Dr. Jeff Masters' WunderBlog

Hurricane Irene pounds Puerto Rico, heads for Hispaniola

Posted by: Dr. Jeff Masters, 14:40 GMT le 22 août 2011

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Hurricane Irene strengthened into the season's first Atlantic hurricane at 5am EDT this morning as the eye moved over San Juan, Puerto Rico, and crossed into the ocean just north of the island. Overnight, Irene held its own as the eye passed over the most mountainous portion of Puerto Rico, the El Yunque region. Winds in the higher mountains likely reached Category 2 strength, 96 - 110 mph, according to measurements from the San Juan Terminal Doppler Radar, and the hurricane pounded the island with damaging winds and flooding rains, resulting in widespread tree damage and power failures that hit 800,000 people. The San Juan Airport recorded top winds of 41 mph, gusting to 55 mph, and 2.87" of rain, as of 9am AST. Tropical storm conditions affected the Virgin Islands, with St. Thomas recording sustained winds of 40 mph, gusting to 67 mph, and 4.03" of rain as of 6am AST today. At 7am EDT, the ship Horizon Trader measured sustained northeast winds of 69 mph and wave heights of 11.5 feet at 19°N, in the northern eyewall of Irene. Latest observations from an Air Force hurricane hunter aircraft indicate that Irene is slowly intensifying, with a central pressure of 989 mb observed at 9:42am EDT. The eyewall is not fully formed yet, with a gap on the south side. This gap will need to close off before the hurricane can undergo rapid intensification.

Figure 1. A direct hit: the center of Hurricane Irene passed directly over the Terminal Doppler Radar at San Juan, Puerto Rico between 4am and 5am AST this morning.

Track forecast for Irene
The computer models show good agreement that Irene will pass along the north coast of Hispaniola today, but just a slight wobble in Irene's track to take it farther offshore--or push it onshore, over the mountains--will have major impacts on the ultimate path and strength of the hurricane. A trough of low pressure is expected to move across the Eastern U.S. on Wednesday and Thursday, turning Irene more to the northwest by Wednesday. The timing and strength of this trough varies considerably from model to model, and will be critical in determining where and when Irene will turn to the north. Irene's strength will also matter--a stronger Irene is more likely to turn northward earlier. The most popular solution among the models is to take Irene to the northwest through the Bahamas on Wednesday and Thursday, then into the Southeast U.S. coast in South Carolina or North Carolina on Saturday. Irene would then travel up the mid-Atlantic coast, arriving near Long Island, New York on Monday morning as a strong tropical storm or Category 1 hurricane. One of the models proposing this solution is our best model, the ECMWF. However, we have two other of our very good models suggesting a landfall near Miami on Thursday night is likely (the GFDL and UKMET models.) NHC forecaster Stacy Stewart gave some good reasons in this morning's discussion to favor a track close to the east coast of Florida, but just offshore. Last years' worst performing major the model, the NOGAPS, predicts that Irene will pass out to sea, missing the Southeast U.S. coast. Keep in mind that the average error of a 4-day forecast from NHC is 200 miles, and just a small deviation in the path of a storm moving roughly parallel to the coast will make a huge difference in where it ultimately makes landfall. The NOAA jet will be flying its first dropsonde mission into Irene today, which should result in a more reliable set of model runs first thing Tuesday morning.

Intensity forecast for Irene
Irene is embedded in a large envelope of moisture now, and wind shear is expected to remain low, 5 - 10 knots, for the next five days. With water temperatures very warm, 29 - 30°C, these conditions should allow for intensification except when land is interfering. Satellite loops show that Irene is steadily growing in size, which will protect the storm against major disruption by its passage along the north shore of Hispaniola today. The storm is lacking much development on its southwest side, where dry air is interfering with development. This dry air may help keep southern portions of the Dominican Republic and Haiti from receiving more than 3 - 6 inches of rain. There is at least a 30% chance that passage of the eye over Hispaniola will reduce Irene to a tropical storm tonight and into Tuesday. Due to Hispaniola blocking inflow of moist air from the south, Irene will likely compensate by building an even larger region of heavy thunderstorms to the north, offshore. Thus, when Irene's center finally moves well away from the coast on Tuesday, it will be a bigger storm, with the potential to spread hurricane conditions over a wider area later in the week when it intensifies. One limiting factor for intensification may be in the upper-level outflow pattern. The hurricane is lifting a huge amount of air from the surface to the upper atmosphere, and all that mass has to be efficiently transported away in order for the hurricane to intensify. Right now, upper level outflow is only well-established to the north and east, and the forecast outflow pattern for the coming five days is only moderately favorable. Overall, I think the official NHC forecast of a Category 3 hurricane by Thursday is the right one, though Irene could easily be a Category 2 or Category 4 storm.

