"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, March 5, 2011

Atlas Launch Chances Look Improved, Strong Storms Possible Sunday

Image shows the location of LC41, from which today's  launch of the OTV at 4:09pm is scheduled. Official forecast is calling for predominant favorable sky conditions, with the chance of an intermittent broken deck at 5000 ft. More on this in the the discussion below.

TODAY: Full latitudinal surface trough/cold front progressing through the Deep South late this morning. Tornado Watch box has been issued for parts of Southern Louisiana, Mississippi, and SW Alabama in advance of the boundary. This front will be affecting the Panhandle tonight and the remainder of the state working into early tomorrow morning through sunset (South Central/South Florida) and clearing the state by sunrise Monday with lingering affects far SE Florida/Keys. See image below for a forecast for 1pm tomorrow.

LOCALLY: Atlas V launch scheduled for today. Only factor that would preclude launch now it appears would be winds, which don't look strong enough/nor will be/ to hinder.  Forecast concern is a deck of 5000 Ft level clouds conducive for triggered lightning. But as it appears now, with a good deck of cirrus moving overhead as I type to last into peak heating (early afternoon), this deck will not be able materialize. Any clouds trying to form over the Gulf Stream to be advected toward the coast decay as they slide under the cirrus deck.

Also, any rain showers well offshore are petering out as they approach the East Central Coast as they run under the cirrus deck.  Surface winds at launch should be East to ESE at 12-18mph, gusting to 23mph.  As I type now, the latest observations along False Cape and the landing strip have winds gusting to the 21mph range. Is that too strong? That is not the official forecast, just my line of thinking. As such, believe the launch should be able to go, but bears watching in regards to wind. In any case, looks better than yesterday as of 11am.  We can see the pad from which it will launch is a bit further south of the Shuttle Launch pads per the image above.  The actual vehicle being launched looks for similar in shape to the shuttle, just smaller.

SUNDAY: Winds tonight to die down late night and shift from SE-SSE-S by daybreak. Mild overnight temperatures in the low-mid 60s under partly cloudy skies as some strong storms enter the Panhandle and progress eastward toward the Tallahassee region.  Day break over Central should yield to partly cloudy skies South Central/South Florida to near mostly cloudy far NW North Central. Winds S-SSW at 15mph, gusts to 22mph by midmornign.  Slight chance of showers with increasing mid-upper level clouds.

By late morning one of two weak pre-frontal boundaries will cross Central, perhaps accompanied by a rain shower.  The stronger trough will enter and cross  eastern portions of North Central and East Central Proper (from roughly the Pineda Cswy to Sarasota and points north between 11:30am - 3pm time frame.  During this time a 250mb jet streak is forecast to pass directly over Central Florida providing a lifting mechanism. Additionally, this will occur during peak heating, albeit offset/precluded of greater instability by early day clouds.  Winds with height become increasingly unidirectional working into the afternoon hours, but they do increase namely along and north of the Beach Line - I4/Tampa. line.  Could see a slight sea-breeze as well  further south along the coast as far north as Sebastian/Melbourne Beach area.  Actual cold front does not cross the East Side of the state until near to just after dark. Temperatures aloft tomorrow will be cold with 500mb forecasts showing -15C and 700mb showing 0C.  If this were a summer day, we'd be talking about severe storm likelihoods with those numbers (considering the surface temperature would be in the 90Fs).  Below is a forecast for 1pm EDT tomorrow. Orange areas are weak troughs preceding the front which will take all afternoon to cross the state. The parent surface low near Virginia will be moving NNE nearly paralleling the coast.

However, this is not summer. Expect highs tomorrow, assuming there will be increasing clouds spreading from west to east during the time of heating, to only be in the upper 70Fs, warmer South Central and South with some low 80s SE Florida.  Still, hard to ignore the jet stream streak winds, moderate instability, and weak convergence along the surface boundary, especially right at the coast from Cape Canaveral to Melbourne Beach (especially if a sea breeze develops).  

With this said, believe strong storms are possible all of North Central north of the Beachline from North Tampa Bay east to Oakhill, with better chances the further north one goes.  Slightly less likely chances north of a line from Sarasota to Sebastian Inlet. Immediate East Coast from Daytona to Sebastian between 11AM to 4:00pm (south end). We can iron out the details early tomorrow in regard to timing, and/or the reference to strong storm potential. The "strong' part would be in the form of wind gusts of 40-48mph and tiny hail. And maybe a brief/weak 'spin-up' tornado east of I-95 from Cocoa Beach - Sebastian (however, this chance is close to entirely nil as of this writing).

Further south toward southern South Central to SE Florida will experience convective showers with thunder possible as well, particularly from near Boyton Beach south to Miami along the East Coast beginning mid afternoon through dark. But activity there should be below the 'strong' threshold due to the timing of the boundary entering this area close to, if not after, dark, as well as that fact the mid-upper level winds of substantial strength will be pulling off to the north and east of this area after having crossed Central Florida before the surface boundary (s) arrive down there.

MONDAY: Pleasant day at hand post-front. Temperatures comfortable in the mid-upper 70s. NW winds veering to NNE east late. Could get smoky smelling over much of Brevard due to 'Iron Horse'.

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