2015 Global model runs discussion

[Ntxw]

For those wondering about the model forecasts for the MJO. There isn't a true MJO signal going across the globe, the movement shown is actually Kelvin waves coming out of the CPAC/EPAC in pulses. With a real MJO you will see it loop around usually beginning in the IO>Maritimes>Pacific>Atlantic. Pair of Pacific typhoons (twins) may ripple out more KW's as move east.

This is from a Jeff Master's depiction of a real MJO wave



Persistent blues east of the 180 (dateline) is low frequency Nino forcing and KW waves. It isn't global.

[Weatherwatcher98]

For those wondering about the model forecasts for the MJO. There isn't a true MJO signal going across the globe, the movement shown is actually Kelvin waves coming out of the CPAC/EPAC in pulses. With a real MJO you will see it loop around usually beginning in the IO>Maritimes>Pacific>Atlantic. Pair of Pacific typhoons (twins) may ripple out more KW's as move east.

Thanks I was wondering about that.

[Weatherwatcher98]

If you're waiting on the euro only you may be waiting awhile as far as genesis they aren't the best as sometimes they missed development or where late to the party. Granted, if they come, it will help solidify any model consensus.

Yes, No One model is perfect.

[stormlover2013]

EURO has been money the last month, I am sticking with the one that has been money....

[Weatherwatcher98]

EURO has been money the last month, I am sticking with the one that has been money....

I agree but it has been wrong before. TS Debby is a Great Example. Although it has had an upgrade since then.

[LarryWx]

Interestingly, the 12Z GFS appears rather close to a WC genesis as of hour 144. There is a 1008 WC sfc low that wasn't on yesterday's GFS runs. It probably won't amount to too much in the WC as it likely moves inland but the key to focus on here is whether or not this is a sign of a trend reversal back to a true WC genesis.

If future runs start developing a WC low just 100 miles or so further east, look out.

http://www.nhc.noaa.gov/climo/images/10_11_20_nhc.png

Edit: This 12Z GFS low then moves into the B of C as of 192, which has been the trend for the last few runs.

This low then strengthens to 1002 mb as it appears to be fed by the energy from a EPAC low underneath it. Then it gets stretched out and weakens some in the W GOM.

[Weatherwatcher98]

Interestingly, the 12Z GFS appears rather close to a WC genesis as of hour 144. There is a 1008 WC sfc low that wasn't on yesterday's GFS runs. It probably won't amount to too much in the WC as it likely moves inland but the key to focus on here is whether or not this is a sign of a trend reversal back to a true WC genesis.

If future runs start developing a WC low just 100 miles or so further east, look out.

http://www.nhc.noaa.gov/climo/images/10_11_20_nhc.png

Edit: This 12Z GFS low then moves into the B of C as of 192, which has been the trend for the last few runs.

This low then strengthens to 1002 mb as it appears to be fed by the energy from a EPAC low underneath it.

I saw that, a few past runs then move it Out of the Bay of Campeche East North East towards central/North Florida. That is why I am still keeping an eye on it.

[LarryWx]

Yep, FL is by no means in the clear yet imo.

The 12Z CMC is running and as of hour 102 is similar to its 0Z 114 map with a well organized WC low at 1005 mb.
Preliminary maps suggest it has a TC moving slowly in the middle of the GOM at hour 198 on 10/21.

Edit: These preliminary maps then show a storm move NNE to somewhere in the general vicinity of MS/AL/FL Panhandle late 10/22 and then NE well inland into the SE US at 240 (10/23). I'm not sure it is purely tropical throughout those last couple of days. I'm waiting for the sfc maps.

Edit: 12Z CMC 993 mb (borderline H) landfall Mobile late 10/22. Looks tropical. Heavy rains well inland parts of SE US 10/22-3.

[Alyono]

CMC appears to have an EXTRATROPICAL landfall based upon the simulated IR satellite

[LarryWx]

CMC appears to have an EXTRATROPICAL landfall based upon the simulated IR satellite

Thanks for the clarification on the type of storm at the 12Z CMC's landfall. Could it be subtropical?

Is the 12Z NAVGEM running late?

[LarryWx]

12Z NAVGEM 180 (10/20 PM): back to a H with it being 988 mb then. It is further out toward the middle of the GOM about 200 miles N of the Yucatan moving N

[Hammy]

Realistic chances of anything developing on the Atlantic side of Central America are basically zero. Interesting though that the Euro has been developing a low (subtropical possibly?) in the central Atlantic in about a week, the GFS is now picking up on it as well.

[LarryWx]

Realistic chances of anything developing on the Atlantic side of Central America are basically zero. Interesting though that the Euro has been developing a low (subtropical possibly?) in the central Atlantic in about a week, the GFS is now picking up on it as well.

Going with basically zero chances seems quite bold to me. I can see calling chances low, but already calling for near zero chances for something still a week or so into the future during a climo still busy period in certain areas and while most non-Euro models have something in the WC &/or GOM? Do you also think chances are near zero for the GOM?

Meanwhile, the 12Z Euro has only a weak low at 216 in the Bay of Campeche and nothing forming in the WC prior to that.

[Steve H.]

Yeah, I wouldn't say zero either. The Euro does have an EPAC storm undergoing RI though. And yes, it also has a TD/TS just outside the Lesser Antilles under a building ridge. Meanwhile a coating a snow possible for northern NE this weekend!

[stormlover2013]

Models keep prolonging the situation longer and longer, I don't trust any model passed 6 days so.... to me this is long range so not worried but I am getting bored at work and wouldn't mind tracking a system lol

[gatorcane]

The Euro attempts the daring and bold EPAC to BOC crossover in the long-range. We know how those usually work out.

[stormlover2013]

looks like cold front also would be hybrid

[Ntxw]

Caribbean shear, though not screaming like earlier in the season, is still currently rather higher than normal. That shouldn't change if the models are to be believed within the next 5-7 days. Per OPS and ENS shear picks up substantially as well in the EGOM by this weekend and early next week. Nothing in that frame likely to happen.

If I had to guess whatever forms, IF it does, will be likely the previous events we've seen in this area before many times this season. Strung out most likely and will be well beyond 7 days.

[stormlover2013]

I agree

[Hammy]

? Do you also think chances are near zero for the GOM?

I would say very unlikely for GoM (BoC specifically) given the poor model performance but not zero in that area, more like 20% range. I still don't see anything being particularly likely. Westward trends of the models however tell me there's no chance of development in the Caribbean or eastern Gulf.