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Area forecast discussion 
National Weather Service Tallahassee Florida 
300 am EST Friday Nov 21 2008 


..freezing temperatures expected tonight with the potential for a 
hard freeze well inland... 


Synopsis...04 UTC surface analysis shows a cold front entering the 
northwestern portions of our forecast area. This cold front was 
located at 04 UTC along the Texas and Louisiana Gulf coasts and far 
southern Alabama and south central Georgia before approaching the 
western Atlantic. A large 1040 mb high was analyzed near Aberdeen 
South Dakota. A very tight pressure gradient was analyzed right behind this 
front with winds gusting into the 15 to 20 knot range even at this 
late hour. Dewpoints in the single digits are analyzed near the high 
center. 


The 500 mb analysis from 00 UTC shows an overall trough persisting 
across the eastern Continental U.S. With a potent shortwave moving through the 
middle Mississippi Valley within this trough. Shortwave ridging was 
indicated across the northern rockies with another upper low moving 
into the Pacific northwest and southwestern British Columbia. 


&& 


Short term...(today through sunday). 
The short term period is entirely a temperature forecast as no 
precipitation is expected throughout the first five periods of the 
forecast. 


Today...strong cold and dry advection behind the cold front will 
result in a breezy and cold day across the region as temperatures 
struggle to reach the upper 50s. Winds sustaining around 20 miles per hour with 
gusts to 25 will be the rule by afternoon. Given these winds...will 
issue a lake Wind Advisory for all zones today. 


Tonight...the surface ridge over the High Plains will drop toward 
the middle south during the afternoon hours and then move east across 
Tennessee and take a position over northeast Tennessee by daybreak 
on Saturday. This is not the most favorable surface high position 
for a hard freeze in our region. Though cold advection will be 
continuing...given that the pressure gradient will likely not relax 
enough for surface winds to go calm (this gradient is easily tighter 
than the hard freeze event earlier this week). The gradient is 
especially tighter across our southern zones. It is in these areas 
that a hard freeze is less likely than areas to the north...like 
around Albany. In any event...the probability of a freeze is near 
100 percent at all inland zones...whereas the hard freeze 
probabilities are not near as high. 


The mav doesn't indicate a hard freeze anywhere except for Albany. 
The old met guidance is a little cooler...as is the new nammos. 
Based on the pattern that is present in all the models...will trend 
a little above the mav guidance from US-84 southward...and will stay 
near or just below the mav guidance north of this line. This results 
in a min temperature grid that indicates a hard freeze across our northern 
tier zones. While I don't explicitly have hard freezing conditions 
mentioned in our Florida zones on this forecast package...i'm 
already inheriting a hard freeze watch and I don't have enough 
confidence to lower this watch in Florida. Will update the product 
on the 400 am issuance to mention some uncertainty and let the day 
shift evaluate the need to upgrade to a warning or discontinue. 


Below are some record lows for Saturday morning... 


Tallahassee Florida..........23 in 2000 
Apalachicola Florida.........29 in 1937 
Headland Alabama.............24 in 2000 
Albany Georgia...............22 in 2000 


Saturday...cool day continues as high pressure slips a little 
further southward. Expect temperatures to remain generally in the 
upper 50s most sites. It will be very dry as the high center moves 
into middle Georgia. Dewpoints may drop into the single digits with 
afternoon mixing across our northern zones. 


Saturday night...with the ridge centered northeast of the 
region...and with a gradually modifying airmass...it will be 
difficult for temperatures to drop too low. It looks like a slam 
dunk again for a night of freezing temperatures across our Georgia/Alabama 
zones. The inland Florida zones also will have a good chance of sub 
freezing temperatures. Coastal counties should remain at or just 
above freezing. Will include mention of frost in the forecast here 
as the airmass will be gradually moistening toward daybreak. 


Sunday...as the low level wind direction turns mainly 
easterly...expect temperatures to warm back into the middle 60s under 
mostly sunny skies. 


&& 


Long term...(sunday night through friday). 
The synoptic pattern should remain quite progressive across the 
southern tier of the United States throughout much of the extended 
period...with the ridge axis which is bringing US the shot of cold 
air for this current weekend...pushing quickly off the coastline of 
the Carolinas on Monday. This will allow the next cold front to 
quickly sweep through the County Warning Area with little fanfare on Monday or Monday 
night...as the GFS and European model (ecmwf) have now come into fairly good 
agreement that there will be very little return flow moisture to 
work with. Based on these model trends... believe that our current 
20 percent probability of precipitation will more than suffice for this cold frontal 
passage. Behind this next cold front...the air mass will still keep 
our temperatures below climatology...but it should not be nearly as cold as this 
weekend's blast. That said...some interior locations could see a 
light freeze and/or frost on Wednesday and Thursday mornings as the next ridge 
centers itself near the County Warning Area. These colder temperatures are more evident in 
the bias corrected grids...which should give somewhat of a better 
signal than the mex on days 5-7 due to the inherent weighting of 
climatology in the numerical guidance this far out. Thereafter...the 
next decent chance of rain may not occur until next Friday or the 
upcoming weekend...and would like to have a look at the latest 00 
UTC European model (ecmwf) run before making a decision when to begin probability of precipitation. 


&& 


Marine...infrared satellite shows a rope cloud indicating the leading 
edge of the cold front and the gusty winds behind it moving into our 
coastal waters at 08 UTC. Behind this line...winds are in the Small Craft Advisory 
category and will continue throughout much of the day. With the 
ridge expected to park north of the region...a tight gradient will 
keep winds elevated at Small Craft Advisory levels through Saturday morning before 
weakening. After this time...conditions over the waters should 
remain below headline criteria into next week. 


