Edouard Heading To Galveston? August 4, 2008

Look to latest post for most recently updated information. 

Track Edouard’s Progress with this National Interactive Radar…zoom to street level!

Edouard Track EVE 08.03Spaghetti tracks

Funny thing happened today.  The NHC issued the first report on Tropical Depression number 5. They made it a tropical storm in a day or so and took near Galveston on Tuesday. An hour later, a hurricane hunter reported a pressure drop of 5 mb and slightly increased winds.  In a very uncommon move, they immediately issued a new report and discussion that made it Tropical Storm Edouard and increased its intensity a bit by landfall.  By the 10 PM CDT report, the circulation remained but other elements decreased.  In the earlier discussion, they mentioned that the GFDL was an outlyer but made it a hurricane.  Now, in the late discussion, they mention that the storm has weakened and not continued or maintained its intensity but now there are a whole mess of models wanting to make it a hurricane. However, the NHC cautions that the prognosis of those models is based on the data from the quick increase in intensity and the models don’t know yet that the storm didn’t continue to intensify.  So, a return to the more pragmatic approach has come about. 

If you note the on the spaghetti tracks above, there are a majority of models lumped into the Galveston solution.  The official track has shifted just a shade from earler from say Freeport or Lake Jackson, TX to Galveston.  It also goes between Austin and San Antonio at a pretty good clip…perhaps over San Marcos or Wimberly.  The idea is that it will be a strong tropical storm or minimal hurricane at landfall early Tuesday.  The good news is that it should maintain forward speed which means rain amounts will tend to be heavy but not catostrophic.  When it gets to the hill country though, the topography both from a lifting perspective and from a hydrology perspective may prove problematic.  Here is the 11 PM NHC discussion.  The above track is from the US Naval Research Laboratory but is based on the NHC forecast.

WTNT45 KNHC 040230
TCDAT5
TROPICAL STORM EDOUARD DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL052008
1100 PM EDT SUN AUG 03 2008

THE MAXIMUM WINDS ARE SET AT 45 KT BASED ON PEAK FLIGHT-LEVEL WINDS
OF 54 KT AND A VISUAL ESTIMATE OF 55 KT PRIOR TO 00Z FROM THE AIR
FORCE RECONNAISSANCE AIRCRAFT. SINCE THEN…CONVECTION OVER THE
CENTER HAS LARGELY DIMINISHED…AND THE EARLIER INTENSIFICATION
TREND HAS NO DOUBT STOPPED FOR THE TIME BEING. NORTHERLY SHEAR IS
STILL AFFECTING THE CYCLONE…AND WATER VAPOR IMAGERY SHOWS SOME
MID-LEVEL DRY AIR NEAR AND TO THE NORTH OF THE CENTER. GLOBAL MODEL
GUIDANCE INDICATES THAT THIS SHEAR SHOULD DIMINISH OVER THE NEXT
DAY OR SO…AND EDOUARD COULD FIND ITSELF IN A DIFLUENT UPPER
ENVIRONMENT THAT WOULD FAVOR INTENSIFICATION AS IT MOVES INTO THE
NORTHWESTERN GULF.  THE GFDL…SHIPS…LGEM…AND SUPERENSEMBLE ALL
MAKE EDOUARD A HURRICANE. THE LATTER THREE MODELS…HOWEVER…ARE
HEAVILY INFLUENCED BY THE RECENT STRENGTHENING TREND…A TREND
WHICH IS NO LONGER OCCURRING. CONSEQUENTLY…THE OFFICIAL FORECAST
LIES SLIGHTLY BELOW THIS GUIDANCE…BRINGING EDOUARD TO JUST BELOW
HURRICANE STRENGTH. 

THE INITIAL MOTION IS 270/4. THE CYCLONE IS EXPECTED TO MOVE TO THE
WEST AND THEN WEST-NORTHWEST THROUGH LANDFALL AROUND THE PERIPHERY
OF MID- TO UPPER-LEVEL HIGH PRESSURE OVER THE SOUTH-CENTRAL UNITED
STATES.  MODEL GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO.
HOWEVER…BECAUSE EDOUARD IS MOVING AT A VERY OBLIQUE ANGLE TO THE
COASTLINE…SMALL ERRORS IN THE FORECAST TRACK WOULD RESULT IN
LARGE DIFFERENCES IN THE LANDFALL LOCATION. CONSEQUENTLY…AND AS
ILLUSTRATED BY THE NHC WIND SPEED PROBABILITY PRODUCT…THE CHANCES
OF EXPERIENCING TROPICAL STORM CONDITIONS ARE ROUGHLY EQUAL FROM
MORGAN CITY ALL THE WAY TO GALVESTON BAY. THE OFFICIAL FORECAST IS
ADJUSTED SLIGHTLY NORTH OF THE PREVIOUS ADVISORY AND IS CLOSE TO
THE CENTER OF A RELATIVELY NARROW GUIDANCE ENVELOPE.

FORECAST POSITIONS AND MAX WINDS

INITIAL      04/0300Z 28.1N  88.5W    45 KT
12HR VT     04/1200Z 28.2N  89.7W    45 KT
24HR VT     05/0000Z 28.6N  91.9W    50 KT
36HR VT     05/1200Z 29.3N  94.1W    60 KT
48HR VT     06/0000Z 30.0N  96.5W    40 KT…INLAND
72HR VT     07/0000Z 31.0N 101.0W    20 KT…REMNANT LOW
96HR VT     08/0000Z…DISSIPATED

$$
FORECASTER FRANKLIN