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Post Tropical Cyclone Debby


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TROPICAL STORM DEBBY DISCUSSION NUMBER 5

NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012

1000 AM CDT SUN JUN 24 2012

IT IS A VERY DIFFICULT AND HIGHLY UNCERTAIN FORECAST THIS MORNING.

DEBBY HAS BEEN MOVING VERY SLOWLY TOWARD THE NORTHEAST...040 AT 3

KNOTS...WHILE THE WIND RADII HAVE BEEN EXPANDING IN THE EASTERN

SEMICIRCLE. THIS HAS PROMPTED ADDITIONAL TROPICAL STORM WARNINGS

AND WATCHES FOR PORTIONS OF THE FLORIDA COAST.

DEBBY CONTINUES TO BE SHEARED WITH MOST OF THE THUNDERSTORM ACTIVITY

NORTH AND EAST OF THE CENTER. THIS SHEAR IS EXPECTED TO CONTINUE

FOR THE NEXT DAY OR SO...ALTHOUGH SOME DECREASE IN THE SHEAR IS

POSSIBLE AFTER THAT...PARTICULARLY IF THE ECMWF VERIFIES. THE

OFFICIAL FORECAST IS A LITTLE LESS AGGRESSIVE THAN THE PREVIOUS

FORECAST...BUT REMAINS ABOVE MOST OF THE EXPLICIT INTENSITY

GUIDANCE.

THE TRACK FORECAST IS EVEN MORE COMPLEX. THE GFS INSISTS ON A TRACK

TOWARD THE NORTHEAST AS DEBBY BECOMES EMBEDDED WITHIN A LARGE

MID-LATITUDE TROUGH. HOWEVER...THE ECMWF AND THE HWRF BUILD A RIDGE

TO THE NORTH OF DEBBY AND FORECAST A WESTWARD TRACK. GIVEN THE

WESTWARD TURN INHERITED FROM THE PREVIOUS FORECAST...AS WELL AS THE

HISTORICAL STRONG RECORD OF THE ECMWF...THE NEW OFFICIAL FORECAST

MOVES DEBBY INITIALLY A LITTLE BIT TO THE NORTHEAST TO REFLECT

CURRENT TRENDS BUT THEN TURNS THE CYCLONE BACK TOWARD THE WEST OR

WEST-NORTHWEST IN 24 TO 36 HOURS. A MAJORITY OF THE GFS ENSEMBLE

MEMBERS NOW ARE CONSISTENT WITH THE DETERMINISTIC RUN...WHICH WAS

NOT THE CASE YESTERDAY...MAKING A STRONGER CASE FOR THE EASTWARD

SOLUTION. WE MUST BE READY TO MAKE A CHANGE OF THE FORECAST TRACK

AT ANY TIME.

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Interesting track-forecast discussion:

GIVEN THE WESTWARD TURN INHERITED FROM THE PREVIOUS FORECAST...AS WELL AS THE HISTORICAL STRONG RECORD OF THE ECMWF...THE NEW OFFICIAL FORECAST MOVES DEBBY INITIALLY A LITTLE BIT TO THE NORTHEAST TO REFLECT CURRENT TRENDS BUT THEN TURNS THE CYCLONE BACK TOWARD THE WEST OR WEST-NORTHWEST IN 24 TO 36 HOURS. A MAJORITY OF THE GFS ENSEMBLE MEMBERS NOW ARE CONSISTENT WITH THE DETERMINISTIC RUN...WHICH WAS NOT THE CASE YESTERDAY...MAKING A STRONGER CASE FOR THE EASTWARD SOLUTION. WE MUST BE READY TO MAKE A CHANGE OF THE FORECAST TRACK AT ANY TIME.

I'll bet they're way over this system. :lol:

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TROPICAL STORM DEBBY DISCUSSION NUMBER 5

NWS NATIONAL HURRICANE CENTER MIAMI FL AL042012

1000 AM CDT SUN JUN 24 2012

IT IS A VERY DIFFICULT AND HIGHLY UNCERTAIN FORECAST THIS MORNING.