Irene's impact on the Dominican Republic
Heavy rains from Irene have already reached the eastern tip of the Dominican Republic, where Punta Cana has seen wind gusts up to 29 mph this morning. The northeast coast of the country near Samana will receive the worst of Irene's wrath, with sustained winds of 50 - 70 mph and gusts above hurricane force likely to cause widespread tree damage and power outages today. Passage along the coast of the island may weaken Irene to a tropical storm by Tuesday morning, and wind damage in Puerto Plata may be less severe than at Samana. The capital of Santo Domingo will see lesser winds, perhaps 30 - 50 mph, with gusts to 60 mph. The main danger to the Dominican Republic will be Irene's torrential rains, which are likely to reach 20 inches in some mountainous regions, causing dangerous flash floods and mudslides.

Irene's impact on Haiti
No nation in the Caribbean is more vulnerable to hurricanes than Haiti, whose northern reaches are expected to receive torrential rains of 5 - 10 inches from Irene. During the 2008 hurricane season, four storms--Fay, Gustav, Hanna, and Ike--dumped heavy rains on Haiti, leaving over 1,000 people dead or missing. The path and intensity of Hurricane Irene are very similar to that of Hurricane Jeanne of 2004, which dumped 13 inches of rains on the nation's northern mountains. The rugged hillsides, stripped bare of 98% of their forest cover thanks to deforestation, let flood waters rampage into large areas of the country, killing over 3000 people, mostly in the town of Gonaives, the nation's 4th largest city. Jeanne ranks as the 12th deadliest hurricane of all time on the list of the 30 most deadly Atlantic hurricanes, and Irene's rains are capable of causing a similar disaster. During 2004 and again this year, ocean temperatures off the coast of Haiti were 1 - 1.5°C above average, one of the top five values seen in the past 100 years. Since more water vapor evaporates into the air from record warm waters, the potential for devastating floods from hurricanes is much higher in these situations. However, satellite images of Jeanne show the storm had much more moisture on its south side when it hit Hispaniola than Irene currently has, so I am hopeful that Irene's rains will not be as intense as Jeanne's were.

Figure 2. Track of Hurricane Jeanne of 2004, which followed a path very similar to what is expected from Hurricane Irene along the north coast of Hispaniola. Irene is not going to do a big loop like Jeanne did, though.

As bad as the hurricanes of 2004 and 2008 were, the January 2010 earthquake was far worse. Up to 316,000 may have been killed, and the capital city of Port-Au-Prince was devastated, leaving over 1.5 million people living under tarps during the 2010 hurricane season. Fortunately, Hurricane Tomas missed making a direct hit on Haiti, and Haiti escaped major loss of life during the 2010 hurricane season. This year, approximately 595,000 Haitians still live underneath tarps outdoors thanks to the earthquake, and these unfortunate people will be at risk of being swept away by flash flooding from Irene's torrential rains. However, Port-Au-Prince lies to the south of where Irene's main rains will fall, and I doubt the earthquake refugee camps will suffer from a major flooding disaster.

Figure 3. Hospital admissions (black bars) and death rate in percent (red line) for Haiti's cholera epidemic of 2010 - 2011. The cholera epidemic surged out of control after Hurricane Tomas dumped heavy rains on Haiti on November 4, 2010, with hospitalizations increasing by a factor of three for over a month. Over 3% of all people who contracted cholera died after Tomas' rains. However, sanitation and medical care improved in the following months, and the death rate fell by a factor of five to 0.7% by the summer of 2011. Another surge in cholera cases occurred in June 2011, doubling after heavy rainy season rains occurred. Cholera deaths doubled during the surge, but the death rate remained constant at 0.7%. Image credit: Pan American Health Organization.

