Image: Forecast images for 7AM Christmas morning show a developing low pressure system developing in the North Central Gulf, courtesy of tail end Charlie energy associated with the remnants of the last of the Pineapple Express that plagued California for many days. We also see the leading edge of energy associated with a "Polar Express" blast diving south across the mid-Mississippi River Valley Basin. It currently looks like the two trains will phase/sync/collide just off the South Carolina coast the day after Christmas.
TODAY: Happy day before Christmas and Christmas Eve to all! It's looking quite pleasant out there early this afternoon over all of Florida. The warmest temperatures (low 70s) are found from West Palm Beach to Miami along the east coast. Once again, I'm under-playing the official forecast high temperatures for extreme East Central Florida this afternoon as due north winds blow over the intracoastal waters keeping high temperatures this afternoon in the low end mid-60s range. Yesterday, unbeknownst to others outside this area, it was actually very cool out on the islands with a high in the low 60s under a partly to occasionally cloudy sky close to the coast during peak heating. As a result, it stayed pretty darned cool over the islands yesterday as opposed to the Orlando area where wide spread mid-60s occurred, and the steady NNW-N breezy did not help matters.
The wind today has died a little, and clouds do not appear as though they will pose any problems this afternoon as opposed to yesterday. They are offshore, but are having a hard time penetrating any closer to the coast the past 2-3 hours, so it looks like we'll be scott free of them for the most part. The wind is a bit amplified beyond what was expected this early afternoon hour, but seems to be once again, like yesterday, limited in strength to only those areas near the waterways.
All things given, expect the wind to die down significantly by sunset of shortly thereafter as the mean directional vector becomes more easterly and weakens under a clear sky.
TONIGHT: Mainly clear through midnight with an overnight low hugging the low 50s along the coast and in the mid-40s inland.
CHRISTMAS DAY OUTLOOK: Light and variable wind at sunrise with the day dawning at temperatures about 3-5 degrees warmer than this morning. By 9-10am a more southerly wind component will become evident as high pressure now over the Carolina will have moved ESE overnight and well into the Atlantic in prelude to the approaching "Polar"/modified "Pineapple" Express ensemble pushing east out of the South Central Plains. The two systems will be pushing east in tandem throughout Christmas Day but remain separate entities. The southern most system now crossing Texas ("Pineapple") will cross the Northern Gulf during the day but remain a non-player for the peninsula as far as the rain gauges are concerned during Christmas Day, but do expect that some high level cloud streamers will begin to infiltrate by late morning and increase in coverage during the course of the day well in advance of its more direct influence after night fall, Christmas night.
As such, like recent days, I'm underscoring the official high temperature forecast for tomorrow, since given the low sun angle at this time of year any clouds worthy of note will put a damper on what temperature could otherwise be reached under clearer/cloud free sky conditions. As such, believe upper 60s will be the rule with 70s reaching from South or maybe Central Brevard and points south. Winds will assume a more SSW-SW component by noon or shortly thereafter (as the upper level clouds increase) to the 12-18mph range during the main course of the afternoon and some peoples' Christmas Dinner. Overall, it will be a nice day though ... Merry Christmas.
CHRISTMAS NIGHT: A warm, winter night for peninsular Central and South Florida (that is, as far as 'warm winter nights' go in Florida). In other words, probably one of the warmest 'overnights' we've had in quite sometime as winds will remain elevated ahead of the approaching/gathering storm system to our NW-WNW. Clouds increasing and lowering ceilings overnight will aid in keeping the temperatures up; another way of looking at it is that everything that prime radiational cooling "is"...this night will most certainly be 'not'. Rains will first affect the panhandle before midnight and rapidly spread east and south after midnight of the 26th, Sunday affect everyone north of Vero Beach by sunrise. Rainfall totals do not look very impressive, and some areas won't see any rain at all. If perhaps a showers can gain some altitude in the only moderately (at best) unstable atmosphere accompanied by good speed sheer, those healthier showers could put down some good wind gusts. For the most part though, should those occur it will be before day break or within one hour after that time frame.
