Area forecast discussion...updated
National Weather Service Amarillo Texas
700 PM CDT Monday may 20 2013
Aviation...
/00z tafs/ a cold front has slid south of the kama terminal...with
winds out of the northwest to north at all three terminals. Winds
are expected to be out of the north to northeast through the taf
forecast period with speeds between 10-15 kts and gusty...although a
surface high moving across the southern Texas Panhandle can cause winds
to become light /under 10 kts/ and variable after 21z Tuesday. VFR
conditions through the taf forecast with increasing middle level clouds
later this evening and continuing into Tuesday. Scattered showers and
isolated thunderstorms over southeastern Colorado/northeastern nm will
continue to move to the east. Have left out thunderstorms in the vicinity mention at kguy/kdht
for now but will continue to monitor radar trends and update as
necessary.
Clk
&&
Previous discussion... /issued 354 PM CDT Monday may 20 2013/
Short term...tonight through Tuesday
Not many changes made to this period. Slight chances for showers
will continue over mainly the northern and northwestern panhandles
this evening and again tomorrow afternoon. A cold front will bring
temperatures down tonight and tomorrow with lows in the 40s and 50s
expected tonight and highs in the 70s to lower 80s for tomorrow.
Simpson
Long term...Tuesday evening through next Monday.
Main focus through early next week is on thunderstorm chances...and
attendant severe weather potential...both of which look to be on the
increase later this week.
A few showers may linger into the early evening hours Tuesday across
the northwest panhandles as the last of any upper forcing associated
with the upper low that/S been stationed to our north the last
couple days slides east of the area.
Upper ridging will build into the area on Wednesday as the
aforementioned upper low works east across the upper Midwest and the
next western upper low works slowly east across the Pacific northwest.
Temperatures quickly rebound from the brief cool down tomorrow as
the front washes out/retreats north. Some moisture/instability
returns to eastern portions of the panhandles...but forcing for
convection looks minimal with the upper ridging building in and not
much surface focus as well. Thus will keep probability of precipitation silent for now...but
continue to monitor this timeframe. A cold front will backdoor into
the area Wednesday night. A low level jet may provide enough Theta-E
advection/isentropic lift over the frontal boundary Wednesday night
to trigger some elevated convection. Again...confidence in this not
quite enough to insert probability of precipitation at this point but definitely something
to monitor.
Upper ridging remains over the region Thursday...however
thunderstorm chances still look to be on the increase. The frontal
boundary is expected to stall...and be draped northwest to southeast
somewhere across the area during the day on Thursday. The dryline
will likely mix eastward into the western panhandles during the
afternoon...possibly intersecting the front somewhere across the
area...although the exact location of these boundaries is still
uncertain at this time. East/southeasterly low-level flow will keep
decent moisture in place...resulting in more than sufficient instability
to support severe convection. Despite pretty weak flow aloft with the
upper ridge...a good veering profile from east/southeast at the
surface to west/southwest aloft will result in deep layer shear
values somewhere on the order of 30-40 kts. Thus severe weather will
be a possibility with any convection that develops. The biggest
question at this point is forcing. Given the ridging aloft...the
surface boundaries will have to provide the forcing. Coverage will
likely be isolated to scattered given the lack of forcing aloft...but
those storms that do develop will pose a severe threat.
Friday through the Holiday weekend...a persistent southwest flow
aloft sets up on the western periphery of the upper ridge ahead of
the western upper trough. This will maintain persistent Lee surface
troughing through the period...with the dryline likely either
setting up in eastern nm or mixing into the western panhandles each
afternoon. Will see daily chances for afternoon and evening
thunderstorms in this pattern...with any weak shortwaves ejecting
out of the western upper trough enhancing thunderstorm chances.
Convective coverage will likely not be too widespread on any given
day given a lack of stronger forcing...but isolated to scattered
convection will be a daily possibility. Shear looks to be rather
modest /averaging 30 kts/ but sufficient when combined with the
expected instability to support the threat for a few strong or
severe storms each afternoon and evening.
Temperatures expected to run above average...but not to The Levels
we saw last week.
Kb
Fire weather...
elevated fire weather conditions will continue across the southwest
Texas Panhandle until around sunset this evening. Beyond this
evening...no elevated or critical fire weather conditions are
expected through the week as winds will either be too light or
relative humidities too high.
Kb
&&
Ama watches/warnings/advisories...
Texas...none.
OK...none.
&&
$$
05/15
