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fxus65 kpub 030550 aaa 
afdpub 


Area forecast discussion...updated 
National Weather Service Pueblo Colorado 
1050 PM MST Tuesday Dec 2 2008 


Short term... 
front evident in kftg radar loop across NE Colorado...still looks on 
target to hit the Palmer Divide around midnight with gusts up to 
30 to 40 miles per hour possible behind the front. Lxv has been reporting 
snow the past couple hours and web cam appears to show a nice 
dusting of snow on Road surfaces. Radar mosaic loops showing a 
band of precipitation extending from klxv back to the southwest across 
kmtj...with this area prognosticated to move into the SW mts in the next 
couple hours. Based on latest radar trends...have opted to 
increase probability of precipitation farther west. Still not expecting much change in 
snow amounts...mainly a light event from the mts...with generally 
isolated snow showers possible across the southeast plains. -Kt 


&& 


Previous discussion... /issued 343 PM MST Tuesday Dec 2 2008/ 


Short term... 
(tonight and wednesday) 


Winds have remained rather quiet thus far this afternoon over the lower 
elevations...with stronger westerly winds remaining over the hyr terrain as 
the lower atmos has remained decoupled. This has resulted in some 
unusual temperature swings for the I-25 corridor...with temperatures rising at 
kpub to a near-record 71 degree earlier this morning...then falling and 
remaining at a current 68 degree...as low level winds shifted and remained 
to the S and southeast. Still a couple hours left in the afternoon...but 
looks like winds will remain on the light side through this evening. 


The cold front is pretty much on schedule at this time...currently racing 
through central Wyoming. Expect the front to reach our area around midnight 
tonight...with a shift to gusty nearly winds. Model trends continue to 
indicate less and less quantitative precipitation forecast with this system...so have trimmed back 
probability of precipitation a bit overnight. Most likely spot for snow accums will be the 
northern mts and Lake County...where the higher elevs may reach low end 
advisory criteria by Wednesday morning. Since impact appears minimal will 
hold off on any headlines. Over the plains...isentropic surfaces dont 
show much in the way of lift and upper support looks weak. Soundings 
do show a modest low level moist layer and with frontal passage could squeeze out 
some moisture...but not expecting much in the way of accums. 


Main impact tomorrow will be significantly cooler weather...with 
afternoon highs as much as 30 degree lower over the plains. Will be a 
rather raw day with cloudy conditions prevailing much of the morning. 
Any chance at precipitation should come to an end from northwest to southeast in the 
afternoon. 44 


Long term... 
(wednesday night through tuesday) 


.Much colder with a little light snow possible Wednesday night 
through Thursday evening...warming and drying Friday through 
Sunday...then big questions... 


Wednesday night through Thursday night...models are in pretty fair 
agreement on the strength and track of the next system to move 
through...although precipitation forecasts vary a little. System 
should move through southern Colorado as an open wave tracking 
across the northeast corner of the state on Thursday. At the 
surface...cold high pressure will be dropping south through the 
Central Plains...will low level upslope flow over eastern 
Colorado. Southeastern Colorado will be under the right rear 
entrance region of the jet Thursday...which should provide enough 
lift for some scattered light snow. Snowfall for most areas should 
be pretty light if at all...but the atmosphere will support banded 
precipitation which could mean localized higher snowfall amounts 
under the more intense/persistent bands. Temperatures on Thursday 
will be pretty chilly...generally not out of the 30s anywhere. 


Friday through Sunday...upper ridge will build in over the 
region...for warming temperatures and generally dry weather. 
Temperatures will be close to average on Friday...and then probably 
15 degrees above average for Saturday and Sunday. 


Be questions regarding the forecast beginning late Sunday through 
Tuesday. The 12z gfs40 kept it dry and mild around here. The 12z 
high resolution European model (ecmwf) had a major trough moving into Colorado...with 
decent amounts of snow...especially on the plains. And now the 
18z gfs40 (just coming in) indicates a good size trough moving 
through... but warmer and drier than the 12z European model (ecmwf). Models have 
been very fickle lately...with major phase changes every other 
run...especially the GFS. So...confidence in long range forecast 
is extremely low right now. Have opted to follow suit with 
surrounding forecast offices and introduce some low probability of precipitation during 
this time frame...more to indicate the possibility rather than the 
probability of precipitation. Lw 


Aviation... 
main concern in the short term continues to be low level wind shear over the I-25 
corridor...as surface winds remain rather light and variable...while 
winds just above the surface continue gusting in the 30 knots range. 
However...winds aloft will continue to quiet down through the 
early evening. A cold front will move through eastern Colorado in the 
06z to 09z time frame tonight...resulting in a wind shift to the 
north with gusty surface winds continuing for several hours. MVFR ceilings 
will be likely over a good portion of the southeastern Colorado plains...with 
some local IFR ceilings possible particularly over the Palmer Divide 
early Wednesday morning. 44 


&& 


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


$$ 


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