2010 Hurricane Season: Slight Up-tick
February 5, 2010
After a quiet 2009 atlantic tropical season, all focus now points towards the 2010 season, which officially begins June 1.
Klotzbach and Gray have already released their early season forecast, calling for 11 – 16 named storms, of which 6 – 8 will form into hurricanes, and 3 – 5 which will reach intense status (category 3+). This indicates a slightly above “average” season. K/G is observing slightly higher SST’s forecasted for the beginning of the tropical season, along with a subsidence of the current moderate/significant El Niño conditions as we move to the hurricane season (though some of the CPC evaluations suggest a chance that it persists through the end of spring).
The Weather Research Center has also released their early forecast, calling for 8 named storms, and 5 hurricanes. WRC additionally forecasts a 90% chance of landfall in Western Florida, along with a 70% chance of landfall in Eastern Florida.
Check the Towers Watson Hurricane Blog (formerly Towers Perrin Hurricane Blog) for updated seasonal forecast info, headlines from the 2010 National Hurricane Conference, and public articles of interest.
Hurricane Ida making landfall in the U.S.
Ida reorganizes, early Tuesday landfall, heavy precip expected
November 9, 2009
Tropical Storm Ida is currently just below hurricane strength, with recorded sustained winds at 70 mph. Landfall is expected overnight, and rain bands north of the system are already affecting the Gulf Coast.
Earlier today, the system showed strong signs of weakening and transition due to moderate shear and cooler water temperatures along with some dry air entrainment. However, an afternoon burst of convection near the eye has allowed Ida to maintain strength, and the NHC forecasters expect the system to remain tropical in its characteristics overnight.
Post landfall, Ida will move sharply to the east as an extratropical system. The main threat from Ida will be flooding and potential severe thunderstorm activity inland as the moderate shear will feed convective aspects along with energy associated with the transition. Coastal regions are already preparing for potential flooding.
We will continue to monitor the system as it makes landfall.
Ida heads towards Gulf Coast: Tuesday morning Landfall expected
November 9, 2009
The NHC is predicting a Tuesday morning landfall for Hurricane Ida somewhere between the Mobile area and the Florida Panhandle. The most recent analysis (4:00 AM CST) shows roughly an equal chance of Ida making landfall as a Cat-1 or as a Tropical Storm.
Ida has become quite interesting in the last 6 hours. The system has moved into an area of increased shear and is being steered by a high pressure system over the North Carolina coast, and the exact landfall of Ida will be determined by the path this High takes. Because of the high, and interaction with increased shear, Ida will take a sharp turn to the east in the near future. The models seem to agree that this will occur post-landfall.
Additionally, Ida will continue to experience cooler waters as it nears the coast. This factor, along with a recent influx of dry air, has caused a significant amount of disorganization to the structure. The latest satellite imagery shows most of the heavy convection to the north of the center, just off the coast of AL and FL.
However, new imagery shows two new convective “flares” to the east and west of the central low pressure. Analysts are now debating whether Ida is going through a transition to Extratropical, or if it is simply reorganizing prior to landfall (which would support the NHC forecasts).
We will continue to monitor the system as the day goes on.
November Hurricane Activity
October 27, 2009
The “official” 2009 Atlantic Hurricane season is now winding down with 1 week and 1 month remaining until November 30. While uncommon, the southeast United States has experienced multiple November landfalls from tropical systems in the past.
The largest event occurred on November 21, 1985, when Hurricane Kate made landfall in the Florida Panhandle as a category-2 storm. The 1985 PCS estimates totalled $77 million dollars. This equates to $154 million if adjusted for inflation. The i-CAT damage estimator, which accounts for increases in inflation, exposure growth, and property values, estimates 2009 damage at $1.220 billion (includes non-PCS losses).
November Atlantic Tropical Activity (NOAA)
The 2009 season currently has recorded 8 Named Storms, 2 of which reached hurricane strength, and both which reached intense hurricane strength (>111 mph winds). These values are below most estimates from the forecasting experts. Only Claudette made landfall, as a moderate Tropical Storm.
Globally, Tropical Cyclone Accumulated Cyclone Energy (ACE) is running at low levels not seen in 30 years. The North Atlantic ACE value is 45% of the annual average (through 10/31).
Erika 5th storm of 2009 season
September 2, 2009
On September 1st at 5:00 PM EST, the 5th Tropical System of 2009, Erika, formed north of the Leeward Islands.
