"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"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".

Tuesday, June 26, 2012

Debby Should Be "Doing It" Today thru Wednesday

Latest Mesoscale Analysis at 300mb (jet stream) Shows upper low in western Gulf
Continues. It seems likely it was this feature that got the ECMWF model off target
from the onset as relayed several posts ago . Possible future track of Debby (center not important)

TODAY: Debby is appearing quite stationary per first glimpses of visible satellite imagery. It is interesting that short term model indicates the center will come nearly ashore by noontime, only to relocate back offshore once again near to just south of Cedar Key, Florida. Either way, seems not to make much of a difference where the Center is located in regard to surface winds, since the strongest winds appear to be driven by the mid-level low pressure feature down to 2000 ft above ground.  The strongest winds this hour are not near the storm but rather toward the Keys and along SW Florida coastal areas and East Central Coastal areas. Rain showers are on the way right now as I type, which could contain wind gusts in the 40-55mph range. This will be the case most the day off and on as vort lobes rotate through, but more on this below. However infrequent that might be.

Latest radar likely well outdated by the time this post even comes out. Yellow lines
show 'most likelihood' for activity through at least mid-afternoon outside of the rains toward NE Florida related in another fashion to the storm. The only rain band that is most linked directly to Debby appears is along the West Coast north of Tampa
 TODAY: Rain-bands and showers on the move early on today. With quick motion and some/few cloud breaks and considering Debby has been behaving in a diurnal fashion for a few days now, expect there could be more moving in and 'popping in and out' rather quickly in increasing fashion after 10AM through mid-afternoon.  Wind profiles do not really support tornadoes today, not to say it is not impossible. Also must keep in mind that any variation in the configuration of the surface to mid-level features could change everything. So , it is 'possible' a tornado watch will be required by mid-late morning through early afternoon, but the primary concern would be strong wind gusts and straight-line winds due to the stronger winds just above the deck through the mid-levels being dragged to the surface in and near the rain storms. This sort of activity may or may not be handled on a case-by-case basis by the National Weather Service Offices as needed.

DEBBY: Models are coming into closer agreement with the future track of the storm. Bear in mind, as Debby moves into the coast much of the surface circulation up toward 2000 ft could start to weaken and become more broad, closely matching that of the mid-levels. In doing so, the stronger winds will NOT be near the center but south of it. Thus, the winds could continue, possibly more gusty tomorrow from Southern Volusia County toward Indian River through St. Lucie Counties.  The storm's timing is fairly close between guidance, with an exit off the east coast toward Wednesday evening. Debbie will be dragging a low level trough along its SW Flank, and this along with complex variables closer to the center will be the prime areas of interest for additional rainfall.  The GFS has been very good with this storm all along, as was favored in these posts when reading between the lines. It seems the ECMWF was picking up on the upper level low noted in that top image as had been noted. But, never can tell for sure. In any case, the two models are now in agreement with bringing the 850mb low center in toward Brooksville and exiting off the east coast somewhere between Ormond Beach and Oak Hill. A surface circulation will be in there as well which could exist within those bounds.
Graphic devised at 6AM, Tuesday, June 26th  See details below. It's not as complicated as it might first appear
DESCRIPTION OF GRAPHIC: Red lines show potential future track. This is inline with the GFS plots from several days ago. (see image further down)

RED LINES: Possible future track of surface to mid-level center
PURPLE: Chance of most concentrated activity today outside of the rains further north caused by indirectly related synoptic scale features. This zone 'might' require a tornado watch.
YELLOW: Bounds for best chances of quick moving squally like periods. Note, there could be very long breaks between periods of rain today, and some areas will receive very little rain if any.
GREEN: Further South, there remains a chance of similar activity today, but believe the chance of spin ups will be much less due to winds being more unidirectional with height further from the surface to mid-level circulations

**NOTE: As always, monitor TV or weather radio or other media outlooks from time to time, especially before heading out somewhere today to remain abreast of short-term conditions..and be alert for potential watches and warnings which could be forthcoming. The Storm Prediction Center has much of the state in a "Slight Risk" for severe weather related activity due to winds and a 2% Tornado risk, which is quite small. Not to say though, that it only takes 1 in the wrong place (such as one's house) to make all the difference. I see on radar right now a heavier cell which appears to be heading this way, and even that is not being warned for. Not really expecting much lightning today. BUT, any storm which is producing thunder, even if not frequent, will need to be taken with a serious conviction. It will take the taller storms today to really get rotation going outside of other factors to complex to go into detail over in a blog post.
THIS IMAGE IS FROM JUNE 22nd. Note the lavender arrows and question mark concerning possible future course. At this time , the forecast had been (officially) looking toward Texas
 Now, as of this hour, we see the new Official Forecast Track and zone of uncertainty.

Latest outlook will likely narrow down, this is close to what as a mere blog poster 'seems reasonable', although we could probably take off a good 75 miles at least from the north side of the cone and 30 miles from the south side of the cone.
WEDNESDAY: So far the heaviest rains with Debby could occur from Brevard through Indian River Counties on this day, under the one prerequisite. One teeny tiny factor..that being, that indeed Debby actually takes the forecast track. The GFS took a big jump overnight in moving the storm out when the previous run had Debby loitering around for several more days, but other models agree on the new timing issue. 

That is the best we can do at this point. Should Debby not get hinged up closely enough with the trough to the north, it's an entirely different ball game. Note also the graphic above. It is possible Debbie might work a little south today into tonight, if not while crossing the state somewhere along the line. But as noted, the center really is not the most important factor. The southern edge of the cone is possible where the strongest winds will occur on Wednesday, after-all, and maybe so even the rains to fall will be greater as well with time going through tonight into the earlier periods of the day (where they would be further north) , due to the trough hanging back behind the storm.

BEYOND: So far, it is looking quite dry. The official forecast is calling for thunderstorms each day toward the weekend, but I'm not seeing it yet. There will be sinking motions behind the storm, so it will take a good two days for things to get realigned. Warm toward the east coast with highs in the low-mid 90Fs are possible by Friday (if Debby moves out as currently surmised);   high pressure in the mid-levels could lag and suppress rainfall altogether except toward South Florida until the weekend. Even so, any activity appears will be restricted to late day interior sea breeze collisions with little steering.

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