Irene is forecast to become a category 4 hurricane at it’s peak, which would be approximately 2 AM friday. A category four hurricane has *sustained* winds between 131-155 MPH. Irene is currently a category 2 hurricane (96-110 MPH), forecast to be a category 3 (111-130 MPH) hurricane by tomorrow. Infra-red satellite imagery shows that Irene has begun to intensify quite a bit over the last 12 or or so hours, and is really about to kick it into high gear! Irene is moving over very warm waters with a relatively unobstructed intake of that heat, which will result in further intensification. Because of this, it is completely within the realm of possibility for Irene to become even stronger more quickly. Irene needs to be watched very closely, because she could become quite strong and may even make landfall as a category 4 hurricane instead of the forecast category 3.

Irene has not yet developed a well defined eye wall (see left image), which is interesting. I am not well versed in hurricane forecasting, this is a first for me, so I am not quite sure what this indicates. However, I would guess that this means that Irene is not a “mature” hurricane yet. The fact that it is not fully organized might have to do with the fact that portions of Irene are over the Dominican Republic. Once Irene moves out into the bahamas, I expect we will see an eye wall develop on satellite and it will probably correspond with the category 3+ conditions. If you look at this visible satellite image from this morning, you can see the lack of a well defined eye wall. However, you can also see a very intense updraft and the further strengthening of Irene.

I’ll close this off with the forecast text from the National Hurricane Center. If you are in the path of Irene, you need to start getting prepared! If you are chasing Irene, I wish you the best of luck. Stay safe!

HURRICANE IRENE DISCUSSION NUMBER 12

NWS NATIONAL HURRICANE CENTER MIAMI FL AL092011

500 AM EDT TUE AUG 23 2011

SMOOTHING THROUGH ALL OF THE AIRCRAFT FIXES SINCE IRENE MOVED OFF THE COAST OF PUERTO RICO MORE THAN 18 HOURS AGO YIELDS A LONG TERM MOTION OF 295/10 KT…WHICH IS USED FOR THIS ADVISORY. THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK REASONING. THE 23/00Z G-IV JET AIRCRAFT AND AIR FORCE C-130 DROPSONDE DATA APPEAR TO HAVE SETTLED DOWN THE MODELS…AND THERE IS CONSIDERABLY LESS DIFFERENCE AMONG THE VARIOUS MODEL SOLUTIONS NOW. THE OVERWHELMING CONSENSUS IS THAT IRENE WILL GRADUALLY TURN NORTHWESTWARD OVER THE NEXT 2-3 DAYS AND THEN MOVE NORTHWARD THROUGH A DEVELOPING BREAK IN THE SUBTROPICAL RIDGE OVER THE SOUTHEASTERN UNITED STATES. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND LIES VERY CLOSE TO CONSENSUS MODELS TVCN AND TVCA.

AN EARLIER RECON FLIGHT INDICATED THE PRESSURE HAD ONLY FALLEN BY 2 MB DOWN TO 978 MB…AND THE OVERALL APPEARANCE IN SATELLITE IMAGERY HAS CHANGED LITTLE SINCE THE PREVIOUS ADVISORY. AS A RESULT…THE INITIAL INTENSITY IS BEING HELD AT 85 KT…WHICH COULD BE GENEROUS. IRENE IS FORECAST TO REMAIN IN A RELATIVELY LOW VERTICAL WIND SHEAR ENVIRONMENT AND OVER SSTS NEAR 30C. THAT COMBINATION…ALONG WITH EXPANDING OUTFLOW IN ALL QUADRANTS…SHOULD ALLOW FOR IRENE TO BECOME A MAJOR HURRICANE WITHIN THE NEXT 24 HOURS ONCE THE CYCLONE CLEARS THE EFFECTS OF HISPANIOLA…AND PROBABLY MAINTAIN MAJOR HURRICANE STATUS THROUGHOUT THE REMAINDER OF THE 5-DAY FORECAST PERIOD. THE INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY AND CLOSELY FOLLOWS A BLEND OF THE HWRF AND GFDL MODEL INTENSITY FORECASTS…AND CONVERSION OF THE SURFACE PRESSURES DEPICTED IN THE GFS AND ECMWF MODELS.

WIND RADII WERE EXPANDED BASED ON A BLEND OF RECON FLIGHT-LEVEL WINDS…SFMR WINDS…AND SURFACE OBSERVATIONS.

IRENE IS FORECAST TO BECOME A LARGER THAN AVERAGE HURRICANE. IT IS IMPORTANT TO REMIND USERS NOT TO FOCUS ON THE EXACT FORECAST TRACK…ESPECIALLY AT DAYS 4 AND 5…SINCE THE MOST RECENT 5-YEAR AVERAGE ERRORS AT THOSE FORECAST TIMES ARE 200 AND 250 MILES… RESPECTIVELY.

1. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH THE REMNANTS OF GASTON CONTINUE TO SHOW SIGNS OF ORGANIZATION. ENVIRONMENTAL CONDITIONS ARE CONDUCIVE FOR RE-DEVELOPMENT OF THIS SYSTEM AND A TROPICAL DEPRESSION COULD RE-FORM IN THIS AREA AT ANY TIME. THERE IS A HIGH CHANCE…80 PERCENT…OF THIS SYSTEM BECOMING A TROPICAL CYCLONE AGAIN DURING THE NEXT 48 HOURS AS IT MOVES WESTWARD AT ABOUT 10 MPH.

I apologize that I do not have more information at this moment, but I will keep you people updated as this storm strengthens. I do have a feeling that this hurricane has a good chance to impact the Gulf, so be aware.

Right now there are TWO hurricanes out in the Atlantic. Hurricane Danielle is dying off, while Hurricane Earl is only just getting up to speed. There is also a tropical depression, likely to become a storm within the next few days. As you can see, the season is picking up speed and is extremely active just as the National Hurricane Center predicted. Even though Danielle never made landfall, it looks as if Earl will make landfall somewhere in the Eastern U.S.      In the image at left. the center of the hurricane can be anywhere in the circle, and the path can also shift. You can also see that this storm will reach maximum strength at a Category 4. Category 4 means windspeeds can be in the range of 131-155 MPH! Here is the current advisory on Hurricane Earl.

DISCUSSION AND 48-HOUR OUTLOOK

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AT 800 PM AST…0000 UTC…THE CENTER OF HURRICANE EARL WAS LOCATED NEAR LATITUDE 17.7NORTH…LONGITUDE 60.3 WEST. EARL IS MOVING TOWARD THE WEST-NORTHWEST NEAR 14 MPH…22 KM/HR…AND THIS GENERAL MOTION WITH SOME DECREASE IN FORWARD SPEED IS EXPECTED DURING THE NEXT DAY OR SO. A TURN TOWARD THE NORTHWEST IS FORECAST MONDAY NIGHT OR TUESDAY. ON THE FORECAST TRACK…THE CENTER OF EARL WILL PASS NEAR OR OVER THE NORTHERNMOST LEEWARD ISLANDS TONIGHT AND MONDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 85 MPH…140 KM/HR…WITH HIGHER GUSTS. EARL IS A CATEGORY ONE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. ADDITIONAL STRENGTHENING IS EXPECTED DURING THE NEXT 48 HOURS AND EARL IS FORECAST TO BECOME A MAJOR HURRICANE ON MONDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 45 MILES…75 KM…FROM THE CENTER…AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175 MILES…280 KM.

THE MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE RESERVE UNIT HURRICANE HUNTER PLANE IS 972 MB…28.70 INCHES.

As far as the new tropical depression, it looks like it will take a similar path to Danielle, meaning it will stay in the Atlantic. However, it is too early to say for certain, so there IS still time for it to turn towards the west. The intensity models show the depression not getting too strong, but again, it is pretty early to make definitive forecasts.

So, thats about it for now. I didn’t include Danielle because it will die within the next few days. However, you can see how active this season already is. I would keep an eye on Earl, so stay tuned for updates. Thank you for reading.

DISCUSSION AND 48-HOUR OUTLOOK

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AT 100 PM CDT…1800 UTC…THE CENTER OF TROPICAL STORM ALEX WAS LOCATED NEAR LATITUDE 22.9 NORTH…LONGITUDE 93.6 WEST. ALEX IS NOW MOVING TOWARD THE NORTHWEST NEAR 13 MPH…21 KM/HR. A GRADUAL TURN TOWARD THE WEST-NORTHWEST IS EXPECTED ON WEDNESDAY. ON THE FORECAST TRACK…THE CENTER OF ALEX WILL APPROACH THE COAST OF NORTHEASTERN MEXICO AND SOUTHERN TEXAS ON WEDNESDAY AND MAKE LANDFALL WEDNESDAY NIGHT. MAXIMUM SUSTAINED WINDS ARE NEAR 70 MPH…110 KM/HR…WITH HIGHER GUSTS. STRENGTHENING IS FORECAST DURING THE NEXT 36 HR OR SO BEFORE LANDFALL…AND ALEX IS LIKELY TO BECOME A HURRICANE LATER TODAY. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 140 MILES…220 KM FROM THE CENTER. NOAA BUOY 42055…LOCATED ABOUT 65 MILES SOUTHWEST OF THE CENTER…RECENTLY REPORTED 1-MINUTE MEAN WINDS OF 38 MPH… 61 KM/HR…AND A WIND GUST OF 45 MPH…72 KM/HR. THE MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT IS 981 MB…28.97 INCHES.

The storm surge forecast is showing heights ranging anywhere from 3 ft to 6 ft as the hurricane moves in over southern Tx/Mexico. This is not a good thing because of how close to sea level most of the gulf is. If you are at 3 ft or below, I would recommend taking some precaution before this storm moves in. At one point this hurricane was forecast to reach Category 2 strength, but the latest observations indicate that it will remain a Category 1 hurricane until it makes landfall, where it will weaken. Again, the center will make landfall on the Tx/Mex border, but the rest of the storm will impact the majority of the gulf. Take action as needed, but thankfully this wont be too serious. However, please take local National Weather Service advisories seriously. Be safe.