Atlantic Tropical Action 2014

[Amped]

Do systems that only make it to TD status count?

Regardless, TD#2 was likely briefly a TS at its peak.

I dont know, because its just an arbitrary stat. As long as we dont count them any other year either, I think its fine.

[Weathergun]

86kt FL wind and 72kt SFMR wind found in NE quad of Bertha
 

NOAA VDM reported a partial eyewall. AF Dropsonde also reported a surface wind of 83kts in the NE Quad. Probably a gust. But I think Bertha is 70-75kt hurricane.

[LongBeachSurfFreak]

Only concerning thing from an intensification standpoint is the appearance that the low-level circulation is running away from the convection in the eastern and southern quadrant. Northwesterly shear might not be soon to give way if the system to its west continues to produce deep convection. The most recent runs of the HRRR have been suggesting that Bertha might run away from the current convective plume over the center, so keep an eye on it. 

 

 

Amazing that this is what the Atlantic has become the past two seasons. Just look at this images posted in the WPAC thread. 

 

I remain excited for Bertha putting on a nice round of deepening the next 24 hours. It might even over-preform a little up into the 80kt range. 25-35 north has been the only real intensification region. And shes nice and close to the Gulf Stream. 

[Weathergun]

Official 11am: Hurricane Bertha winds 80mph. NHC believes its leveled off, though.

[IsentropicLift]

It's amazing that the globals can't predict convection correctly 12 hours in advance but yet can lock onto a TC track ten days out. Never once has this track ever waivered.

[phil882]

I'm kinda shocked Bertha has rapidly intensified the last 24 hours (was 40 knots yesterday at this time). Somehow the storm managed to develop a very tight inner core. Even though the pressure (998 hPa) is fairly unimpressive, those winds are being enhanced by higher than normal environmental pressure (somewhere around 1016 hPa), as well as the rapid forward motion of Bertha. 

 

There are some things working in Bertha's favor that could have foreshadowed this:

 

1) SSTs are around 29 degrees C, the warmest Bertha will ever experience. 

 

2) The shear vector, northwesterly, is actually advecting deep moisture over Bertha. That's why dry air intrusion has been kept to a minimum the last 24 hours or so. If that shear vector moves to northeast, however, there is more dry air in Bertha's proximity in that direction and that would likely lead to the end of intensification. Note the arc clouds emanating from Bertha in that direction... thats the dry air waiting to be entrained into Bertha if the shear vector changes.

 

With that said, I thought Bertha would struggle to maintain convection near the low-level circulation. I'm quite surprised its fought off that (possibly helped because the system to its west didn't produce major burst of deep convection last night). 

[Floydbuster]

As crappy as Bertha is, theres a good chance of it reaching Cat1. I dont know when the last time the first 2 storms of the season became hurricanes was.

 

1983

[IsentropicLift]

IR loop looks more like an open wave then a cane

 

[IsentropicLift]

The system over SW Florida looks better on IR then Bertha.

[U_Thant]

One of the worst presentations of a hurricane (albeit minimum) I think I've ever seen in my life.

 

Bertha's presentation may be more craptacular than the GOMEX's Hurricane Earl of 1998

[PSUBlizzicane2007]

Bertha's presentation may be more craptacular than the GOMEX's Hurricane Earl of 1998

I don't think any will ever beat Earl. A cat 2 Hurricane with an exposed llc lol

[U_Thant]

I don't think any will ever beat Earl. A cat 2 Hurricane with an exposed llc lol

[Superstorm93]

The system off of Florida is actually modifying the overall flow of Hurricane Bertha this afternoon.

Should begin to inject drier air into the circulation as it races to the NE. Definitely was an interesting case of a strong LLC taking advantage of marginally favorable conditions.

IMO, The SW Atlantic should be the region with the highest ACE this season.

 

[CUmet]

Judging from the burst-like IR pattern, microwave imagery depicting a highly asymmetric structure, and aircraft observations of rain rate, this appears to have been an asymmetric RI case.  These asymmetric RI events do occasionally occur (see papers on Irene 1999 and Gabrielle 2001).  Often times with sheared TCs, you see a large convective burst on one side of the vortex due to the shear tilting over the vortex and forcing vertical motion on that side.  Every once in a while, that convective burst (for reasons unknown) happens to be closer to the TC center inside the RMW.  Convection inside the RMW favors rapid intensification, based on theoretical arguments and supported by observations.