Another danger is that Irene's rains will worsen the cholera epidemic that surfaced after the earthquake. Cholera is a water-borne disease, and spreads readily after heavy rains. As of August 12, 2011, the 2010 - 2011 cholera epidemic had infected 419,000 Haitians, killing 5,968. After Hurricane Tomas passed on November 5, 2010, cholera cases exploded, with hospital admissions more than tripling for over a month. Similarly, heavy rains in June 2011 during the country's usual rainy season caused doubled cholera cases and deaths for several weeks. We can expect that Irene's rains will cause at least a doubling of cholera cases for a month or more. This will lead to several hundred additional cholera deaths, given the disease's 0.7% mortality rate this summer in Haiti (during June and July 2011, 95,212 cases were reported, with 626 deaths.) An increase in cholera deaths due to Irene's rains is also a concern in the Dominican Republic, where cholera has sickened 14,000 people and killed 92 as of the end of July.

Organizations Active in Haitian Relief Efforts:
Portlight disaster relief
Lambi Fund of Haiti
Haiti Hope Fund
Catholic Relief Services of Haiti

Links
For those of you wanting to know your odds of receiving hurricane force or tropical storm force winds, I recommend the NHC wind probability product.

Wunderground has detailed storm surge maps for the U.S. coast.

See my 2010 post, Haiti's tragic hurricane history.

An exceptionally active of hurricane season
Hurricane season is only one-third over, and we've already had almost a full years' activity already. Tropical Storm Irene is the 9th named storm this year, and an average season has just 10 - 11 named storms. Irene's formation date of August 20 ties 2011 with 1936 as the 2nd earliest date for formation of the season's 9th storm. Only 2005 was more active this early. However, the first eight storms of the year have done far less damage than is typical. All eight storms stayed below hurricane strength, making 2011 the first hurricane season since record keeping began in 1851 to have more than six consecutive tropical storms that did not reach hurricane strength. As I discussed in Friday's post, a major reason for this is the lack of vertical instability over the tropical Atlantic so far this year. We've had a large amount of dry, sinking air over the tropical Atlantic, and the usual amount of dry, dusty air from the Sahara, both helping to keep the atmosphere stable and stop this year's storms from intensifying into hurricanes. Hurricane activity typically ramps up big-time by August 20, with more than 80% of all the hurricanes and 65% of all the tropical storms occurring after that date. At our current pace, 2011 will become the second busiest Atlantic hurricane season on record, with 24 - 27 named storms. There are only 21 names in the list of names for a hurricane season, so we may have to break out the Greek alphabet again in late October this year, as occurred in 2005. Ironically, this was the last time the current set of names was used in the Atlantic, so 16 of this year's 21 names are repeats of 2005. I'm not too happy about seeing another hurricane season challenge the Hurricane Season of 2005 in any way, and let's hope we don't retire another five names this year, like occurred in 2005! With vertical instability much lower this year than in 2005, and that year having already seen one storm (Dennis) retired by this point in the season, I doubt that will happen, though.

Figure 4. The annual cycle of average hurricane frequency in the Atlantic. Historically, about 35% of all the tropical storms and 15% of all the hurricanes will have occurred by August 20.

Which model should you trust?
Wunderground provides a web page with computer model forecasts for many of the best-performing models used to predict hurricane tracks. So which is the best? Well, the best forecasts are made by combining the forecasts from three or more models into a "consensus" forecast. Over the past decade, NHC has greatly improved their forecasts by relying on consensus forecast models made using various combinations of the GFS, GFDL, NOGAPS, UKMET, HWRF, and ECMWF models. If you average together the track forecasts from these models, the NHC official forecast will rarely depart much from it, and the NHC forecast has been hard to beat over the past few years. The single best-performing model over the past two years has been the ECMWF (European Center model). This model out-performed the official NHC forecast in 2010 for 1-day, 2-day, 3-day and 4-day forecasts, and in 2009 for 4-day and 5-day forecasts. You can view ECMWF forecasts on our wundermap with the model layer turned on. The European Center does not permit public display of tropical storm positions from their hurricane tracking module of their model, so we are unable to put ECMWF forecasts on our computer model forecast page that plots positions from the other major models. As seen in Figure 5, over the past two years, the GFS and GFDL model have been the next best models, with the UKMET model not far behind. Last year, the NOGAPS model did very poorly, forcing NHC to come up with some new consensus models this year, the TCOA and TVCA, that do not include the NOGAPS model. For those interested in learning more about the models, NOAA has a great training video (updated for 2011.)

