LESLIE STRENGTHENING OVER THE TROPICAL ATLANTIC…

5:00 PM AST Thu Aug 30
Location: 28.2°N 50.3°W
Moving: NNW at 13 mph
Min pressure: 982 mb
Max sustained: 90 mph

TROPICAL STORM LESLIE DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
500 PM EDT THU AUG 30 2012

LESLIE HAS QUICKLY ORGANIZED TODAY WITH PROMINENT BANDING FEATURES
AND INCREASED CONVECTION NEAR THE CENTER.  THE INITIAL INTENSITY IS
SET TO 40 KT AS A BLEND OF THE SUBJECTIVE AND MICROWAVE ESTIMATES.
GLOBAL MODELS ALL BUILD AN UPPER-LEVEL ANTICYCLONE NEAR THE STORM
FOR THE NEXT FEW DAYS...WHICH WOULD SEEM TO BE A FAVORABLE
ENVIRONMENT FOR FURTHER STRENGTHENING.  MOST OF THE GUIDANCE
SUGGESTS THAT LESLIE WILL BECOME A HURRICANE IN A DAY OR TWO...AND
THERE ARE EVEN A COUPLE MODELS THAT SHOW IT NEAR MAJOR HURRICANE
STRENGTH IN A FEW DAYS.  THE NHC FORECAST IS RAISED FROM THE
PREVIOUS ONE...AND IS A LITTLE BELOW THE ROBUST LGEM/SHIPS GUIDANCE
THROUGHOUT THE PERIOD.  WHILE THE TIMING IS IMPOSSIBLE TO
PINPOINT...IT WOULD NOT BE SURPRISING IF LESLIE BECAME STRONGER
THAN FORECAST IN THE THREE-TO-FIVE DAY PERIOD.  

THE INITIAL MOTION IS ABOUT 280/18.  LESLIE SHOULD TURN TOWARD THE
WEST-NORTHWEST IN THE NEXT 12 HOURS OR SO AS IT MOVES AROUND THE
SOUTHWESTERN SIDE OF THE SUBTROPICAL RIDGE.  A SERIES OF TROUGHS IS
EXPECTED TO DIG BETWEEN 60W-70W...WHICH SHOULD CAUSE THE STORM TO
MAKE A GRADUAL TURN TOWARD THE NORTHWEST AND NORTH IN A FEW DAYS.
MODEL GUIDANCE IS IN VERY GOOD AGREEMENT FOR THE FIRST THREE
DAYS...THEN SOME DIVERGENCE OCCURS ON WHICH TROUGH MIGHT RECURVE
THE CYCLONE.  AT THE END OF THE PERIOD...SPEED DIFFERENCES BECOME
VERY IMPORTANT ON WHETHER LESLIE MOVES QUICKLY OUT TO SEA...AS
SUGGESTED BY THE GFS...OR GETS STUCK UNDER A RIDGE...AS FORECAST BY
THE ECMWF.  THE NHC FORECAST IS BASICALLY AN UPDATE OF THE
PREVIOUS ONE...STILL A BIT FASTER AND WEST OF THE MODEL CONSENSUS.  

GLOBAL MODELS SHOW THIS SYSTEM BECOMING RATHER LARGE...SO THE WIND
RADII FORECAST HAS BEEN SIGNIFICANTLY EXPANDED.

Isaac Will Continue To Dump Extremely Heavy Rain Across The Lower Mississippi Valley; New Tropical Depression Likely To Develop Out In The Central Atlantic Today (30)

Written by Rob Lightbown Crown Weather, Aug 30, 2012 -6:26am

Tropical Storm Isaac:
Isaac will continue to dump very heavy rainfall amounts on parts of the lower Mississippi Valley from today through Friday. Additionally, there will be a risk for spin-up tornadoes today across eastern and southeastern Louisiana, southeastern Arkansas, central and southern Mississippi, southern Alabama and the Florida Panhandle.

Copious amounts of moisture associated with Isaac will spread north and then northeastward this Labor Day weekend and heavy rainfall is possible across the Ohio Valley on Saturday and across the Ohio Valley and the Mid-Atlantic states on Sunday and Labor Day.

Looking elsewhere in the tropics this morning: Tropical Storm Kirk is of no threat to land and is expected to track into the open Atlantic over the next few days.

Invest 98L located out in the central Atlantic is likely to develop into a tropical depression today. This system is expected to track west-northwestward over the next few days. Now, given the fact that this system is developing rather quickly, the chances of it making it as far west as the United States coastline is quite low. The reason why is because there is no strong high pressure system located to the north of 98L. The latest global forecast guidance agrees with this assessment.

The GFS model guidance forecasts that 98L/Leslie northward out into the open Atlantic around 60 West Longitude. The Canadian model also turns this system up and out just east of 60 West Longitude. The European model seems to suggest that 98L/Leslie will be pulled northwestward towards Cape Cod in 9 to 10 days from now thanks to the trough of low pressure created over the eastern US by what will be left of Isaac. All of the hurricane track models forecast a curve northward right around 60 West Longitude.

At this point, I agree with the idea that 98L/Leslie will turn out into the open Atlantic by Sunday and Monday and at this point I do not think that this system will be a threat either to the United States or to much of the Caribbean.

For more on this story go to:

http://www.crownweather.com/?page_id=4557

Invest 98L Information