U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 191941 
Storm Prediction Center ac 191940 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0240 PM CDT Sat Apr 19 2014 

Valid 192000z - 201200z 

..no severe thunderstorm areas forecast... 

isolated strong storms are possible today in far West Texas and 
southern New Mexico. Some of these storms could briefly exceed 
severe limits. 

Convection continues to evolve as expected per prior forecast 
reasoning...and thus little changes necessary to the outlook at this time 
aside from a few very minor line adjustments. Except for an 
isolated/marginal severe event possibly occurring in vicinity of the Florida East 
Coast...or later over the Central Plains...the focus for 
isolated/low-end severe risk remains over far West Texas and adjacent southeastern 
nm. Here...isolated hail and/or a locally damaging wind gust or two 
may occur with a few of the strongest storms that evolve 
across/spread northeastward into the 5% risk area this afternoon. 

.Goss.. 04/19/2014 

Previous discussion... /issued 1107 am CDT Sat Apr 19 2014/ 

No significant change in two-stream...slowly progressive pattern 
expected this period. In the southern branch...NE Gulf of Mexico low 
should continue east-northeast to off the Georgia CST by early sun as upstream 
trough now over the northern Gulf of California broadens and reaches eastern nm/far West 
Texas. Within the latter trough...lead impulse now nearing El Paso 
should weaken as it continues NE toward the southern High Plains this 
afternoon...while upstream vorticity center now over northern Sonora continues 
east-northeast into southern nm. 

At lower levels...surface low expected to move slowly east off the NE Florida CST 
later today. Deeper wind shift line/cold front trailing S from the 
low has already moved off the east CST of Florida...but a 
shallower/reinforcing wind shift will progress east/southeast across northern and 
central parts of the peninsula this afternoon. In the central u... cold 
front attendant to northern stream trough over ND should settle S/southeast into 
southern Nebraska/northwest Kansas before becoming stationary later today/tngt. 

While thunderstorms for the most part will remain sub-severe over the nation 
this period...some risk for severe weather will exist in association 
with the upper systems affecting far West Texas/southern nm. A more 
conditional/isolated severe risk will accompany any storms forming along 
fronts over the Central Plains and over eastern Florida. 

..srn nm/far West Texas today through this evening... 
Thunderstorms now over southern nm/far West Texas are associated with lead upper impulse 
of SW U.S. Upper trough. The storms should strengthen later today with 
continued surface heating and the inflow of modest low-level moisture 
across southern portions of the southern High Plains. Although the upper 
impulse/ascent will move NE beyond axis of greatest moisture return 
later today...given residual band of 40-50 knots southwesterly middle-level flow and 
relatively cool 500 mb temperatures...setup may support a few 
storms/small clusters with a risk for severe hail/locally damaging wind. An 
additional round of storms may affect much the same region 
tonight/early sun as upstream vorticity approaches from northern Sonora. 

..cntrl plains this afn/eve... 
Some potential will exist for late day thunderstorm development along 
stalling front over northwest Kansas and southern Nebraska. But the region largely will 
be subject to shortwave ridging through this evening. And...while low to 
middle-level lapse rates will be sufficiently steep for storms...moisture 
will be limited. Some increase in storm coverage/strength may occur 
tonight/early sun over parts of Nebraska as nocturnal low level jet increases and as West 
Texas upper impulse approaches the region. While an isolated instance of 
marginally severe hail may occur...at this time it is doubtful that coverage 
justifies inclusion of 5% probabilities. 

..ern Florida this afternoon... 
Isolated diurnal storms may form along trailing wind shift line/cold 
front crossing east central Florida this afternoon before associated surface low moves 
offshore. Given sufficient convergence along the front and/or along 
sea breeze boundary...a storm or two could grow sufficiently strong 
to pose a brief risk for severe hail or wind. The overall 
threat...however...appears too low to warrant inclusion of 5% 
probabilities given weak low-level confluence suggested by area vwp 

Mesoscale Discussion

acus11 kwns 192023 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 192022 

Mesoscale discussion 0371 
National Weather Service Storm Prediction Center Norman OK 
0322 PM CDT Sat Apr 19 2014 

Areas affected...far West Texas and extreme southeastern nm 

Concerning...severe potential...watch unlikely 

Valid 192022z - 192215z 

Probability of watch issuance...20 percent 

Summary...storms are expected to increase in coverage from far western 
Texas through extreme southeastern nm into early evening. The stronger storms 
may produce large hail and locally strong wind gusts. A ww is not 

Discussion...skies have cleared and boundary layer destabilization 
is underway over far western Texas in wake of lead impulse moving northeastward 
through eastern nm and western Texas. Near surface dewpoints in the upper 40s 
to low 50s and steep middle-level lapse rates are supporting 500-1000 
j/kg MLCAPE as temperatures warm through the 70s. Orographic forcing 
and deep ascent accompanying an upstream impulse lifting northeastward within 
southeastern periphery of an upper low is supporting numerous thunderstorms 
over the higher terrain of northern Mexico. This activity will continue 
developing northeastward into western Texas and southern nm. Though flow through the 
lowest 3 km is modest...40-45 knots effective bulk shear may support at 
least weak-middle level updraft rotation with some of the storms. 
Isolated hail approaching severe limits and locally strong wind 
gusts will accompany the stronger cores. 

.Dial/corfidi.. 04/19/2014 

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


Latitude...Lon 31140563 31480605 32000648 32170569 31980455 31530397 
31060390 30710409 30550437 30500469 30640494 30840527