Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Amarillo Texas
1149 PM CST Wednesday Jan 28 2015
for the 06z tafs...little change to previous aviation afd reasoning.
Periods of mainly middle and high level cloudiness are expected for this
forecast cycle. North winds will increase somewhat around middle morning
Thursday...then diminish late Thursday afternoon. No precipitation is
anticipated during the next 24 hours. VFR conditions will prevail
through late Thursday evening.
Previous discussion... /issued 556 PM CST Wednesday Jan 28 2015/
for the 00z tafs...surface cold front moving across the region will be a
dry one with no precipitation expected. Periods of mainly middle and
high level clouds foreseen this cycle. VFR conditions are expected at
all terminal sites through late Thursday afternoon.
Previous discussion... /issued 504 PM CST Wednesday Jan 28 2015/
Short term...tonight and Thursday...
an upper-level shortwave trough was moving across the Central Plains
this afternoon...helping to flatten the upper ridge that brought the
unseasonably warm weather to the area the past couple of days. A
surface trough also sliding across the Central Plains resulted in a
wind shift out of the north. Despite the Lower Middle and upper-level
heights associated with the upper trough...mostly sunny skies and the
mild air mass remaining in place...temperatures this afternoon once
again soared into the upper 60s to the lower 70s. In addition winds
were breezy this afternoon from a tightening pressure gradient on the
south side of the upper trough. Winds will diminish this evening as
the pressure gradient relaxes.
The upper trough will push a cold front into the area later tonight.
Colder air upstream will filter into the area Thursday...knocking
high temperatures back into the upper 40s to lower 50s. Attention
then turns to an upper-level trough that will lift out of the
eastern Pacific Thursday. Ahead of this system...middle and high level
clouds will increase and thicken throughout the day. However expect
large scale lift and associated precipitation to hold off until Friday.
Long term...Friday through Wednesday
heights begin falling on Friday night as an upper level low over the
southwest U.S. Deepens. Models continue to agree on the influence of
a shortwave in the northern stream of the jet over the panhandles.
Upslope flow starts to bring in chances for precipitation on Friday
morning over the central and southern Texas Panhandle...more like
Friday afternoon and evening further north. Morning and afternoon
model runs trended a bit drier than previous solutions through the
weekend...so that may also change how this forecast evolves. The
trickiest part will be precipitation type through this event.
Friday starts out cold enough for snow or a rain/snow mix over most
of the central and western combined panhandles...all rain to the east
as temperatures there will likely reach the low 40s. Overnight most
areas should return to the middle 30s or lower and allow for a rain/snow mix
to the east and more likely snow over the western panhandles. The
greatest lift and influence from the shortwave arrive on Saturday
when precipitation chances become more likely...however temperature becomes
the key player here and confidence continues to remain low in what
the main precipitation type will be. Models have trended quite a bit warmer
this morning and afternoon for Saturday/S high temperatures. At this time
have opted to keep a rain/snow mix across most of the panhandles but
if the warming/drying trend of today/S runs continue...rain may
become a more likely scenario for all but the far western Texas
Panhandle. The 12z European model (ecmwf) does linger precipitation chances through Sunday
but for now have opted to end things Sunday morning. Total
accumulations for the event range between a half to 1 inch in the
eastern combined panhandles and 1 to 3 inches across the rest of the
forecast area. However temperature may be the biggest factor for those snowfall
totals as the system nears.
Dry weather returns under northwesterly flow which should bring near
or just above normal temperatures for the beginning of the workweek.
The next chance for precipitation looks to be middle to late next week.