719 
fxus64 kepz 192059 
afdepz 


Area forecast discussion 
National Weather Service El Paso Texas/Santa Teresa nm 
259 PM MDT Tuesday Aug 19 2008 


Synopsis... 
enough middle-level moisture remains over the region on the back side 
of an exiting upper-level low pressure system to produce scattered 
mountain and isolated lowland thunderstorms this evening. Another 
round of storms with similar coverage is expected again Wednesday. 
Thursday through the weekend an upper-level ridge will build over 
the region from the west. Temperatures will warm to above normal 
and storm activity will be reduced significantly. 


&& 


Discussion... 
synoptically the upper level low is slowly exiting east over North Texas. 
A deep trough has moved into the Pacific northwest. A ridge of high pressure 
is building over the Desert Southwest. Over our region what 
appears to be a shear zone is oriented across the Gila southeast 
into the far West Texas counties. It is along this line that that 
storms developed last night and have again today. Moisture is 
beginning to dwindle as seen in the drying of the water vapor 
satellite imagery...but remains high enough (over an inch pw) to 
combine with some instability aloft and heating below to generate 
isolated to scattered thunderstorms. The pattern will be slow to 
change so Wednesday looks to be a similar day weather wise. A bit 
of a reduction in moisture may show up in slightly less coverage 
of storms. 


Thursday the ridge over Arizona is proged to expand east over nm. 
Continued drying of the atmosphere is expected. Temperatures will 
be warmer to end the week...but the lower moisture levels should 
limit storm activity to mainly the mountains through the weekend. 
Temperatures will be above seasonal normals as strong high 
pressure centers over northern New Mexico. The GFS shows some 
moisture within the high so will have to keep some minimal probability of precipitation 
across the area. 


Monday and Tuesday the ridge is shown to shift back to the west a bit. 
This would place the area under northerly flow aloft on the east 
perimeter of the high and allow increased moisture to move back in 
while disturbances track over from the north. Thus will have to 
watch this and consider increasing storm chances for day 6 and 7. 


&& 


Aviation... 
valid 20/0000z - 21/0000z 
mainly VFR through the period. However...isolated to scattered 
afternoon and evening thunderstorms will cause areas of MVFR to 
IFR conditions with low ceilings and visibility. Winds will be 
strong and gusty near any thunderstorm. Shower and thunderstorm 
activity will diminish Thursday. 


&& 


Fire weather... 
low pressure over the Southern Plains will continue to bring moist 
air and weak disturbances across the area this evening into tonight 
and again on Wednesday. This will allow scattered thunderstorms 
across higher elevations...while the lower deserts will have 
isolated showers and thunderstorms. High pressure aloft building 
over Arizona will slowly shift eastward into New Mexico Thursday. 
This will bring a decrease in shower and thunderstorm activity for 
Thursday into the weekend with afternoon temperatures above normal. 


&& 


Preliminary point temps/pops... 
El Paso 68 94 70 96 72 / 20 20 20 10 20 
Sierra Blanca Texas 62 91 65 93 66 / 20 20 20 10 20 
Las Cruces 66 94 68 96 70 / 20 20 20 10 20 
Alamogordo 64 92 68 93 69 / 20 20 20 10 20 
Cloudcroft 47 71 49 74 51 / 20 30 20 20 20 
Truth or Consequences 63 91 68 93 69 / 30 20 20 10 20 
Silver City 60 88 61 88 62 / 30 20 20 10 20 
Deming 65 94 68 95 68 / 20 20 20 10 20 
Lordsburg 65 93 67 95 67 / 30 20 20 10 20 


&& 


Epz watches/warnings/advisories... 
nm...none. 
Texas...none. 
&& 


$$ 


14/21