Figure 5. Skill of computer model forecasts of Atlantic named storms 2010. OFCL=Official NHC forecast; GFS=Global Forecast System model; GFDL=Geophysical Fluid Dynamic Laboratory model; HWRF=Hurricane Weather Research Forecasting model; NOGAPS=Navy Operational Global Prediction System model; UKMET=United Kingdom Met Office model; ECMWF=European Center for Medium Range Weather Forecasting model; TVCN=one of the consensus models that lends together all (or most) of the above models. Image credit: National Hurricane Center 2010 verification report.

Next post
There will be 2 - 3 posts per day in my blog this week during Irene, with Angela Fritz and Rob Carver doing some of the afternoon and evening posts.

Jeff Masters

Tropical Storm Irene hits Puerto Rico (lobdellJ)

Tropical Storm Irene hits the north coast of Puerto Rico

Tropical Storm Irene from Maunabo, PR (ronmil)

The first bands or Irene approaching Maunabo, Puerto Rico (SE corner)...

Irene (reefchild)

Irene @OPkB OceanParkBeach Puerto Rico 7pm

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101. hahaguy 15:10 GMT le 22 août 2011
Quoting wxhatt: The NAM (North American Model) should not be relied upon for Tropical Systems. It is only used for short term forcasting. But it is good at predicting the atmosphere around storms as I've been told. Member Since: 12 août 2007 Posts: 2 Comments: 2838

102. Inactivity 15:10 GMT le 22 août 2011
This could end badly. Right now it is aimed at South Carolina according to the nhc, but just about anything could happen at this point. Member Since: 23 juin 2010 Posts: 0 Comments: 264

104. 900MB 15:10 GMT le 22 août 2011
On the wind speed probability Cat 3 in the forecast. Noticed they ramped up the odds of Cat 3 big time on this report. Member Since: 11 juin 2006 Posts: 0 Comments: 615

105. DookiePBC 15:10 GMT le 22 août 2011
Looks like the spiders in my pile of hurricane shutters in the corner of the garage will be getting a reprieve for now. But what is good news for South Florida is bad news for people in Freeport in the Bahamas. Yikes! Member Since: 1 septembre 2009 Posts: 0 Comments: 435

106. canecast 15:10 GMT le 22 août 2011
"ALTHOUGH IT IS TOO EARLY TO BE CERTAIN...THE CURRENT GUIDANCE LESSENS THE THREAT TO SOUTH FLORIDA." NHC Welcome news for us in SFl. Member Since: 21 août 2007 Posts: 0 Comments: 211

107. MoltenIce 15:10 GMT le 22 août 2011
A word of advice from Dr. Avila "DO NOT TO FOCUS ON THE EXACT FORECAST TRACK...ESPECIALLY AT DAYS 4 TO 5...SINCE THE MOST RECENT 5-YEAR AVERAGE ERRORS AT THOSE FORECAST TIMES ARE 200 AND 250 MILES...RESPECTIVELY." Member Since: 11 août 2010 Posts: 0 Comments: 552

108. reedzone 15:11 GMT le 22 août 2011
These models will be useless until we have the models tonight with the Hurricane Hunter info in them. The 00Z models that is. Florida to North Carolina needs to closely watch this storm, Florida is NOT in the clear yet, not even close! Member Since: 1 juillet 2008 Posts: 13 Comments: 7249

109. RevInFL 15:11 GMT le 22 août 2011
So is East Central Florida in the clear? I am not wishing this beast on anybody but I am wondering because of plans for Friday. Thanks all. I am learning a lot from this blog. Member Since: 6 septembre 2008 Posts: 0 Comments: 123

