Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 171001

Area Forecast Discussion
National Weather Service Tucson AZ
301 AM MST Fri Mar 17 2017

.SYNOPSIS...Near record high temperatures will continue through
the weekend and into early next week. A storm system is expected
to move across the region during the middle of the new week,
which will result in cooler temperatures, gusty winds and a chance
of showers.


.DISCUSSION...A strong ridge of high pressure over the desert
southwest will keep near record high temperatures as the main
story through the weekend and even into early next week. Daily and
monthly records as well as records involving 90 and 95 degree
days at TIA are discussed in the climate section below.

Less significant for our area but no less interesting, we continue
to monitor a moisture increase from central Mexico into Chihuahua
that was manifest as a complex of thunderstorms in southern
Chihuahua last night. The associated 700hPa theta-e ridge should
nose a little further northward, wrapping into the back side of
the high pressure system. Convection should spread deeper into
Chihuahua and eastern Sonora early in the weekend. We will
probably see no more than a few cu fields and maybe a buildup or
two near far southern mountains Saturday or Sunday afternoon.

As the ridge axis phases eastward and builds through the southern
and central plains late in the weekend, a chaotic picture out in
the Pacific begins to consolidate into a large scale mean trough
position near and off the Pacific coast. With a more amplified
pattern, some of the energy currently south of the Aleutian
Islands should make it into Southern California as part of a
consolidated 3 impulse system that extends from southeast Alaska
all the way down the west coast.

We`ll see gusty southwesterly winds develop ahead of this system
as early as late Tuesday afternoon, with strongest winds Wednesday
into Wednesday evening for our part of the state. Best chance of
precip will be north of our area, but we should see a few showers
later Wednesday afternoon and/or Wednesday evening. Temperatures
will drop around 20 degrees with the system, back to near or a
little below seasonal averages for late March. Temperatures will
be slow to recover as another system pushes through the region
north of us next weekend.


.AVIATION....AVIATION...Valid through 18/12Z.
No weather concerns with patches of thin cirrus level clouds at
times. SFC wind generally less than 12 kts, with just a few
afternoon gusts to 15-20 kts.

Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Dry conditions and well above normal temperatures
will occur into early next week. 20-foot winds will mainly be
terrain driven at less than 15 mph today. Thereafter, expect
generally south to southwest winds with afternoon gusts to near 20
mph Saturday through next Monday. A storm system moving into the
area is expected to bring gusty winds, though still probably
below critical thresholds, along with low RH levels Tuesday. As
the storm moves just north of our area Wednesday, moisture will
increase with a chance of showers and continued windy conditions.


.CLIMATE...The average monthly temperature for Tucson (TIA)
through March 16th ranks as the warmest to date (and at this
point it looks like a sure thing to end the month still in the
lead). We`ve had a total of 5 90 degree days so far, with 4 in a
row through Thursday. The current high temperature forecast for
Tucson has a run of 90+ highs continuing through at least Monday.
Record for consecutive March days with 90+ highs is 5 days, first
set in 1910 then later tied in 1989 and 2015. All-time March
record for the number of 90+ days is 8 set in 1910. If the
forecast holds through Monday, that would be 8 consecutive days
and 9 total (with one more possible on Tuesday). The forecast of
95 for Saturday would be the first of the year, and tie for 4th
earliest occurrence of 95.






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