271 
fxus65 kpub 210748 aaa 
afdpub 


Area forecast discussion...updated 
National Weather Service Pueblo Colorado 
1248 am MST Friday Nov 21 2008 


Update... 


A quick update to issue a dense fog advisory for northern El Paso 
County through this morning. Model sounding data indicates the 
dense fog/stratus will continue at least through sunrise...and 
rush hour will be starting around 400 am or 500 am. Live web cams 
from Glendale to the County line along I-25 showing near zero 
visibility in the dense freezing fog. Metze 


&& 


Previous discussion... /issued 334 PM MST Thursday Nov 20 2008/ 


Short term... 
(tonight and tomorrow) 


Currently...a stationary front is still located across southern 
Colorado. There is no longer any precipitation across the Front 
Range. A stratus layer lies across the I-25 corridor and the 
eastern plains. 


Tonight...the stratus layer will remain across the area into 
tomorrow morning. The winds will remain out of the south southwest 
and then gradually turn light. There will be patchy fog along the 
eastern most mountains...the southern portion of the San Luis 
valley...the I-25 corridor and the eastern plains. The big question 
for this evening is the intensity of the fog and how the stratus 
layer will affect temperatures. With the flow from the 
northwest...and looking at 700mb temperatures it looks that the 
temperatures will be similar to last night. With no major incoming 
moisture...and only drizzle across southern Colorado...the strength 
of the fog will be determined by any upslope flow that occurs and 
any settling moisture. This fog will be patchy at best but will 
reduce visibilities in the early morning hours. 


Tomorrow...with the stratus dissipating by middle day and the 
temperatures rebounding the biggest question is the strength of the 
gradient along the Colorado and Kansas border. This surface gradient 
will allow for gusty winds...but will not be near any advisory 
level. With only a weak Lee trough passing through northern Colorado 
the skies will clear by the afternoon leading to warmer temperatures. 


Long term... 
(friday night through next thursday) 


Fairly quiet weather through the weekend...with a couple of weak 
fronts brushing by the eastern plains early Saturday and Sunday 
afternoon. Saturday system has very little cold air with it...and 
with increased mixing high temperatures will likely warm several degrees 
versus Friday. Sunday system looks a little colder...though it may 
arrive too late to have much impact on high temperatures except for the 
far northeast portion of the area. Trimmed back maxes a few 
degrees over Prowers/Kiowa counties to account for 
thus...remainder of the area will see little change. Upper ridge 
rebuilds over The Rockies early next week...with warm and dry 
conditions through at least Tuesday afternoon. Prognosticated 700 mb 
temperatures stay generally below 4c...suggesting maximum temperatures could reach 
into the 60s over the plains by Tuesday afternoon. 


Discounted the 12z GFS solution for Wed/Thu...as it breaks 
continuity with its earlier runs plus the 12z European model (ecmwf). Will thus 
keep warm and mostly dry forecast in place Wednesday...though moisture 
could increase enough along the Continental Divide to generate a 
few showers by late in the day. Forecast gets tricky 
Thursday...with upper low lurking somewhere over the southwest and 
cold air poised to drop south over the northern plains. Stuck 
close to the 12z European model (ecmwf) for Thanksgiving day forecast...which keeps 
most cold air north until evening...and best lift and precipitation 
chances limited to mainly the higher mountains. Post Thanksgiving 
travel/shopping weekend looks cold and snowy if European 
verifies...though details are far from certain. 


Aviation...ceilings will remain in MVFR range this evening. The 
ceilings look to clear out by 16z tomorrow. There will be a light 
fog that will reduce visibilities between 11z-16z. After this 
time frame VFR conditions will occur. Jmc 


&& 


Pub watches/warnings/advisories... 


Dense fog advisory until 8 am MST this morning for coz084. 


&& 


$$ 


17/17