DEBBY HAS BEEN MOVING VERY SLOWLY TOWARD THE NORTHEAST...040 AT 3

KNOTS...WHILE THE WIND RADII HAVE BEEN EXPANDING IN THE EASTERN

SEMICIRCLE. THIS HAS PROMPTED ADDITIONAL TROPICAL STORM WARNINGS

AND WATCHES FOR PORTIONS OF THE FLORIDA COAST.

DEBBY CONTINUES TO BE SHEARED WITH MOST OF THE THUNDERSTORM ACTIVITY

NORTH AND EAST OF THE CENTER. THIS SHEAR IS EXPECTED TO CONTINUE

FOR THE NEXT DAY OR SO...ALTHOUGH SOME DECREASE IN THE SHEAR IS

POSSIBLE AFTER THAT...PARTICULARLY IF THE ECMWF VERIFIES. THE

OFFICIAL FORECAST IS A LITTLE LESS AGGRESSIVE THAN THE PREVIOUS

FORECAST...BUT REMAINS ABOVE MOST OF THE EXPLICIT INTENSITY

GUIDANCE.

THE TRACK FORECAST IS EVEN MORE COMPLEX. THE GFS INSISTS ON A TRACK

TOWARD THE NORTHEAST AS DEBBY BECOMES EMBEDDED WITHIN A LARGE

MID-LATITUDE TROUGH. HOWEVER...THE ECMWF AND THE HWRF BUILD A RIDGE

TO THE NORTH OF DEBBY AND FORECAST A WESTWARD TRACK. GIVEN THE

WESTWARD TURN INHERITED FROM THE PREVIOUS FORECAST...AS WELL AS THE

HISTORICAL STRONG RECORD OF THE ECMWF...THE NEW OFFICIAL FORECAST

MOVES DEBBY INITIALLY A LITTLE BIT TO THE NORTHEAST TO REFLECT

CURRENT TRENDS BUT THEN TURNS THE CYCLONE BACK TOWARD THE WEST OR

WEST-NORTHWEST IN 24 TO 36 HOURS. A MAJORITY OF THE GFS ENSEMBLE

MEMBERS NOW ARE CONSISTENT WITH THE DETERMINISTIC RUN...WHICH WAS

NOT THE CASE YESTERDAY...MAKING A STRONGER CASE FOR THE EASTWARD

SOLUTION. WE MUST BE READY TO MAKE A CHANGE OF THE FORECAST TRACK

AT ANY TIME.

haha, just not this time ok folks

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New forecast track very similar to the 00Z Euro and EC ensemble mean, hedged slightly to the east to account for trends this morning. It makes sense, for the sake of not confusing the public. If 12Z Euro is east, we'll probably see substantial changes to the 4pm advisory.

I'm actually more surprised they keep it a hurricane Wed morning. For the first time in Debby's short life, dry air over the western Gulf could become an issue. Given the fact that the mid-level and low-level centers continue to be misaligned, it wouldn't take much to really disrupt the circulation. The proximity to land and a consistent northward trend relative to previous forecast tracks also makes forecasting much more intensification a risky bet.

Edit to add: 8 new posts in the time it took me to type this? You guys are trigger happy! :gun:

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kind of surprised they're not hedging their swath bets a little more, so if the east trend continues the next few runs they don't have to make a near 180

The cone of uncertainty is not adjustable. It accounts for the average track error for 2/3rds of all storms.

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When I got on today, I was expecting a more organized system that could actually sustain and strengthen throughout the day.

What I have is a tropical cyclone getting blasted by shear and going the exact opposite way it was forecast to do yesterday. Not to mention that it's streaking this early in the day.

Fun times...

SAT_GUL_VIS_ANI.gif

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And something that seriously needs to be reevaluated.

That last line by Avila almost asks for it.

Some folks are raking Avila through the coals for that comment...but I get where he went with it...and given *history* I can see why they hold onto the EC.

I agree with your first point 100% as well. If they need to adjust at the intermediate they should be allowed to (if there's cause to do so).

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