110. popartpete 15:11 GMT le 22 août 2011
Link This is the "Gale of 1878", which I think is possible climatological comparable storm to Irene. See the 61 over the Jersey Shore, that is 61 knots and is just under winds of hurricane force. Add in the forward momentum, and winds were over hurricane strength. The best explanation I could find was this: "the northeast quadrant is where the largest extent in the wind field occurs since the storm's forward motion by itself will create wind which is added to the wind flowing around the storm itself. The strongest winds are nearly always on the right side of the storm's forward motion and often in the right-front quadrant relative to the storm's forward motion. So direction and speed of the storm's forward motion will impact the extent of the wind field in each quadrant." This storm had a big impact in the Northeast, and was weaker than Irene is expected to be. We'll see. I hope not. All of our power lines, phone and cable are out on poles. Winds of 80, 90 or 100 miles per hour would be devastating here. I'm not wishcasting, in fact I'm reverse wishcasting, but we are overdue in the Northeast by decades. The last few computer models I saw didn't look to good for up here. P.S. I'm in Seaside Heights, yes home of 'Jersey Shore'. Maybe it will blow their balcony and hot tub away, or at least Snooki's Bumpit. Member Since: 10 juillet 2007 Posts: 0 Comments: 416

112. tropicfreak 15:11 GMT le 22 août 2011
Quoting BoroDad17: Well East on latest advisory. And a big shift east too. Puts FL out of the crosshairs. Member Since: 2 septembre 2006 Posts: 110 Comments: 6612

113. nash28 15:11 GMT le 22 août 2011
Quoting Patrap: ..that noise we heard was presslord fainting I think. No worries... I am here in Charleston. As long as I am here it'll stay away. LOL! Member Since: 11 juillet 2005 Posts: 190 Comments: 16972

115. Dem86Mets 15:12 GMT le 22 août 2011
Quoting DookiePBC: Dewey... Good call. I think the 5pm cone of DOOM will be the last one to include Florida. Same, the wishcasting on this blog is so pointless. The storm is going to be east of Florida, people just don't want to believe it. So what if this does not hit Florida, The eastern seaboard is still going to be dealing with a possible MAJOR hurricane! Member Since: 18 août 2011 Posts: 0 Comments: 67

116. Ameister12 15:12 GMT le 22 août 2011
NHC has Irene hitting Charleston, SC as a Major Hurricane. Member Since: 9 août 2009 Posts: 9 Comments: 3628

117. atmoaggie 15:12 GMT le 22 août 2011
Quoting WeatherNerdPR: Irene was mean! LoL Hey, there. Good night's sleep? ;-) Member Since: 16 août 2007 Posts: 6 Comments: 12461

118. WeatherfanPR 15:13 GMT le 22 août 2011
HURRICANE IRENE DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011 1100 AM AST MON AUG 22 2011 BASED ON THE LATEST GUIDANCE... THE OFFICIAL TRACK FORECAST HAS BEEN SHIFTED TO THE EAST...BUT STILL REMAINS SLIGHTLY WEST OF THE MODEL CONSENSUS. ALTHOUGH IT IS TOO EARLY TO BE CERTAIN...THE CURRENT GUIDANCE LESSENS THE THREAT TO SOUTH FLORIDA. looking good for Tampa Bay Area so I'm grateful :o) Member Since: 23 août 2006 Posts: 0 Comments: 1516

119. NEwxguy 15:13 GMT le 22 août 2011
Quoting bigeasystormcaster: Looks like it might be a fish-storm from here on out. The 12th blog? What took you so long? Member Since: 6 septembre 2007 Posts: 820 Comments: 13282

120. MahFL 15:13 GMT le 22 août 2011
No...not out to sea :( Member Since: 9 juin 2004 Posts: 0 Comments: 2467

121. wxhatt 15:13 GMT le 22 août 2011
Quoting AllStar17: Why does it stop at 115 mph? They don't think it would intensify further over the Gulf Stream? Storm intensity is also affected by the upper air pattern and surrounding dry air. Don't just look at the SST's. Member Since: 5 octobre 2005 Posts: 2 Comments: 834

