N. ATL Hurricane Season 2013 Discussions

[srainhoutx]

While we are still about 2 ½ months out from the beginning of the North Atlantic Hurricane Season, some trends are developing suggesting conditions may be a bit more conducive for development across the MDR and the Caribbean. The Updated Seasonal Eurosip will be out on March 15th and if the trends that the February Seasonal Eurosip suggested are correct, lower pressures are expected over the Western Atlantic and Caribbean. Other areas of note are somewhat higher SST’s across the MDR. While it is too soon to know with any certainty and remembering it only takes one land falling Hurricane to make for a very bad season, conditions do appear a bit more favorable for developing Tropical Cyclones. Colorado State University should be issuing their Season Forecast in early April.

[Ptarmigan]

March EURO Forecast.

2012


2013


2012 Euro forecasted higher than normal sea level pressure in the deep tropics. 2013 Euro forecasts normal sea level pressure for the deep tropics. This could mean a more active Caribbean and Gulf, which increases risk for landfall on the Gulf Coast.

[srainhoutx]

Some interesting trends via the March update of the Seasonal European Tropical forecast. The Eurosip suggest a much different pattern than what we saw last year with normal to lower pressures across the MDR and into the Caribbean and Gulf. It is noteworthy that the Eurosip is also suggesting lower pressure over Texas and near or slightly above normal temps and normal rainfall as well for the June/July/August time frame. We will see.

March 2013 MSLP

March 2012 MSLP

[Ptarmigan]

Some interesting trends via the March update of the Seasonal European Tropical forecast. The Eurosip suggest a much different pattern than what we saw last year with normal to lower pressures across the MDR and into the Caribbean and Gulf. It is noteworthy that the Eurosip is also suggesting lower pressure over Texas and near or slightly above normal temps and normal rainfall as well for the June/July/August time frame. We will see.

March 2013 MSLP

03222013 March Season Eurosip Tropics_tercile32summary_mean32sea32level32pressure_332months.gif

March 2012 MSLP

03222013 March 2012 Eurosip MSLP Tropics_tercile32summary_mean32sea32level32pressure_332months.gif

If the forecast is true, this summer could be wetter than normal. Hopefully that is the case. 2012 forecast showed higher than normal pressure, but it ended up being a wet July.

Summer 2011 was hot and dry despite the fact the sea level pressure slightly below average.

[unome]

SciGuy's blog today http://blog.chron.com/sciguy/2013/04/fo ... -atlantic/

with early thoughts from Gray and Klotzbach, Bastardi/Weatherbell & Weather Services International ( http://www.wsi.com/221144c3-0012-41a4-a ... etails.htm )

AMS sees ENSO neutrsl for at least the next 3 months http://www.bom.gov.au/climate/tropnote/tropnote.shtml
All dynamical models surveyed by the Bureau of Meteorology indicate neutral ENSO conditions are likely to continue throughout the autumn and winter months, although predictions through the April to June period are known to be less skilful. Four of the seven models suggest NINO3.4 will return to positive values by the end of winter, but still remain within the neutral range.

NOAA's early forecast comes out next month

WU's blog post by Dr Jeff Masters also inclused thoughts from Tropical Storm Risk, Inc. ( http://www.tropicalstormrisk.com/ )
http://www.wunderground.com/blog/JeffMa ... rynum=2381

[Katdaddy]

It might be cold and rather Wintry evening but the 2013 Hurricane Season is 51 days out. Its time to start thinking "What If" and getting a plan ready just in case.

My concern has been another Middle TX Coast hit by large CAT 3 or greater tropical cyclone. That will be the worst case scenario for the Upper TX Coast. Rita 2005 was frightening as she entered the GOM and was forecast to slam the Middle TX Coast but thankfully recurved more NNW into extreme SW LA. IKE was another extreme concern but went inland just E of Galveston. As bad as IKE was, it could have been much worse. The surge was a CAT 4 but the widespread winds were CAT 1.
Bring IKE 30 miles SW down the coast to Freeport and increase the sustained winds to 160MPH and the outcome would have much different.

