East coast trough is an important player
Posted by
Gianmarc on 8/20/2011, 11:17 am
There's a lot of talk about current invests turning into Florida-bound storms down the road. I don't see how it's possible to envision such a scenario right now when there is a pronounced, stationary trough that's been lingering off the east coast for nearly a week.
WV Loop showing the east-coast trough:
http://www.goes.noaa.gov/GSSLOOPS/ecwv.html
I know some models forecast a ridge to build in over the basin, and we do currently see a ridge insinuating itself into the picture from the east Atlantic, but keep in mind that storms head for Florida not because of a Bermuda high but because of a secondary ridge that builds in over the eastern U.S. and blocks the storm from moving poleward. A strong Bermuda high is only good enough to nudge a storm toward the Bahamas--you typically need a secondary ridge to seal Florida's fate.
Right now we do not see EITHER scenario panning out. We a lot of troughiness over the central Atlantic and a trough that is staying put off the east coast, and even if that system eventually gets kicked out of the way it will still leave a weakness in its wake that will not be plugged up instantaneously.
It will take a ridge over the eastern U.S. to close that door, otherwise any storm headed that way will ride that weakness up and out of the picture. By the way, the ridge that's been planted over TX all summer is drifting WEST, not east, and it is forecast to continue doing so.
WV loop showing troughiness over central Atlantic:
http://www.goes.noaa.gov/HURRLOOPS/huwvloop.html
Quote from latest Dallas-Fort Worth forecast discussion, issued this morning:
.PREV DISCUSSION... /ISSUED 323 AM CDT SAT AUG 20 2011/
THE UPPER LEVEL RIDGE OF HIGH PRESSURE THAT IS CURRENTLY CENTERED
OVER TEXAS AND BRINGING RECORD HEAT WILL SLOWLY SHIFT WESTWARD
THROUGH NEXT WEEK AND BRING INCREASING NORTH/NORTHWEST FLOW TO THE
REGION. THIS WILL RESULT IN SLIGHTLY COOLER TEMPERATURES THROUGH
NEXT WEEK A VERY SLIGHT INCREASE IN RAIN CHANCES. NEAR RECORD HIGH
TEMPERATURES ARE EXPECTED THE NEXT TWO TO THREE DAYS...THEN THE
SLIGHT COOL DOWN WILL BEGIN. TRIPLE DIGIT HIGH TEMPERATURES ARE
STILL EXPECTED IN MOST LOCATIONS THROUGH FRIDAY...BUT INSTEAD OF
HIGHS IN EXCESS OF 105 DEGREES THEY WILL BE CLOSER TO 100. WE WILL
LEAVE THE HEAT ADVISORY IN PLACE THROUGH SUNDAY EVENING.
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East coast trough is an important player - Gianmarc, 8/20/2011, 11:17 am Post A Reply
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