Erika is currently (as of 2:00 PM EST 9/2/09) exhibiting sustained winds of 40 mph and is moving West at 10 mph.
The NHC is forecasting Erika to remain a Tropical Storm thru Saturday morning. The models then have the system being affected by 20- 25 knot wind shear, and then it gets interesting. Some models show the system surviving the shear and quickly intensifying in the warm waters. Others, including the NHC, show a significant chance of dissipation, tropical depression strength, or sustaining tropical storm strength.
We will continue to monitor the situation as needed over the holiday weekend.
Danny hangs on by a nail, begins northward motion
August 28, 2009
Tropical Storm Danny has begun its northward motion based on the latest reconnaissance. Winds have dipped in many areas of the storm, however one region did record sustained winds of 40-45 mph, thus holding on to the “tropical storm” designation.
Danny may strengthen slightly as it moves under an area of moderate upper level convergence over the next 24 hours. However the system will then encounter strong shear associated with a surface front measuring around 35 knots, which will eventually convert Danny to an extra-tropical system at roughly 36 hours.
The chance of the east coast experiencing sustained tropical storm forced winds (35+ mph) is relatively low at this time.
You can see from the image below from Wunderblog just how much the storm has struggled with the shear affecting the convection. The areas of heaviest activity are well east of the central rotation, which has caused multiple reformations thus far.
Danny rests overnight, track shifts further east
August 28, 2009
Tropical Storm Danny continues to exhibit strange behavior and shape, but aircraft recon is still recording sustained winds around 40 mph in the strongest quadrants to the East of the low pressure center. Significant wind shear has kept most of the convection from forming around the low and hindered possible strengthening overnight.
Danny will encounter an upper level ridge which should provide enough stability to increase winds to 50 mph over the next 24 hours. However a deep surface trough will begin to overtake the storm and its forward, or rather northeastward motion will pick up speed.
Tropical Storm Watches remain in effect for the Outer Banks, but the probability of experiencing TS winds is relatively low at 20-30%. The TS wind speed probabilities for Cape Hatteras have decreased a bit as well for the weekend. Rip tides will again be present, though the wave activity is not as large as Bill, which was a strong Cat-2 (and growing) at a similar latitude last week.
GOES Floater 090828 1145UTC
Slightly weaker Danny begins slow movement North
August 27, 2009
The most recent hurricane aircraft recon has indicated that the winds from Tropical Storm Danny have become somewhat better organized in the western front. However the overall max sustained winds have weakened slightly to 50 mph.
Satellite imagery shows a strong presence of dry air to the west of the system. This will hold Danny’s intensity steady over the next 24 hours. The system will then unite with an upper level high which will provide a small window for potential strengthening in 24 – 36 hours.
Although some models are in disagreement, most do not predict Danny to reach hurricane strength.
The NHC forecast track has not changed significantly, and Tropical Storm Watches have been issued for the Outer Banks of NC. The forecast still brings Danny to Cape Hatteras late Saturday afternoon.
Water Vapor Image -click for loop-
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Unusual Danny continues to gain steam
August 27, 2009
Tropical Storm Danny continues to strengthen with sustained winds up to 60 mph as of 5:00 AM Thursday morning. Danny is displaying some odd wind fields, with the strongest winds being observed well North and East of the central low.
Satellite imagery indicates heavy convection in this area, with good counter-clockwise flow at the upper levels in the NE and NW. There is still no clear central rotation at the lower levels.
Despite the odd current configuration, the NHC is still forecasting Danny to reach hurricane status early Saturday morning east of the Outer Banks
The system will then increase in forward speed as it turns north and encounters a strong cold front over the Eastern US.
JSL Satellite Image -click for loop-
Bill weakens, waves dont as storm heads to Nova Scotia
August 21, 2009
The latest guidance from the NHC shows Bill has weakened slightly to a strong Cat-2 hurricane after encountering some moderate shear. There is a good chance the system will reorganize as shear diminishes and hits warmer waters Friday. However the forecast shows Bill slowing to a weak Cat-2/strong Cat-1 as Saturday progresses.
The forecast models are in good agreement on the track, taking Bill due North Friday night, before making a NE turn into Sunday.
The greatest threat to the US will be in the form of coastal erosion as high seas will affect the eastern seaboard from Florida to Maine. The highest expected seas will occur near Cape Cod, which could experience 20′ waves. The threat from rip currents is moderate and expected to increase as Bill travels North.
We will continue to monitor the system and provide updates as necessary.