2013 make 52 years since Carla slammed the Middle TX Coast. Its only a matter of time

[sambucol]

I'm somewhat concerned about our area for this hurricane season.

[srainhoutx]

I'm somewhat concerned about our area for this hurricane season.

One of the factors that early indicators are suggesting is that the Caribbean may well be a bit less hostile than 2012 and that tends to favor more activity potential for the Gulf.

[srainhoutx]

The latest EUROSIP seasonal long range forecast released April 22nd suggests lower pressures across the Caribbean and Gulf through September. That is certainly a change from last year.

[wxman57]

The August-September-October Euro Mean Sea Level pressure anomaly forecast has higher pressures over the Subtropical Atlantic and not as high pressures in the MDR westward to the Gulf. Not lower-than-normal, but not as high as farther north. Suggests less activity in the subtropics and more activity farther south in the deep tropics in 2013.

[srainhoutx]

As we near the mid point of May, there have been some indications via the long range ensemble guidance that pressures will lower across the Western Caribbean and Eastern Pacific as the Continental jet stream pattern lifts N and our typical monsoonal tropical troughiness develops along and just N of South America. There have been some indications that a more favorable MJO pulse may arrive during the later half of May into early June that may aid tropical development the EPAC or Western North Atlantic Basin. We will see.

[sambucol]

The heavy hitters who discuss Indian Ocean convection, Kelvin waves, MJO and the such, seem to think the GFS is a bit too fast with progressing the MJO into our part of the planet, but most seem to think it'll get here in June.

So, considering smart people with advanced degrees think the GFS is sort of correct but too fast, I present the first Phantom/Fantasy (Phantasy) Cane of 2013. Well, phantasy TC, anyway,




My lawn only got half an inch of rain today, the Western Gulf isn't warm, a weak little TC, as long as it doesn't go all Allison in early June would be fine by me.

Does the MJO mean more hurricanes? And will that up our chances of a storm this season when it gets here in June?

[Paul Robison]

The heavy hitters who discuss Indian Ocean convection, Kelvin waves, MJO and the such, seem to think the GFS is a bit too fast with progressing the MJO into our part of the planet, but most seem to think it'll get here in June.

So, considering smart people with advanced degrees think the GFS is sort of correct but too fast, I present the first Phantom/Fantasy (Phantasy) Cane of 2013. Well, phantasy TC, anyway,




My lawn only got half an inch of rain today, the Western Gulf isn't warm, a weak little TC, as long as it doesn't go all Allison in early June would be fine by me.

Does the MJO mean more hurricanes? And will that up our chances of a storm this season when it gets here in June?

Appears so, friend, take a look at what HGX says in today's WX discussion:


UPPER RIDGE EXPANDS UP OUT OF MEXICO THURSDAY THROUGH SUNDAY WITH
THE 500 RIDGE CENTERED OVER SETX SATURDAY AN SUNDAY. THIS SHOULD
LEAD TO WARMER TEMPERATURES RETURNING AND HAVE GONE ABOVE GUIDANCE
FOR THE AFTERNOON FRI-SUN TIMEFRAME TEMPERATURES. RAIN CHANCES
FALL OFF AND MOIST SOUTHEAST FLOW RESUMES. ALSO OF INTEREST LOOKS
TO BE A TROPICAL WAVE MOVING OUT OF THE CARIBBEAN AND POSSIBLY
IMPACTING SETX AND WESTERN GULF MONDAY AND TUESDAY NEXT WEEK.


Anybody think this will ramp up into a very strong Alicia or Rita-type storm? Is it worth losing any sleep over?

[Paul Robison]

The heavy hitters who discuss Indian Ocean convection, Kelvin waves, MJO and the such, seem to think the GFS is a bit too fast with progressing the MJO into our part of the planet, but most seem to think it'll get here in June.

