Saturday, August 13, 2011

Tropical Storm Franklin and other Atlantic blobs and blobettes: August 13, Update A

It’s really not my fault that I’m about to say this: I don’t agree with the NHC.

FAKE Tropical Storm Franklin was named at 5am EST this morning. In my opinion this is not a Tropical Storm. This is an area of circulation that is associated with a low pressure front that is moving across the northern Atlantic. It has convection. Next winter when I see a storm with circulation heading towards Europe (maybe a nice snow storm), I will make sure to send you all a picture of that ‘Tropical Storm’ too.

Why Fake Franklin isn’t a TS:

1. He developed at 37.9N. The tropics are from 30N to 30S.

2. He is moving NE at 20mph. Tropical Storms generally move at ~16-17 mph or slower. Fast moving low pressure fronts can cross the US in just under a week. They move at speeds of ~20mph or higher.

3. Water temperatures are 25-26 deg C. Tropical Storms need water of 26.5 deg to sustain them once they have formed, and at least that warm in forming.

4. The vorticity (fancy schmancy jargon to indicate the circulation) is not isolated (which is what we see in a Tropical Storm), but is connected to the vorticity of a low pressure front extending to the northeast Atlantic. I’ve included the visible satellite image to show you the front that this is connected to. “Fake Franklin” is that mass of clouds at ~40N, 60W.

5. His wind speed is estimated to be 40mph and his central pressure is estimated to be 1006mb. TS wind speed range: 39-73mph. He’s barely a TS by this definition, as 1mph is within the error margin. They say that satellite based estimates of wind speed are 30-35kts, which translates to 34.5-40.25mph (1 kt=1.15 mph). Hardly convincing. And anyway, mid-latitude cyclones can have higher wind speeds (gale force winds make for some gripping sailing in the north Atlantic!) and pressures as low as 970mb, so this is no indication.

Just because the seasonal forecast was increased to 19 named storms doesn’t mean that we need to make sure we have that many!! Grrr. It’s so so grrr… What a complete and utter waste of a name. This is the second one this season I think.

Now, about the other Atlantic Blobs and Blobettes:

They are all hovering around the 20-30% chance of forming. Oh and look! They are in the tropics over water temperatures of 26-30 deg C. That makes a change.

None of them have any decent circulation or convection at the moment. I was going to write about the wonderful and fascinating Saharan Air Layer (SAL) and its impact on these systems, but I think I’ll have a cup of tea and some English pancakes (hmm) and maybe talk about the SAL when I tell you what Fake Franklin is doing (mumble grumble).


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DISCLAIMER:These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know.

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