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Atlantic Tropical Action 2013

HurricaneJosh

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Ed Lizard

Ed Lizard

Posted
Posted

You can call me a weenie, but I don't think the GFS development of a strong wave or even a depression in a week is  completely unfounded.

 

I will say, just a glance of the 192 hour 4 panel, that system is closing in on the Lesser Antilles, low level flow is getting stronger (divergent and the beginning of increasing shear), and the upper level Easterlies are Southerlies past the islands in the Caribbean, or the weakening of the system post truncation is probably not just an artifact of lower resolution.

 

Wishcasting beyond the reasonable limits of the model, on August 1st and 2nd on the lower res GFS four panels, this is entering the SW Caribbean, 850 mb winds are slowing (convergent), there is still a clear 700 mb moisture surge, and upper flow is weakly anti-cyclonic as the system approaches Belize.  

 

Sorry about my glass half full optimism for early August Central America opportunities for the people that chase.

 

 

Is the GFS the new 'King of the Tropics'?????

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Superstorm93

Superstorm93

Posted
Posted

lol...

 

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT WED JUL 24 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON RECENTLY
UPGRADED TROPICAL STORM DORIAN...LOCATED SEVERAL HUNDRED MILES
WEST OF THE CAPE VERDE ISLANDS.

A SURFACE LOW PRESSURE SYSTEM HAS DEVELOPED BENEATH AN UPPER-LEVEL
TROUGH ABOUT 500 MILES EAST OF BERMUDA. UPPER-LEVEL WINDS ARE
EXPECTED TO GRADUALLY BECOME MORE FAVORABLE FOR DEVELOPMENT OVER
THE NEXT COUPLE OF DAYS AS THE DISTURBANCE MOVES NORTHWESTWARD TO
NORTHWARD AT 10 TO 15 MPH. THIS SYSTEM HAS A LOW CHANCE...20
PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

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phil882

phil882

Posted
Posted

Is the GFS the new 'King of the Tropics'?????

 

I think you still have to watch the cumulus scheme with the GFS sometimes. Even though it perceived this wave developing from many days out, it was also forecasting TCG immediately on the African coastline which didn't quite occur. It took an extra 24-36 hours under the favorable divergent outflow associated with the upper level portion of the CCKW, plus the added shear vorticity from westerly winds on the low-level portion of the CCKW to really get the wave cranking south of the Cape Verde islands. I think this is more of a case that the GFS simply got lucky that a strong CCKW was moving through the area at the same time the wave emerged. That didn't work out so well for the wave that it forecasted to develop in mid-July  which ended up being a complete dud. 

 

The lesson here... global model guidance has gotten substantially better at forecasting TCG, but that doesn't mean there aren't false alarms, and the GFS still tends to be the boy who cried wolf moreso than the ECMWF. 

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wxtrackercody

wxtrackercody

Posted
Posted

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD
1502Z WED JUL 24 2013


DUE TO THE THREAT OF CWD NEXT WEEK FOR THE TROPICAL SYSTEM IN THE
ATLANTIC, NCEP/NCO IS MOVING THE "GO LIVE" OF THE NEW WCOSS
SUPERCOMPUTERS UP TO TOMORROW, THURSDAY 7/25.

THE PRODUCTION SUITE ON WCOSS SYSTEM TIDE WILL BEGIN SENDING OUT
THE OFFICIAL OPERATIONAL PRODUCTS AT ROUGHLY 1230Z. DATA
DISSEMINATION FROM THE CURRENT CCS SUPERCOMPUTER WILL CEASE AT
THAT POINT, ALTHOUGH A FEW MODELS WILL CONTINUE TO COME FROM THE
CCS AS THEY BLEED OFF OVER THE FIRST FEW HOURS AFTER THE SWITCH
TO WCOSS SYSTEM TIDE.

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It's Always Sunny

It's Always Sunny

Posted
Posted

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE

NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD

1502Z WED JUL 24 2013

DUE TO THE THREAT OF CWD NEXT WEEK FOR THE TROPICAL SYSTEM IN THE

ATLANTIC, NCEP/NCO IS MOVING THE "GO LIVE" OF THE NEW WCOSS

SUPERCOMPUTERS UP TO TOMORROW, THURSDAY 7/25.

THE PRODUCTION SUITE ON WCOSS SYSTEM TIDE WILL BEGIN SENDING OUT

THE OFFICIAL OPERATIONAL PRODUCTS AT ROUGHLY 1230Z. DATA

DISSEMINATION FROM THE CURRENT CCS SUPERCOMPUTER WILL CEASE AT

THAT POINT, ALTHOUGH A FEW MODELS WILL CONTINUE TO COME FROM THE

CCS AS THEY BLEED OFF OVER THE FIRST FEW HOURS AFTER THE SWITCH

TO WCOSS SYSTEM TIDE.

Do you have the exact link for that? Would like to share it with friends.

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wxmeddler

wxmeddler

Posted
Posted

^^  I wish I knew what that meant.

 

I'll decode..

