FXUS65 KTWC 291032

Area Forecast Discussion
National Weather Service Tucson AZ
332 AM MST Wed Jan 29 2020

.SYNOPSIS...Another weather system will bring a few mainly
mountain showers to the area this afternoon into Thursday morning.
Gusty winds at times with several more degrees of cooling. High
pressure will bring dry conditions and another jump in
temperatures by this weekend. A stronger and colder storm is
possible early next week.


.DISCUSSION...A storm system continues to dig south through the
Great Basin and into Arizona this morning. A chance of showers
mainly in the mountains this afternoon and evening. 1 or 2 inches
of snow possible above 7000 feet.

As a prelude to a stronger coastal split flow, a strong ridge of
high pressure will elongate from offshore through Arizona over the
weekend. A weather system will drop down and under this feature
Friday, brushing our far eastern zones and slowing the warming
trend. As our temperatures climb to several degrees above average
over the weekend.

A much stronger split should be set up by Monday, with ensemble
means digging a stronger and colder low into southern portions of
the Great Basin, including our area. A hybrid trajectory should
also allow this system to import a lot more moisture than today`s
system. Still some timing and track issues to work out, but this
storm is shaping up to be a big weather maker for SE AZ, with
windy conditions possible Monday, and a decent chance of valley
rain and mountain snow Monday night or Tuesday. It`s still early,
but this looks like a much colder system with the potential of
snow levels touching valley floors in portions of Cochise, Graham
and Santa Cruz counties. Stay tuned.


.AVIATION...Valid through 30/12Z.
SKC until SCT clouds above 15k MSL move into the area from the NW.
Isolated -SHRA develop this afternoon from KTUS east with lowering
cloud bases around precipitation. Precipitation should be east of
the forecast area by end of the valid period. Surface winds variable
this morning becoming WLY-NWLY 10-15 kts with ocnl gusts to 25 kts.
Light winds return to the area late in the valid period. Aviation
discussion not updated for TAF amendments.


.FIRE WEATHER...A weather system passing through the area today and
tonight will bring light amounts of valley rain and mountain snow,
mainly from Tucson east. Dry Thursday through the weekend before the
next system impacts the area early next week. The early next week
system will bring a better chance of precipitation along with cooler
temperatures and gusty southerly winds. Still some uncertainty in
the model data on how strong the winds will be early next week.




Fire Weather....Glueck

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NWS TWC Office Area Forecast Discussion