"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".

Thursday, August 11, 2011

Showery With Some Storms South Florida, Early to Late Evening Possible East Side of State Late/Tonight

Very difficult forecast today as we transition OUT of a pattern. Deepest Moisture is over South Florida at time as surface to upper level troughs linger later today just off the entire East Coast

TODAY: Hot North Central to North East Florida. Today is the day the water balloon of high pressure over Texas is being flattened from storms systems riding over its is spreading outward west and east into Florida and a bit into New Mexico. Net result is warm air on the wings of westerly winds for higher than normal temperatures for August due to lack of cloud cover by late morning through peak heating . The east coast sea breeze is expected to develop...but perhaps fairly late today after peak heating which should allow the temperature to reach near record highs from JAX to MLB. Most of those highs will likely be realized though in locations where official observation points are not located (near A1A) we might never know. Mid 90Fs should be the norm..with upper 90Fs in many locations. South Florida might become quite warm as well with the lack of a seabreeze and a small delay in showers toward the east side (later than yesterday)..but records are not expected.

RAINS TODAY: Showers have gone up early off the tip of SE Florida as shown in this recent radar image. Those showers are moving slowly off to the east.  Further north, a pocket of mid level moisture resides over East Central Florida as noted by the fog report at Daytona and near foggy conditions at Canaveral. A RARITY for August at the beach! More anomalies abound as has been the case all summer.

The best chances for rain today are all along and south (east to west) of Lake Okeechobee..from near West Palm to Port Charolette where the high PWAT (precipitable water) resides at and over 2". Moisture decreases the further north one goes. South Florida is capped only at the low levels this with some day time heating the wheels should be set in motion for another day like the past has been noted, South Florida recovers very quickly..or at least, that has been the ongoing theme all summer.

The trend in this pattern has been for each subsequent day to exhibit less believe this will again be the case today over South Florida.  The keys have some showers now..and could again see some storms today, however, any storms further to their north could spread high anvil clouds south and shut the keys down by late afternoon. Storm motion should be west to east over South Florida at 10-13mph.  The only fly in the ointment would be if, like yesterday, activity over SW Florida sends out an outflow boundary eastward. This would progress storm motion coupled with forward motion propagation..leading to shower/storm activity over-running itself. Thus, that would account for lack of significant storm storms over-run before getting well formed. The best chances for lightning in that case, and as pictured above, will be along the west and east coasts. No sea breeze is expected over South Florida today.

CENTRAL/NORTH FLORIDA: CONDITIONAL on forward (eastward) motion of the Mid-and upper level troughs now departing. Last night a generous lightning storm moved SSE from St. Augustine to Daytona...this was in a area depicted to be of much lower PWAT air, due to a dry slot in the mid-levels. This activity was likely instigated by a mid-level vort max rotating through the mid-level trough as it pulled offshore.  IF that trough moves very little...or in fact remains nearly in place today just off shore (but a bit further south)...moisture could 'pool' near the base of the trough. A sea breeze is expected today as noted in the previous paragraph...with a deeper westerly flow at the surface..and moisture convergence would superficially rise the low level PWAT air due to moisture convergence very close to the St. Johns River and south..just west of I-95 toward Vero Beach. With that in mind, moisture convergence/sea breeze convergence storms could form on the east side of the state after 4pm (especially South of SR 50) in Brevard County to Vero Beach.  Further northward progression of isolated storms is also possible as noted in the image.  Much of this is 'conditional' as stated and might not ever materialize at all. 

 This overall forecast portion is based on two consecutive runs of the NAM model (Not Always Manifested) has been the case all summer.  However, latest RUC runs (Run Under Cover) are showing storms to form between 4-5 pm and last until well after dark almost right over the coastal area of Brevard (and nothing further north). The 2AM run of the GFS...the Goofus...hasn't been so goofy this year at all except in long range tropical outlooks, as would be expected well out in time.  In looking at the Going For Something 2am is running close to the earlier NAM runs..with showers/storms as I've included this area as shown in the image.

FRIDAY: Much of the same pattern, but less of it even more so...and activity should be much further west late in the day...but I'm not fully sold. The GFS has been less aggressive with the extent of the ballooning high pressure from Texas to affect Florida in the latest 2 runs. I also definitely recall another point in time when it over forecast this to occur..and what was to be a long duration dry spell for Central and North Florida amounted to maybe 2 days....Shower activity over the Keys looks to continue..with less activity over South Florida except SW Florida..but with sea breezes at play from both well as likely a Lake breeze as the gradient decreases..Okeechobee County and the east side of the Lake toward interior Palm Beach and Martin Counties might also get in on some rainfall. Another hot day to start..but believe sea breezes will play a big factor further north late in the day..just exactly where will have to be determined tomorrow morning. My guess is that it will be more toward the interior of West Central in toward Orlando and Central Osceola County...near Kissimmee or just to the east of that location.

SAT/TUESDAY: Transition back to a modification of the last 4 days. The only difference this go around is that the mid-upper level troughs are not expected to dig as far south  this go around. Even that will have to be reassessed..although last time (for the past several days) the GFS had a good handle on the evolution of what eventually transpired.

Net affect with the above given, SW-W flow will develop, but since the steering troughs will not be as deeply entrenched, the winds aloft should be a bit lighter, allowing for development on most days of an east coast sea breeze. Sunday through Tuesday are shown for afternoon storms to development along these sea breezes and shift off the east coast mid-late afternoon to early evening. Since these troughs will not be as entrenched..and no tropical moisture is looming to the south, South Florida might not be fully into the playing fields for bigger rains... dependent more on moisture convergence associated with Lake and Sea breezes...combined with outflow interactions.

TROPICS: Beyond Tuesday or Wednesday...much of Florida's weather appears will be dependent on the extent of the high pressure over Texas. For now, I'm riding with PERSISTENCE..and that high over TEXAS has been persistent since early spring. Until we see the writing ON THE WALL..see no reason to deviate, even though the GFS is trying to weaken it and bring tropical entities this has done that in the past all why should it be any different next week? 

With is more likely that the trough over Florida and the SE states will persist...with storms possible over the interior and toward the East side through Friday of next week...although that might be stretching it.  

The run of the 2pm GFS last night showed 2 tropical Storms or perhaps Hurricanes to affect Florida either directly or indirectly in about 12 days, 6 hours..those were all but completely gone. The next run was showing a tropical wave to affect the state late next week.......which is dwindled down from two tropical waves on the 8pm run to one wave on the 2am run early this morning at 2am . Thus, the trend has been to weaken the high over Texas..and shift Florida into a tropical, showery regime at some point in time later this month. I mention this because sooner or later..this regime is likely to come into play...I'd be watching the last week of August time frame..or anytime after the 23rd for a big change, since climatologically this is when Central Florida starts to wane on day to day storm activity to a very small degree. But on the other hand..and has been mentioned time and time again in previous posts since spring..this year has been anything BUT climatological~!

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