&& 


Aviation...with the next Arctic cold front poised just to our 
north...some very patchy and light MVFR fog has formed at vld and 
pfn...but expect this to be very short lived as the northwest winds begin 
to mix the low levels of the atmosphere very quickly. Also...a deck 
of broken SC/St between 4 and 5 kft has formed along and the just out 
ahead of the front itself...so some of the taf locations may 
experience a 2-4 hour period of VFR ceilings before sunrise this morning. 
After sunrise... expect generally clear skies with increasingly 
gusty north-northwest winds at all of the taf sites which should diminish 
around sunset. At this time...believe the surface winds will be strong 
enough to preclude any low level wind shear problems today. 


&& 


Fire weather...extremely dry air will move into the region and 
combine with gusty winds to easily allow US to meet red flag 
criteria in all Three States today. Less wind...but drier air on 
Saturday will result in long durations and the need for red flag 
warnings in all Three States again. A gradual moistening trend on 
Sunday looks to eliminate any red flag concerns. 


&& 


Preliminary point temps/pops... 
Tallahassee 57 27 59 30 66 / 0 0 0 0 0 
Panama City 57 34 61 38 66 / 0 0 0 0 0 
Dothan 53 27 58 29 65 / 0 0 0 0 0 
Albany 55 24 57 26 64 / 0 0 0 0 0 
Valdosta 58 28 57 29 65 / 0 0 0 0 0 
Cross City 61 26 63 31 68 / 0 0 0 0 0 


&& 


Tae watches/warnings/advisories... 
Alabama...Lake Wind Advisory from 9 am this morning to 4 PM CST this 
afternoon for the following zones: Coffee...Dale...Geneva... 
Henry...Houston. 


Hard freeze watch from late tonight through Saturday morning 
for the following zones: Coffee...Dale...Geneva...Henry... 
Houston. 


Red flag warning from 11 am this morning to 4 PM CST this 
afternoon for the following zones: Coffee...Dale...Geneva... 
Henry...Houston. 


Red flag warning from 11 am to 4 PM CST Saturday for the 
following zones: Coffee...Dale...Geneva...Henry...Houston. 


Georgia...Lake Wind Advisory from 10 am this morning to 5 PM EST this 
afternoon for the following zones: Baker...Ben Hill... 
Berrien...Brooks...Calhoun...Clay...Colquitt...Cook... 
Decatur...Dougherty...early...Grady...Irwin...Lanier... 
Lee...Lowndes...Miller...Mitchell...Quitman...Randolph... 
Seminole...Terrell...Thomas...Tift...Turner...Worth. 


Hard freeze watch from late tonight through Saturday morning 
for the following zones: Baker...Ben Hill...Berrien...Brooks... 
Calhoun...Clay...Colquitt...Cook...Decatur...Dougherty... 
early...Grady...Irwin...Lanier...Lee...Lowndes...Miller... 
Mitchell...Quitman...Randolph...Seminole...Terrell... 
Thomas...Tift...Turner...Worth. 


Red flag warning from noon today to 5 PM EST this afternoon for 
the following zones: Baker...Ben Hill...Berrien...Brooks... 
Calhoun...Clay...Colquitt...Cook...Decatur...Dougherty... 
early...Grady...Irwin...Lanier...Lee...Lowndes...Miller... 
Mitchell...Quitman...Randolph...Seminole...Terrell... 
Thomas...Tift...Turner...Worth. 


Red flag warning from 12 PM to 5 PM EST Saturday for the 
following zones: Baker...Ben Hill...Berrien...Brooks... 
Calhoun...Clay...Colquitt...Cook...Decatur...Dougherty... 
early...Grady...Irwin...Lanier...Lee...Lowndes...Miller... 
Mitchell...Quitman...Randolph...Seminole...Terrell... 
Thomas...Tift...Turner...Worth. 


Florida...Lake Wind Advisory from 10 am EST /9 am CST/ this morning to 5 
PM EST /4 PM CST/ this afternoon for the following zones: 
Bay...Calhoun...coastal Walton...Dixie...Franklin... 
Gadsden...Gulf...Holmes...inland Walton...Jackson... 
Jefferson...Lafayette...Leon...Liberty...Madison...Taylor... 
Wakulla...Washington. 


Hard freeze watch from late tonight through Saturday morning 
for the following zones: Bay...Calhoun...coastal Walton... 
Dixie...Franklin...Gadsden...Gulf...Holmes...inland 
Walton...Jackson...Jefferson...Lafayette...Leon...Liberty... 
Madison...Taylor...Wakulla...Washington. 


Red flag warning from noon EST /11 am CST/ today to 6 PM EST /5 
PM CST/ this afternoon for the following zones: Bay... 
Calhoun...coastal Walton...Dixie...Franklin...Gadsden... 
Gulf...Holmes...inland Walton...Jackson...Jefferson... 
Lafayette...Leon...Liberty...Madison...Taylor...Wakulla... 
Washington. 


Red flag warning from 12 PM EST /11 am CST/ to 6 PM EST /5 PM 
CST/ Saturday for the following zones: Bay...Calhoun... 
coastal Walton...Dixie...Franklin...Gadsden...Gulf... 
Holmes...inland Walton...Jackson...Jefferson...Lafayette... 
Leon...Liberty...Madison...Taylor...Wakulla...Washington. 


GM...Small Craft Advisory from 7 am this morning to 7 PM EST 
Saturday from Destin to the Suwannee River entrance out to 60 
nautical miles. 


&& 


$$ 


Long term/aviation/fire weather...Gould 
rest of discussion...Godsey 

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