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Tropical Global Model Runs Discussion 2017

GaWx said:
Further to this: the 12Z EPS has a whopping 16 hurricanes from the 50 members or 32% of them, which is 3 more than any previous run! Also, keep in mind that the EPS members are supposedly run at a lower resolution than the operational meaning SLPs can easily be underdone.
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Larry,
I swear I swore any adult beverages off until after the close of business Friday ... Why are you challenging the vow? ... LOL
 
A large area of cloudiness and showers extending from the
northwestern Caribbean Sea across Cuba to the Bahamas is associated
with a surface trough interacting with an upper-level low. An area
of low pressure is likely to form from this weather system while it
moves northward across Cuba and near the east coast of the Florida
peninsula during the next few days, and environmental conditions
appear conducive for development before upper-level winds become
less favorable early next week. Regardless of development, this
system is likely to produce locally heavy rainfall over portions of
Cuba, southern Florida, the Florida Keys, and the Bahamas during the
next several days.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...40 percent.
 
Anyone up for 3 storms at once in 10 days again? The GFS, CMC, and Euro have 3 systems near the same area.
gfs_mslp_wind_atl_42.png
ecmwf_uv850_vort_atl_11.png
gem_z850_vort_atl_41.png
 
The 12Z GEFS is VERY active in the W Caribbean starting about a week from now. Most members have at least a TS and eventually about half or more of the members have a H. Subsequently, during the period 10/7-10, many of the members hit FL with a few other members still having a TC milling around in the Gulf. I count at least 6 of the 20 members hitting FL with a H and at least half the members hitting them with a TS+ just during the period 10/7-10!

The significance of this GEFS run is that it isn't an 18Z GEFS run. The 18Z has been very biased active but not the 12Z. This is the most active non-18Z GEFS by far for early October in/near the W Caribbean.

Meanwhile, the 12Z Euro has backed way off of its prior runs showing a W. Caribbean TC.
 
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The 12Z EPS suggests that the 12Z Euro operational is somewhat of an outlier with the EPS mean having the E US ridging holding on much longer than the op and similar to both its 0Z run as well as the 12Z GEFS and 12Z GEPS means. As a result, the 12Z EPS actually has a good bit more TC activity than its 0Z run for FL during the 10/7-10 interval, similar to but not as active as the very active 12Z GEFS there.

The 12Z GEPS also has some activity in FL and more than its own 0Z run.

Conclusion: Despite what the 12Z Euro showed, FL and nearby areas do still appear to be at an appreciable risk around 10/7-10 for a W Caribbean originating TC to hit them from below based on all 3 major 12Z ensemble runs.

***Edit: this has nothing to do with newly designated 99L, found in the FL Straits. 99L could become a TC or STC this weekend just off of NE FL. See that separate thread.***
 
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I know it is the Happy Hour GFS, my favorite run lol, but like the 12Z GFS, the 18Z GFS gives FL a big blow with a strong TC hit on S FL on 10/7 this run. The period 10/7-10 was suggested by the 3 main 12Z ensemble runs to be the period FL is at highest risk from getting a hit from below.

Edit: Note that after this S FL hit from what easily could be a H, it runs up the SE US coast 10/8-9 as a still formidable TC. The most worrisome aspect of that would likely be the enhanced risk of major coastal flooding due to significant and long-fetched onshore winds being progged to start 9/30 and lasting at least through 10/8. The highest astronomic tides of October, which are near and just after the full moon, are during 10/6-9. If a strong TC were to then come along around 10/7-9, the coasts of FL/GA/SC would likely be at risk from another major coastal flooding event. Fortunately, this is still pretty far out in forecast time. But it obviously is something worth monitoring
 
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The 18Z GEFS is similar to the 12Z GEFS with many members becoming a TS+ and 8 (40%) becoming a H. Five of those Hs hit FL during 10/7-10. Two of those later hit GA/SC/NC 10/9-10 still as Hs. One hits TX/LA 10/13-14. Keep in mind that the members are run on low resolution. So, the # of Hs could easily be underdone. Then again, it is the 18Z GEFS.
 