122. ncstorm 15:13 GMT le 22 août 2011
Irene will be huge when it nears the bahamas..to say Florida is out of the clear, I dont think so..they could still have hurricane force winds even if it passes off to the east..the coastal sections of Florida still could have damage and flooding.. Member Since: 19 août 2006 Posts: 7 Comments: 8845

123. 7544 15:13 GMT le 22 août 2011
so if you have a major in andors island what will the the effects in south fla could they still get ts force winds tia Member Since: 6 mai 2007 Posts: 0 Comments: 6021

125. FrankZapper 15:13 GMT le 22 août 2011
All clear in Dade Member Since: 26 mai 2011 Posts: 0 Comments: 1193

127. DookiePBC 15:15 GMT le 22 août 2011
Quoting Dem86Mets: Same, the wishcasting on this blog is so pointless. The storm is going to be east of Florida, people just don't want to believe it. So what if this does not hit Florida, The eastern seaboard is still going to be dealing with a possible MAJOR hurricane! Exactly...what is good news for one person (South Florida in this case) is generally going to be bad news for someone else (in this case the northern Bahamas and somewhere up the coast). Member Since: 1 septembre 2009 Posts: 0 Comments: 435

128. NOLALawyer 15:15 GMT le 22 août 2011
Quoting DFWjc: Hey NOLA are you up to about 500(including a certain u-know-who)? LOL Not quite, but I am approaching triple digits. I am an equal opportunity ignorer. Trolls, downcasters, naked swirl-casters, fishcasters.....they all have a happy home on my list. LOL. Member Since: 3 septembre 2009 Posts: 0 Comments: 517

130. hurricanehanna 15:15 GMT le 22 août 2011
Quoting USAFwxguy: Critical to that track is the near-term miss of Hispaniola, as the Dr mentioned. If ever there was nothing "written in stone" this is it. I remember two other "I" storms that did not do as they were told by the NHC. Link Link Could Irene do something like this with the trough in place and High Pressure over the GOM? Member Since: 5 septembre 2007 Posts: 0 Comments: 3214

131. Ryuujin 15:15 GMT le 22 août 2011
Quoting reedzone: These models will be useless until we have the models tonight with the Hurricane Hunter info in them. The 00Z models that is. Florida to North Carolina needs to closely watch this storm, Florida is NOT in the clear yet, not even close! Reed don't make yourself look silly. This is why people mock you on this blog. Florida isn't clear yet by any means, but don't act like the threat of impact hasn't lessened.. It certainly has. But we will see in the long run. Member Since: 20 août 2010 Posts: 0 Comments: 365