If the shear doesn't decrease though, the shear eventually wins out and the RI can come to a spectacular end.  This may be what is occurring now, as convection has greatly weakened over the past few hours.  We'll have to see if a new burst forms once the boundary layer moistens and recovers in the wake of the outflow (seen by the arc clouds racing northwards).

[N. OF PIKE]

I better get swell from this at ruggles /newport thursday! What you think Long Island surf poster

[IsentropicLift]

Down to 75MPH

 

000
WTNT33 KNHC 042041
TCPAT3

BULLETIN
HURRICANE BERTHA ADVISORY NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL032014
500 PM EDT MON AUG 04 2014

...BERTHA CONTINUES NORTHWARD...
...NO THREAT TO LAND...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...29.4N 73.6W
ABOUT 560 MI...900 KM WSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 500 PM EDT...2100 UTC...THE CENTER OF HURRICANE BERTHA WAS
LOCATED NEAR LATITUDE 29.4 NORTH...LONGITUDE 73.6 WEST.  BERTHA IS
MOVING TOWARD THE NORTH NEAR 18 MPH...30 KM/H...AND A GRADUAL TURN
TOWARD THE NORTHEAST WITH INCREASING FORWARD SPEED IS EXPECTED OVER
THE NEXT 48 HOURS.  ON THE FORECAST TRACK...BERTHA WILL PASS ABOUT
MIDWAY BETWEEN THE U.S. EAST COAST AND BERMUDA ON TUESDAY.

MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 75 MPH...120
KM/H...WITH HIGHER GUSTS...OVER A SMALL AREA NORTHEAST OF THE
CENTER.  GRADUAL WEAKENING IS FORECAST DURING THE NEXT 48 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 25 MILES...35 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140
MILES...220 KM...MAINLY TO THE NORTHEAST AND EAST OF THE CENTER.

THE MINIMUM CENTRAL PRESSURE ESTIMATED FROM NOAA HURRICANE HUNTER
AIRCRAFT OBSERVATIONS IS 998 MB...29.47 INCHES.


HAZARDS AFFECTING LAND
----------------------
NONE.


NEXT ADVISORY
-------------
NEXT COMPLETE ADVISORY...1100 PM EDT.
 

[IsentropicLift]

NHC forecasting 50kts of vertical wind shear in about 36 hours. Game Over. Discussion suggesting that it might already be an open wave. Waiting for recon.

[icebreaker5221]

I did a bit of quick research and not taking into account of the current ENSO state (La Nina/El Nino be they weak, neutral or strong) AMO, PDO NAO, EPO and AO, but strictly based off the Day 11+ Analogs issued July 31st with the top 10 Analogs years that are somewhat correlated with the current upper air pattern regime expected...and this is what those analogs suggest...tropical cyclone wise. There are some notable Hurricanes within those analog years. The analogs just offer clues to past general weather patterns across North America and what happened during the analog years across the Tropical North Atlantic Basin.

 

CPC July 31st Day 11+ Analogs:

07312014 CPC Day 11+ Analogs 814analog_off.gif

 

1975:

08012014 1975 NALT Hurricanes 1280px-1975_Atlantic_hurricane_season_map.png

 

1958:

08012014 1958_Atlantic_hurricane_season_map.png

 

1985:

08012014 1985 1280px-1985_Atlantic_hurricane_season_map.png

 

2005:

08012014 2005_Atlantic_hurricane_season_summary_map.png

 

1951:

08012014 1951_Atlantic_hurricane_season_map.png

 

2008:

08012014 2008 2008_Atlantic_hurricane_season_summary_map.png

 

1983:

08012014 1983 1280px-1983_Atlantic_hurricane_season_map.png

 

1991:

08012014 1991 1280px-1991_Atlantic_hurricane_season_map.png

 

1999:

08012014 1999_Atlantic_hurricane_season_map.png

 

1961:

08012014 1961 1280px-1961_Atlantic_hurricane_season_map.png

 

 

Interestingly, 1961, 1999, 2005 and 2008 all remain top analogues still, with 2008 actually on there twice this time.  I don't think a 500 mb analogue technique has much merit for genesis or TC activity (although it probably does a little bit, e.g. strength of trough/ridge over N Africa and effect on SAL / easterly wave activity), but it can definitely provide some clues for steering flow. 

 

That said, all 4 of those seasons had a significant TC for Texas:

1961 (Carla)

1999 (Bret)

2005 (Rita)

2008 (Ike)

 

Let's see what happens...

 

[Amped]

1983

Thanks. Not a very active season, did have Alicia though.

