"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".

Sunday, August 20, 2017

Dry For Eclipse Monday : 'Unsettled' With Rain -- Storm Chances Tuesday & Beyond

"Arcus Accessory on the Archway!" - Canaveral Cruise Terminals -
Friday, August 18, 2017

An unsettled weather pattern of showers and thunder being possible (even at times over night (especially over the Atlantic) with some 'early on-set ' days possible with varying others modes of operation at hand beginning mid-day Tuesday or as late as earlier on Wednesday through end of month (a few details further in post) for today...

SUNDAY: Remnants of a tropical wave already encroaching in on the southeast 1/3 of state to glide over the state today mainly south of I-4.  Wind will be light in the moisture laden air-mass though mainly east to southeast up through the column less than 12 knts.  Guidance is split on how far 'east and north' rain could occur today with greater agreement that points to Southwest Florida.

The area from mainly Indian River and Brevard toward Osceola and eastern Orange Counties is a 'questionable region' in regard to whether they will experience mainly cloud cover or actual rain-showers/storms. The HRRR (High Resolution Rapid Refresh) model is consistent on saying 'no chances' (at least early this morning) whereas the 4KM NAM model for the same time is and has been  consistent on saying 'Yes' to the chances for this AOI (Area of Interest). 

The greater chance of storms/ rain for the mid-late afternoon is along Southwest Florida where the best chance of the combination of moisture and low level convergence along the West Coast sea breeze will occur. 

If the areas of Brevard/southern Volusia/Indian River and maybe even St Lucie are to see showers/storms it would be from south to north between 11AM heading toward the 2pm hour (generally speaking).

MONDAY: Sunday's activity will be the first in the next wave of the set to move in, which is on Tuesday. Between waves will be a lull in the action. Enhanced water vapor imagery clearly shows the respite timed nicely for "Eclipse Monday 2017". GFS does show rain storm potential however earlier in the day with a rapid decrease moving to the 'critical eclipse time-frame' of early to mid afternoon as the remaining moisture from Sunday's wave moves west and out of the picture. 

With that said, not to be surprised (just in case) if showers and cloud cover are still sensible (especially along the east coast) early in the day on Monday.


Expect forecasts to shift around rather significantly , almost on a daily basis,  from Tuesday on out at times due to the uncertainty of where, when, or even if an area (or areas) of low pressure might form, especially in the Wednesday - Sunday time frame. 

 A rather complex scenario is at hand in regard to surface and mid level features in regard to the evolution of circumstances, though there appears to be agreement. more or less. that abundant tropical moisture in the mode of PWAT air (precipitable water) values being near to well above the 2.00" mark (comparably speaking, in winter months it is normally 1/2" - 1/4" (or even less at times - aka 'dry air'))

The onset of the moisture is along the leading edge of an AOA being watched by the Hurricane Center which is not forecast but by one model to develop beyond an 'organized wave'. There does seem to be some agreement later on though after this area moves over the southern 1/2 of the state that a weak surface to even mid-level area of low pressure will form either over or just to the east of the state, but it's just too soon to say with any confidence if , when, or where that might occur.  

Apart from a wide mode of potentialities, regardless of what transpires there has been at this point no risk of a bona fide 'tropical threat' outside of perhaps what eventually might evolve for some areas of localized flooding in flood prone areas due to heavy rainfall (mainly during the afternoon and evenings) with consecutive convective days occurring back to back. And if a system does evolve into the realm of the naming convention type it is seen so far to do so east of the state and remain far enough away to not have a direct impact.

Arcus Shelf Accessory from Parent Thunderstorm over the Banana River - Port Canaveral, August 2017

Initially rain fall could occur most anywhere at any time (though mainly later morning through late afternoon) south of I-4 (Tuesday/Wednesday time frame), but as an upper level trough builds south from northern latitudes in response to ridging over the Western U.S., the steering flow becomes progressively more southwest toward the northeast especially as we head  into Friday through Next Weekend. If a low pressure area does form east of the state there could be one or two days of decreased activity with northerly flow to the west of the system, but it's too far out in time to hedge any bets on if that will occur; so far , even if that does occur as the GFS has been implying, moisture is foreseen to remain ample from 'some rain' chances even if so .

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