- Täna
- Homme
- Day Three
000
acus01 kwns 211959
swody1
Storm Prediction Center ac 211958
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
0258 PM CDT Sat Apr 21 2018
Valid 212000z - 221200z
..there is a slight risk of severe thunderstorms over a small part
of North Texas...
..there is a marginal risk of severe thunderstorms over portions of
Texas into Louisiana...
...
Isolated severe thunderstorms are possible from
northwest/north-central Texas this afternoon to East Texas and
northern Louisiana tonight.
For short-term details across northwest/north-central Texas this
afternoon, please see mesoscale discussion 280. Elsewhere, no significant changes
were made to the previous outlook.
A sporadic lightning strike will remain possible this afternoon
across northwest Montana in association with an upper-level impulse,
where large-scale ascent has contributed to scattered showers.
Coverage is expected to remain below 10 percent.
.Bunting.. 04/21/2018
Previous discussion... /issued 1049 am CDT Sat Apr 21 2018/
...
An upper low is centered today over eastern Colorado/western KS, with
band of strong westerly flow around the south side of the low across
Texas. A large area of showers and thunderstorms is affecting much of
OK and north-central Texas within the strong low-level advection
regime. This activity should spread northeastward and away from
North Texas by mid afternoon.
In the wake of the morning activity, some heating/destabilization is
expected west of ftw, leading to an area of sufficient cape and
low-level convergence for isolated thunderstorm development.
Low-level shear will decrease through the day as winds veer/weaken,
but the consensus of 12z cam solutions suggests 1 or 2 strong/severe
storms will develop in this small area, capable of large hail. The
threat should focus in the 22-02z period. After that, storm
intensities are expected to diminish but overall mesoscale
organization may increase as storms become oriented into a line. A
marginal risk of gusty winds or hail will persist through much of
the night as storms spread into East Texas and northern la.
$$
Mesoscale Discussion
000
acus11 kwns 211841
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 211841
txz000-212115-
Mesoscale discussion 0280
National Weather Service Storm Prediction Center Norman OK
0141 PM CDT Sat Apr 21 2018
Areas affected...north-central Texas
Concerning...severe potential...watch unlikely
Valid 211841z - 212115z
Probability of watch issuance...20 percent
Summary...a severe threat is expected to develop across parts of
north-central Texas this afternoon. Large hail and damaging wind
gusts will be possible with the strongest of storms. However, the
severe threat should remain isolated and weather watch issuance
appears unlikely.
Discussion...the latest surface analysis shows a 1008 mb low over
the Low Rolling Plains of West Texas. A warm front extends eastward
from the low across north-central Texas. South of this boundary,
surface dewpoints are generally in the upper 50s and lower 60s f.
This is contributing to a narrow corridor of weak instability from
the Texas Hill country northward into the Low Rolling Plains where
MLCAPE values are estimated in the 250 to 500 j/kg range according
to objective analysis.
Surface-based convection has initiated to the northwest of Abilene,
Texas over the last hour. This convection is located just to the west
of the strongest instability and near a pronounced vorticity Max
analyzed by the rap. The Abilene WSR-88D vwp shows strong deep-layer
shear with 0-6 km shear estimated to be from 50 to 55 kts. In
addition, forecast soundings suggest an area of steep mid-level
lapse rates exists near the instability Max. These factors should be
supportive of strong updrafts capable of producing hail. Isolated
large hail could occur with any storm that develops persistent
rotation. An isolated wind damage threat may also develop mainly
after convection matures later this afternoon especially if a short
line segment can organize. Isolated storm coverage and the small
affected area make weather watch issuance unlikely.
.Broyles/Hart.. 04/21/2018
..please see www.Spc.NOAA.Gov for graphic product...
Attention...WFO...fwd...sjt...
Latitude...Lon 32329942 31869804 31829722 32269689 32779688 33209734
33319801 33339919 33259969 33099984 32829984 32329942