132. interstatelover7165 15:16 GMT le 22 août 2011
000 WTNT44 KNHC 221504 TCDAT4 HURRICANE IRENE DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011 1100 AM AST MON AUG 22 2011 DATA FROM A RECONNAISSANCE PLANE...RADAR AND SATELLITE IMAGERY INDICATE THAT IRENE HAS CONTINUED TO GRADUALLY BECOME BETTER ORGANIZED. HOWEVER THE WINDS WINDS HAVE NOT INCREASED SIGNIFICANTLY AND THE MINIMUM CENTRAL PRESSURE WAS AROUND 988 MB IN THE LAST CENTER DROPSONDE. THE INITIAL INTENSITY HAS BEEN INCREASED TO 70 KNOTS IN THIS ADVISORY. SINCE THE CORE OF THE HURRICANE IS NOT FORECAST TO MOVE DIRECTLY OVER THE HIGH TERRAIN OF HISPANIOLA...AND THE OCEANIC AND ATMOSPHERIC CONDITIONS ARE QUITE FAVORABLE... THE OFFICIAL FORECAST CALLS FOR INTENSIFICATION...AND MAKES IRENE A CATEGORY 3 HURRICANE AS IT MOVES ACROSS THE CENTRAL BAHAMAS. THIS IS CONSISTENT WITH MOST OF THE DYNAMICAL GUIDANCE AND IN FACT...EVEN GLOBAL MODELS FORECAST A SIGNIFICANT DROP IN THE CENTRAL PRESSURE OVER THE NEXT TWO OR THREE DAYS. IRENE IS BECOMING A LARGE CYCLONE...AND BASED ON BUOY OBSERVATIONS THE TROPICAL STORM FORCE WINDS EXTEND 160 N MI TO THE NORTHEAST OF THE CENTER. RADAR AND RECONNAISSANCE FIXES INDICATE THAT THE HURRICANE IS MOVING TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT ABOUT 12 KNOTS. IRENE IS CURRENTLY LOCATED SOUTH OF A NARROW SUBTROPICAL RIDGE WHICH IS FORCING THE CYCLONE ON A WEST-NORTHWEST TRACK. HOWEVER...MOST OF THE GLOBAL MODELS SHOW THE GRADUAL DEVELOPMENT A LARGE UPPER TROUGH ALONG THE UNITED STATES EAST COAST. THIS PATTERN WILL INDUCE A MORE NORTHWESTWARD AND THEN NORTHWARD TRACK THROUGH THE FORECAST PERIOD WITH A DECREASE IN FORWARD SPEED. BASED ON THE LATEST GUIDANCE... THE OFFICIAL TRACK FORECAST HAS BEEN SHIFTED TO THE EAST...BUT STILL REMAINS SLIGHTLY WEST OF THE MODEL CONSENSUS. ALTHOUGH IT IS TOO EARLY TO BE CERTAIN...THE CURRENT GUIDANCE LESSENS THE THREAT TO SOUTH FLORIDA. DO NOT TO FOCUS ON THE EXACT FORECAST TRACK...ESPECIALLY AT DAYS 4 TO 5...SINCE THE MOST RECENT 5-YEAR AVERAGE ERRORS AT THOSE FORECAST TIMES ARE 200 AND 250 MILES...RESPECTIVELY. FORECAST POSITIONS AND MAX WINDS INIT 22/1500Z 19.2N 67.5W 70 KT 80 MPH 12H 23/0000Z 19.9N 69.2W 75 KT 85 MPH 24H 23/1200Z 20.5N 71.4W 80 KT 90 MPH 36H 24/0000Z 21.2N 73.2W 85 KT 100 MPH 48H 24/1200Z 22.0N 75.0W 90 KT 105 MPH 72H 25/1200Z 25.0N 77.5W 100 KT 115 MPH 96H 26/1200Z 28.5N 79.0W 100 KT 115 MPH 120H 27/1200Z 32.5N 80.0W 100 KT 115 MPH $$ FORECASTER AVILA Member Since: 18 août 2011 Posts: 0 Comments: 879

134. hydrus 15:16 GMT le 22 août 2011
Thank you for the update Dr... Member Since: 27 septembre 2007 Posts: 1 Comments: 14702

136. reedzone 15:16 GMT le 22 août 2011
Quoting RevInFL: So is East Central Florida in the clear? I am not wishing this beast on anybody but I am wondering because of plans for Friday. Thanks all. I am learning a lot from this blog. no Member Since: 1 juillet 2008 Posts: 13 Comments: 7249

138. whepton3 15:16 GMT le 22 août 2011
Quoting RevInFL: So is East Central Florida in the clear? I am not wishing this beast on anybody but I am wondering because of plans for Friday. Thanks all. I am learning a lot from this blog. The situation is suggesting that... However, ECFL is still in the cone. This from the NHC: ALTHOUGH IT IS TOO EARLY TO BE CERTAIN...THE CURRENT GUIDANCE LESSENS THE THREAT TO SOUTH FLORIDA. DO NOT TO FOCUS ON THE EXACT FORECAST TRACK...ESPECIALLY AT DAYS 4 TO 5...SINCE THE MOST RECENT 5-YEAR AVERAGE ERRORS AT THOSE FORECAST TIMES ARE 200 AND 250 MILES...RESPECTIVELY. Remain aware of the situation over the next few days is still a good idea. Member Since: 19 juillet 2010 Posts: 0 Comments: 637

139. CaneHunter031472 15:16 GMT le 22 août 2011
South Carolina I hope you are taking notice the time to get ready is now. Florida keep an eye on this, but it seems that there is hope for you. Member Since: 1 août 2007 Posts: 0 Comments: 895

