GFS, UKMET, and Euro to a certain extent are in agreement of developing another disturbance from the remains of TD 5 next week in the Northern Gulf. HPC has mentioned a potential feedback issue regarding the GFS, but with other guidance like the Canadian are sniffing out something, there may in fact be something to it. We shall see.

The 12z Euro brings it all the way back to the Texas coast in 6 to 7 days, while the GFS is at the TX/LA line. Both models bring the area a very good chance of rain.

[desiredwxgd]

5-Day QPF

[srainhoutx]

Appears that the Cape Verde season is on the horizon...

HPC:

ON THE MEDIUM TO LONG RANGE...LOOKING UPSTREAM OVER THE
ATLANTIC...MODELS SHOW THE SUBTROPICAL RIDGE AT 250/500 HPA
LIFTING NORTH TOWARDS THE AZORES...PAVING THE WAY FOR A BROAD/DEEP
TUTT OVER THE EASTERN ATLANTIC TO RETROGRESS TOWARDS THE NORTHEAST
CARIBBEAN. AS THE PATTERN EVOLVES...VERTICAL WIND SHEAR ACROSS THE
TROPICAL ATLANTIC IS LIKELY TO EBB...THUS MAKING IT MORE CONDUCIVE
TO CYCLONE FORMATION. THE GLOBAL GUIDANCE IS RESPONDING TO THIS
SCENARIO...AS THEY ARE STARTING TO SHOW RISK OF CYCLONES
DEVELOPING OFF THE COAST OF AFRICA. ALTHOUGH THERE ARE LARGE
DIFFERENCES AMONG THE MODELS ON THE TIMING...THE RISK OF FORMATION
IS WHAT COUNTS.

[srainhoutx]

Looking at the wide view to the Central Atlantic, there is a disturbance in the SW Caribbean that has be festering. This could be an EPAC system eventually. With that said, we may need to watch that area as it has been rather active all season. There is long history of cyclogenesis in that area during late August/early September.

[srainhoutx]

Guidance continues to advertise a pattern change around the middle of next week as a strong wave exits Africa and develops, follow by a second wave that also develops via the guidance following closely behind. What is not certain is where these Cape Verde storms track. Guidance has shifted W each run toward the Caribbean Islands before a recurve toward the East Coast and Bermuda. We will need to keep an eye on these long trackers as the CV season looks to start in earnest. It is a good reminder for folks to plan and prepare early as it appears that tropical activity will be on the increase and will likely become rather active into September. Hang on, we could be in for a bumpy ride the next 6-8 weeks.