"But seeing they could not See; hearing they could not Hear"
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"From its chamber comes the whirlwind, and cold from the scattering winds." - Job 37:9.

"The wind blows to the south and turns to the north; round and round it goes, ever returning on its course".

Saturday, August 4, 2012

Chances of Rain/Thunder Much Later Today/Tonight with Wave?

Storm Prediction Center mesoscale analysis extracted from the Rapid Refresh/RUC shows the surface based axis of the Tropical Wave has entered South Florida and tilting toward the NE. The mid-level
axis is a bit further back to the east (barely) . PROBLEM, the axis in the mid-levels is dry with the bulk of the moisture well behind it and along the northern 'crest of the wave'
TODAY: Winds at Canaveral have actually gone N-NNE in some locations per surface observations. Prime indicator that East Central is still ahead of the tropical wave - wind shift line  axis at the low levels. It appears the greatest moisture in the mid-levels needed to make rain resides yet further back than this surface wind shift line with a dry slot apparent as of the latest guidance. The dry slot could take nearly all day to clear the coast and shift inland, but per some guidance will throw in as shown below the rain chances later today toward late afternoon and into the evening. The NAM continues to show a tiny vorticity center in the mid-levels as is shown above moving directly over the Cape Canaveral/Titsuville area and then continuing toward Ocala then into the Big Bend heading into Sunday.  Meanwhile, with the dry slot, very muggy with possible showers mainly west of the river intracoastals but more and most likely near the first area where moisture increases and along sea breeze boundaries toward the SW Coast and interior. Best rain chances eventually could well be near and north of the vorticity lobe where coastal convergence will be maximized due to slightly stronger low-mid level winds (but nothing significant in the wind regard).

SW Coast region with inland showers possible about anywhere most likely much later (if at all) toward the East Coast from Brevard County and North . Again though, this is a mere rough guesstimate so as always consult the Official Forecast from the National Weather Surface.  We may eventually be hearing about the chance of waterspouts come late today or tonight from any strong, onshore rolling shower  or storm, but again the time (if ever) is questionable in regard to rainfall chances
  TONIGHT: NAM is consistent with bringing this vorticity center shown into coastal Central Florida with the surface reflection of a weak low level circulation over South Florida, The entire trough moves WNW over night with greater moisture continuing from what is currently in place on Sunday behind it being dragged behind on its tail flank. It is noted that temperatures aloft are much warmer now, or are forecast to warm, thus thunder might be hard to come by heading into Sunday.  It could well be that any rain showers with cool winds will stabilize large areas right from the get go, and with such slow movement of shower activity it might be that widespread coverage at one  time will be hard to come by if ever. This is more of a 'different slant of the story' from the main broadcast weather headlines possibly been heard elsewhere.

Meanwhile, Storm Ernesto is moving West into the Caribbean as we read and speak. The official guidance can be seen on the future track on any channel. Interestingly, the GFS shows the track to move a little toward   the south, and the latest guidance on CIMMS shows the Deep Layer Mean flow for this 'less than well organized system' could take it in a more WSW direction for quite some time by later today and into tonight, into Southern regions of the Yucatan or a bit further north. Based on those tid bits of  (model data) information as well as the Euro which last I looked took it practically into Central America the concerns for other than Jamaica are as of right now not too high, at least not in regard to Florida's perspective.  

Locally, rain chances look questionable to me through Monday, with both locations and timing of rainfall a tough call. With warm air aloft, any rain cooled air regions will have a tough time manifesting much of anything more due to limited instability as cloud cover increases. We'll just have to see how it all plays out. Could end up being a mainly nocturnal event from start to finish near the east coast and eventually a broader area heading into Monday.

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