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Area forecast discussion 
National Weather Service Lubbock Texas 
541 PM CST Tuesday Dec 2 2008 


Aviation... 
VFR high clouds in short term with potential still for low level 
wind shear this evening as surface winds already decoupled both at 
kcds and klbb. Surface low pressure will move east of terminals by 
daybreak Wednesday allowing a strong cold front to pass both 
terminals around 13z. Low clouds should follow quickly at kcds 
especially and eventually by early afternoon at klbb. An upper level 
low pressure system will move from near kabq at 15z Wednesday to 
just west of klbb at 21z Wednesday. Clouds should thicken to west 
of klbb with chance of light precipitation late in the day. Thermal 
profiles may support light snow to fairly low elevations. McQueen 


&& 


Previous discussion... /issued 305 PM CST Tuesday Dec 2 2008/ 


Short term... 
the short term will feature a temperature roller coaster as today/S 
unseasonably warm weather is to be replaced by blustery conditions 
by midday Wednesday. 


Southern Plains cyclogenesis will continue overnight as a middle/upper 
level shortwave trough over the Great Basin digs/propagates 
southeastward toward the southern rockies. Height/pressure falls 
will be sufficient to maintain modest downslope breezes overnight... 
so despite notably dry air over the western South Plains... 
temperatures should generally remain a few degrees warmer than 
lastnight/S minima. 


A cold Canadian airmass now ridging into the northern plains will 
push southward tonight. Solutions suggest the developing Southern 
Plains surface low will translate southeastward over Oklahoma late 
tonight/early Wednesday in advance of the approaching upper air trough... 
and this should usher the said airmass southward over West Texas... 
with an associated strong frontal passage and abrupt onset of gusty northerly 
winds between 12-18z. In fact...mslp gradients may support winds 
approaching advisory criteria /sustained 30+mph/ over the extreme 
southeastern Panhandle/northern rolling plains tomorrow morning. 
Will maintain a mention of such in the hazardous weather outlook. 
Otherwise...forecast profiles suggest Post frontal stratus will 
increase over the region and will combine with strong cold air advection to result 
in a 25-30 degree decrease in daytime temperatures relative to today. 


The models continue to generate light quantitative precipitation forecast associated with the middle 
level cold core/trough axis as it translates overhead tomorrow 
afternoon. This as thermal profiles cool notably...but remain 
slightly warmer than freezing. Will maintain a slight chance of rain 
showers over the northwest forecast area where best forcing/ascent is prognosticated. 
Model trends will need to be monitored for a possibility that light 
precipitation /if any/ could fall as snow flurries. The probability 
of measurable rainfall in this scenario remain 20 percent. 


Long term... 
surface high pressure to settle in over the plains states with temperatures a 
little cooler than seasonal norms expected Thu/Fri. Weak front to 
move through the area Saturday but with increasing heights and 
thicknesses due to upper level short wave ridging...the weekend 
should be the warmest part of the 7-day forecast. Some uncertainty 
enters into the forecast for Monday/Tuesday as GFS and its ensembles differ 
from the European model (ecmwf) with handling of cutoff energy off the southern calif 
coast and its subsequent ejection eastward. Will trend toward the 
GFS and its ensembles per HPC discussion. This will also yield 
good forecast to forecast continuity. Cooler temperatures...increased cloud cover 
and just below mentionable temperatures to be maintained from previous 
forecast. 


Fire weather... 
transient/intermittent critical fire weather conditions were met in 
two counties of the extreme southwestern South Plains per the West 
Texas mesonet for a two hour period today. Increasingly thick cirrus 
has thus far helped to prevent a widespread/persistent red flag 
event. Cloud cover is prognosticated to thin from southwest to northeast by 
late afternoon/early evening...but this trend will likely be too 
late to greatly enhance mixing/near-surface wind speeds. Thus 
despite currently critical relative humidity values between 10-15 
percent...the likelihood of widespread and/or persistent critical 
fire weather appears to be low and no headlines are anticipated. 


&& 


Preliminary point temps/pops... 
Friona 37 45 20 44 18 / 10 20 0 0 0 
Tulia 40 44 18 42 19 / 10 20 0 0 0 
Plainview 40 47 20 41 22 / 10 20 0 0 0 
Levelland 38 49 21 45 23 / 10 20 0 0 0 
Lubbock 39 49 24 45 23 / 10 10 0 0 0 
Denver City 44 57 27 45 25 / 10 10 0 0 0 
Brownfield 40 53 23 46 28 / 10 10 0 0 0 
Childress 38 50 24 44 23 / 0 20 0 0 0 
spur 41 52 24 47 24 / 0 10 0 0 0 
Aspermont 44 54 25 48 23 / 0 10 0 0 0 


&& 


Lub watches/warnings/advisories... 
none. 
&& 


$$ 


05/99/99