FXUS64 KLUB 180916

Area Forecast Discussion
National Weather Service Lubbock TX
316 AM CST Mon Dec 18 2017


With the past few model runs, some things have come into better
agreement while others remain unclear. Models are in good agreement
with the closed upper low over northwestern Mexico slowing moving
east and opening up as it passes over the South Plains Tuesday
afternoon and evening. While the bulk of the moisture will stay to
the southeast, there is an upper level jet and an area of enhanced
lift over the Rolling Plains. This will result in a slight chance of
showers and thunderstorms for the Rolling Plains with a few
hundredths of rain possible.

As the upper level wave moves off to the east, flow will be zonal
Wednesday and Thursday ahead of the next trough. Westerly
downsloping surface winds will help to warm temperatures to 15
degrees above normal on Thursday. Guidance has come into better
agreement with a dry forecast for the weekend. What was a strong
closed low over New Mexico a few runs ago is now an open wave in all
solutions. The upper level trough over the Rockies will open up and
weaken some as it moves across the central plains. The timing of the
associated cold front is still on track for Friday morning. While
temperatures will be cool behind the front on Friday, the coldest
air will be delayed until Sunday. Surface winds will become westerly
Friday afternoon and will help to warm temperatures to the upper 40s
for Saturday. An upper level short wave will move out of the Rockies
on Sunday and will bring a reinforcing shot of cold air. Confidence
is higher for cooler temperatures on Sunday and the GFS has 850mb
temps down to -13C for Sunday morning. Beyond Sunday models diverge
and there is less confidence. The ECMWF keeps the large upper level
trough over the West coast before it slowly translates east mid
week. This would suggest cold temperatures will linger. The GFS is
more progressive with the trough moving east and the ridge over the
west coast amplifying quickly. Warm air under the ridge just to the
west would suggest a quicker warm up. For now have gone with the
cooler solution with highs in the 30s on Monday.




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