Severe Weather Threat - 1/18-1/23

:nana: :nana: :nana:

Day 3 shows it's beginning over TX.



Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0228 AM CST Fri Jan 13 2017

Valid 151200Z - 161200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
WEST AND CENTRAL TEXAS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS...

...SUMMARY...
A severe threat with large hail and isolated wind damage will be
possible on Sunday across parts of the southern Plains.

...Southern Plains...
An upper-level low will move northeastward across southern New
Mexico on Sunday as a negatively tilted upper-level trough moves
into the Rio Grande Valley. Thunderstorm activity could be ongoing
just ahead of the upper-level trough across far west Texas into far
southeastern New Mexico at the start of the period. The models are
consistent with moving this convection slowly eastward across the
southern high Plains during the day on Sunday. At the surface, a
trough is forecast to move into west Texas as a cold front advances
from west to east from the Pecos Valley into western parts of the
Texas Hill Country. Surface dewpoints ahead of the front will likely
be 50s F with weak instability developing by afternoon.

The greatest potential for a severe threat would be just ahead of
the mid-level jet on the southern end of a cluster of storms
forecast to be located near San Angelo by afternoon. This threat
would extend southward toward the Rio Grande Valley where storms are
forecast to have access to the greatest instability. NAM forecast
soundings valid 00Z/Monday just to the south of San Angelo show a
surface dewpoint of 57 F, MLCAPE of 700 J/kg, 0-6 km shear near 60
kts and steep lapse rates from 700 to 500 mb. This should be enough
for a supercell threat with isolated large hail associated with the
stronger updrafts. A veering wind profile with height may also help
downdrafts produce damaging wind gusts. Further to the north into
parts of northwest Texas, surface dewpoints will not be as high but
strong deep-layer shear and steep mid-level lapse rates may be
enough for hail and isolated damaging wind gusts especially if a
line of storms can organize during the late afternoon.

455 AM CST FRI JAN 13 2017

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
LOUISIANA...SOUTH MISSISSIPPI AND THE ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

AREAS OF DENSE FOG MAY AFFECT SOUTHEAST LOUISIANA AND SOUTH
MISSISSIPPI AND THE ADJACENT COASTAL WATERS AND TIDAL LAKES THIS
MORNING. A DENSE FOG ADVISORY IS IN EFFECT FOR LAND AREAS UNTIL 9 AM
CST AND FOR MARINE AREAS UNTIL NOON CST. DENSE FOG MAY REDUCE THE
VISIBILITY TO 1/2 MILE OR LESS AT TIMES.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

AREAS OF DENSE FOG MAY DEVELOP OVER PROTECTED AND NEARSHORE WATERS
AND OVER INLAND AREAS EACH NIGHT AND MORNING THROUGH THE
WEEKEND.

A STORM SYSTEM IS EXPECTED TO THE TRACK NORTHEAST ACROSS THE
CENTRAL PLAINS AND MID MISSISSIPPI VALLEY NEXT WEEK. THE
ASSOCIATED SURFACE COLD FRONT WILL APPROACH THE OUTLOOK AREA
DURING THE FIRST HALF OF NEXT WEEK. A FEW STRONG STORMS AND HEAVY
RAINFALL WILL BE POSSIBLE WITH THIS SYSTEM. THERE IS STILL SOME
UNCERTAINTY ON TIMING AND STRENGTH WITH THIS SYSTEM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0347 AM CST Sun Jan 15 2017

Valid 181200Z - 231200Z

...DISCUSSION...
The medium range models including the ECMWF and GFS begin the day 4
to 8 period with an upper-level trough in the Ohio Valley and move
this feature eastward to the mid Atlantic coast on Wednesday/Day 4.
Although there is spread among the solutions, the models suggest
that west to southwest mid-level flow will be in place across the
southeastern United States. Although weak instability is forecast on
Wednesday, thunderstorms could develop across the lower Mississippi
Valley during the day. On Thursday/Day 5, the ECMWF and GFS bring an
upper-level trough into the southern Plains with the ECMWF a bit
faster moving the trough eastward. Thunderstorm development and
possibly a severe threat could take place ahead of the upper-level
trough on Thursday anywhere from the Texas Coastal Plains eastward
into the lower Mississippi Valley depending upon the timing of the
system. On Friday/Day 6, both solutions bring another upper-level
trough in the southern Plains and suggest moisture advection will
occur across parts of the western and central Gulf Coast States.
This would make thunderstorm development again possible on Friday
afternoon from the Texas Coastal Plains eastward into the lower
Mississippi Valley. On Saturday/Day 7 and Sunday/Day 8, the ECMWF
and GFS both move a strong mid-level jet across northern Mexico. The
exit region of the mid-level jet is forecast to spread across the
Gulf Coast States with the warm sector returning northward into the
region. This would suggest a severe threat would be possible in
parts of the Gulf Coast States each day but uncertainty is
considerable during the latter part of the day 4 to 8 period.

Does anyone know how long KLIX will be down?

Thanks SKYSUMMIT! No not at all especially with the weather we suppose to have this week.

Dr. Forbes' TOR:CON

Today

A chance of an isolated severe thunderstorm along a stalled front in east TX, possibly a brief weak tornado. TORCON - 1



Wednesday 1/18

A chance of an isolated severe thunderstorm in middle and upper coastal TX, southwest as a wave of low pressure may form along the stationary front. TORCON - 1



Thursday 1/19

Isolated severe thunderstorms in upper coastal TX, LA, west MS, southeast AR as an upper-air disturbance moves into the region. TORCON - 2



Friday 1/20

Probably no severe thunderstorms, but a low chance of an isolated severe thunderstorm in the FL panhandle and south GA.
TORCON - near zero. Locally heavy rain in CA, OR.

Saturday 1/21

Scattered severe thunderstorms in extreme east TX, LA, MS, west-central and south AL, west FL panhandle, with storms possibly becoming severe in east TX as early as early morning. TORCON - 3. At this time low-level wind shear looks relatively weak, holding down the tornado threat, but that could increase if more of a surface low and low-level jet develop.



Sunday 1/22

Details could change as there is uncertainty in the forecast, but it appears that a significant severe thunderstorm threat could develop in southeast LA, central and east MS, AL, GA, FL panhandle and possibly northeast FL, east half TN, possibly southeast KY. TORCON - 4 AL, GA, and FL panhandle; 3 rest of area for now.