"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"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".

Wednesday, November 16, 2011

Near Record High Temperatures, Small Shower Chance Late Day/Evening

TODAY'S HIGHLIGHTS features surface to mid-level ridge across South Central which will drop only slightly south during the day. Satellite image at sunrise reveals areas of either very low ceilings or fog. Deepest moisture resides over the East Central Gulf and along a cold front approaching the Panhandle later tonight (where some thunder could occur)

RECAP: Showers formed yesterday in the proscribed zone in the prior two day's of posts from Southern Polk County and across most all of Central Osceola County toward dark, eventually dying off toward 10pm as they reached the Titusville area. There has again been some fog reports, but not with the greater coverage of Monday morning. Lower clouds seemed to be the more prevalent mode, as temperatures in many areas statewide were mostly in the low-upper 70Fs, warmest along the SE Coast near the warmer Gulf Stream waters from West Palm and South where winds remained off the Atlantic overnight.

TODAY: Not all the much different from yesterday, but there are some minor changes, mostly in the strengthening S-SSW-SW gradient low level wind flow north of the ridge axis shown above as the frontal boundary and supporting mid-level trough approaches from the Deep South region, positively tilted toward the Ohio Valley. This can best be seen at the 2000 ft level, as forcing and wind fields at the surface are weak and less discernible for presentation purposes.

Latest RUC roughly shows the front to be located at 2000 ft. above ground as shown, with ridging across South and South Central Florida along the high pressure ridge axis emanating from east of Bermuda. Both of those ridges will drop generally another 50 miles south during the day, and place Central Florida from generally 20 miles south of the CDL (Central Diving Line) and north in stronger SW-WSW flow from 2000 ft and up by mid-late afternoon.   Recall from the first image, deeper (but not tremendous) moisture is over the East Central Gulf. This moisture will circulate east and north during the day into those locations along and north of the ridge axis, or roughly from  Melbourne Beach to Tampa Bay and north by sunset. Dry air is being advected into South Florida north of Cuba. 
 TODAY: Frontal boundary to enter the Panhandle by tonight. Winds today over North Central and North Florida from SW-WSW becoming more southerly toward South Central and SE South Florida.

The RUC model indicates the best moisture will rotate in later this afternoon toward Brooksville and exit the east side of the state very close to a track following along I-4, where showers could occur. 

On the other hand, the latest NAM is depicting a scenario similar to what occurred late yesterday/last night, only about 20 miles further south and east. This would place the area of Central Osceola County again in the better rain chance as well as the area very close to 528/Port Canaveral/Cocoa Beach/as far south as Melbourne Beach for a rain chance between 6pm -10pm as opposed to the more northern area of interest of the RUC. Either one is game, but at this time resting on the NAM which has not been the favored model for quite some time (since summer). However, it seems to have been doing fairly well during the first 18 hour time frame and always one or two steps ahead of the RUC, and did well yesterday.  

These showers could actually emanate/result from a weak Lake Okeechobee Shadow affect (there was one visible yesterday), which would provide the moisture convergence necessary to result in some lower topped showers. I saw one lightning strike on Lightning Tracker last night toward Southern Polk County, but for now will leave it out (which could change) for today. CAPE (instability) appears that it will be even stronger today, but lapse rates on the other hand look weaker which will 'negate CAPE'.   See first image above for those areas highlighted in lime green.

TEMPERATURES: Otherwise, outside of the rain chance it could be pleasantly warm today under partly cloudy skies. Highs in the mid-80Fs interior South and Central Florida. With clouds starting the day in many locations, some records could be toyed with toward the west side of Lake Okeechobee running along a diagonal toward Interior Volusia under to condition that there is good spatial separation in the clouds during the peak sun angle hours. The coolest areas today will be downwind of any water body which would mean the areas east of US1, to the north and northeast of larger inland lakes, and along the north shores of Lake Okeechobee.

TONIGHT: Frontal boundary will be working across the Panhandle. Best chance for some repeat fog conditions appears to be further south tonight, essentially almost anywhere near and south of Lake Okeechobee. Surface winds and especially just above the ground tonight should be too strong for fog north of The Lake  as the frontal boundary approaches and the pressure gradient between that feature and high pressure over South Florida remains firmly in place over that region, resulting in much lighter winds at all levels over South Florida.

THURSDAY: Front will be working from NNW-SSE during the day. Latest guidance generally agrees that the front will work past Gainesville toward I-4 between 11AM -1pm, and will be accompanied by a good 6 hour window of most cloudy/cloudy skies and perhaps some sprinkles. Instability will be able to build further south of the I-4 during the afternoon further from the cloud cover,  with winds from the SW-WSW resulting in highs in the lower to maybe mid-80Fs depending on how soon the leading edge of cloud cover moves in. Although there is a chance of less than measurable rain along the front, the better chance for measurable rain will be toward the East Side of the state South of I-4 to north of Sebastian Inlet from 2-8pm. Frontal passage across the CDL (Central Dividing Line) should be close to 6-7pm time frame. The front then washes out at the surface south of the Beachline Zone and continues south at  the 925mb level (around 2000 ft above ground) through South Florida, finally becoming fully absorbed at all levels near Dade County. Rain showers continue mainly down the east coast on and behind the boundary with a continued chance all day Friday, mainly Southern Portions of Palm Beach County , Broward, and Northern Dade.  High pressure will quickly work east behind the front tomorrow through Friday from western Kansas through Arkansas and finally the Carolinas on Saturday. Pressure gradient wind behind the front as this high pressure rapidly builds east increases over the Atlantic and works in along the Florida east coast overnight Thursday night/early Friday and works down the coast Friday afternoon into Saturday. NE-ENE winds initially in the 20-30mph range will decrease most locations by mid-day Friday but remain in the 15-28mph (esp. South Florida) all day Friday, gradually weakening on Saturday.

TEMPERATURES BEHIND THE FRONT : Not a big cold down, with the most notable temperature impacts interior North Central toward Ocala and North, with other areas feeling lower 60Fs interior to near 65F Coastal East Central from the Port and South for morning coffee. South Florida will not feel much of a change at all. The bigger impact is to the afternoon high temperatures which have been running well above climatology   the past few days, which will return to near or just below normal, but remain comfortable  enough to preclude breaking out winter wear, or for the most part, even fall wear.

BEYOND: GFS continues to imply that as the flow becomes more easterly to ESE just above the deck that some remnant energy from the front will circulate back north toward East Central late Saturday or early Sunday with rain showers resulting, mainly low topped sprinkles with accumulations possible. It is also consistent, however, with ending any rain chance by day break Monday...from which point on, the weather appears will be quite bland with no impacts other than a return to inland fog or low clouds by Tuesday and Wednesday mornings  as winds weaken.

THANKSGIVING: Outlooks for Thanksgiving a Bleak Friday will be included commencing Thursday.   

No comments: