Tropical Wave SW of Cabo Verde Islands: (Is Invest 96L)

[NDG]

The UKMET has certainly over done ridging (a reoccurring model bias this season perhaps), but the ECMWF has been solid:
https://i.imgur.com/1oDC5By.png

https://i.imgur.com/I0ohJ87.png

The upcoming pattern is difficult though, and I'd expect all the models will fall below the 0.9 anom correlation next week. It will be interesting to see how the Scandinavian high retrogression impacts steering flow as well. If I had to make a forecast, I would lean towards recurve as well (given current position of ECMWF development), but it's certainly not a guarantee.

The Euro has also been biased with ridging across the eastern US, but more in the SE US, like I said in its 96-168 hr forecast.
The chart that showed of the Euro's good performance is for the whole northern hemisphere over all, but it has clearly not performing too well with the troughiness across the SE US.

https://i.imgur.com/ZvWwNtx.gif

I wouldn't exactly call it a bias, but certainly a slightly failed forecast with the current digging of the EC trough (and with that being said, still verified as the most accurate of the available global models). The UKMET has consistently done this with numerous troughs, however (including troughing along the NW/West Coast).

I also remember very clearly missing the trough last week on its 96-168 hr forecast range, so this is not the first time.

[TheStormExpert]

:uarrow: I on the other hand if anything, I think that both the Euro and UKMET have over done on ridging across the eastern US in their 96-168 hr forecast.

I do think that the pattern will eventually change to more ridging across the eastern US, but it may not do so until the end of August into September, like it did in 2004.

The way I see it the UKMET overdoes the ridging while the GFS overdoes troughiness. The Euro is usually an average in between the two a lot of times.

[TheStormExpert]

I expect this trough pattern to last the next 2-3 weeks then from about last 2 weeks of August into sept we should see a more August type sept pattern, this is like a fall pattern right now

This is the pattern that folks in Florida are happy hasn’t panned out during the last MANY winters since 2010.

[TheStormExpert]

I also noticed the CFS long range model was showing a rainfall swath in August from across all the Greater Antilles into the eastern Gulf, hinting maybe at a Georges (1998) like track?

[SoupBone]

I expect this trough pattern to last the next 2-3 weeks then from about last 2 weeks of August into sept we should see a more August type sept pattern, this is like a fall pattern right now

Why would it switch? We've seen seasons where troughs hung around for the duration, albeit against the norm.

[USTropics]

The Euro has also been biased with ridging across the eastern US, but more in the SE US, like I said in its 96-168 hr forecast.
The chart that showed of the Euro's good performance is for the whole northern hemisphere over all, but it has clearly not performing too well with the troughiness across the SE US.

https://i.imgur.com/ZvWwNtx.gif

I wouldn't exactly call it a bias, but certainly a slightly failed forecast with the current digging of the EC trough (and with that being said, still verified as the most accurate of the available global models). The UKMET has consistently done this with numerous troughs, however (including troughing along the NW/West Coast).

I also remember very clearly missing the trough last week on its 96-168 hr forecast range, so this is not the first time.

We're kind of splitting hairs here, and I'm in agreement the ECMWF hasn't forecasted the troughs as accurately as it typically does (to the point where the WPC diagnostic team threw out the ECMWF ensemble package in some of their forecasts last week), but it's a relative issue, I don't believe it's a long-term bias (three weeks ago it was overdoing the troughs consistently). There's no quantitative data to focus just on the EC troughs (short of following the models daily like we do), but the anom correlation chart for the NH (20-80N) is the best 'insight' we have, and relative to the other models, ECMWF is more consistent (and yes, it does miss badly like last week). Rarely do you see the ECMWF dip down to 0.8 anom correlation like it did last week though.

[TheStormExpert]

I expect this trough pattern to last the next 2-3 weeks then from about last 2 weeks of August into sept we should see a more August type sept pattern, this is like a fall pattern right now

Why would it switch? We've seen seasons where troughs hung around for the duration, albeit against the norm.

I just can’t see it abruptly switching either.

[stormlover2013]

I expect this trough pattern to last the next 2-3 weeks then from about last 2 weeks of August into sept we should see a more August type sept pattern, this is like a fall pattern right now

Why would it switch? We've seen seasons where troughs hung around for the duration, albeit against the norm.

It can’t stay this way the entire summer and it won’t!!

Just this type of pattern will not last all summer. I mean look what occurred two weeks ago. Midwest and northeast were hot

[blp]

I don't trust the models on ridge/trough setup past 7 days. It does not matter if we are in a -NAO or +NAO because those represent a longer pattern. We are talking about the daily forecast ridge/trough were small changes in the pattern could have big implications. We need to wait a little longer to see how this plays out.

[Aric Dunn]

I don't trust the models on ridge/trough setup past 7 days. It does not matter if we are in a -NAO or +NAO because those represent a longer pattern. We are talking about the daily forecast ridge/trough were small changes in the pattern could have big implications. We need to wait a little longer to see how this plays out.

Correct. Being there are no big trough on eother camp we are looking at small subtle differences in tiiming and placment. We wont know anything with any degree of certainty in this kind of set up past 3 days.

[GCANE]

It's sucking in a lot of ITCZ moisture

[floridasun78]

i have say let wait next wed see if trough moving closer to east coast pull next invest out to sea or will high build too strong to move out to sea i think models don't have agreement on trough vs high pressure position yet it bit far into future

[cycloneye]

I am going on a limb to say it should be Invest 96L this afternoon or evening.

[Aric Dunn]

I am going on a limb to say it should be Invest 96L this afternoon or evening.

Yeah it should be lol

[USTropics]

A bit more consolidation of vorticity on the 12z GFS compared to the last 4 runs as the wave approaches the Caribbean:

[LarryWx]

This becomes a recurving weak Bahama Mama day 10 on the 12Z GFS fwiw. Way too close for comfort for the SE US at this still far point in the forecast.

[cycloneye]

GFS gets it going in the Bahamas.

[NDG]

I expect this trough pattern to last the next 2-3 weeks then from about last 2 weeks of August into sept we should see a more August type sept pattern, this is like a fall pattern right now

Why would it switch? We've seen seasons where troughs hung around for the duration, albeit against the norm.

It can’t stay this way the entire summer and it won’t!!

Just this type of pattern will not last all summer. I mean look what occurred two weeks ago. Midwest and northeast were hot

It has happened before. Below are the years that there was a persistent -NAO from May to August but came late Aug through September into October the NAO changed to positive.

1956, 1963, 1969, 1974, 1980, 2004(-NAO Aug), 2007, 2009, 2011, 2016

The Euro monthly forecast is still persistent that ridging will return to the eastern & western Atlantic starting next month, in 5 days it will update its forecast for August so we shall see.

[SFLcane]

This becomes a recurving weak Bahama Mama day 10 on the 12Z GFS fwiw. Way too close for comfort for the SE US at this still far point in the forecast.

Expect more adjustments westward if you asked me.

[LarryWx]

This becomes a recurving weak Bahama Mama day 10 on the 12Z GFS fwiw. Way too close for comfort for the SE US at this still far point in the forecast.

Expect more adjustments westward if you asked me.

General model bias of a tendency for too much E US troughing would agree with you fwiw.