Updraft: August 23, 2012 Archive

Scattered rain & thunder today; Tampa & Mobile Bay still in Isaac's possible path

Posted at 8:19 AM on August 23, 2012 by Paul Huttner
Filed under: Hurricanes

Scattered rain & thunder possible today in most of Minnesota

Isaac still a threat to RNC in Tampa Monday night (GFS model)

"Mobile Bay" solution painted by Euro Model

-Latest Twin Cities radar loop here

Source: Twin Cities NWS

Thursday thunder?

Look for a mixed weather bag today for the start of the 2012 edition of the Minnesota State Fair.

Spotty am showers may give way to mixed PM sun...and another batch of PM & evening T-Storms.

Highs should crack the 80s, and it may actually feel like August for a while today.

I'll be out at the MPR building on The Daily Circuit with Craig Edwards from 10am to 11am today. Hope to see you there!

Isaac still aiming at eastern Gulf of Mexico:

The latest model runs still seem to favor Hurricane Isaac approaching the Florida Keys late Sunday, then churning into the eastern Gulf by Monday.

Source: http://derecho.math.uwm.edu/models/al092012.png

The overnight GFS run has Isaac just southwest west of Tampa by midnight Tuesday.

Source: WxUnderground

The Euro has shifted slightly east, but still favors the westernmost solution with a landfall near Pensacola or Mobile Bay.

Source: WxUnderground

Either way Isaac will be a player early next week in Florida and the Gulf.

Stay tuned!

PH

Isaac trends west; Tampa breathing easier? New Orleans in play?

Posted at 5:44 PM on August 23, 2012 by Paul Huttner (3 Comments)
Filed under: Hurricanes

Westward trend in Isaac's track in latest forecast models

Tampa breathing easier? With each passing model run

Pensacola, Mobile Bay & New Orleans landfall chances increasing

European model leading the way on westward trend

Scattered showers in Metro & Minnesota into early Friday

Near 90 for the metro and southern Minnesota by Friday afternoon?

Source: Twin Cities NWS

Tracking Isaac:

The latest model trends support a westward shift in the official NHC track forecast from Isaac.

Source: NOAA/NHC

It now appears more likely that Isaac will clip Haiti Friday, cross Cuba sometime this weekend, and emerge into the Gulf of Mexico and gain hurricane strength on Monday.

http://derecho.math.uwm.edu/models/al092012.png

NOAA'a National Hurricane Center explains the shift...and lingering track uncertainties in their forecast discussion.

THE GUIDANCE HAS SHIFTED A LITTLE WESTWARD IN RESPONSE TO THE GLOBAL MODELS FORECASTING THE WEAKNESS IN THE SUBTROPICAL RIDGE TO BE SOMEWHAT FARTHER WEST THAN BEFORE. THE ECMWF IN PARTICULAR HAS MADE A SIGNIFICANT SHIFT...SHOWING A WEST-NW MOTION INTO THE CENTRAL GULF OF MEXICO BY DAY 5.

DESPITE THE GENERAL WESTWARD SHIFT...THE HWRF AND CANADIAN MODELS STILL CALL FOR ISAAC TO MOVE UP THE FLORIDA PENINSULA. THUS... SIGNIFICANT UNCERTAINTY REMAINS ABOUT THE THREAT ISAAC POSES TO FLORIDA AND OTHER PORTIONS OF THE GULF COAST. THE 96-120 HR POINTS HAVE BEEN SHIFTED A LITTLE WESTWARD FROM THE PREVIOUS ADVISORY AND LIE NEAR THE CENTER OF THE GUIDANCE ENVELOPE AND THE CONSENSUS MODELS.

Here's a great way to visualize the westward trend in the "official" NHC tracks over the past few days.

The European model remains the westernmost solution, and now takes a strong Isaac to the Louisiana Coast next Thursday.

Source: WxUnderground

The European is among the most reliable models in the past few years for hurricane tracks. The USA's GFS model is a close 2nd.

Source: National Hurricane Center 2011 verification report.

Overall trends favor putting Isaac into the Gulf Monday where Isaac may have some breathing room to grow. The chances of a USA landfall with Isaac look high....probably 80% at this point.

Friday's model runs should be critical in refining Isaac's eventual track and landfall.

PH

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