So, considering smart people with advanced degrees think the GFS is sort of correct but too fast, I present the first Phantom/Fantasy (Phantasy) Cane of 2013. Well, phantasy TC, anyway,




My lawn only got half an inch of rain today, the Western Gulf isn't warm, a weak little TC, as long as it doesn't go all Allison in early June would be fine by me.

Does the MJO mean more hurricanes? And will that up our chances of a storm this season when it gets here in June?

Funny HGX should mention that:

UPPER RIDGE EXPANDS UP OUT OF MEXICO THURSDAY THROUGH SUNDAY WITH
THE 500 RIDGE CENTERED OVER SETX SATURDAY AN SUNDAY. THIS SHOULD
LEAD TO WARMER TEMPERATURES RETURNING AND HAVE GONE ABOVE GUIDANCE
FOR THE AFTERNOON FRI-SUN TIMEFRAME TEMPERATURES. RAIN CHANCES
FALL OFF AND MOIST SOUTHEAST FLOW RESUMES. ALSO OF INTEREST LOOKS
TO BE A TROPICAL WAVE MOVING OUT OF THE CARIBBEAN AND POSSIBLY
IMPACTING SETX AND WESTERN GULF MONDAY AND TUESDAY NEXT WEEK.

[srainhoutx]

In its 2013 Atlantic hurricane season outlook issued today, NOAA’s Climate Prediction Center is forecasting an active or extremely active season this year.

For the six-month hurricane season, which begins June 1, NOAA’s Atlantic Hurricane Season Outlook says there is a 70 percent likelihood of 13 to 20 named storms (winds of 39 mph or higher), of which 7 to 11 could become hurricanes (winds of 74 mph or higher), including 3 to 6 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher).

These ranges are well above the seasonal average of 12 named storms, 6 hurricanes and 3 major hurricanes.

http://www.noaanews.noaa.gov/stories201 ... antic.html

[srainhoutx]

The 12Z Euro is suggesting a tropical wave may move generally W across the Gulf during the first few days of June. While any development appears very unlikely due to higher wind shear, it does serve as a reminder that Hurricane Season is upon us once again. We will see.

[srainhoutx]

While we are still a week away and things can and certainly do change, as experienced yesterday across S Central Texas abundant tropical moisture is pooling as the monsoonal trough begins to lift N and embedded disturbance fester near the Gulf of Tehuantepec and the Western Caribbean as well as the Bay of Campeche in the next 7-10 days. NWS Houston/Galveston does mention this area as pressures lower and the weak upper ridging develops over the SE United States. One point of interest will be the rather persistent troughing to our W and an area of weakening along the western flack of the SE upper ridge. The models are already 'sniffing' some development potential, but a big mean tropical cyclone doesn't appear to be in the cards ~vs~ increasing chance of an area of disturbed weather (tropical wave) moving across the Gulf. What this could mean is an increase in more tropical rains for Louisiana and Texas as we begin the first half June.

HGX:

THE EXTENDED (EARLY JUNE) PATTERN BECOMES INTERESTING...ESPECIALLY
IN THE TROPICS/CARIBBEAN. WHEREAS ANY WESTERN DISTURBANCE SHOULD
REMAIN OFF ACROSS THE NORTHERN PLAINS PER SOUTHERN PLAINS WEAK
RIDGING...THE SOUTHEASTERN GULF CHANNEL BETWEEN THE YUCATAN AND
THE FLORIDA KEYS IS BEING MODELED TO BECOME INCREASINGLY MORE
UNSETTLED. NOT APPEARING TO BE A CLEAR-CUT TUTT AS OF NOW...BUT
MORE OF LOWERING PRESSURES/HEIGHTS THAT EVOLVE NORTHEAST TOWARDS
THE KEYS THROUGH DAY 10. MAY BE SOMETHING TO FOCUS ON AS WE HEAD
INTO THE OFFICIAL START OF THE 2013 HURRICANE SEASON.

