U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 061959 
Storm Prediction Center ac 061957 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0257 PM CDT Tuesday Oct 06 2015 

Valid 062000z - 071200z 

..there is a slight risk of severe thunderstorms from southeastern Arizona through southern nm and 
far West Texas... 

..there is a marginal risk of severe thunderstorms from eastern Arizona through central and 
southern nm and far West Texas... 

A few strong to severe thunderstorms remain possible this afternoon 
and early this evening over portions of Arizona...New Mexico and far 
West Texas. Large hail will be the primary threat...but some storms 
may also produce strong wind gusts. 


Ongoing forecast remains on track...and have therefore made only 
minor adjustments. Thunderstorms have undergone a general intensity 
increase due to boundary layer destabilization from eastern Arizona through 
nm and far West Texas. Latest objective analysis indicates MLCAPE has 
increased to 500-800 j/kg in this region...and storms are forming 
within an environment characterized by 30-40 knots effective bulk 
shear...supportive of a few rotating updrafts. 

For more information reference sels mesoscale discussion 1842. 

.Dial.. 10/06/2015 

Previous discussion... /issued 1127 am CDT Tuesday Oct 06 2015/ 

..se Arizona to southern nm/West Texas this afternoon/evening... 
A closed low over the lower Colorado River valley will drift eastward over southern 
Arizona through tonight while gradually weakening. Downstream from the 
low...a modest feed of low-level moisture /boundary layer dewpoints 
in the middle 50s/ will persist into Southeast Arizona/southern nm/far West Texas...beneath a 
belt of 35-40 knots southwesterly midlevel flow. Daytime heating in cloud 
breaks will boost MLCAPE to 500-1000 j/kg this afternoon from Southeast Arizona 
into southern nm/far West Texas...though the magnitude of buoyancy will be 
limited somewhat by the modest low-level moisture and midlevel lapse 
rates of 6.5-7 c/km. The net result will be an environment with 
sufficient buoyancy and deep-layer vertical shear/straight 
hodographs to support a risk for splitting/supercell storms capable 
of producing isolated large hail and perhaps strong outflow gusts. 
Any tornado risk will generally remain limited by weak low-level 
shear/hodograph curvature that is typical of 
equivalent-barotropic-low warm sectors lacking cyclogenesis. 

..co Front Range this afternoon/evening... 
Low-level flow will become southeasterly today across eastern Colorado...which will 
help maintain boundary layer dewpoints of 48-50 f and perhaps a weak 
Denver cyclone by afternoon. Clouds may be slow to clear in NE Colorado 
over the High Plains...with stronger surface heating limited to 
areas near or S of Denver this afternoon. The 12z Denver sounding 
suggests that surface temperatures need to warm to the low-middle 70s 
to eliminate convective inhibition for surface parcels...and MLCAPE 
will still only approach 500 j/kg. Moreover...deep-layer vertical 
shear will remain relatively weak...so any risk for strong storms 
appears too marginal to warrant any severe probabilities. 

Mesoscale Discussion

acus11 kwns 062222 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 062221 

Mesoscale discussion 1843 
National Weather Service Storm Prediction Center Norman OK 
0521 PM CDT Tuesday Oct 06 2015 

Areas affected...trans-Pecos of far West Texas 

Concerning...severe potential...watch unlikely 

Valid 062221z - 062345z 

Probability of watch issuance...20 percent 

Summary...a couple supercells may persist through about an hour 
after sunset but will likely remain confined west of the Pecos River. 
Severe hail will remain the primary hazard. 

Discussion...supercells have formed near the Davis Mountains on the 
fringe of a moderately favorable combination of MLCAPE near 1000 
j/kg and effective shear around 40 knots. This activity will likely 
remain tied to the higher terrain and struggle to progress eastward as 
surface dew points dry out into the upper 40s to lower 50s towards 
maf/sjt. Additional upstream convection over northern Chihuahua may 
progress east of the Rio Grande given greater buoyancy along this river 
amid lower 60s surface dew points. While low-level winds should 
remain weak into mid-evening...deep-layer speed shear is favorable 
for middle-level mesocyclones and growth of severe hail. 

.Grams/Hart.. 10/06/2015 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 30530491 30990397 31060329 31030294 30750292 30340301 
30080321 29860388 29810465 30530491