"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".

Saturday, February 12, 2011

Cool Day In Florida While Much Of Country Warms

Images: 1) Mid-morning visible satellite image shows extensive clouds over South Florida/Keys with embedded light rain showers, also showing a thin strip of mid-level clouds (if you enlarge the image you can see it) across Central Florida; 2) Photo of what the thin strip of clouds over Central Florida looks like from the ground in Cape Canaveral 3) Latest generalized surface plot of the temperatures across the state. Note the cool air over South Florida under the clouds (although the temperature there is not as cold as shown). Wind barbs show prevailing NNW wind down the state veering more toward NNE on the west side of South Florida.

SYNOPSIS: Low pressure pulling further north and east from the Mid-Atlantic Coast late this morning with cold front having cleared all of Florida. Broad expanse of East/West oriented high pressure stretches from Florida, across the Northern Gulf into Texas and further west in the Intermountain Region, with the axis pointing toward North Florida. Troughs of low pressure over the far NE and NW States of the U.S. This will generally be the pattern through Tuesday as ridging builds northward over the South and Central Plains as well as the Desert Southwest, eventually into the North Plains. Looks like into early next week the places NOT to be are the NE and Pacific NW.

TODAY THRU MONDAY EVENING: Cool days in store through Monday, with cold morning lows. The period through Tuesday morning is strictly a play with temperature numbers for the state; that is, once South Florida and the Keys can be free of their showers and clouds. Looks like the NAM model wasn't totally off base with clouds over South Florida as it showed would be occurring at this time today in its run a day and a half ago (whereas the GFS showed nothing of the sort). This 'event' of clouds and rain unfolded as it showed it would, just about 150 miles further south. Looks like conditions will be much improved down there (as is already beginning to occur)...with the big changes for most areas between 11:30AM - 1:30pm this afternoon, just in time to catch peak heating to warm them up. Not so sure how warm the Keys will get though since clouds will linger the longest there and winds are quite brisk from the N-NNE.

Temperatures today I'm expecting to peak in the mid-upper 50s over North Central Florida with low to mid 60s south central and south once the clouds clear. Winds will remain from the NNW all day and be brisk, with gusts to just below 30mph through 3:30pm before gradually dying off after peak heating is reached. I'd draw the 60F degree isotherm somewhere south of SR 520 from near Melbourne slanting west to just south of Sarasota on the west side of the state for the high temperature this afternoon. North of that line temps will top in the upper 50s, mid 50s further north. Most of the state will warm under full sun given the higher sun angle we are starting to achieve, but once it gets low in the sky they will start to fall rapidly over North Florida and to some degree Central Florida as well with such low dew point air in place not holding the heat in.

Temperature forecast for the next two days is very tricky with very dry air moving in now as I write, with some stations on the KSC mesonet (the mesonet is a network of unmanned weather observation stations which collect information such as temperature, dewpoint, and wind)) reporting dew points in the mid-teens to mid 20s up to Jacksonville. This is a modified continental air mass from the Central Plains (where it got to well below zero the other morning in places like NE Oklahoma where it was minus 25F to minus 31F degrees (below zero). Obviously, it's not going to be anywhere near that cold here, but the point is, even though this isn't coming directly from the North Pole anymore, it's still has a punch.

TONIGHT/SUNDAY MORNING: Winds will quickly abate during sunset to the first hour after sunset as temperatures do as well, especially west of SR A1A. Morning lows could be in the mid-upper 30s inland, with some spots of frost, although this is questionable given how dry the air is. But given the recent light rain some ground moisture may still be available for frost generation in those areas with the most prolonged near calm winds or those that are wind protected. A1A from Port Canaveral and south is another tricky one. But believe that most areas there will read similar to this morning or perhaps a degree or two cooler far East Central (my place was 45F at the lowest this morning)...but it will be colder to the north as well as to the south from what they had there this morning under the clouds last night through mid-morning.

SUNDAY AFTERNOON: Similar to today but less breezy and perhaps a good 5 degrees warmer than today.

MONDAY: No cloud issues other than coastal SE Florida where perhaps some coastal stratocumulus clouds could move in over night (these might actually start to be seen tomorrow afternoon down there). Low in the upper 40s A1A to low-mid 40s inland, coldest over the interior down toward SW Florida.

TUESDAY MORNING: Mid-level trough rides over the flattened ridge over the Deep South, skirting through Florida from the North or NNE at the lowest levels as somewhat of a backdoor cold front. But fear not. This front will harbor a profound switch in wind direction to one from the NE to eventually east then ESE into mid-late week. This will obliterate the low dew point air, thus making overnight lows much more comfortable, especially along A1A up and down the coast. But this will also leave that same area the coolest in the afternoon with fresh winds off the Atlantic, especially north of Patrick AFB. Could start to see periods of stratocumulus clouds move in as well, and maybe a rain showers spit from Ft. Pierce and south near the coast, but north of there should remain rain free.

LATE WEDNESDAY/NEXT WEEKEND: Warming overnight lows, with lows barely getting below 62F along A1A Central (warmer south) over night by Thursday with afternoon highs in the mid-70s ...closer to low 70s north of Sebastian Inlet along A1A.

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