2015 Global model runs discussion

[Hammy]

To those knocking the model runs these are the same models many on this board praise all the time. You can't have it both ways. Anyway like I said before still too far to take serious but \some thing to be aware of next week. It's that time of year. IMO

I think most of us quit praising the models following the mess with Erika's runs as well as the generally poor performance this season.

[Alyono]

Larry Crosgrove said on his page that ensembles don't do a good job on tropical systems

they do a very good job at predicting the probability of genesis. I do not have the genesis probs yet (available soon). However, the control should be somewhat similar to the deterministic, though much weaker due to differences in resolution.

Using the ensembles for a deterministic track is the wrong way to use an ensemble. They are best used for risk management purposes

[wxman57]

Only 2 of the 50 EC ensemble members have any low pressure area in the NW Gulf late next week. Most agree with the GFS - nothing there.

[Steve]

Pattern storm, eh? If he's right, and based on the models I've looked at, piled up energy between the wave down south Caribbean and a surge from the EPAC behind a lifting out trough and building high pressure where the BoC is an area of lower pressure and potential genesis. As the trough lifts out in 5-7 days, look underneath the building high. Classic pattern reversal that you usually see more frequently from the east rather than the southwest. But whatever. We'll see.

[Alyono]

EC ensembles based upon the 12Z output on the EC website are showing a high chance of a weak system forming in the SW Gulf. Still, a low chance of anything reaching TS intensity (between 10 and 20 percent)

[Stormcenter]

It all depends on who you want to believe. IMO

Only 2 of the 50 EC ensemble members have any low pressure area in the NW Gulf late next week. Most agree with the GFS - nothing there.

[wxmann_91]

To those knocking the model runs these are the same models many on this board praise all the time. You can't have it both ways. Anyway like I said before still too far to take serious but \some thing to be aware of next week. It's that time of year. IMO

Praise is the last word that should be used for the models and their performance this year.

[Rgv20]

Only 2 of the 50 EC ensemble members have any low pressure area in the NW Gulf late next week. Most agree with the GFS - nothing there.

Yeap the Operational ECMWF is alone on developing a Hurricane in the GOM. Also of note the ECMWF Control run shows nothing which is surprising as it typically follows the Operational run.

[NDG]

The Euro's long range solution of forecasting a deepening a hurricane in the GOM needs to be thrown out just on the fact that it keeps moving the time, it keeps it keeps it in its 8-10 day range forecast run after run.

[CYCLONE MIKE]

Reminds me of the good ole days when the gfs would always show a major hitting a major coastal city and it was always 10-14 days out. My how the euro has changed and its not for the better.

[gatorcane]

The Euro's long range solution of forecasting a deepening a hurricane in the GOM needs to be thrown out just on the fact that it keeps moving the time, it keeps it keeps it in its 8-10 day range forecast run after run.

Yeah good point. I compiled some data from the last 3 days of ECMWF runs. Two things that I notice:

1. Development start time keeps coming in which is telling me something may very well try to form on the BOC or Western GOM area starting in the Sun.-Mon timeframe.
2. The hurricane potential is highly questionable because of what NDG pointed out as the model is not bringing in the timeframe on that.

Mon 00Z: Development starts: 168 hours, hurricane forms: 192 hours
Mon 12Z: Development starts: 168 hours, hurricane forms: N/A
Tues 00Z: Development starts: 144 hours, hurricane forms: 240 hours
Tues 12Z: Development starts: 120 hours, hurricane forms: 216 hours
Wed 00Z: Development starts: 120 hours, hurricane forms: N/A
Wed 12Z: Development starts: 96 hours, hurricane forms: 192 hours

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products.

[Yellow Evan]

Reminds me of the good ole days when the gfs would always show a major hitting a major coastal city and it was always 10-14 days out. My how the euro has changed and its not for the better.

The GFS and ECMWF have flipped flopped roles this year it seems.

[stormlover2013]

An interesting debate is shaping up about tropical weather possibilities over the next 12 days.

1) The operational ECMWF and GFS schemes are outliers with their forecasts of a major hurricane and tropical wave, respectively. The most likely outcome is for an impulse entering the equatorial moisture axis below Central America to get caught up in the fetch laid down by Hurricane Linda. That is right; a system jumping across the Isthmus of Tehuantepec into the Bay of Campeche, steadily migrating northward up along the western shoreline of the Gulf of Mexico.

2) I do not believe for a minute the "I do not see any system" or "look out for a monster" comments that are shaping up here on Facebook and on Twitter. When presented with two extremes, I often like to go in the middle. So we should see a depression or tropical storm that shoots into the Houston TX metro and then gets caught up and accelerated into a cold front pushing out of the Midwest into the Northeast. Witness the storm track map, which is my first guess.

