645 
fxus66 kmfr 052028 
afdmfr 


Area forecast discussion 
National Weather Service Medford or 
128 PM PDT Sat Jul 5 2008 


Discussion...00z NGM/NAM/GFS in. 


The Pacific northwest is currently under weak nearly zonal flow 
with embedded weak short waves. These disturbances will bring a 
slight chance of showers from the Cascades west and Siskiyous 
north today...and to the Cascades around Crater Lake tonight as 
the last of these systems moves through the area. 


A hot ridge will then build over the area from the south...and the 
furnace will be turned on Sunday. 500 mb heights will rise 
Sunday into Tuesday before leveling off. At low levels a strong 
thermal trough will develop Sunday and persist through at least 
Tuesday. This will bring strong winds to the coastal waters along 
with low level offshore flow in the nighttime hours when the 
trough moves offshore. At this time it looks like the offshore 
flow will peak Monday night. 


Precipitation will end Sunday morning and high temperatures inland 
will climb to above normal values Sunday and continue up to very 
hot values Tuesday and Wednesday. The heat wave will peak on 
Wednesday. 


The ridge will begin to weaken Wednesday as an upper trough moves 
in from the west. This trough will strengthen as it moves onshore 
Thursday night. No precipitation is expected with this 
system...but it will put an end to the offshore event and bring in 
some onshore flow Friday...along with cooler temperatures. 


Another ridge will then build over the area...but it will not be 
nearly as strong or long-lasting as the previous one. Expect 
weaker offshore low level flow to develop Friday night and maybe 
Saturday night. Saturdays highs will be about the same as 
fridays...and Sunday highs will be cooler as the ridge weakens. 


&& 


Aviation...VFR conditions will prevail through tonight...except 
for patchy MVFR ceilings along the coast and near higher terrain. Some 
MVFR visibilities in smoke will prevail over western Siskiyou 
County. All areas other than the smoky areas will clear to VFR by 
Sunday afternoon. 


&& 


Mfr watches/warnings/advisories... 
or...none. 


California...none. 


Pacific coastal waters...gale watch from Sunday afternoon through 
Wednesday afternoon for pzz356-pzz376. 
Small Craft Advisory for winds from 5 am to 5 PM PDT Sunday for 
pzz356-pzz376. 
Hazardous seas watch from Sunday afternoon through Wednesday 
afternoon for pzz356-pzz376. 
Small Craft Advisory for hazardous seas from 5 am to 5 PM PDT 
Sunday for pzz356-pzz376. 
Small Craft Advisory for winds from 2 PM Sunday to 5 PM PDT 
Wednesday for pzz350-pzz370. 
Small Craft Advisory for hazardous seas from 2 PM Sunday to 5 PM 
PDT Wednesday for pzz350-pzz370. 


$$ 


15/15/18