Bertha Becomes a Ragged Hurricane and We Start Looking West
(updated 11:25 pm ET) Most of the forecast (track and intensity) has held up over the last 24 hours, but Bertha has not kept all of her belongings together. As the sun set this evening, a ragged and naked center became apparent protruding from the northern side of recent bursts of convection. Winds remain at 75 mph, and thus this is a category 1 hurricane, but appearance is more like that of a highly sheared tropical storm. Thankfully appearance does not go into the error figures at the end of the season.
Early this morning and into the early afternoon the aircraft reconnaissance found truly impressive winds upwards of 85 mph at the surface. There is some theory that downdrafts in the core of Bertha caused higher winds. These winds evaporated this afternoon, and recent recon shows winds in the high tropical storm force winds range (65- 70 mph). Water temperatures are cooler than the earlier SHIPS guidance previously showed. Although humidity remains high, shear is also high as evidenced with the satellite appearance above. The trough is clearly evident to the west of Bertha. This shear is only forecast to increase as the east trough takes a more prominent role in Bertha’s future. I think upper divergence overpowered lower convergence surrounding this system, which has led in part to the demise of Bertha.
11pm Information from the NHC (Official):
- Winds: 75 mph
- Pressure: 1001 mb
- Movement: NNE at 20 mph
- TS WARNINGS: None
- TS Watches: None
- Gusty winds and rain are possible on the eastern end of Newfoundland in Canada. Confidence is low.
- Waves will increase on the east coast to 5-8 feet well off the coast of New England. Possibly up to 3 or 4 feet near shore.
What’s Next For Bertha?
The track forecast remains pretty straightforward with a track between the Bermuda High and the east coast trough. Bertha will become more entrenched in the east coast trough, and with wind speeds in that trough pushing 100 mph, Bertha is sure to accelerate toward the north Atlantic. Most – 95% – of the track models keep Bertha off the coast of Newfoundland with the closest approach occurring on Thursday. The way that Bertha is going, we may not be talking about a tropical system by that time.
I think that the time for intensification is over, and the future is much more bleak than it was yesterday.
The Future Is Very Interesting in the Central Pacific:
The above hurricane is Hurricane Iselle, which is currently traversing the eastern Pacific. It may look beautiful now, but it may also be the first of two impacts on Hawaii this month, which makes it terrifying. Thankfully shear and slightly lower SSTs will keep Iselle in check. The current forecast from the NHC calls for Iselle to move through the Hawaiian chain as a weak to moderate tropical storm.
Something that also makes Iselle unique is that it is close to being called an Annular Hurricane, which is a rare type of hurricane especially in the central pacific. The Central Pacific Hurricane Center may inherit this hurricane some time tomorrow morning as it crosses 140°W. What is an annular hurricane? Check out this week’s Meteorology Mumbo.
I said this was the first of two hits for Hawai’i this month The second one comes from Julio in the middle of next week. Two systems in roughly one week’s time is pretty rare as the basin sees a whopping 4-5 storms in the whole basin during the year. The picture above shows the aggregate possibility of tropical storm force winds from the two storms over the next five days. These probabilities for Hawaii will increase as the storms get closer to the islands.
I’ll be watching these three storms this week, and I have updated the information on Bertha at 11pm ET.
Posted on Monday, August 4th, 2014, in Tropical Weather. Bookmark the permalink. Leave a comment.
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