AFTER THE RAIN (CHANCE) EARLY SUNDAY: Once again, will undercut forecast high temperature forecasts I'm seeing so widely media-fied early this afternoon. Believe the cold front associated with the original modified air mass "Pineapple Express" will be cutting the peninsula in half from NE to SW at sunrise and cross all of Central Florida from NW to SE between 6:00AM -9:AM.
My take is that the warmest time of day will be during those hours ahead of the front. Winds will quickly shift to a more WNW component after frontal passage with a clearing line of clouds to follow within the 3 hours after its passage. I can hear the "Polar Express" horns blowing throughout the day as its core passes just to the north and meets the "Pineapple" off South Carolina by Sunday night. The modified "Pineapple Express" air mass is about to become more of "Polar Express" airmass heading toward Monday morning.
MEANWHILE FOR THE REST OF THE DAY: For the most part, the entirety of the day light hours of Sunday will be defined by cold air advection, modifying from Pacific to Polar origin behind the departing low pressure system and in advance of the cold arctic push. As such, expect the air not only to be very cool all day but very windy as well with wind gusts exceeding the 30mph range, especially across and near any bodies of water. After our warm morning, assuming one is awake to feel it, the majority of the day will be spent with the temperature holding steady near or just above 50F from Cocoa Beach to Orlando (roughly SR 520)...and colder in the mid-40s further north, while south of this line mid-upper 50s will dominate, the further south one goes, the warmer and into the 60s it can be.
SUNDAY NIGHT-MONDAY: Cold air advection will continue all day Monday from sunrise to set. Again believe the high temperature forecasts are being over played for North Brevard toward Daytona Beach and inland areas near I-4 north of Orlando for Monday afternoon. The NW wind trajectory will be pointed roughly from west of Ocala toward Cape Canaveral...as such, believe this area will fail to breach th 5-0 Fahrenheit mark, or if so, for only a brief time (and not long enough in my mind).
Regardless, with the elevated wind (although not as strong as that on Sunday afternoon), it will still feel too cool for comfort. Monday morning would see an advection freeze late in the overSundaynight to earlyMondaymorning hours, but this episode doesn't not look to be quite as infringing as the past one we had.
Due to the wind, temperatures spreads won't be as amplified as they would be under a radiational cool-off, with probably a lot of mid-upper 30s to be found but playing with and under the freezing mark north of a line running east/west from Daytona Beach North.
TUESDAY: Another cold day in store but with significantly less wind. Still, cold is cold enough. This will likely be the coldest morning of the remaining days of 2010 for most of Central and South Florida. Afternoon temperatures should present us with more reasonably sane afternoon high temperatures, but still well below what would be considered 'normal'...mainly in the mid-upper 50s.
WEDNESDAY: Let the flip flip begin! Cool/to cold start to the day...but high pressure associated with the tail end of our "Polar" cold engine shifts east as do our surface winds. Afternoons back into the 60s and overnight lows by the following morning (Thursday) significantly warmer than those of Monday, Tuesday, and for some Wednesday and well into the 40s.
THURSDAY-NEW YEARS DAY: Could be a big warm up to end the year as height levels for the standard 850mb -500mb levels are forecast to be on a BIG rise and winds maintain a SE-S-SW component for a good 2-3 days, at least. This could be a big warm up all the way up to the Eastern Great Lakes in fact, and would provide the long term, southerly wind component which we have not seen in a very long time; that which would be necessary to successfully and completely modify the air mass into a greater atmospheric depths of which we have not seen for quite some time.
Footnote: Should this tremendous air mass modification indeed take place, this would provide the fuel for a vigorous Gulf Storm type system to take shape during the first week of the 2011. The models have been flipping around with the prospect, but for now will only raise a timid yellow flag with one eye open at a potentially significant severe weather event for someone in the Deep South to Florida during the first week of January.