U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 241237 
Storm Prediction Center ac 241235 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0735 am CDT sun Sep 24 2017 

Valid 241300z - 251200z 

..there is a marginal risk of severe thunderstorms Minnesota... 

isolated damaging winds and a brief tornado are possible in 
Minnesota from 3 to 8 PM CDT. 

Maintained a marginal risk. 

Consensus of guidance suggests a weak cyclone over south-central NE 
will track northeast along a quasi-stationary front into 
west-central Minnesota by evening. Robust diabatic heating is anticipated 
over much of central and southern Minnesota amid 60-65 f surface dew 
points. While poor 700-500 mb lapse rates around 5 c/km will hinder 
buoyancy and updraft acceleration, the presence of 40-50 kt 700-mb 
south-southwesterlies along the frontal zone suggest that a few 
rotating updrafts should evolve with northeast-moving clusters and 
short-line segments in the late afternoon to early evening. Storms 
will weaken after sunset owing to the weak instability aloft and 
nocturnal boundary-layer stabilization. 

..trans-Pecos to the Raton Mesa... 
Considered a marginal risk for hail over The Trans-Pecos and the 
Raton Mesa vicinity. 

In the wake of a meridional stratiform convective band over the 
central/southern High Plains, upper 50s to lower 60s surface dew 
points remains common. Isolated storms should develop over the 
higher terrain of The Trans-Pecos by late afternoon and persist into 
the evening. Farther north across eastern nm, guidance strongly 
suggests that convective redevelopment will be delayed until tonight 
as low-level upslope flow increases. Mid to upper-level speed shear 
in both regions should be adequate for a couple weakly rotating 
updrafts. However, weak mid-level lapse rates sampled by 12z 
Albuquerque and El Paso soundings suggest the probability of severe 
hail is too low to warrant a risk area. 

.Grams/Jewell.. 09/24/2017 


Mesoscale Discussion

acus11 kwns 232256 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 232255 

Mesoscale discussion 1669 
National Weather Service Storm Prediction Center Norman OK 
0555 PM CDT Sat Sep 23 2017 

Areas affected...portions of southeastern nm and far West Texas 

Concerning...severe potential...watch unlikely 

Valid 232255z - 240100z 

Probability of watch issuance...5 percent 

Summary...a couple instances of large hail and strong/damaging winds 
may occur with isolated supercells over the next several hours. The 
overall severe threat is expected to remain very isolated, and watch 
issuance is not anticipated. 

Discussion...a couple supercells have developed late this afternoon 
within a modest low-level upslope flow regime across parts of 
southeastern nm and far West Texas. Winds strengthen to around 35-40 kt 
at mid levels as a highly amplified large-scale trough remains 
centered over the Great Basin. A veering wind profile per recent 
vwps from kmaf is also contributing to around 35-45 kt of effective 
bulk shear, which will allow for continued supercell structures 
through the evening. A narrow corridor of weak to moderate 
instability has developed across this region where some clearing has 
occurred. Given ongoing supercell structures and recent mrms mesh 
data, isolated large hail will continue to be a threat. Strong to 
locally damaging winds may also occur where low-level lapse rates 
have steepened due to diurnal heating. Both instability and shear 
weaken with eastward extent, and with the loss of diurnal heating 
that will occur later this evening, storms should eventually 
decrease in intensity. The ongoing threat for large hail and 
strong/damaging winds is expected to remain too isolated to warrant 
watch issuance. 

.Gleason/Edwards.. 09/23/2017 

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


Latitude...Lon 31010570 31880547 32730498 33590412 33770282 32930238 
31820227 30880244 29910268 29440348 29500409 29720467 
30500499 31010570