Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tucson Arizona
910 am MST Tuesday Oct 21 2014
Synopsis...there is a chance of showers or thunderstorms east of
Tucson into this evening. Strong high pressure will then bring dry
conditions the second half of the week along with much warmer
temperatures. Near record high temperatures are possible in some
locations Thursday into Saturday.
Discussion...weak upper low over southwestern New Mexico this morning will
fill and move eastward into south central New Mexico by this
evening. There is enough moisture to support isolated to scattered
showers and thunderstorms across Greenlee...Graham and Cochise
counties from late this morning into this evening. The bulk of these
showers/thunderstorms should be confined mainly near the mountains as per
the RUC hrrr. There is a slight chance of showers late tonight near
the New Mexico border.
High pressure aloft will then amplify over the southwestern Continental U.S. Wed-Fri.
The upper high will then move east of the area Sat in response to a
low pressure trough entering the West Coast. Increasing heights/
thicknesses will support a strong warming trend...with record or
near record high temperatures thur-Sat. Assuming prognosticated 850-700 mb
thicknesses around 165.5 dm to be reality...high temperatures will average
about 9-12 degrees f or so above normal values. Saturday may very well
be the warmest day as the upper ridge axis moves east of the area.
Thereafter...a pronounced cooling trend is on tap sun-Monday given
height/thickness falls as the West Coast trough moves eastward into the
Aviation...valid through 22/18z.
Isolated to scattered -tsra/-shra will occur east of ktus this
afternoon and evening. Dry conditions will then occur area-wide late
tonight through Wednesday morning. Cloud decks ktus vicinity eastward
late this morning into this evening will be at 6-10k feet above ground level...then
clear skies to scattered clouds around 10k feet above ground level late tonight into
Wednesday morning. Expect clear skies to scattered clouds above 20k
feet above ground level west of ktus through Wednesday morning. Surface wind will be
less than 10 kts through Wednesday morning. Aviation discussion not
updated for taf amendments.
Fire weather...expect isolated to scattered showers and
thunderstorms this afternoon and evening east of Tucson. Dry
conditions will then prevail Wednesday into early next week. 20-foot
winds will generally be terrain driven and less than 15 miles per hour this
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