Weather

185 
fxus65 kpub 071053 
afdpub 


Area forecast discussion 
National Weather Service Pueblo Colorado 
453 am MDT sun Sep 7 2008 


Short term... 
(today and tonight) 


Current water vapor imagery and RUC upper air analysis indicating 
moderate west to northwest aloft as longwave upper trough continues 
to traverse across the upper Midwest. Water vapor imagery also 
indicating an embedded short wave and 90+kt jet core diving down the 
backside of the trough across western Montana with another weak wave 
moving across the desert SW at this time. At the surface...high pressure across 
the northern and Central High plains continues to build into the 
southern High Plains keeping moist low level upslope flow in place 
across eastern Colorado with satellite and observations indicating a 
5k-7k feet cloud deck across the much of eastern Colorado with local 
MVFR ceilings across the lower eastern slopes at this time. 


Today and tonight...have leaned current forecast closer to the GFS 
solution as the latest NAM runs seem to be a tad hot on generating 
quantitative precipitation forecast across the eastern plains. At any rate...western Montana short 
wave prognosticated to continue to dig across the northern rockies with 
desert SW wave moving across central New Mexico and into western 
Texas this evening. With the moderate westerly flow aloft across 
the state...Lee troughing to develop across the I-25 corridor 
through the early afternoon with a surface low developing across the 
southeast plains late this afternoon. Should see clouds slowly dissipate 
from west to east across the plains through the early afternoon 
keeping the coolest temperatures across the far southeast plains. Models 
continue to indicate a low level jet developing across the western 
Kansas border early this evening...which interacts with warm front 
lifting back across the northeastern plains and northwest Kansas 
tonight. Surface low continues into western Kansas overnight with cold 
front sliding back to near the Palmer dvd by 12z Monday. Have 
increased probability of precipitation across the far eastern plains this evening and 
along the Palmer dvd overnight with best moisture and lift along 
developing warm front this evening and along cold front overnight. 
Storm Prediction Center has a slight risk of severe weather across the northeast 
plains and into extreme eastern Kiowa County with elevated 
instability along and north of warm front bringing a threat of 
large hail...though will only mention the possibility in the severe weather potential statement 
at this time. Again...not much change out west with dry conditions and 
temperatures around seasonal averages. -Mw 


Long term... 
(monday through saturday) 


..another cold front to move through eastern Colorado Monday... 


Another cold front will roll through the eastern Colorado plains 
early Monday...promising brisk winds...much cooler temperatures and 
a slight chance of showers. The models break out some light precipitation 
early Monday along and behind the front. Then...late in the 
afternoon...they break out precipitation over the eastern mountains...right 
where the cold...moist...stable air is butted up against the 
warmer...more unstable air to the west. In this narrow zone along 
the mountains...the cap could be weak enough and the airmass 
unstable enough for the atmosphere to overturn and generate a few 
showers or thunderstorms late in the day into the evening. If the 
nam12 is correct in the amount of cooling to take place at 700 
mb...some wet snow showers could fall in the mountains above 
10500 feet Monday evening. Elsewhere...precipitation chances during the 
afternoon and evening look close to none. The airmass over the 
plains looks too stable and the airmass west of the eastern 
mountain ranges looks too dry. Temperatures tomorrow look pretty 
chilly across the plains...at least 15 degrees below average. The 
mountains and high valleys will generally stay west of the front 
so readings there will be comparable to previous days...and still 
at or above average. 


Tuesday and Wednesday look warmer with the return of a more Summer 
like...monsoonal pattern. Temperatures should be close to average 
on Tuesday...and then well above average on Wednesday. A fragmented 
monsoon plume will eject northeast across the state for afternoon and 
evening thunderstorms each day...mainly over and near the mountains. 


On Thursday...we could be looking at another shortwave and cold front 
moving through with a better chance of showers and cooler temperatures 
lingering into Friday. However...confidence in this is low at this 
point because there is a lot of discrepancy in how the wave will 
come across...both model-to-model and run-to-run. 


If the models are correct...Saturday would turn out a little warmer and 
drier than on Friday...with a slight chance of thunderstorms across 
the southeast plains. Temperatures would be back close to average. 
Again...confidence is low in how things will turn out at the end of 
the week so stay tuned. Lw 


&& 


Aviation... 
5k-8k cloud deck with local MVFR ceilings across the eastern 
plains to dissipate from west to east through the morning. Isolated 
to scattered thunderstorms and rain possible across the eastern plains late this 
afternoon and evening with best chances across the far eastern 
plains. Another cold front is expected to move across northeastern 
Colorado to near the Palmer dvd by early Monday morning...with gusty 
northerly winds and MVFR and local IFR ceilings developing behind 
boundary. -Mw 


&& 


Pub watches/warnings/advisories... 
none. 
&& 


$$ 


23/50