22 July 2008

Cristobal heading out to sea, Dolly heading for land...

Cristobal is now east of Cape Cod, south of Nova Scotia, and is a 55kt tropical storm.  It will continue heading generally eastward into the north central Atlantic and should only be a tropical system for another day or two.

Dolly, on the other hand, is of much greater concern.  Over the last 18 hours, the huge rainband that was far removed from the center has dissipated in favor on centralized deep convection.  This is the needed ingredient for strengthening: focusing the latent heating over the center.  The latest intensity is 60kts and 991mb, and is getting closer to hurricane status every hour.  It's also getting closer to landfall every hour... now just 200 miles southeast of Brownsville and heading NW at 10kts.  Landfall is expected early tomorrow morning near Brownsville as a hurricane.

Intensity at landfall is a tricky thing... the storm is showing every sign of rapid intensification, and it's at the classic current intensity to begin RI.  Vertical shear is basically negligible, and SSTs are 29C+.  So the problem is how fast will Dolly intensify on its approach?  NHC is forecasting landfall at 80kts, which is line with the model guidance, but models (and people) don't forecast RI well.

You can already see outer rainbands approaching the coast, and the eyewall is coming into view as well:
I will also keep a running loop of the short-range Brownsville radar at: http://einstein.atmos.colostate.edu/~mcnoldy/tropics/dolly08/Dolly_22-23Jul08.gif
The latest watches and warnings for Texas and Mexico are plotted graphically at:

And the easterly wave that exited Africa yesterday is looking very impressive.  It's now near the Cape Verde islands, and is consolidating its circulation.  It has a 1009mb Low, and is moving W at 15kts.  It is not forecast to intensify real quickly, but very gradually, and continue heading W-WNW.

Please visit my tropical Atlantic headquarters.

No comments:

Post a Comment