Persistent Current Patter Remains In Place Through Tuesday

Sunday morning rain-shower near the Coast of North Brevard County. This shower seemed to form along the leading edge of wind surge, which never quite made it beyond the immediate coast...and after which retreated to offshore. This could be the chain of events that unfolds the next two or three mornings, which an enhanced area of more prolonged rainfall somewhere between Coastal North Brevard toward St. Augustine each day during that time frame.

General Area of Rain shower activity today (mostly isolated), except possibly along the coast from North Brevard, through Volusia, and into Flagler County where there is potential for some higher rainfall totals. Little change in the current pattern is expected through Tuesday.

TODAY-TUESDAY: Little change in the overall pattern appears to be in order for the next 48-72 hours. Weak low pressure that formed near the Carolina Coast slid NNE ward during the past 24 hours and has left a remnant mid-level boundary just off the SE U.S. coast. 


Yesterday, the end of that boundary reached into the JAX area, whereas this morning the boundary had pushed south toward Daytona as high pressure built down the Appalachians. It is that boundary which will be the prime instigator for potential more coastal rain events due to the fact that this thinly stretched out boundary cannot progress further east due to a vast high pressure area extending completely across the Atlantic to the coast of Africa and southern portions of Europe.  It is possible that heavy rain fall events could occur in the next 48 hours somewhere along coastal North Central to Northeast Florida from overnight to early morning and one or more of these days. Meanwhile, a frontal boundary will be inching in from the west (now across the Southern and Central Plains)...but the log jam will be hard to break. Thus, little change for a while until 'something gives'.


The weather today is a far cry from what occurred on this date in 1926 (85 years ago), the year of the Great Miami Hurricane. Even as little as 24 hours prior to that storm, hurricane warnings were not hoisted. 


I will add that there is also a secondary bubble of high pressure over the SE States center just NNW of Florida. This appears to have broken off from the fixture that was over Texas most of this year (since early mid-spring time) which generate the drought there. That high pressure is almost completely gone for now, but an even large high pressure dome could be in the making for much of the Western U.S. during the week ahead. It was the leading (and in sinking( side of that high pressure that was responsible for the string of dry days over Florida last week. That high pressure will gradually flatten out with time, with a portion eventually  ejecting eastward into the Atlantic with the other portion retrograding into the NW Gulf and back into Texas. This process will be a slow one though.

Did you hear about the big rainfall totals overnight Friday night into early Saturday near Jacksonville? Here is a Storm Total (of rainfall) obtained via weathertap.com compiled from the JAX radar yesterday morning, followed by a preliminary informational statement release by that office. This was Day 1 evidence of that boundary at play. 

"A FRONT STALLED OUT OVER THE AREA COUPLED
WITH A MID LEVEL DISTURBANCE HELPED PRODUCE STRONG STORMS WITH
HEAVY RAIN ACROSS A PORTION OF THE JAX METRO AREA. 3.35 INCHES OF
RAIN WAS REPORTED AT CRAIG FIELD OVERNITE. HOWEVER...THERE HAVE
BEEN DOPPLER ESTIMATES OF NEARLY 10 INCHES NEAR JAX AND PONTE VEDRA
BEACH. MAJOR FLOODING WITH UP TO 3 FEET OF STANDING WATER AT JAX BCH
AND 6 INCHES OF STANDING WATER IN A CLUB NEAR ARLINGTON.
DOPPLER RADAR CONTINUES TO INDICATE CONVERGENT BANDS OF SHOWERS...
SOME HEAVY...ALONG THE COAST" - JAX (Jacksonville NWS Office)

Meanwhile, this morning the same sort of event occurred in Volusia County, although not nearly to such a degree. It appears it might not be over quite yet, even though as of this time the rain there has ended, more lurks very close to the coast if not already back on shore as I type. I've noted an area of interest in lavender where more convergent rain-bands could set up today or tonight in the first image.


Elsewhere, despite model guidance and actual 'near current' data portraying dry conditions over South Florida, rain showers moved into Palm Beach County..much to everyone's surprise. These are low topped showers, but nonetheless persistent. These showers appeared yesterday morning and once again this morning despite lack of rock hard evidence that would call for them to be placed in a forecast due to lack of any sufficient surface features other than some moisture.  There appears to be a small cyclonic circulation approaching far SE Florida as of noon time, so more showers could move into Dade/Broward Counties, and after a break toward the Keys, they might be in for more later today and tonight as well.


Otherwise, when looking at parameters to support thunderstorms, the most unstable atmosphere has been along the east coast of Central Florida mainly from Central Volusia to Central Indian River Counties. Despite these parameters that are based on low level factors, the mid-levels are too dry to support anything other than low topped showers in the absence of a triggering mechanism other than convergence which happens rather sporadically and haphazardly. Only closer to the near 'phantom boundary' near Volusia/Flagler where moisture is deeper through a greater extent of the atmosphere does it appear more certain that rain chances should  be higher, as well as some thunder. Even an offshore waterspout should not be counted out. A YouTube friend of mine shared that he saw a waterspout offshore South Brevard Saturday morning, but this was not noted in official documentation released from MLB.


MONDAY/TUESDAY: As it appears now, little will change in the given on again/off again pattern until a deeper, stronger  trough can approach from the west   toward the state to nudge high pressure out of the way.  I will write that this was originally portrayed to occur (several days ago) in full by Saturday, then Sunday..but it keeps being pushed further out in time. Thus, although a BIG change is expected to transition through on Wednesday and be in full affect by Thursday..we'll just have to keep monitoring. It is the time of year for the first cold front to reach Central Florida, so this train of reasoning is not out of the question.


BEYOND: With the above already stated, one can make the assumption (and if 'reading' the models, it would be a fact)..that by Thursday the mean moisture advection will commence from the SouthWestern Atlantic and even the northern Caribbean. This would bring forth even deeper atmospheric moisture and a return to thunderstorms, especially by late Wednesday and more so on Thursday through Saturday. That is the course of thought as of this morning, but it will take two more model runs (or by tomorrow morning) for this to be more assured.  In the great beyond, a combination of the front (trough) from the continent is depicted to merge with moist/cyclonic (low pressure) circulation from the Caribbean over Florida, at which point the GFS looses credibility completely. The over all trend though, is increased rain chances on Wednesday as thunder storms become more likely (or in other terms, beyond occurring in only random/isolated fashion).

Sunday Morning, September 18, 2011