[GaWx]

 IF the just released Euro weeklies are accurate for mid to late August, there would be no long lasting above normal heat in the SE though there could be in the NE with a little above normal 500 mb ridging centered nearby. The SE would be below that ridging, which would keep it from getting too hot for too long there. Also, with this setup, IF there are any tropical cyclones offshore the SE coast, this/these may not recurve easily off the SE as is the case with Bertha. Looking at precip. anomalies, the weeklies have the tropics pretty dry overall for weeks 2-4 with wetter above that in the subtropics in the general vicinity of 25-30 N over/near the SE US.

[Superstorm93]

Disturbance off of Florida looks better than a 65 knot hurricane. 

 

These are strange times...

 

[AvantHiatus]

NHC is not required to differentiate between gradient winds and heat exchange winds from the TC. Bertha is not really a 65kt cane by itself, it is embedded in the anomalous WAR (West Atlantic Ridge). Hopefully this warrants some attention in the post-season analysis.

 

[bluewave]

Driest air at 500 mb over the Tropical Atlantic between 10-20 north on record for the month of July.

It was also the record driest July for the whole Tropical Atlantic region at 500 mb. This follows

the general long term June-September drying trend.

 

 

 

 

 

 

 

 

 

[thewxmann]

Driest air at 500 mb over the Tropical Atlantic between 10-20 north on record for the month of July.

It was also the record driest July for the whole Tropical Atlantic region at 500 mb. This follows

the general long term June-September drying trend.

 

DRY.png

 

TAJUL.png

 

JJAS.png

 

Based on those charts it's safe to say this season has overperformed. Pretty good.

[LongBeachSurfFreak]

I better get swell from this at ruggles /newport thursday! What you think Long Island surf poster

 

I wouldn't wait until Thursday. Tomorrow is the day. What ever swell is left Thursday will be from a weakening recurring storm. The swell for tomorrow has already been generated when Bertha was at peak intensity moving directly at us in Southern NE/LI which created a nice period of captured fetch. This period of captured fetch and the fact that all the strongest winds were on the side of the storm pointed at use should turn some heads swell size wise tomorrow. For what looked like such a mess the interaction with the WAR is going to have NE/LI surfers very very happy tomorrow!

[Zeus]

Fact: the little wave approaching the Lesser Antilles is adorable.

[icebreaker5221]

Driest air at 500 mb over the Tropical Atlantic between 10-20 north on record for the month of July.

It was also the record driest July for the whole Tropical Atlantic region at 500 mb. This follows

the general long term June-September drying trend.

 

I would be careful in my interpretation of that.  Without a doubt, the last several seasons have been drier than normal; but NCEP/NCAR reanalysis also shows a drying trend for most of the globe, with many regions shown to be 10% or more drier now than they were in the 50s.  I don't believe ERAI shows a similar pattern globally (even accounting for the fact that ERAI only goes back to 1979). 

 

That extreme moistening over Nino 1-2 also looks suspect to me.

 

[wxmx]

It is becoming more clear now that we won't have El Niño for the rest of the hurricane season, other than maybe the tail end. CFS v2 graphics have correctly forecasted an improved upper level shear environment over the MDR since it switched to mostly below normal around mid July. The shear forecasts continue to show below normal shear for the rest of the season.

 

Above normal MSLP, strong trades and dry atmospheric conditions have been plaguing the MDR, and they will probably continue to do so, but models are suggesting that average MSLP will take control in the short and mid range, which would slacken the trade winds.

 

Overall it appears that we are heading for a near average season, instead of the well below most expected before the start of the season. 

[jconsor]

Too bad there's no more recon and no buoys nearby.  Bertha is lighting up over the Gulf Stream.  I think there's a decent chance it re-attains hurricane intensity, with about 24 hours left over 26C+ SSTs.

 

http://www.opc.ncep.noaa.gov/lightning/index.php?basin=atl&sector=s&sat=IR&loop=1#contents

 

HRRR suggests strengthening next 12 hours as well.

[Superstorm93]

Just a little aside here, but it looks like the Caribbean has dramatically dropped in shear over the past few days. In addition, TCHP/OHC is relatively high for this time of year throughout the region. My main focus for a major system still remains to be the SW Atlantic over the coming weeks, however it would not surprise me at all if we see one red-meat tropical cyclone moving through the Caribbean at some point over the next 14-21 days. 

 

 

 

The CFS (Courtesy of Kyle Macritch) shows the MJO heading into our most favorable regions in addition to shear dropping below average from 40-80W (10N-20N) 

 

 

 

We already have a decent wave entering the Caribbean, but it'll be interesting to see whether or not the Caribbean does indeed become favorable enough to support a TC.