First Day of Fall, Rain Chances Increase Through Wednesday

Red Sky in Morning, Sailor Take Warning
Fall Began at 4:44 AM EDT as the  Sun Crossed the Equator Heading South 

TODAY: Pattern shift had commenced overnight with a return to westerly type winds for the most part for the next few days (finally) after a long period of easterlies. The pattern shift is not a surprise, it's been foreseen for several days in various forms but guidance seems to be coming together and what will happen next at the most superficial level . 

A frontal boundary like feature near I-10  will oscillate North and South for a few days while a prefrontal trough will oscillate north south somewhere across Central Florida. The prefrontal boundary seems to be the focus of where some of the larger rainfall totals (mainly toward the east coast) could occur in the next few days, with some lightning, but strong or severe storms so far do not appear to be in the cards this go around.

Image above is only a sample for today. Animation of the above image showed brisk SSW flow at the low levels but westerly flow well aloft. High clouds could shut down thunder and heavy rain chances along I-4 and north for the most part with better concentrations south of I-4 toward the Vero Beach area and/or Ft. Pierce. There remains a slight dry slot almost coincident with a thin band of high clouds across South Florida so far as off early afternoon, although things could change late today, but if the drier air seen on the SPC (Storm Prediction Center) Mesoscale Analysis Page holds true  there would be little rainfall over South florida today.  

There could be a second surge of shower and/or storm activity to move in along the west coast toward or after dark, so rain sometime over night is not completely out of the question east side if this does occur and can manage to hold itself together.

MONDAY/TUESDAY: One of these days seems to be a more active day, and the the GFS has been consistent with that  day being Tuesday. Thunder on that day more likely from near Melbourne and south toward West Palm Beach to perhaps the Boynton Beach area with heavier rainfall totals. Instability is not all that impressive any day with weak lapse rates as air aloft is not particularly cold. Most rains will be a result of the pre-frontal boundary or the front itself as we get closer to Wednesday.

So far it appears that beyond Wednesday the boundary will slide south as high pressure reasserts itself and we enter a continuance of NE winds for quite some time to come which is not conducive for rainfall but for perhaps far SW Florida. Little change in temperatures, dictated mainly by the degree of cloud cover and/or rainfall mainly during the daytime. It will be a tad cooler though mainly far east side   overnight  as a result of losing the overnight easterly winds which had been blowing from above warm ocean waters the past week.

Fall began today at 4:44AM EDT. According to one table, the day/night will be of equi-length on Friday, September 27th, 2013 with sunrise and sunset both at 7:13 AM/PM respectively. From then on out the days will be shorter than the 'nights'. Daylight Savings Time does not end, however, until November 3.