DUE TO THE THREAT OF Critcal Weather Days (CWD) NEXT WEEK FOR THE TROPICAL SYSTEM (Dorian) IN THEATLANTIC, National Center for Environmental Prediction (The people who run the American models, NAM, GFS, etc>) (NCEP/NCO) IS MOVING THE "GO LIVE" (start date) OF THE NEW WCOSSSUPERCOMPUTERS UP TO TOMORROW, THURSDAY 7/25.THE PRODUCTION SUITE ON WCOSS (The new supercomputers) SYSTEM TIDE WILL BEGIN SENDING OUTTHE OFFICIAL OPERATIONAL PRODUCTS AT ROUGHLY 1230Z (8:30AM EDT).  DATADISSEMINATION FROM THE CURRENT CCS SUPERCOMPUTER (the old super computer) WILL CEASE ATTHAT POINT, ALTHOUGH A FEW MODELS (WaveWatch III?) WILL CONTINUE TO COME FROM THECCS AS THEY BLEED OFF OVER THE FIRST FEW HOURS AFTER THE SWITCHTO WCOSS SYSTEM TIDE (order of model operations, ie. when models get run).

post-741-0-14014200-1374715027_thumb.png

 

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Ed Lizard

Ed Lizard

Posted
Posted

I'm assuming they had to change some code (on more than one model, I'm guessing)  if they are already identifying problems, say with the NAM in urban environments on warm, humid days.

 

I saw mention on Dorian thread that WCOSS run GFS seemed weaker with Dorian in a few days.

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wxtrackercody

wxtrackercody

Posted
Posted

I'm assuming they had to change some code (on more than one model, I'm guessing)  if they are already identifying problems, say with the NAM in urban environments on warm, humid days.

 

I saw mention on Dorian thread that WCOSS run GFS seemed weaker with Dorian in a few days.

The WCOSS GFS fails to acknowledge Dorian as a mid-grade tropical storm at the time altogether. 

 

Not exactly excited about this switch....though admittedly, it's not just the GFS. None of the models recognize Dorian as Dorian.

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Ed Lizard

Ed Lizard

Posted
Posted

The WCOSS GFS fails to acknowledge Dorian as a mid-grade tropical storm at the time altogether. 

 

Not exactly excited about this switch....though admittedly, it's not just the GFS. None of the models recognize Dorian as Dorian.

 

So, was there some remarkable new data entered into the 12Z GFS that know runs Dorian into Hispaniola, or is the change of the previous GFS tracks, showing a close approach to the East Coast but a recurve, an artifact of the computer change.

 

Or is that unknowable?

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Ed Lizard

Ed Lizard

Posted
Posted

Only partly about Dorian.

 

Looking for my pre-Sandy weenie thread, do you know which model was suggesting a Northeast hurricane landfall even before the Euro?

 

The Canadian.

 

But, anyway.

 

http://www.americanwx.com/bb/index.php/topic/35846-atlantic-tropical-action-2012-part-ii/page-31#entry1797928

 

 

 

 

Pure wishcasting from 240 hour Euro, Hurricane Sandy gets captured by the polar trough, and produced multi-day Halloween Storm Part Deux for the SNE subforum that people will make movies about.


Much better than yesterday's 12Z moderate tropical storm for Florida.

So much better.



I hope I'm not 5 posted for a month for this...


ETA Just checked SNE subforum banter thread, and I'm not the only person in Weenie Wonderland


http://en.wikipedia.org/wiki/Snow_Hurricane_of_1804

 

 

 

 

PerfectStormDeux.gif

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phil882

phil882

Posted
Posted

 

This has been in the works for many years now and should be exciting to see TCG finally being tested out into the beginning of the medium range. I know there is already a bunch of talk of the MJO and CCKW here at AmericanWx, but expect that to only increase as equatorial wave oscillations will be front and center for the prospects of development going further out in time. It helps that global models are beginning to become good enough to sniff out genesis at such a range. 

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icebreaker5221

icebreaker5221

Posted
Posted

Slightly stronger than average easterlies from 10-20 N throughout much of the month of July have spread slightly cooler waters across much of the basin, particularly the western N Atlantic.  At the same time, anomalous westerlies around 30 N have helped to advect much warmer than average surface waters to the sub-tropical N Atlantic, north of the MDR. 

 

post-378-0-55266600-1374853843_thumb.gif

 

 

If we can get a few persistent cutoff lows and/or PV breakoffs from the tails of stalled-out cold fronts, I suspect Aug (and possibly Sep if the pattern persists) will produce a greater than average number of tropical transition genesis events / high-latitude tropical storms a la 2012. 

 

post-378-0-43440900-1374853850_thumb.gif

 

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Ed Lizard

Ed Lizard

Posted
Posted

Is the GFS the new 'King of the Tropics'?????

 

 

On the July 19th post this was a quote of, I noted that the GFS runs that developed Dorian, as it approaches the islands, started to weaken it due to faster 850 mb flow (shear and divergence) and the beginning of a change of 250 mb flow direction, such that I didn't think the GFS dissipating it completely after the truncation was just an artifact.

 

Or, while not perfect, the GFS from a week ago was predicting the development, than the weakening, of Dorian.  When the Euro was predicting nothing.  Again, palace coup possible against King Euro?

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