Area Forecast Discussion
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FXUS64 KLUB 290436
AFDLUB

Area Forecast Discussion
National Weather Service Lubbock TX
1136 PM CDT SAT MAY 28 2016

.AVIATION...
No sig changes to the TAFs this cycle. TS managed to stay south of
the terminals and is generally waning. Stratus still expected to
develop toward 12z with MVFR the best guess but IFR not out of the
question. TS seems a good bet sometime after 15z, but timing and
placement still difficult to gauge. A short wave trough moving
toward KELP may kick off an early round late Sunday morning.
Otherwise, standard diurnal hours of mid to late afternoon seem
like best chance for storm initiation.

&&

.PREV DISCUSSION... /issued 628 PM CDT SAT MAY 28 2016/

AVIATION...
A surge of low level moisture is headed northward through the
Permian Basin and Big Country. Scattered TS developing along it
should stay to the south of the terminals. However, stratus
looking likely late tonight, in particular at KLBB and KPVW. Best
guess right now is MVFR category through Sunday morning. Focus
then shifts to TS chances for Sunday afternoon. Low confidence at
this time as moisture available but weak forcing and lack of
discernable low level convergence leads to questions regarding
location and timing of initiation. Will keep mention out for now.

PREV DISCUSSION... /issued 400 PM CDT SAT MAY 28 2016/

SHORT TERM...
Winds are expected to back to the southeast by this evening and
allow higher dewpoints off to the southeast to push into the FA.
These higher dewpoints along with a developing 30-40 knot LLJ
overnight will allow for low level clouds to develop from southeast
to northwest. Models have had (very) mixed feelings for possible
convection tonight with the most bullish being the NAM. The NAM
hints at a disturbance pushing around the upper ridge that is just
to our west and uses it to develop overnight convection. WV imagery
shows the closest disturbance being located over southern Chihuahua
and will stay to the south of the FA on its current trajectory.
Another disturbance can be seen just off the west coast of the Baja
peninsula, but this area of lift wouldn`t arrive until some time
tomorrow. Overnight PoPs will keep most thunderstorm activity to our
south which our southern counties having some mention of precip to
account for outflow boundaries that could push into the FA from
convection to our south.

Some lingering showers and thunderstorms will be possible in the
morning, otherwise things will stay relatively quiet until the
afternoon. A dryline will set up just west of the TX/NM state line
early tomorrow afternoon. Skies ahead of the dryline will be broken
to overcast (mostly in the lower levels). This will allow for
differential heating to take place near the dryline. Aided by
surface convergence as well as lift from an upper level jet and
disturbance moving across the region should allow for convective
development by mid afternoon. Plenty of instability will be in place
east of the dryline as the boundary layer warms through the day
thanks to WAA. 0-6 km shear will increase through the day as well to
40-50 knots by the late afternoon/early evening. This will allow for
any convection that develops to be severe. The main severe threat
will be large hail to start with as there will be sufficient dry air
in the mid to upper levels - and will then transition to more of
a wind threat as the upper level moistening occurs and low level
directional shear increases. One thing of note that is shown by
the GFS and NAM is the presence of a moderately strong inversion
between the H800 and H700 levels. The cap does eventually erode by
some time in the afternoon, but the time it erodes could wreak
havoc on the time convection initiates. This will be a forecast
issue that will be determined best in the near term tomorrow
morning/afternoon. Aldrich

LONG TERM...
The ongoing storms are likely to organize into a cluster or two
Sunday evening. Although there is plenty of disagreement where
this will occur, there will be an increasing threat of locally
heavy rain and severe wind gust potential where it does.

The forecast for Memorial day still likely hinges quite a bit on
what transpires Sunday night. In general, convective chances may
refocus out toward the state line Monday afternoon as the upper
low draws closer. Instability and shear may be somewhat reduced
from Sunday, limiting the sever weather threat. About the same
goes for Tuesday. By Tuesday night, a cold front moving into the
area from the north along with the upper-low slowly edging ever
closer should increase rain chances across the entire area. The
Tuesday night into Wednesday morning period will bring some heavy
rain potential along the front, especially in the Rolling Plains.

The upper trough finally passes across the area on Wednesday,
bringing cool and showery weather. With the front well off to our
south by Wednesday afternoon, it appears instability will be too
limited for any severe potential and precip should be light. Cool
surface ridging and northerly flow aloft will produce stable
conditions Thursday into Friday. We`ll have to watch our northwest
counties for any storms that get steered their direction from
diurnal development in northern NM, but at this time it appears
the activity will remain to our west. Cooler than average temps
should continue through Friday then start warming up Saturday as
upper ridge builds to our west.

&&

.LUB Watches/Warnings/Advisories...
None.
&&

$$

07


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