3) This looks to me to be a big rainmaker, but could also bring some gusty winds upon landfall or with the "racing along the front with thunderstorms" period around September 18-19. The 18z GFS and 12z GGEM precipitation total maps are close to my thinking.

I will pass along more IF and WHEN this feature takes shape.

That was posted from Larry crosgrove

[srainhoutx]

Evening briefing from Jeff:

Decent looking cold front heading for SE TX this weekend…will bring a good taste of Fall…but trouble appears to be developing for next week.



Initial cold front is lurking across N TX this afternoon with scattered showers and a few thunderstorms in progress mainly across our SW counties where the deepest moisture is found. Boundary to our north is fairly ill defined and muddled by early day convective outflows. Ingredients continue to come together for a fairly active Thursday and Friday across the region as the initial weak front stalls across the area and interacts with deep tropical moisture and passing short waves. Each passing short wave will help to ignite rounds of showers and thunderstorms. Not overly confident on the heavy rainfall aspect as storms look loosely organized and any training should be short lived. Still cannot discount the copious moisture profiles (PWS around 2.0 inches) which will support those high short term rainfall rates which usually leads to street flooding in urban areas.



Secondary and much stronger front moves across Friday night…possibly with a line of thunderstorms. Significantly cooler and drier air mass will usher into the area on Saturday with even some cold air advection. Dewpoints fall into the 50’s and possibly even the 40’s with overnight lows on Sunday into the lower 60’s and upper 50’s with highs only in the mid 80’s. This will be a significant reprieve from the months of hot and humid conditions. This “great” fall weather will not last long and changes will be fairly abrupt next week.



Next Week:



Tropical cyclone formation possible over the southern/western Gulf of Mexico early to mid next week.



Forecast models remain consistent on their solutions, but inconsistent between each other on what will transpire over the western Gulf of Mexico next week. The ECWMF remains an aggressive outlier with the development and then rapid intensification of a tropical system in the NW Gulf off the TX coast. The GFS is the weaker solution and maintains an ill defined broad circulation that drifts over the NW Gulf..more of a coastal trough feature. The CMC is stronger than the GFS and weaker than the ECWMF and also significantly further south over the Bay of Campeche with formation from mid level energy crossing across from the eastern Pacific.



Think there is enough support that something is going to attempt to develop along the NE MX/S TX coast southward into the Bay of Campeche early next week. This could be an ill defined tropical wave tracking through the Caribbean Sea or the formation of a coastal trough off the tail end of the weekend front. Overall steering pattern is for anything that is to develop to track generally toward the north (or in the direction of TX) with high pressure to the east and low pressure to the west. This development appears at the tail end of a deep eastern US trough (responsible for the weekend cold front), but it appears the trough may be too far removed by the time of formation to greatly affect the track and it is very possible any system is left to meander over the NW Gulf for a few days.



Will maintain continuity for now with WPC and go with a weak closed surface low/trough moving northward off the MX coast early next week to offshore of S TX by Tuesday/Wednesday. Extremely dry air mass will rapidly moisten on Tuesday as surge of tropical moisture heads northward over the western Gulf. Will bring strong rain chances toward the coast on Tuesday and then likely inland on Wednesday regardless of development. Past experience with such setups in mid September usually result in a slower return of rain chances as the very dry air takes longer to moisten than models suggests.



Other aspect will likely be tides as ENE to NE surface winds post front on Saturday into early next week helps to pile water toward the coast. This is a favored tidal pile-up wind direction along the upper TX coast so will have to start watching tides likely by Monday of next week. Any tropical formation to our SSW/S will only increase the pressure gradient and winds and help foster higher tides.



As always the forecast confidence is low and residents should monitor forecast going into this weekend.

[Hammy]

-IF- the models turn out to be correct and something forms, I think it could go something like 11E/Hermine in 2010.

[Hurricaneman]

-IF- the models turn out to be correct and something forms, I think it could go something like 11E/Hermine in 2010.

Could be and if it had taken a more northerly track Hermine in 2010 could have been a substancial hurricane so lucky to take that NW bend at the end but what if this possible new area does something similar except stays offshore the Euro may not be on drugs afterall in that case

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or storm2k.org. For official information, please refer to the NHC and NWS products

[Alyono]

Hermine was moving quickly. Almost certainly wouldn't have been more than a mid range cat 1 had it made landfall farther up the coast

[Alyono]

weak low in the Gulf from the MU

[Steve]

Not much on GFS. Tropical surge?

[Alyono]

Canadian is MUCH weaker

EC needs to rethink how they make their upgrades. They went from a known problem of underdeveloping TCs to taking the title from the CMC as the -removed- model