Sep-tacular Sunday; NYC tornado; The immense challenge of weather forecasting

Sep-tacular Sunday Does it get any better?

60s & 70s for highs in most of Minnesota this weekend

Source: Twin Cities NWS

Patchy frost? 30s for lows in northern Minnesota this weekend

Severe Saturday in the northeast Derecheo & tornadoes

New hurricane intensity & "effect" scale? Revamping the Saffir-Simpson Scale

Predicting the future: Weather forecasting shows great gains in the face of immense challenges

They also seem to possess a high-frequency-trader's skill for managing risk. Expert meteorologists are forced to arbitrage a torrent of information to make their predictions as accurate as possible. After receiving weather forecasts generated by supercomputers, they interpret and parse them by, among other things, comparing them with various conflicting models or what their colleagues are seeing in the field or what they already know about certain weather patterns -- or, often, all of the above.

More on the immense tasks facing today's weather forecasters from the New York Times below...

http://www.therockwells.net/webcam/webcam.htm

Football Weather: What happened to my summer?

I suppose we shouldn't complain, but that's what people do best when it comes to weather.

This has been the longest "summer" I can recall in Minnesota. Ice out and trees blooming in March. 80 on St. Patty's Day? Lilacs in April. Swimmable lakes in May.

I suppose a "real" cold front was due. It is September after all.

This weekend feels like late September or October. A rare brisk northwest breeze whipped up a few serious whitecaps on areas lakes Saturday.

Forecast models picked up on a change in the intensity of our new northwest flow regime. With temps in the upper 30s up north, a touch of frost is possible up north this weekend.

As high pressure settles in Sunday things should quiet down. Sunday looks the sunnier, gentler day of the weekend.

Of course the best day in sight looks like Monday, with highs back into the mid-upper 70s. Has there been a bad Monday this summer?

Source: Twin Cities NWS

The warm dry weather comes with a price. A growing drought, and high fire danger in Minnesota early this week.

The overall weather pattern the next 2 weeks looks to alternate between warmer spells in the upper 70s to near 80 degrees, punctuated by cooler Canadian fronts with northwest winds that will drop temps into the 60s. Pretty typical stuff for September.

Rare NYC tornado & derecheo slams Northeast Saturday:

Severe storms hammered the east Saturday from Pennsylvania through New York & New Jersey. A rare waterspput/tornado (where have I heard this lately) tore up parts of Brooklyn in NYC.

PUBLIC INFORMATION STATEMENT

NATIONAL WEATHER SERVICE NEW YORK NY

425 PM EDT SAT SEP 8 2012

...TORNADO CONFIRMED NEAR BREEZY POINT IN QUEENS COUNTY NY...

LOCATION...BREEZY POINT IN QUEENS COUNTY NY

DATE...SEPTEMBER 8 2012

ESTIMATED TIME...1058 AM EDT

MAXIMUM EF-SCALE RATING...EF0

ESTIMATED MAXIMUM WIND SPEED...70 MPH

MAXIMUM PATH WIDTH...50 YARDS

PATH LENGTH...200 YARDS

BEGINNING LAT/LON...40.55N / 73.93W

ENDING LAT/LON...40.56N / 73.93W

* FATALITIES...0

* INJURIES...0

* THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT(S) AND PUBLICATION IN NWS STORM DATA.

...SUMMARY...

THE NATIONAL WEATHER SERVICE IN NEW YORK NY HAS CONFIRMED A TORNADO NEAR BREEZY POINT IN QUEENS COUNTY NY ON SEPTEMBER 8 2012.

A WATERSPOUT THAT BEGAN OVER THE NEW YORK HARBOR ENTRANCE WATERS MOVED ONSHORE AT THE BREEZY POINT SURF CLUB...AND PASSED OFFSHORE NEAR BEACH 216TH STREET. THE PARENT STORM CROSSED ROCKAWAY INLET AND MAY HAVE SPAWNED AN ADDITIONAL TORNADO IN THE CANARSIE SECTION OF BROOKLYN. A DAMAGE SURVEY THERE IS STILL ONGOING.

Source: NOAA/SPC

Here are the latest storm reports form NOAA's Storm Prediction Center. (SPC)

Source: NOAA/SPC

Did Isaac expose the need for a new "Hurricane Intensity Scale?"

Let's face it, forecasting Isaac was a big pain in the you know what from the beginning.

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The forecast track started out in Florida, then flipped back and forth between Tampa and the Gulf Coast...finally landing in New Orleans...and doing the two step as it stalled near the coast.

Yeah, like any forecast model is going to nail that one a week out.