GaWx said:
The 18Z GEFS is similar to the 12Z GEFS with many members becoming a TS+ and 8 (40%) becoming a H. Five of those Hs hit FL during 10/7-10. Two of those later hit GA/SC/NC 10/9-10 still as Hs. One hits TX/LA 10/13-14. Keep in mind that the members are run on low resolution. So, the # of Hs could easily be underdone. Then again, it is the 18Z GEFS.
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Larry,
Just got in at 9:20 PM from the Court thing.
Eyes are totally bleary and mind is drained ... so pardon the lack of scouring backwards to catch up -- are we in a bad spot or looking at something bad on the models?
Thanks!
Phil
 
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the 0z GFS brings a storm up from Cuba over Miami then into Charleston next weekend(October 7-8), it strengthens all the way to Charleston from the 990s over Miami to the low 980s approaching SC

The CMC brings a weak storm into SW FL around the same time(another storm dies after Cuba into the Bahamas in the frames just before lol)
 
pcbjr said:
Larry,
Just got in at 9:20 PM from the Court thing.
Eyes are totally bleary and mind is drained ... so pardon the lack of scouring backwards to catch up -- are we in a bad spot or looking at something bad on the models?
Thanks!
Phil
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The models since 12Z . It is still quite a bit too far out to call it a bad spot. Just something to follow.

The 0Z GEFS continues the notable threat to FL around 10/7-11 with 4 of its 20 members hitting FL as a H during that interval. There are a total of 6 Hs but keep in mind the low resolution that is used. So, now we have all 3 12Z ensembles as well as the 18Z/0Z GEFS, the last 3 GFS runs, and the last 2 CMC runs implying a significant TC threat to FL from below ~8-11 days from now.
 
Something else to watch.
2. A tropical wave is producing cloudiness and showers over the
northeastern Caribbean Sea and the adjacent Atlantic waters.
Although there are no signs of organization and surface pressures
are not falling at this time, conditions could become a little more
favorable for some development next week while the system moves
toward the west-northwest. This system is expected to bring
locally heavy rains over the northern Leeward Islands, including
Puerto Rico and the U.S. Virgin Islands.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.
 
^As Forsyth implied, this isn't referring to the W. Caribbean potential, the genesis of which would appear to be still 5-7 days away, that is on most models. Instead, this is referring to an additional potential genesis just north of the Caribbean. Whereas the main op models have shown very little with this, a few EPS and GEPS members have shown this to develop around Tue-Wed of next week north of the Caribbean moving WNW underneath the big high toward the SE US.
 
GaWx said:
The models since 12Z . It is still quite a bit too far out to call it a bad spot. Just something to follow.

The 0Z GEFS continues the notable threat to FL around 10/7-11 with 4 of its 20 members hitting FL as a H during that interval. There are a total of 6 Hs but keep in mind the low resolution that is used. So, now we have all 3 12Z ensembles as well as the 18Z/0Z GEFS, the last 3 GFS runs, and the last 2 CMC runs implying a significant TC threat to FL from below ~8-11 days from now.
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Regarding the W Caribbean potential, the 6Z GEFS has easily been the quietest GEFS run for W. Caribbean potential for just about every day for the last 10+ days. Yet, even it has a good number of TC hits 10/6-9 on FL.

Despite the 0Z Euro's op's lack of anything significant, the 0Z EPS also has multiple members with FL TC hits 10/6-12.
 
The ridiculously warm W. Caribbean says that FL must stay on extra alert for any H that might hit them in Oct due to this: there have been 10 major H hits on FL in Oct since 1865 (about one every 15 years on average) and those 10 seasons had these Nino 3.4 anomalies (credit to Eric Webb for pre-1950 data):

SON trimonthly average : -0.03, -0.30, -0.32, -0.39, -0.40, -0.50, -0.66, -0.80, -1.00. and -1.10

So, not one +SON and no real strongly -SON. These SON's pretty much surround where we are projected to go for the SON average per the Sept. dynamic model forecast plume average, which is -0.50. Most of the better models like Euro, UKMET, JMA, CFSv2, Australian, Korean, etc., are within the -0.30 to -0.90 range:

http://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table

The 10 seasons with major H hits on FL in Oct since 1865, ALL of which originated in the W Caribbean:
1873, 1894, 1906, 1909, 1921, 1926, 1950, 1964, 1995, and 2005....so about one every 15 years.
 
GFS into the Panhandle at 0z

CMC at 0z has a big storm hitting close to where Irma hit in SW FL then going into the Carolinas

both valid at day 8

0z Euro has a storm going about over Tampa-Orlando SW-NE at the same time
 
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