765 
fxus65 kboi 240310 cca 
afdboi 


Area forecast discussion 
area forecast discussion 
National Weather Service Boise Idaho 
910 PM MDT Wednesday Jul 23 2008 


Discussion...no changes to the current forecast. Current forecast 
on track as showers and thunderstorms continue to move northeast of 
the forecast area. Will leave the small mention of showers and 
thunderstorms over northeast section of zone 11 as upper level jet 
and associated shortwave continue to move to the northeast. Ridge 
of high pressure will build over the forecast are Thursday and 
Friday for a return to dry conditions and warming temperatures. 


&& 


Aviation...VFR conditions with clear skies and light winds through 
Thursday morning. Not anticipating fog development at McCall 
Thursday morning as drier air moves into the region. 
However...locally IFR fog is possible in the Long Valley or in 
sheltered mountains valleys by tomorrow morning. Fog will dissipate 
by 14z. VFR conditions through Thursday afternoon with light surface 
winds and light to moderate west winds aloft. 


&& 


Previous discussion... 
short term...tonight through Friday...an upper level wave with weak 
jet support will brush the far northern portion of the central 
mountains with a slight chance of showers and thunderstorms 
tonight...north of McCall. Visible imagery shows buildups/towering cumulus developing 
back to the SW from the Panhandle/northwestern Montana and that trend is expected 
to continue through late afternoon...along a narrow Theta-E ridge 
and water vapor axis. South of McCall though even clouds are 
expected to remain minimal with clear skies developing over southeast 
Oregon and SW Idaho later tonight. Drying today may not have been 
quite enough to inhibit formation of patchy fog in the Long Valley 
for a couple hours early Thursday as dew points there continue 
around 50 as of 2 PM. Warm and dry west-southwest flow with rising slightly 
heights/thicknesses Thursday will bring highs up slightly then a 
building ridge Friday will be accompanied by an enhanced thermal 
axis over Idaho...for hotter highs approaching the century mark. 
Moisture and instability in the northern stream remains to our northwest 
and monsoon flow has shifted to our southeast...so look for a dry forecast 
in the short term. While highs bake at around 8f above normal by 
Friday...clear nights with light diurnal winds are expected to allow 
low temperatures to be near normal in the short term. 


Long term...Friday night through Wednesday...Friday night through 
Monday there is still very little difference between models except 
in details of minor shortwaves rippling through the west-southwest 
flow aloft over the northwest states. Analog blends based on the 
latest models continue to give US very warm temperatures trough 
Monday...5-8 degrees above normal for the highs and a couple of 
degrees above normal for the lows. Monsoon moisture lurks just to 
our south. After Monday all but the European model (ecmwf) want to back the flow into 
the south bringing this moisture directly over our County Warning Area. There is of 
course uncertainty regarding details of this pattern change...but 
going along with the majority of operational models as well as the 
GFS ensemble mean we increased coverage of afternoon and evening 
thunderstorms Wednesday on the Idaho side. 


&& 


Boi watches/warnings/advisories... 
Idaho...none. 
Or...none. 
&& 


$$ 


Weather.Gov/Boise 


Discussion........ja 
aviation..........js 
previous short term...vm 
previous long term....jt/dd