Woke up this morning to a pleasant surprise that Frances is experiencing 15-20 kt (17-23 MPH) of westerly shear. Not only that, this shear is now expected to persist until just before landfall.
I must have missed a lot in my reading, but this is the first I remember about wind shear being mentioned even as late as last night, where Frances' ragged appearance was generally explained as being eyewall replacement cycles. Yet this morning I see a very well developed strong upper high SW of Frances creating this shear.
Have to ask, and hopefully some of the professional mets can explain, with all the data we have these days, is it impossible to forecast the existance of shear, even in the short term?
Question About Forecasting
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dougjp
- Tropical Depression
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Question About Forecasting
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dougjp
- Tropical Depression
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- Location: Ontario, Canada, eh? Hazel survivor :)
I am greatly concerned there seems to be no answer. Today's shear event was favorable, however its just as possible that if shear exists over another storm, and nobody can accurately predict or notice data just 12-24 hours out that indicates shear completely disappears, rapid intensification could occur close to landfall and nobody predicts it, resulting in major loss of life. 
The chain is as strong as the weakest link.
The chain is as strong as the weakest link.
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Hyperstorm
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I'm not a professional met, but since you didn't get an answer, I'll give it to you.
This shear was forecasted to occur by the SHIPS and GFDL models way in advance of today...more than 48 hours ago. Therefore, we cannot say that this was surprising. What happened was that the forecasters at the NHC decided to ignore these models because they appeared to be unrealistic.
Shear can be predicted days in advance, however, it's never a high-confidence prediction because patterns can change in a matter of hours...
This shear was forecasted to occur by the SHIPS and GFDL models way in advance of today...more than 48 hours ago. Therefore, we cannot say that this was surprising. What happened was that the forecasters at the NHC decided to ignore these models because they appeared to be unrealistic.
Shear can be predicted days in advance, however, it's never a high-confidence prediction because patterns can change in a matter of hours...
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dennis1x1
i agree hyper....the SHIPS model predicted a 10 kt decrease 72 hours from 3 days ago....very good analysis from the SHIPS it appears.
the intensity models typically strengthen strenghten strengthen over time...when you see a substantial decrease down the road it should be taken into consideration..and it wasnt.
the best news is that the SHIPS brings her down ANOTHER 10mph over the next 24 hours....
the intensity models typically strengthen strenghten strengthen over time...when you see a substantial decrease down the road it should be taken into consideration..and it wasnt.
the best news is that the SHIPS brings her down ANOTHER 10mph over the next 24 hours....
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Hyperstorm
- Category 5
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- Location: Ocala, FL
dennis1x1 wrote:i agree hyper....the SHIPS model predicted a 10 kt decrease 72 hours from 3 days ago....very good analysis from the SHIPS it appears.
the intensity models typically strengthen strenghten strengthen over time...when you see a substantial decrease down the road it should be taken into consideration..and it wasnt.
the best news is that the SHIPS brings her down ANOTHER 10mph over the next 24 hours....
I agree. Very well said...
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