Perhaps the most telling part of Isaac is that it was another example of a "Category 1" storm doing Cateogy 3 damage. Isaac's slow forward speed unleashed a long duration, slow motion pounding of the Louisana Coast. Storm surge damage from Isaac was much worse in Plaquemines Parish southeast of New Orleans, than it was with Katrina...a Category 4 monster.

We've known for years that storm surge and rainfall are far more devastating (and cause many more deaths and far more damage) than hurricane wind speed.

Many voices within the hurricane forecasting community are speaking out about the need to come up with a new scale that more accurately reflect the effects from hurricanes.

Here's an excerpt from AMS President Marshall Shepherd on the need for more clarity with hruuicanes.

Lessons from Isaac: Communicating the hurricane hazard

As a meteorologist intrigued by storms since childhood, Hurricane Isaac was an interesting storm to observe from many perspectives. However, increasingly I have become concerned about how we communicate the hurricane threat to the public and emergency managers. The added backdrop of the looming Republican National Convention and a possible landfall in the New Orleans/Mississippi area exactly 7 years after Hurricane Katrina provided additional nuance and urgency. Herein, I offer a few thoughts to stimulate thought and discussion as we go forward.

The Rain and Category Bias: A major concern for me is that media and public familiarity with the Saffir-Simpson (SS) scale leads to underestimation of the most deadly threat of a hurricane, inland freshwater flooding. It is very common to see a reporter on the beach in the wind, struggling to stand. It is also common to focus on what the SS category of the storm is and when it will become a hurricane or a "category 3" storm. A gentleman from Plaquemines Parish, discussing a levee breach and severe flooding in the Parish said, "we didn't leave because they were saying it was not going to be a Katrina, but we wish we did". This illustrates, in my view, an over dependence on assuming threats are only associated with major hurricanes. In fact, our own studies have shown that weaker storms can be significant rain-flood producers. With Isaac, the storm was also very large in area and moving very slowly. This combination led to localized rainfall totals in the 20 to 30 inch range. The "water" from rainfall and flooding is just as significant as the wind and surge. Is it time to consider an augmentation of the Saffir Simpson scale to capture the rainfall-flood threat? It is a difficult science problem, but probably one worth investigating. I also argue that our media colleagues must consider their coverage strategy and category "anticipation" or hype carefully.

I agree that it's time to come up with a "Hurricane Effect Scale" that focuses more accurately on the anticipated effects from incoming hurricanes. Flood threat from heavy rainfall and storm surge should probably be the most highlighted aspects, with wind damage potential coming in second. Why not marry the Fujita EF Scale with hurricane winds? After all...wind damage is wind damage no matter the source.

Predicting the Future: Do people really understand the monumental task of Weather Forecasting?

If I only had a dollar for every time I've heard the throwaway line at parties....

"Wow I wish I had a job where I could be wrong half the time and still get paid!"

I get that some people's favorite sport is blaming the weatherman. And to be fair, I get just as many people who come up to me and say how amazed they are by what we do...and how truly interesting they find the science behind weather forecasting.

I like to challenge people to take a stab at predicting anything in the future. Try it some time.

-What are the 3 top news headlines going to be tomorrow?

-Who will win each NFL game this weekend, and by how much?

-Who will win the Presidency in November, and by how much?

There is enough data available in advance to make an educated guess at any of these "forecasts."

Think you can be right 90% of the time? That's how often weather forecasters are right about tomorrow's forecast, often with far less "initial data" to work with. You simply remember the 1 in 10 times we're wrong.

Here's a great piece from the New York Times on just how complicated weather forecasting is, and why we've made great strides in predicting the future when many other fields of future prediction (like economists) have not fared as well.

In 1972, the service's high-temperature forecast missed by an average of six degrees when made three days in advance. Now it's down to three degrees. More stunning, in 1940, the chance of an American being killed by lightning was about 1 in 400,000. Today it's 1 in 11 million. This is partly because of changes in living patterns (more of our work is done indoors), but it's also because better weather forecasts have helped us prepare.

Perhaps the most impressive gains have been in hurricane forecasting. Just 25 years ago, when the National Hurricane Center tried to predict where a hurricane would hit three days in advance of landfall, it missed by an average of 350 miles. - Now the average miss is only about 100 miles.

Why are weather forecasters succeeding when other predictors fail? It's because long ago they came to accept the imperfections in their knowledge. That helped them understand that even the most sophisticated computers, combing through seemingly limitless data, are painfully ill equipped to predict something as dynamic as weather all by themselves. So as fields like economics began relying more on Big Data, meteorologists recognized that data on its own isn't enough.

Enjoy our 1st early fall-like weekend!

PH