30 June 2011

Arlene makes landfall

At about 15Z today, the center of Tropical Storm Arlene crossed the Mexican coastline near Cabo Rojo (about 45 miles south of Tampico) with 55kt sustained winds and up to a foot of rain further inland over the higher terrain.

Over the next day, it will weaken, produce a lot of rain, and eventually completely dissipate.  Elsewhere, the basin is quiet... but when the time comes, the next name on the list is Bret.

Please visit my tropical Atlantic headquarters.

29 June 2011

First storm of the season forms in Bay of Campeche

Not long after yesterday's update was sent out, the area of disturbed weather was upgraded to Tropical Storm Arlene, the first of the season.  As of the 15Z advisory today, it is a 45kt storm with a 1000mb central pressure.  It's located 155 miles ESE of Tampico MX and heading W at 7kts.  As expected, the vertical shear has decreased, and the storm was quick to take advantage of the improved environment.  Further strengthening is forecast prior to landfall, perhaps nearing or reaching hurricane intensity.

The track should bring the storm onto land during the overnight hours very close to Tampico.  Even at minimal hurricane intensity, by far, the greatest threat is the heavy rain that comes with tropical systems.  Strong winds and a 2-4' storm surge will also occur along the coast, especially north of where the center crosses the coast.  You can monitor the latest track forecast, watches, and warnings at http://www.nhc.noaa.gov/storm_graphics/AT01/refresh/AL0111W_NL+gif/

Finally, you can follow Arlene on radar at http://einstein.atmos.colostate.edu/~mcnoldy/tropics/arlene11/Arlene_29-30Jun11.gif

Please visit my tropical Atlantic headquarters.

28 June 2011

Bay of Campeche disturbance getting organized

Over the past week or so, there has been a persistent area of convection and depressed surface pressures over the Yucatan Peninsula and into the Bay of Campeche.  This disturbance is currently centered near 21.0N 93.4W, tracking WNW at 6kts, and has a 1006mb central pressure.  The circulation is broad and ill-defined, but has been improving gradually.

This system is expected to continue organizing as the sea surface temperatures remain at about 28.5C and the vertical shear decreases from the current 15kts to around 7kts by tomorrow evening.  Landfall will occur sometime Wednesday night into early Thursday morning near Tampico MX, and by far, the most significant threat will be the heavy rainfall.  The graphic below shows the forecast precipitation totals starting today and running through Sunday:

Should this get named, the first name this season is Arlene.  Climatologically, the first named storm in the Atlantic forms on July 9, so this would be just slightly ahead of an average season.

Please visit my tropical Atlantic headquarters.

01 June 2011

First day of hurricane season comes with a couple of disturbances

Today is the first day of the Atlantic hurricane season.  To help usher it in, there are two areas of disturbed weather to keep an eye on.

The first, a very compact system labeled AL93, has been tracking toward the southwest over the past day and has just made "landfall" near Daytona Beach FL as a 1013mb Low.  It is bringing heavy rain, hail, and/or gusty winds to much of the central FL peninsula, and will soon enter the northeast Gulf of Mexico.  Though unlikely, there is a chance that this will re-develop over the Gulf and head generally westward as a Tropical Storm.  I won't say any more about that unless it actually survives the Florida transit.

The second area of disturbed weather is in the central Caribbean, north of Colombia/Panama centered near 12N 77W.  It is nearly stationary, and although environmental conditions are unfavorable now, they could improve in 2-3 days, allowing this to develop and crawl NW-N toward the Yucatan-Cuba area.

The first couple of names on this year's roster are Arlene and Bret.  Since the blog format is new this season, I'm sending the posts to the old mailing list as well.

I'd also like to point out that the CSU's June 1 Seasonal Forecast is available at http://hurricane.atmos.colostate.edu/Forecasts/2011/june2011/jun2011.pdf ... the short version is that 2011 should be an active season, though not as active as the historic 2010 season.  The forecast calls for 16 named storms, 9 hurricanes, and 5 major hurricanes, or about 75% higher than average.

Please visit my tropical Atlantic headquarters.