- 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
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.
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
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.
..please see www.Spc.NOAA.Gov for graphic product...
Latitude...Lon 31140563 31480605 32000648 32170569 31980455 31530397
31060390 30710409 30550437 30500469 30640494 30840527