Forecast Discussion

Forecast Discussion for TWC NWS Office
FXUS65 KTWC 210931

Area Forecast Discussion
National Weather Service Tucson AZ
231 AM MST Tue Mar 21 2023

.SYNOPSIS...A strong storm system will affect the area through
Wednesday night with periods of strong winds today into Wednesday
and scattered showers mainly on Wednesday. It will also usher in
much cooler temperatures Wednesday into the weekend.


.DISCUSSION...A strong storm currently approaching the California
coast will gradually translate eastward while filling. This system
will have a variety of significant impacts for Arizona, heavy
precipitation for central and northern parts of the state and periods
of strong and gusty winds for southern Arizona, our focus.

Ensemble solutions continue to suggest central and western Pima
county are potentially looking at a climatologically significant wind
event with the NAEFS showing it at a greater than 99th percentile
event for late March and the ECMWF EFI also showing this area to also
be well outside climatology. Tweaked the winds in this area a bit
and we also decided to hoist a wind advisory for that area east to
Cochise County at this time. This has been debated the last couple of
days as not every locations within the advisory area will meet
criteria and it isn`t expected to be consistently windy everywhere
either. With typical storm systems the Sierra Vista area can get
cranked up, however this storm has a bit more of a southerly
component which may limit the downslope affect. Anyway, for now we
have the advisory from 18z through 12z Wednesday for Pima, Santa Cruz
and Cochise counties. The wind will impact fewer locations during
the nighttime hours and will be hit and miss. Also, will likely need
to extend into Wednesday for eastern areas on later shifts once we
see how this plays out. In other words, adjustments are likely.

As for precipitation, the trend for southern Arizona continues to see
diminished modeled rainfall while central and northern AZ remains the
focus. Not really expecting any rainfall today and much of tonight
and will need to wait until Wednesday when the front gets closer.
Even then it will more than likely be scattered showers rather than
a solid area of precipitation. Parts of southeast Cochise county may
not even see any rain from this event. As far as snow, the snow level
will remain quite high through most of the time it is precipitating
with a few inches above 8,000 for the Sky Islands. The high
elevations of the White mountains will be closer to the focus of
heavier precipitation and should see up to a foot of new snow through
this event above about 8-8500 feet.

Lastly, this system will bring rather cool air along with it with
highs running 10-20 degrees cooler Wednesday and Thursday. Then
lingering troughiness across the west will hold temperatures well
below climo through the weekend although precipitation should remain
to our north.


.AVIATION...Valid through 22/12Z.
SCT-BKN clouds 9-13k ft MSL through the period with local MVFR CIGS
and mtn obscurations in SCT SHRA north of KAVQ-KSAD-KCFT after 21/18Z
becoming NRMS SHRA/ISOLD TSRA aft 22/06Z. S-SW SFC winds increasing
to 18-28 kts with gusts 35-45 kts aft 18Z especially south of KGXF-
KAVQ-KLSB creating ISOLD BLDU. Aviation discussion not updated for
TAF amendments.


.FIRE WEATHER...A strong storm system will bring strong and gusty
winds to the area today through Wednesday and scattered precipitation
very late tonight through Wednesday night and possibly into early
Thursday. Cooler than normal temperatures will linger through the
weekend with the air mass gradually drying out resulting in Min RH
levels dipping into the single digits early next week.


Wind Advisory from 11 AM this morning to 5 AM MST Wednesday for



Fire Weather....Cerniglia

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NWS TWC Office Area Forecast Discussion