Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 241628

Area Forecast Discussion
National Weather Service Tucson AZ
928 AM MST Mon Oct 24 2016

.SYNOPSIS...Unseasonably warm daytime temperatures will continue this
week. Expect isolated to perhaps scattered showers and thunderstorms
mainly east of Tucson into tonight. Dry conditions will then prevail
Tuesday into this weekend.


.DISCUSSION...IR/visible satellite imagery and surface observations
depicted mostly clear skies near the New Mexico border to mostly
cloudy skies across western Pima County at this time. Mainly
cirriform clouds were spreading ewd/newd across southeast AZ ahead
of a deep upper trough near the West Coast. Dewpoints at lower
elevations valid 16Z ranged from around 40 degs near the New Mexico
border to around 50 degs across western Pima County. These temps
were about 2-5 degs lower versus 24 hours ago. Surface temps valid
16Z were 2-10 degs cooler versus this time Sunday.

24/12Z KTWC sounding total precip water value of 0.96 inch was
nearly 0.10 inch high versus 24 hours ago. A very dry surface-700 mb
layer existed with the column nearly saturated around 600 mb and 400
mb. A pronounced temp inversion existed in the 600-500 mb layer.
24/12Z upper air plots depicted a deep low just west of the Pacific
Northwest coast and a trough axis extended southward to near 25N/
125W, or well west of the Baja California Spur. Meanwhile, high
pressure was centered near southern Baja California with a ridge
axis extending north into the northern CONUS. Moderate to fast
swly/wly flow prevailed across southeast AZ.

Mainly mid and high-level clouds will increase today as the mid-
level trough axis moves eastward into southern California. Have
noted that the 24/06Z Univ of AZ WRF-NAM and some HRRR solutions
suggest that a few showers/tstms may occur late this afternoon and
evening perhaps as far west as the Rincon Mountains just east of
Tucson, but more likely across eastern sections. The coverage of any
showers/tstms will be quite limited, though. For the time being,
will make no changes to the inherited forecast that depicts isolated
to scattered showers and thundestorms mainly east of Tucson into


.AVIATION...Valid through 25/18Z.
Expect ISOLD to perhaps SCT -TSRA/-SHRA mainly east of KTUS to the
New Mexico border into tonight. Otherwise, SCT-BKN clouds around 10k-
15k ft AGL with OVC layers above 20k ft AGL by late this afternoon
and continuing into Tuesday morning. Surface wind variable in
direction less than 12 kts thru the valid period. Aviation
discussion not updated for TAF amendments.


.FIRE WEATHER...Expect isolated to scattered showers and
thunderstorms mainly east of Tucson through tonight. Dry conditions
will then occur Tuesday into this weekend. Above normal daytime
temperatures will continue through the period, with 20-foot winds
less than 15 mph outside of any thunderstorms.


.CLIMATE...Well above normal temperatures are forecast to continue
through the end of the month. The forecast high of 96 degrees at the
Tucson airport for Thursday, October 27 would be the latest 95 on
record by one day (the record is October 26, 2001). The rest of this
month will continue to see us challenge for the warmest October on


.PREV DISCUSSION /253 AM MST/...Modest moisture will combine with a
mid level impulse from the eastern Pacific to bring clouds and a few
showers later today and tonight. A few lightning strikes possible,
but in general expect limited rainfall amounts. Best chances for
showers and thunderstorms will be north of our area.

Otherwise, we continue to see well above average heights and
thicknesses for late October as we bounce between zonal flows under
lows lifting through northern tier states alternating with strong
high pressure through the desert southwest and northern Mexico.
Recent record and near record high temperatures will back off a few
degrees with the current system, then high pressure brings near
record highs back the second half of the week.

Thursday looks like the hottest day with the latest 95 degree day
ever in the calendar year likely for Tucson International Airport.
98 is not out of the question, and we even have a small chance at
100 at TIA. That`s just unacceptable.

The soonest we would see a break in this unseasonably warm pattern
would be the first week in November. Until then, we will challenge
for the warmest October on record.






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