"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, January 15, 2011

Going from "Benign" to "Beastly" By Monday? 'Bears' Watching

Images: 1) Forecast for Sunday night; 2) Forecast for tonight 3) Current Cape temperatures; 4) graphic depiction of 7:45AM Saturday morning temperature. Note the warmest air from Daytona Beach Shores along A1A to Miami and across the Keys

TODAY: Benign weather pattern will remain in place through the weekend with very mild temperatures along the east coast tomorrow morning once again with comfortable afternoon temperatures in the low and maybe some mid- 70s. Inverted trough from the Cape and off to the NE was evident yesterday and remains in place today through Sunday. Note the warmest temperature at sunrise in the image above is at the eastern most tip of the Cape. Local LDIS picks up on the trough in the wind and moisture fields nicely (with greatest low level moisture along it , penetrating Brevard Country), and model guidance has as well. This trough may play a bit of 'forecast havoc' in regards to afternoon high temperatures, namely they may be warmer then thought. Should it manifest as a bit more 'defined' surface winds may remain ever so light backed from the NW today allowing the mercury to rise minus an onshore, cooling component.

NOTE: This trough, benign as it may be now, will be a big player into Monday as we will read below.

The KSC sounding shows a strong inversion at 5000 ft (roughly 850mb) with moisture trapped just below the inversion. Very weak wind fields are in place under the inversion level while westerlies prevail above it and strengthen with height. Cape temperatures yesterday morning were 10F degrees warmer from those of Thursday, and nearly 10F degrees warmer again this morning from Friday morning. Once again, temperatures fell very little after 8 or 9pm as was the case the night before. In short, temperatures are moderating and the cold snap is gone for all but North Florida.

Might add, the low in Tallahassee yesterday was 18F (Crestview was 15F!!), and the low there this morning was 20F. Additionally, Tallahassee finally broke 50F degrees for the first time in 5 days yesterday. Just a side note if we thought it was cold over Central and South Florida.

Otherwise, low level ridging continues from near the Texas Big Bend and across the Deep South as a subtropical jet streams from Southern Texas eastward to nearly across the Florida Straits while the main polar jet stream remains to the north of Florida within an upper level trough along the eastern U.S. seaboard through mid-week. Main storm impulses at this time continue across the Great Lakes and the Northeast States.

SYNOPSIS FORECAST: Most importantly for late in the weekend, a mid-level impulse passing over Mexico crosses Southern Texas on Sunday, providing for thunderstorm chances there tomorrow and continues along the subtropical jet, crossing the Central Gulf of Mexico during the overnight hours into Monday morning.

Meanwhile, the inverted trough closely snugging the Cape since yesterday remains in place during that time and becomes better organized as mid-level impulses crossing the NE and mid-Atlantic States within the upper level trough enhance it. The trough remains in place though due to high pressure to its east. This trough, benign as it may currently be now, becomes a major player (as previously noted above) during the day Monday afternoon into Tuesday morning.

SUNDAY: Mid-Level, subtropical impulse crosses Southern Texas during the day and enters the Gulf of Mexico overnight into Monday morning and begins to strengthen, possibly manifesting as a weak surface low Monday morning in the Central Gulf. Locally, very little change from today with temperatures in the upper 60s and low 70s along and south of a line running from the tip of the near shore inverted trough and across the state to Tampa Bay. Periods of stratocumulus clouds possible at any time but rain free. Morning lows once again warmest along the east coast, with inland temperatures moderating tonight as moisture levels increase slowly. In short, tomorrow's high temperature will be close to today but with a broader expanse 70s northward.

MONDAY MORNING: Very mild morning once again with lows along the coast probably in the low 60s and cooler inland. Expecting rapid transition in the sky this day as the Gulf disturbance/impulse/short wave/low (?) moves ENE and begins to integrate with the tail end of that inverted trough still remaining near the Cape over the weekend. This is why I noted earlier that the feature could become important. Somewhat of a pseudo warm front will form in advance of the approaching system, which by the way I fully expect to be exhibiting lightning strikes in the Central Gulf at sunrise, Monday. High clouds well in advance of this system will likely begin streaming overhead well in advance of its approach system which will aid in keeping overnight temperatures warmer, but also hamper temperatures rises during the day.

LATE MONDAY MORNING BEYOND: Big question mark! It is appearing more assured that Central Florida, close to the pseudo warm front will initially experience overrunning cloud coverage and eventually rain fall by around noon time which could evolve into thunderstorms by afternoon and early evening as the wind profiles and veering wind profiles associated with the trough approach the west coast and cross what appears will be the Central or South Central Peninsula during the day. Just exactly where it will cross and its intensity remains yet to be unknown, so there is great uncertainty in how events will unfold during this time frame. It is possible we could be seeing strong/severe thunderstorms embedded within the rain zone anywhere from south of a line from Cape Canaveral to North Tampa Bay area, in other words...all of the South half of the state. The area of greatest threat will be narrowed in on more later tomorrow, and likely be watched intently by official outlets (the National Weather Service) come Monday morning. Be sure to tune in to your most favored weather resource before bed time Sunday night and especially upon awakening Monday morning!! We may see issuance of a severe thunderstorm watch, although believe at this time that the limited coverage of severe parameters amassing may preclude such.

TUESDAY-THURSDAY: The impulse crosses Florida overnight Monday with a more assured surface low formation ongoing just east of the Cape as it runs along the trough that will have been in place there since Friday (yesterday). A cold front of sorts will following the front but with almost no changes in the temperature department. As noted yesterday, the next cold period would not come once again as one piece meal system. In stead, we may see a lull in rain chances after Tuesday morning and through out the day with the true cold front still on the approach for Wednesday. As was the case last time, most of the moisture will be swept out with the first system, but enough will remain for some light rainfall accompanying the front proper which is timed to pass early Thursday.

THURSDAY: With the second front crossing Thursday the atmosphere will yet to fully dry out, but it will be cooler Thursday with the driest of air to arrive sometime Friday, January 21st. I normally think of January 21st as being Florida's "cold core" time, or about the time that it's most assured to be cold here if one were to draw a date out of the hat. Maybe not so oddly, this is exactly one month after the time the sun is at its lowest angle (the first day of winter, December 21st) which jives perfectly with the time lag between the lowest sun angle and the coldest temperatures (1 month). Looks like this year will be no different.

FRIDAY-SATURDAY: Another cold event similar to this last one. Same temperature regime as well with one or two very cold mornings everywhere but the A1A strip from the Cape To Miami again escapes the worst with a prevalent NW-NNW wind regime under advection freeze (windy) conditions. Naturally, this is well beyond any scope of reality (in case this all reads as sounding like absolute 'truth'). This is simply what information is showing early this morning. I have not waited for morning weather model runs to make this post, namely because when I saw the overnight runs this morning there was no big surprises. In short, should this forecast come to fruition, then yesterday's comment about there being no cold air on the horizon was a bust. We'll see what eventually transpires.

IN THE MEANTIME: Watch for updates from all offices as we approach late Sunday. Monday will remain sketchy and become possibly briefly somewhat traumatic contingent upon how parameters evolve. Consider this a heads up on there being a true 'heads up' "Bears" watching...Grrrr!

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