140. WeatherNerdPR 15:16 GMT le 22 août 2011
Quoting atmoaggie: Hey, there. Good night's sleep? ;-) Barely any sleep at all, and sometime between four and five in the morning, the eye of Irene ran over me. Member Since: 7 juillet 2010 Posts: 0 Comments: 5490

141. overwash12 15:16 GMT le 22 août 2011
If Irene misses U.S. will everbody admit we are all amatuers? Member Since: 24 juin 2007 Posts: 0 Comments: 1056

142. islander101010 15:17 GMT le 22 août 2011
Quoting NOLALawyer: It is symbolic, and it makes me feel better to announce another head placed on a pike. My castle is well decorated with heads this season. ? how about some hurricane info instead of this crap next time im ignoring you Member Since: 11 septembre 2010 Posts: 0 Comments: 3073

143. 900MB 15:17 GMT le 22 août 2011
Quoting reedzone: These models will be useless until we have the models tonight with the Hurricane Hunter info in them. The 00Z models that is. Florida to North Carolina needs to closely watch this storm, Florida is NOT in the clear yet, not even close! Reed- I would go sar as to say the Entire East Coast should watch all the way up to Cape Cod. If this thing hugs the coast or only scrapes NC, there is a whole lotta coast that should be watching. if we end up strong Cat 3 SC, the remnants alone could do damage all the way to Rhode Island. Member Since: 11 juin 2006 Posts: 0 Comments: 615

144. nola70119 15:17 GMT le 22 août 2011
"The storm is lacking much development on its southwest side, where dry air is interfering with development." Thanks for confirming this Dr. Masters. If it wasn't for the dry air this could be a much more dangerous storm. Member Since: 16 juin 2006 Posts: 0 Comments: 1535

145. Refracto 15:17 GMT le 22 août 2011
IMO, the more interaction Irene has, if any, with the mountains of the DR, the weaker a storm, hence the more west the track. Crucial times right now. Member Since: 3 juin 2008 Posts: 0 Comments: 4

146. Dem86Mets 15:17 GMT le 22 août 2011
Quoting 7544: so if you have a major in andors island what will the the effects in south fla could they still get ts force winds tia Even if we get 30 mph winds and some showers, that is a typical summer thunder storm here in Florida. For us it will be a non event, for others it appears not so lucky. Member Since: 18 août 2011 Posts: 0 Comments: 67

147. AllStar17 15:18 GMT le 22 août 2011
Quoting wxhatt: Storm intensity is also affected by the upper air pattern and surrounding dry air. Don't just look at the SST's. I know that....conditions should be quite favorable. Member Since: 29 juin 2009 Posts: 13 Comments: 5145

148. Jedkins01 15:18 GMT le 22 août 2011
Well the newest track out of the NHC is looking that much better for Florida. Hopefully this trend will continue further. Even still though, there are still several days left, and it would not be wise to let your guard down in Florida, always be prepared, but don't get stressed or lose sleep over it though. Computer models are continuing to trend east, it looks like my predictions of Florida having minimal hurricane impacts is still being spared. So far the reason for this is what I expected, continued troughs of low pressure in the east and a strong ridge over Texas holding out. However, it does bare some concern to me that this pattern of shielding Florida is becoming less profound as the season goes on, unfortunately. Whatever the case, always be prepared and have a plan for the rest of the season. The worst of the season is yet to come. Member Since: 21 août 2008 Posts: 0 Comments: 5420

149. wxhatt 15:18 GMT le 22 août 2011
Quoting hahaguy: But it is good at predicting the atmosphere around storms as I've been told. That's true to a degree, but I was referring to his question on why it isn't going to south Florida from this far out in time. Member Since: 5 octobre 2005 Posts: 2 Comments: 834

151. atmoaggie 15:18 GMT le 22 août 2011
Quoting FLdewey: That cone is going to keep on moving... From NHC - Official track forecast shifted east, but still remains slightly west of the model consensus. Heading EAST! I think so, too... Unless she doesn't intensify as much as expected in the next 36 hours, which is quite possible, IMO. (Read: dry air and/or terrain) Member Since: 16 août 2007 Posts: 6 Comments: 12461

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