"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, January 5, 2011

Best Rain Chance From After Sunset to Sunrise - North of SR520

Images: First three images are 'actuals'. Satellite image clearly shows the southern extent of mid-level cloud coverage just north of 528 early this afternoon. We also see a forecast for moisture content (Integrated Liquid) in the last image for 1pm which matches nicely with satellite. The third image shows the average mid-level winds and greatest moisture, and lastly the first image shows an analysis of the current low pressure location near the Panhandle with a warm developing across North Central Florida with the warmer air to its south.

TODAY: Warm this afternoon everywhere south of the warm front (in the warm sector) where it is also most free of concentrated cloud cover. Warm front won't lift much further north than its current location, so things are very touch and go just along and north of The Beach Line this afternoon, particularly after 4:30pm. Further north, a strong bowing line segment (thunderstorm) is generating severe thunderstorm warning or two out of the Tallahassee NWS Office...this could put a kink in the forecast locally late today, amongst other numerous kinks.

But for the time being, sunny to partly cloudy sky conditions will prevail into at least mid-afternoon with highs in the mid-upper 70s south of the warm front. Winds are light and variable early this afternoon, but a more assured SSW-SW wind will develop around sunset or shortly thereafter as the cold front and low pressure system push east across the Western and Central Panhandle toward Jacksonville. I have noted some patches of ACCAS (altocumulus castellnus) clouds since late morning over my area, indicative of some mid-level instability. Might be important for the over night hours in regards to the strength of rain showers or maybe even some thunder.

In noticing the latest satellite trend, the sunniest spot was generally East Central Florida, with afternoon bubbly stratocumulus clouds forming to the S-WSW under the afternoon sun, heading this way. They should be here in an hour or two, with others filling in almost directly over head.

TONIGHT: Overcast over night with very mild temperatures holding into the low-mid 60s as SW-WSW pick up in the 15-20mph range. Good bet of rain from near Patrick AFB to just north of a Tampa Bay line anytime after 8pm through sunrise. Currently appears the heaviest (and best chance) of which will fall between 2AM - 6AM early Thursday morning. I do believe the region of most active weather tonight into early Thursday will occur right along and 20-30 miles either side of a line of where that warm front was drawn, namely very close to or just north of SR528. It is also along this area that some strong storms (due to wind gusts) could result from any isolated heavy activity. Rain accumulations could add up pretty good in one spot toward one inch, but such amounts aren't anticipated for more than a tiny sliver/zone due to the fact that storm motion will be a quickly paced from west to east at a good 30mph+.

It is worth noting that" forecast winds" from near 3000 - 10,000ft from around 2am - 7am will be from 30 to near 60kts right along the same area described above, which just so happens to be where I've seen the ACCAS clouds since late this morning. Actually, I've noticed that radar is showing rogue rain echoes over Central Florida which might actually be those ACCAS patches. Any true convection overnight will likely remain somewhat elevated , although per chance should a bubble of activity get more rooted in the boundary layer we'll be hearing thunder and maybe a warning for strong wind gusts will be issued while we're 'under the sheets'. Just a heads up. It will be worth watching the weather segment on the news tonight and/or the weather channel late today into tonight to monitor the latest and greatest (emphasized!). Also, I mentioned that bowing storm line segment earlier. Outflow from that system as it passes north of near Gainesville could have a ripple affect on timing of precipitation or intensity many hours from now. It's too early to speculate but that will be the first harbinger of several causes to pause in any reasonably good forecasters mind. At least for those along and north of the BeeLine.

THURSDAY: The front will be sinking south down the peninsula as the low moves off more toward the east rather than the northeast as zonal flow over the Southeast States prevails on the day Thursday. As such, the front will only go through in piece-meal fashion rather than with one big simultaneously occurring wind shift, drying, clearing, and shoving cold air blast as we often see happen in the winter. Thus, clouds and light rain chances could persist into early afternoon from near the 'magic 538' line and more certainly further south toward South Central Florida. In this regard, the high temperature tomorrow will probably never break into the 70s but rather hold steady from where it will be the time any rain begins or is near by (for those who do not get rain). In other words, mid-60s as a rule for now, but wouldn't be surprised to see even lower readings.

Do believe that any rain chances will go close to nil by 3pm, although one model shows that chance lingering until dark. I'm taking that as a sign of more significant clouds rather than actual rain though. The further south one goes toward South Central and South Florida the lesser the chance of rain will get, namely south of Vero Beach - Sarasota but there later also will be the clearing of clouds and lingering rain chances.

More definitive cooler air begins to finely make its presence none shortly after sunset and throughout all of Thursday night into Friday morning as clouds finely scour out and a minor kink in the zonal flow permits a northwest wind to develop and colder air to move in.

FRIDAY: Very cool day with lows very close to 41F and a high in the low 60s with ample sunshine. Winds will remain somewhat elevated from the WNW-NW for a time but back more toward the W for a brief time as another impulse passes to the north of little impact other than to reassert that indeed, a cold front has passed.

SATURDAY: Another cool start, but maybe not as cold as was previously feared. These systems are riding high and mighty (fast) in the ever changing nearly zonal (generally speaking) pattern, and as a result the changes are also rapidly paced. Regardless, another cool day with lows pretty much the same inland as Friday morning, but the coast might fare much better near 50F. The afternoon will again be cool though with another low 60 degree reading, perhaps some mid-60s. Some high cirrus streamers well overhead could pass from time to time with more west wind. This will also be the coolest morning for South Florida with mostly 50s.

SATURDAY NIGHT-SUNDAY: BIG UNCERTAINTY (exclamation point spelled out). Like the previous GFS run (only faster this go around) we do see a warm up on Sunday afternoon toward the 70F isotherm with another cool morning. This was mentioned yesterday. The biggest change for this period from the previous model run is a sooner over night wind shift to light onshore well before sunrise. End result, the A1A corridor could actually warm up during the overnight hours or hold steady most of the night. Otherwise, no big changes as temperatures begin to return toward normal readings after two full days of below normal for everyone Sunday afternoon. BUT...

LATE SUNDAY AND BEYOND: At this point, don't believe a word you hear until at least you see the news Saturday night, point blank. There's as many different possibilities by late Sunday as there is models. All of which could have a pretty significant impact for the weather all across Central and North Florida in regards to cloud cover and chances of rain already returning (depending on what one chooses to believe). As it stands now, South Florida again escapes the atrocious variabilities no matter what the outcome at this least for now. What we will hear/see is what one particular forecaster favors, the end result will likely not end being any of what we hear today or even through Friday. Additionally, you could probably switch from one channel to the other and receive a different message.

Just to paint one scenario-cast: Another low pressure forms in the East Central Gulf late Sunday with a warm front stretched across Central Florida and isentropic lift along the boundary produces cloud cover and eventually showers. Which of course will affect the temperature. Not biting into any one solution for now, and thus will not project. That's one benefit of having a mere blog post (of few readers). I'm not obligated to come off sounding definitive or having to be oh so sure about a situation in which the true reality is that no one really knows (like the TV Weather Guy/Gal must). They don't get paid to say, "The truth is, we don't know what's going to happen".

I just happen to have The Weather Channel on right now, and they seem to be trending (quite flakily if that's a word) toward the scenario I just described. Noticed they left out any details in regards to related weather events though (how convenient), but they did show a similar placement of a warm front and low pressure system sometime late Sunday into Monday as was just written. There should be a little caption on the screen , "Just for kicks, this might happen by Monday. But not for sure. We'll get back with you on that one".

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