Thoughts on 2013 Atlantic Hurricane Season

[TheStormExpert]

Earlier today I was looking back at the Hurricane Frances thread and noticed speculation on whether he would be turned out to sea by a trough or manage to stay weak enough to not be influenced by it. The key this year will likely be timing of troughs, ridging, and the storms.

[blp]

JB's thoughts on twitter. Continues the 2004 comparison.

CFSV2 continues coldest August for US as a whole since 2004 missive. Euro in line with it pic.twitter.com/7Co0aJTVaN

[blp]

I think the thing you are forgetting is how quick the pressures rebuild over the NW Atlantic once these quick hitting, short wave troughs move through. The key is that these aren't huge sweeping troughs that are the length of the entire coastline. They are quick movers with a very short wavelength. Key difference there. This kind of pattern screams a threat to SE FL from the EAST.

I dont want to sound stupid but how come the chances of sfla getting hit are so high? I know the atlantic ridge is stronger this year but i see nothing but trof after trof coming off the east coast so far. Levi cowan on his tropical tidbits this afternoon showed a map of colder than normal temps forecasted during the month of august...which would imply cold fronts. To me it seems that storms should come closer to the US due to the stronger atlantic high but once they come close enough to the east coast they could turn in to the Carolinas due to all these fronts sweeping through the area. Would that be accurate or is there something I am missing?

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Sent from my HTC EVO 4G LTE

Good point. The type of trough will be very key.

[weatherwindow]

Good evening, everyone...an excellent thread with a perponderance of well reasoned posts. One of the reasons that storm2k remains such a magnet for tropical enthusiasts is that it has acquired and retained a core group of experienced, competent and enthusiastic regulars. Their ongoing contributions, both professional and amateur, result in lively, intelligent discussions which, in turn, attract a continuous stream of newcomers. They, in turn, refresh the discussion and keep the rest of us "honest". A rather special element, here at storm2k, is the respect accorded the "newbies" and their questions. Someone is always willing able to guide them and answer the questions. Anyway, hats off to all and back to the topic at hand.

Ridging and the absence thereof is always a hot topic at this stage of the season. Of late, the persistent ridging, which has dominated the early season, has been punctuated by a more progressive regime with the appearance of several east coast trofs. Lets be careful about seizing on this episode and assuming that it represents a longwave pattern change to persist thru the heart of the season. Yes, for the past few seasons and for many prior to 04-05, a persistent ridge-trof longwave pattern appeared and dominated the heart of those seasons. The trof axis lay over the eastern seaboard or just offshore. Short waves rotating thru the trof generated a persistent southerly to southwesterly midlevel flow resulting in the recurvature of most storms approaching the eastern seaboard. However, the evolving synoptic regime is appears to favor the axis of the longwave trof to shift significantly westward. This, in turn, allows the westward extension of Atlantic ridging, associated with the Bermuda high, to a position over and west of the southeast coast. If this regime verifies, it favors a persistent easterly to southeasterly midlevel flow and blocks recurvature of systems approaching the coast. This evolution is favored by a broad assortment of global and synoptic factors and by midrange guidance. As has been noted earlier, 2004 has been widely suggested as an analog.

As we all remember, the heart of the season was dominated by a blocking pattern resulting in a flurry of Florida landfalls. This pattern is similiar in many aspects to the pattern suggested above and featured persistent ridging over and west of the southeast coast courtesy of high pressure over the western Atlantic and New England. It is important to understand that even if this blocking pattern verifies in 2013, it does not mean that the east coast will be trof-free thru September. Even a stout ridge does not preclude the occasional shortwave from intervening on the coast. The strength and extent of the ridging that is being suggested is not a constant. There is a continuous flexing in the ridge associated with variations in the strength/position of high pressure. Referring to the concerns noted with the recent trofing, lets examine 2004. Early August 2004 exhibited a distinct trofiness. As Charley was approaching the south coast of Cuba and ultimately entering the GOM, an exceptionally strong trof, nearing 3 SD deeper than the norm, was diving southeast into the Gulf. This trof ultimately recurved Charley over the Florida peninsula. The atypical trof dove south to nearly 25degN, again unusual for August. Shortly, after Charley disappeared into the North Atlantic, the trofiness was replaced by the ridging which was to dominate the Western Atlantic and the east coast thru the end of September. The results were Frances, Ivan and Jeanne. Here again, let me emphasize that it is unlikely that the heart of the 2013 hurricane season will resemble all those seasons prior featuring recurvature. It is much more likely to feature multiple landfalls with Florida and the southeast coast in sharp focus....Grtz from KW, Rich

PS..Florida's situation is potentially bleaker than in 2004..as noted repeatedly, south Fla experiences more landfalls in October than any other month. Due to a developing El Nino in 2004, the Caribbean was shutdown for genesis by the end of August. SFla's October landfalls typically develop in the Western Caribbean and recurve over the Fla peninsula. The absence of an El Nino may open the Carib in October

[beoumont]

Below is the most proven long range (longer than 6 days) forecast method, without a doubt, for areas of landfall to come:



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In the recent term: pressures have come down a few mbs. in the tropical Atlantic the last couple of days, the ITCZ has migrated north a few degrees latitude, and the SAL has thinned out considerably. All quite typical as August moves along.

[TheStormExpert]

Here is The Weather Channel's August Temperature and Overall Pattern Outlook. Notice the position of the trough, and the Highs I drew in. The one over the Atlantic extends very close if not over the SE and Mid-Altantic U.S. This pattern would open the door for a landfalling TC along the SE U.S. especially Florida and the Northern Gulf Coast. Though this pattern could always change, I'm just posting what TWC thinks August may be like.

[Hurricaneman]

Here is The Weather Channel's August Temperature and Overall Pattern Outlook. Notice the position of the trough, and the Highs I drew in. The one over the Atlantic extends very close if not over the SE and Mid-Altantic U.S. This pattern would open the door for a landfalling TC along the SE U.S. especially Florida and the Northern Gulf Coast. Though this pattern could always change, I'm just posting what TWC thinks August may be like.

http://img5.imageshack.us/img5/8467/ednj.jpg

thats not a comforting pattern if you live along the Florida coast

[ninel conde]

mid levels continue very dry throughout the tropics

http://tropic.ssec.wisc.edu/real-time/s ... vmid&time=

[Blown Away]

No scientific, but in all my years living in SFL, I don't remember a hurricane strike in SFL when there was above average spring/summer rainfall for the year. This year SFL is above average for rainfall...

[ninel conde]

what was rainfall like last year?

[ninel conde]

what has gone wrong this year? its clear that the 400 mb in march doesnt mean alot. the east pac sst's are great for atlantic development. atlantic sst's are just fine. a multi year trend has continued in several areas. low instability and very dry mid level air.

[Hammy]

While my thoughts may change if something doesn't start showing up in the models soon, I will say that 1996, 1998, 1999, 2002, and 2010 all went through most if not all of the first two thirds of August with nothing and were still fairly busy.

[beoumont]

While my thoughts may change if something doesn't start showing up in the models soon, I will say that 1996, 1998, 1999, 2002, and 2010 all went through most if not all of the first two thirds of August with nothing and were still fairly busy.

The prime example for not getting too antsy early on is the 1961 hurricane season. There was only one named storm before Sept 2nd. By the end of the season there were 3 category #3 hurricanes, 2 category #4s, and 2 category #5s. In other words, what happens before mid August doesn't mean didly. Always keep hope alive.

.................................. . . . . . . . 1961 ...............................

[ninel conde]

on facebook larry cosgrove gives a 1 in 21 chance of erin forming from the bahamas and moving west the next few days.

[Hurricane Alexis]

on facebook larry cosgrove gives a 1 in 21 chance of erin forming from the bahamas and moving west the next few days.

I'm guessing from the ULL forecast to move into that area the next few days?

[Steve H.]

not that I always agree with Larry Cosgrove, at the pattern I'm seeing, something homegrown could be in the offing. The last Erin that I recall in 1995 did develop in the western Atlantic and came across central Florida and into the GOM.

[ninel conde]

on facebook larry cosgrove gives a 1 in 21 chance of erin forming from the bahamas and moving west the next few days.

I'm guessing from the ULL forecast to move into that area the next few days?

yep

[CYCLONE MIKE]

Our local nws office has been mentioning rain chances going up for this weekend for the past few days due to a tropical wave moving west through the gulf. Wonder if this is the same system?

[TropicalAnalystwx13]

on facebook larry cosgrove gives a 1 in 21 chance of erin forming from the bahamas and moving west the next few days.

I'm guessing from the ULL forecast to move into that area the next few days?

yep

No. The potential development is from a forecast stalled-out frontal boundary. Not an upper-level low.

[Sanibel]

TWC said the stalled boundary east of Florida won't develop due to NE shear.