Aw-phelia and Model SaltAdded : Wednesday at 9:23 Blimey... Been a long time since we've had a named weather system with so many plays on the name, but Tropical Storm Ophelia really is becoming a system to watch over the next few days as she moves around the Tropical Atlantic and then gets caught up in a big old long wave upper trough.
Here she is at the moment :-
Over the next few days she moves very little due to lack of upper steering. Usually, we would expect this to churn up the Atlantic waters and bring cooler water to the surface which in turn dissipates the system. But Ophelia sort of meanders around over the next day or two and in a low shear environment with much colder upper air than usual we expect her to maintain or perhaps increase in strength to hurricane force either later tonight or tomorrow.
So, what happens to Ophelia after? This is where it gets interesting. You may remember a couple of days ago the ECMWF ► bringing Ophelia as a fully post tropical system across the UK along with the Canadian GEM model, whilst the GFS ► kept her out in the Atlantic.
The GFS ► has now come around to the same way of thinking as the others and this means that whilst we use the GFS, it doesn't have the same handle on the system as the ECMWF ► or GEM. Any meteorologist who says that one global model is better than another is using a huge broad brush to make an evaluation.
Some global models are better than others at certain scenarios. The ECMWF ► is awesome at upper level ridge/trough intensity forecasting, but the GFS ► is great at boundary level and cyclonic development stuff. What is interesting, is why the GEM did so well. One reason could be that these scenarios where post tropical systems getting caught in upper level troughs are rather common in the Eastern Pacific, in particular where ex-hurricanes merge with the Aleutian low? But we digress.
By Monday we have this from the major models starting with the ECMWF ► :-
The ECMWF ► keeps Ophelia out West and affects Ireland on Tuesday.
The GEM has this :-
Similar timing, track and intensity as the ECMWF ► with a major Atlantic storm for Ireland and the GFS ► has this :-
Slightly further West than both the ECMWF ► and the GEM.
Don't get too hung up on any one of the models. The exact track could still be slightly further East or West than all of them are suggesting, but as the ECMWF ► and GEM have been rather consistent with Ophelia over the last few days it's worth taking a little more note of them and adding a little more salt to the GFS ► output right now.
That said, all three global models indicate Ophelia as a strong cyclone over the northeastern Atlantic early next week with the threat of some heavy rain and strong winds, but at the moment it's just a little too early to say where or whether Ophelia will directly affect the UK or Ireland.
So, keep taking the salt tablets with raw numerical output for the next day or two.
METEOROLOGIST : MARSH |