[srainhoutx]

As Jeff mentioned in his morning e-mail, we'll need to monitor the Western Caribbean and Bay Of Campeche as the weekend unfolds into next week. The monsoonal trough is becoming rather active as a Kelvin Wave progresses E and pressure lower across those areas. The increased tropical moisture from TS Barbara flowing E from the Eastern Pacific is evident this morning and increased convection is firing along the E Coast of the Yucatan.

[srainhoutx]

Update from Jeff:

Saturday, June 1 marks the start of the 2013 hurricane season in the Atlantic basin which includes the Gulf of Mexico and Caribbean Sea. As widely noted over the past few days the 2013 season is expected to be active to extremely active with the number of named storms likely exceeding the historical 30 year average of 12. The forecast calls for:

13-20 named storms (tropical storms)

7-11 hurricanes

3-6 major hurricane (category 3 or higher)

Both atmospheric and ocean conditions across the Atlantic and Pacific are looking favorable to very favorable for tropical cyclone formation, but it should be clearly understood that the forecast for an active hurricane season does not indicate where or if a tropical cyclone will impact the coast.

The following factors/indicators point toward an active season:

1. Warmer than normal Atlantic sea surface temperatures especially in the region between the African coast and the eastern Caribbean Sea where tropical cyclones tend to generate in the late July-mid September period. Warm water temperatures add more “fuel” for tropical cyclone formation and intensification.

2. Forecasted sea level pressures in the area from Africa to central America are expected to be near normal during the peak time (Aug-Oct.) this year suggesting favorable conditions for tropical cyclone formation

3. The lack of any significant El Nino event in the Pacific Ocean is another favorable factor which helps to limit wind shear effects on Atlantic tropical systems.

4. The Atlantic Basin has been in an active state since 1995 (known as the Atlantic Warm Phase) in which hurricane seasons tend to be more active with stronger storms.

While these factors point toward an active hurricane season they do not help to indicate where the greatest risk for landfalling systems may be. For this reason it is advised that all coastal regions have a hurricane plan and kit and make sure those kits are stocked and ready to be used should a tropical system threaten your area.

A few items to keep in mind:

Tropical systems are not a point and have far reaching effects and impacts. The typical error cone shown in National Hurricane Center graphics does not represent the location of impacts, but the error in the forecast track over the past 5 years at the forecast point in time. For example the update error circles for 2013 (2008-2012) are:

12hr - 33 miles

24hr - 52 miles

36hr - 72 miles

48hr - 92 miles

72hr - 128 miles

96hr - 177 miles

120hr – 229 miles

Preparation should be the same across the entire error cone regardless of where the center is expected to landfall.

Recent destructive hurricanes have shown the ability of storm surge to inundate and destroy coastal locations (Katrina, Ike, Rita, and Sandy). The forecasted storm surge is a combination of several factors including the coastal topography, the forward motion, and intensity, and most importantly the radius (how far) the strong winds extend from the center. It is incredibly important that residents focus on the forecast of storm surge and not the hurricane category. The category is a wind based scale and does not indicate the storm surge threat. Storm surge forecast will be impact based and noted in both above mean sea level and above ground level.

Computer model guidance is now widely available on the internet and via many media. Model guidance is just that…guidance…it is NOT “what is going to happen”. For anyone who has followed model tracks and guidance they can greatly vary between each model run (every 6 hours). Hurricane forecasters do not make big jumps each time the models jump one way or the other to avoid the “flip flop” effect. Widely varying solutions tend to lead to lower confidence forecast tracks while tight clustering suggest good agreement and higher forecaster confidence on the track. While model guidance is far from prefect, it is significantly better especially on the track forecast than even just a few years ago. Intensity forecast still have large error especially when concerned with rapid intensification which tends to be under-forecast on the models. This is generally a result of a lack of understanding of inner core dynamics.

[srainhoutx]

The 12Z GFS suggests that EPAC TS Barbara remnants will cross the Isthmus of Tehuantepec into the Bay of Campeche and slowly strengthen as it heads generally N to NNE in the Western Gulf early next week.