Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 180949
Area Forecast Discussion
National Weather Service Tucson AZ
249 AM MST WED MAY 18 2016
.SYNOPSIS...A low pressure system over Arizona this morning will
move slowly through early Thursday. This will result in cooler
temperatures and a chance of showers and thunderstorms later into
Thursday mainly north and east of Tucson. Dry and warmer conditions
will return for the latter part of the weak, then another upper
level system will impact the region this weekend into early next
week with windy conditions.
.DISCUSSION...A low pressure system was spinning over Arizona early
this morning with some showers in the vicinity of the low center.
Latest models showed this system moving east by Thursday with shower
and thunderstorm chances ending later tonight. Will keep a chance in
the White mountains for showers on Thursday as some wrap around
moisture can be anticipated on the backside of the upper low.
Thereafter, medium range models showed a ridge of high pressure
building over the region for warmer daytime temperatures and dry
conditions. This ridge of high pressure will be followed by another
system which will bring breezy to windy conditions to the area this
.AVIATION...VALID THRU 19/12Z.
Isolated showers will linger early this morning, mainly north and
east of KTUS. Then isolated to scattered showers and thunderstorms
will develop as early as late this morning and continuing through
the afternoon, with the most widespread coverage north and east of
KTUS. Variable winds mainly less than 12 kts early this morning,
then trending south late this morning to early afternoon and
becoming west at 10 to 15 knots with higher gusts through the
afternoon. Gusty and variable winds are expected near any showers
and thunderstorms. Cloud coverage will generally be scattered to
broken at 6-10k ft agl through this evening with a bit of clearing
overnight. Aviation discussion not updated for TAF ammendments.
.FIRE WEATHER...Expect isolated showers this morning mainly north
and east of Tucson, then as the day progresses more isolated to
scattered showers and thunderstorms will develop across the entire
region. The best chance of wetting rains will be north and east of
Tucson and especially in the higher elevations. Gusty and erratic
winds are expected near showers and thunderstorms mainly from early
this afternoon through early this evening. Precipitation chances
will decrease tonight, though enough moisture should remain Thursday
for a chance of showers and thunderstorms mainly across the White
mountains. Dry conditions will then prevail area-wide Friday into
early next week.
A few afternoon gusts on Thursday due to daytime heating, otherwise
fairly light winds. Breezy to locally windy conditions will return
Friday and continue through this weekend into early next week as a
low pressure system deepens northwest of the area. Wind speeds may
approach critical levels for portions of the area as early as
Friday, then continuing through the weekend into early next week.
The best potential for critical fire weather thresholds being met
looks to be Sunday for eastern areas.
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