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fxus62 kjax 231118 aaa 
afdjax 


Area forecast discussion...updated 
National Weather Service Jacksonville Florida 
618 am EST Monday Nov 23 2009 


Update...zones were updated for dense fog advisory. 


Short term (mon-wed)...a quasi-stationary front was just south of 
the I-10 corridor and connected to a broad low offshore NE Florida early 
this morning. Considerable low clouds and fog near and north of the 
boundary while patchy dense fog was forming south of the boundary. A 
few areas north of the boundary may still get patchy dense fog due 
to the wet grounds from the recent rain so have mention of patchy 
dense fog everywhere early this morning. Weak isentropic lift in the 
area may also result in occasional light drizzle through the early 
morning hours. 


As the low offshore lifts NE...the front will move south stalling 
across central Florida this afternoon. While the patchy dense fog will 
lift by middle morning...models indicate low clouds lingering through 
most of the morning across NE Florida and much of day across southeast Georgia. This 
will play a major role in temperatures...southeast Georgia likely remaining in the middle 
60s while north cntl Florida will be near 80 as breaks in the cloudiness are 
expected this afternoon. Not much change is expected Tuesday. Will 
continue to see considerable cloudiness across the area as front 
remains nearly stationary to the south with widespread low clouds 
and patchy late night and early morning dense fog. This is due to a 
shallow cool and moist layer being trapped below a low level 
inversion. 


Short wave energy will begin to ride the boundary Tuesday night-Wednesday 
resulting in amplification of coastal trough offshore. This 
results in chance probability of precipitation NE Florida and slight chance for southeast Georgia. 


Long term (thu-sun)...a deep upper level trough...an approaching 
weak surface front and the inverted trough offshore of the southeast Atlantic 
coast will progress downstream of the region late Thursday. Have kept 
low probability of precipitation in for eastern areas on Thanksgiving but that is more 
likely to be mainly in the morning. A trough deepens along 
the eastern U.S. Resulting in strong cold air advection beginning 
over the County Warning Area Friday with temperatures falling below climatology values for the 
weekend. Expect mins in the 30s well inland/40s coast with maxes in 
the 60s under mostly clear skies Sat and sun. 


&& 


Aviation...IFR ceilings are mainly confined over southeast Georgia at 
this time but these ceilings are gradually working their way into NE Florida. 
A narrow area of lower moisture and generally weak isentropic ascent 
appears to be allowing some tempo VFR which will allow for some 
rapid fog development. Have mainly gone with IFR and LIFR through 13z 
with only slow improvement during the day with VFR possible after 
18z but this may be optimistic as low level moisture lingers and 
isentropic ascent may get going again by around 21z. 


&& 


Marine...frontal boundary bisects the coastal waters with slightly 
stronger wind north of front where buoy 41008 had 16 knots at 08z. 
Will highlight scec for the offshore NE marine zone for mainly seas 
as current and prior model runs show winds should come down a bit 
during the day. Winds are expected to increase gradually on Tuesday as 
the front or a coastal trough develops pinching the pressure 
gradient...then a strong cold front sweeps through Thursday with rapid 
increases in northwest flow through Friday. Patchy dense fog will likely 
remain a hazard for the nearshore waters this morning and Tuesday 
morning and have included in the coastal waters forecast package. 


&& 


Preliminary point temps/pops... 
amg 65 48 66 49 / 10 10 10 20 
ssi 70 54 66 55 / 10 10 10 30 
jax 75 54 69 56 / 10 10 20 30 
sgj 75 60 70 61 / 10 20 30 40 
gnv 77 55 71 56 / 10 10 20 40 
ocf 79 57 75 59 / 20 20 30 30 


&& 


Jax watches/warnings/advisories... 
Florida...dense fog advisory until 9 am EST this morning for Alachua- 
Bradford-Clay-Duval-Marion-Nassau-Putnam-St Johns. 


Georgia...none. 
Am...none. 


&& 


$$ 


Pp/ars/aw