Isaac targets New Orleans; 6-12 ft “storm surge” will test levees

Isaac approaching Louisiana Coastline today

85 mph? NHC forecasting a Category 1 hurricane at landfall tonight

6 to 12 feet - expected "storm surge" with Isaac

High tide? Isaac expected to come ashore at high tide tonight

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Levees tested - This will be the 1st significant test of New Orleans levee system since Katrina in 2007

7 years since Hurricane Katrina devastated New Orleans on August 29, 2005

The "eye" of Isaac - Isaac finally forming an eye Tuesday morning off the Louisiana Coast

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Source: NOAA

Here comes Isaac:

Isaac continues to churn away, and confound forecasters in the Gulf of Mexico.

After a week of dueling models and varying intensity forecasts, Isaac is finally bearing down on New Orleans and the mouth of the Mississippi today.

Source: NOAA/NHC

Isaac continues to develop slowly, and has had trouble filling in on the northern "semicircle" ...or northern side of the storm.

As Isaac finally becomes a hurricane today, forecasters at NHC now bring Isaac ashore after midnight tonight/early Tuesday as an 85 mph Category 1 hurricane.

Source: NOAA via WSI

If there's any good news here, it's that Isaac may not have time to develop into a monster Cat 2 or 3 hurricane.

Taking his time:

Isaac is moving slowly today....to the NW around 7 mph. That may pose some problems for New Orleans as the storm crawls ashore tonight.

1) A slower moving storm means Isaac's wind & waves will pound the coast line and the levees on Lake Pontchartrain for a longer period of time.

2) The storm will still have more time to strengthen over the warm (82F+) waters of the Gulf of Mexico.

3) Rainfall totals (currently forecast at 7" to 14") may increase as the storm sits over New Orleans through Wednesday.

4) The storm is expected to come ashore at or near high tide tonight. That may add to Isaac's storm surge, currently forecast at 6 to 12 feet.

Source: NOAA

The surge, wind and waves Isaac will test the upgraded levee system in New Orleans through Wednesday. remember with Katrina the damage came after the hurricane had largely passed. It looked like New Orleans had dodged a bullet, until the levees failed just after the storm. We may not know the full extent of Isaac wrath on New Orleans until sometime late Wednesday or Thursday.

You can watch live coverage from WWL in New Orleans here.


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Drought Buster? Isaac may ease drought in some areas:

One benefit from Isaac may be in some of the drought plagued areas of the Midwest. Check out the forecast 5-day rainfall totals from Isaac below.

Isaac may dump several inches of rain in parts of Arkansas and Missouri. That could help ease drought...and possibly raise flows on the Mississippi River by late this week.

It is possible that some areas may go from drought to flood by this weekend.

Source: NOAA/HPC

Minnesota Forecast: Heat wave ahead

Source: Twin Cities NWS

Some spotty rain will cross Minnesota today, but Isaac's rains will probably stay south of Minnesota.

Instead, get ready for what looks like the hottest week for the rest of 2012.

Source: Twin Cities NWS

High pressure will build into the Upper Midwest this week, as a late August heat wave cranks up.

Temps should stay tolerable today in the upper 80s. A welcome shower or T-Storm can't be ruled out today.

By Wednesday the heat will come with full force and peak Thursday near 100 degree in the metro and southern Minnesota before easing back to around 90 for the Labor Day weekend.

Source: Iowa State University

Get ready for one more blast of AC-worthy heat this summer in Minnesota.

PH