Weather

896 
fxus62 kjax 061832 
afdjax 


Area forecast discussion 
National Weather Service Jacksonville Florida 
230 PM EDT Monday Oct 6 2008 


Synopsis...upper high pressure ridge continues S of the area with 
another ridge extending north over our County Warning Area. Convection 
continues to develop offshore NE Florida ahead of East Coast upper trough 
near the Gulf Stream. Dry air aloft has remained in the middle and 
upper levels over the area. Deeper moisture over the east Gomex is 
gradually lifting NE on west periphery of S Florida ridge. Amplified upper 
trough extends from west Canada to West Texas. Low-level moisture and 
instability has allowed broken cumulus field and generally light to 
moderate small showers to develop across inland areas. Stronger 
convection over the NE Florida Atlantic waters still not making much 
progress inland...although convergence lines occasionally approach 
the coast. Temperatures vary from near 90 over inland areas that have had 
several hours of sun to near 80 along the Atlantic coast. 


Short term...still quite a bit of forecast uncertainty the next 
48 hours. Have generally adjusted probability of precipitation down from previous forecast. 
This being said...there is still a chance that more widespread 
convection from off the Atlantic coast may make its way inland later 
this afternoon or this evening. However...feel that most forcing at this time 
is instability and positive vorticity advection over the warm Gulf 
Stream waters with narrow bands of showers advecting away from 
these areas toward the NE Florida coast. 


Winds will gradually veer to the southeast as high pressure over the New 
England coast slides east and a meridional cold front approaches late 
Wednesday. Rain chances are expected to decrease tonight and Tuesday before 
increasing again ahead of the front. GFS appears to be having 
convective feedback problems generating huge bullseyes of precipitation... 
but MOS probability of precipitation from the models are in fair agreement. Have used a 
blend of MOS for the forecast. 


Patchy fog is expected tonight and Tuesday night...with more widespread 
fog possible Wednesday night if surface wind flow and cloud cover ahead of 
front allow. 


Long term...have sped up the frontal passage early in the extended 
period. Otherwise...little change to existing package. 


&& 


Aviation...expect prevailing VFR with occasional MVFR in passing 
cumulus near the coast...with convection more likely at gnv through 
the remainder of the afternoon. Overnight expect coastal rain showers near the Florida 
Atlantic coast around daybreak with breezy winds around 15g20kt by 
early morning. Have advertised marginal MVFR in br at gnv 
tonight...but boundary layer winds may be too turbulent. 


&& 


Marine...have tweaked the Small Craft Advisory to begin early Tuesday morning and 
persist through Tuesday night. Until then...expect prevailing scec 
offshore. A trough will likely position and become diffuse over the 
area late Wednesday into Thursday which will cause winds to veer and decrease 
trough the end of the week. 


&& 


Preliminary point temps/pops... 
amg 63 84 65 81 / 10 20 20 50 
ssi 70 80 71 78 / 20 10 20 40 
jax 69 82 69 82 / 30 20 20 50 
sgj 73 82 72 82 / 40 20 20 50 
gnv 69 84 69 83 / 40 30 30 60 
ocf 70 85 70 85 / 40 40 20 60 


&& 


Jax watches/warnings/advisories... 
Florida...none. 
Georgia...none. 
Am...Small Craft Advisory from 8 am to midnight Tuesday for 
Altamaha Sound Georgia to Flagler Beach Florida 20 nm to 60 nm offshore. 


&& 


$$ 


Carroll/enyedi/Walker