F
Current Radar or Satellite Image

Flhurricane.com - Central Florida Hurricane Center - Tracking Storms since 1995Hurricanes Without the Hype! Since 1995


92L now up to a 60% chance for development. Recon out there but just under the threshhold for classification, may become a TD later today.
Days since last H. Landfall - US: Any 297 (Idalia) , Major: 297 (Idalia) Florida - Any: 297 (Idalia) Major: 297 (Idalia)
 


General Discussion >> Other Storm Basins

CoconutCandy
User


Reged:
Posts: 245
Loc: Beautiful Honolulu Hawaii
'Explosively' Developing Invest 97C Nearing the Hawaiian Islands
      Tue Sep 21 2010 10:43 PM

Aloha Friends!

Been away most of the season from posting and commenting, but it's nice to be back with something interesting to share with you!

A weak, low level vortex embedded in the Central Pacific Monsoonal Gyre these past few days has begun to develop 'explosively' in the past 12 to 18 hours or so.



And a Tropical Cyclone Formation Alert (TCFA) has recently been issued for this compact, robust little Invest. So apparently the Central Pacific Hurricane Center (CPHC), the Joint Typhoon Warning Center (JTWC), the Navel Research Lab (NRL) and the Fleet Numerical Meteorology and Oceanography Center (FNMOC) feel there are justifications to warrant the posting of a formation alert.



------------------------------------------------------



Additionally, the CPHC has just revised their 'Graphical Tropical Weather Outlook' product to reflect the increasing probability of tropical cyclogenesis, now at 30%, or the beginning of the 'Medium' range.



========================================
CPHC: "An area of showers and thunderstorms is located about 535 miles south southeast of Hilo, Hawaii, and has been moving west northwest near 10 mph. Although thunderstorms have decreased in coverage during the day, slow development is possible. There is a medium chance, 30 percent, of this system becoming a tropical cyclone during the next 48 hours."
========================================

NOTE the forecaster wrote "Although thunderstorms have decreased in coverage during the day ..." to implicitly acknowledge the typical diurnal convective minimum (the sun's heating of the upper levels of the troposphere) and a general warming of the cloud tops. But I suspect that, with the rapidly approaching sunset (local basin time) and the overnight diurnal convective maximum (when the lack of the overhead sun causes the upper troposphere to cool, thus slightly increasing the lapse rate, and promoting the development of bigger, stronger, deeper and more intense thunderstorms) we may very well see some "Bursting Convection", with large cells attaining very cold cloud top temperatures, perhaps in excess of -80 degrees C or more. In a nutshell: Look for large and strong and persistent, or at least cycling, thunderstorms to form very near or over the already very well developed low level circulation center (LLCC).

Pressures have already fallen a least 1 mb since this morning (Hawaii time!) and the anticipated deep, sustained thunderstorms overnight, overlying the LLCC, will surely drop it a few mb's further. It *appears* that tropical cyclogenesis is already well underway.



Early Model Guidance (which can be a bit sketchy while a developing system is still in the 'Invest' stage) seems in fairly good consensus, tracking the system generally NW or WNW through the next day or two, then almost unanimously turns the system towards the WSW or even the SW, as the system will apparently traverse into an area of increasing SW'erly shear, thus collapsing the deep convection and allowing a shallow, low level system to be 'steered' by the prevailing NE'erly trade wind flow.

The SHIPS intensity forecast, too, reflects this scenario by *slightly* strengthening the disturbance initally, but then weakening it, only to restrengthening it again as the shallow system (by that time well WSW of the Hawaiian Islands) finds itself in increasingly warmer Sea Surface Temperatures (SST's) and decreasing upper level shear once again.

The BIG question is, at this point, will the upper shear between the Tropical Disturbance and the Hawaiian Islands slacken, thus allowing a continued NW or WNW motion, or will the disturbance become sheared sufficiently to allow the trades to drive a shallow system towards the SW?

----------- More when I can find the time !! -------------

Edited by CoconutCandy (Wed Sep 22 2010 07:46 PM)

Post Extras Print Post   Remind Me!     Notify Moderator


Entire topic
Subject Posted by Posted on
* 'Explosively' Developing Invest 97C Nearing the Hawaiian Islands CoconutCandy Tue Sep 21 2010 10:43 PM
. * * Re: Developing Invest 97C Near the Hawaiian Islands CoconutCandy   Wed Sep 22 2010 06:55 PM

Extra information
0 registered and 5 anonymous users are browsing this forum.

Moderator:  



Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled

Rating:
Thread views: 3968

Rate this thread

Jump to

Note: This is NOT an official page. It is run by weather hobbyists and should not be used as a replacement for official sources. 
CFHC's main servers are currently located at Hostdime.com in Orlando, FL.
Image Server Network thanks to Mike Potts and Amazon Web Services. If you have static file hosting space that allows dns aliasing contact us to help out! Some Maps Provided by:
Great thanks to all who donated and everyone who uses the site as well. Site designed for 800x600+ resolution
When in doubt, take the word of the National Hurricane Center