Now It’s Tropical Storm Arthur

After grazing the North Carolina coast Arthur will be picked up by a midlatitude front and ushered to sea. Friday’s New England rain will be enhanced (intensified) by Arthur’s moisture. That’s especially true in Eastern Connecticut and more so in Rhode Island and the Cape.

Atlantic TROPICAL STORM ARTHUR - Google Maps

Invest 91 became Tropical Depression 1, which is now Tropical Storm Arthur. I can’t not look!

Early season storms are usually wimps. Not always. Remember Andrew!

Intensity guidance, among the poorest prediction guesses we make, says Arthur will briefly become a hurricane on Friday. I expect no hurricane force winds onshore.

The spaghetti strands continue to be tightly clustered. A good sign, especially since the impact to Connecticut (where many of my friends still live) should be minimal, but still significant.

After grazing the North Carolina coast Arthur will be picked up by a midlatitude front and ushered to sea. Friday’s New England rain will be enhanced (intensified) by Arthur’s moisture. That’s especially true in Eastern Connecticut and more so in Rhode Island and the Cape.

By Saturday Arthur’s east of Cape Cod and steaming away. The weekend is saved in New England and elsewhere!

Remember: Though I do follow tropical systems and post when I can, you should depend on a meteorologist who works fulltime watching your weather. I am flattered people still value my opinion, but I shouldn’t be your ‘final answer.’ – Geoff

The Tropical Watching Begins

The are patterns to the season. Water temperatures and upper winds favor different places for formation at different times of the season. Right now the Atlantic is open for business!

I’ve been watching Colin. He’s the blob of clouds in the satellite image just above this text . Not very impressive looking.

He was a low then a tropical storm, then a remnant low, now a tropical storm again. Way out to sea Colin has posed a threat to no one.

Later storms will transfix me. Not Colin.

I watch storms differently than amateurs. I’m a charts, graphs and maps guy. Much of what I get is raw data. The rest flows from the Hurricane Center.

The National Hurricane Center is run like a university research project. There are forecasts for sure, but it doesn’t end there. Every system is sliced and diced in the open. The Hurricane Center issues written forecast discussions every six hours.

Because of decades old protocols everything is UPPER CASE. Here’s a short snippet (and a link to the full text of the most current discussion).

SOUTHWESTERLY VERTICAL SHEAR OF 20-25 KT CONTINUES TO HINDER SIGNIFICANT INTENSIFICATION OF COLIN…AND THESE UNFAVORABLE CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE NEXT 24 HOURS. HOWEVER…FROM 36 TO 48 HOURS…ALL OF THE GLOBAL MODELS ARE FORECASTING THE VERTICAL SHEAR TO WEAKEN SIGNIFICANTLY AS COLIN PASSES BETWEEN TWO UPPER-LEVEL LOWS AND MOVES UNDER A SMALL RIDGE…WHICH PROVIDES A BRIEF WINDOW OF OPPORTUNITY FOR COLIN TO STRENGTHEN. THE SHIPS AND LGEM MODELS BRING COLIN TO NEAR 60 KT BY 48 HOURS…WHEN THE CYCLONE IS NEAR BERMUDA…AND THIS TREND WAS FOLLOWED FOR THIS ADVISORY PACKAGE.

Nodding off?

Even after a storm dissipates lengthy papers are published. Here’s 43 pages on Katrina!

NHC does a pretty good job mostly–not always. I’m not saying anyone does better, just NHC isn’t always right. That can apply even when a storm is poised for landfall! It’s not like they’re not trying.

The science of forecasting hasn’t been perfected. More data would help. It still won’t totally solve the problem.

It’s easy to be thrown off because NHC issues definitive measurements that make it seem the storm has been measured with a microscope and calipers.

SUMMARY OF 200 AM AST…0600 UTC…INFORMATION
———————————————-
LOCATION…26.3N 67.1W
ABOUT 445 MI…715 KM SSW OF BERMUDA
MAXIMUM SUSTAINED WINDS…50 MPH…85 KM/HR
PRESENT MOVEMENT…NNW OR 335 DEGREES AT 14 MPH…22 KM/HR
MINIMUM CENTRAL PRESSURE…1007 MB…29.74 INCHES

Each of those numbers looks firm and exact. It’s really an estimate. The farther a storm is from shore the rougher those estimates are. Who can question them?

When Colin was first sighted over 2,600 miles from here there wasn’t much more than satellite observations to go by. Instrumentation off the coast of Africa is a little wanting. Everything was an educated guess–no more. It was too far away for the Hurricane Hunter airplanes to even consider.

A bad estimate has little downside when a storm is in an isolated corner of the ocean.

It sometimes seems like the Hurricane Center is cognizant of how their forecasts are used and smooths out the variability in storms. You don’t want people to let their guard down.

The slower a storm moves the more difficult it is to forecast. I’ve never seen the official forecast show a hurricane looping its own track. I’ve seen it happen enough times it no longer surprises me.

The are patterns to the season. Water temperatures and upper winds favor different places for formation at different times of the season. Right now the Atlantic is open for business!

Though the season began June 1 it’s about to hit its most active time peaking the second week in September. It’s seasonal the way the fall colors are predictably seasonal.

I’ll continue to watch Colin for the same reason a ballplayer takes BP in spring training. I need to get back into the rhythm. I need to practice using tools I haven’t used since last fall.

Not every storm will be Colin.

The Hurricane Forecast Arrives

That’s not to say I still don’t worry about a hurricane hitting the Northeast as happened tragically in 1938. I do. I worry a lot.

The Colorado State hurricane forecasters have issued their annual tropical weather call.

We continue to foresee above-average activity for the 2010 Atlantic hurricane season. We have increased our seasonal forecast from the mid-point of our initial early December prediction due to a combination of anomalous warming of Atlantic tropical sea surface temperatures and a more confident view that the current El NiƱo will weaken. We anticipate an above-average probability of United States and Caribbean major hurricane landfall.

What does this mean? Virtually nothing… and I’m not even going to take the cheap shot of mentioning this hurricane forecast comes from the very non-tropical and landlocked state of Colorado!

Unless you are an insurance underwriter or maybe someone selling building supplies hurricanes are anecdotal events. Individual places see hurricanes so infrequently that the difference between it being a 1% or 1.4% chance is meaningless. It’s like considering the odds you’ll get a straight flush every time you’re dealt a poker hand. It can happen, but it mostly won’t.

Even when judged by a broader view these studious projections have shown less than stellar accuracy lately. The same goes with forecasts from ‘for-hire’ forecasters. That’s not to say I still don’t worry about a hurricane hitting the Northeast as happened tragically in 1938. I do. I worry a lot.

In spite of the axiom, lightning and hurricanes often strike twice.