Wildfire in Arizona, June 9 to 16, 2021

Area Forecast Discussion
National Weather Service Tucson AZ
325 PM MST Wed Jun 9 2021

.SYNOPSIS...Strong high pressure will heat things up late in the
week into next week, with temperatures around 10 to 15 degrees
hotter than average Sunday through much of the week. We may see
enough of a moisture increase during the week for clouds and
thunderstorm chances to knock the heat back a bit in southern and
eastern areas by Wednesday.

&&

.DISCUSSION...An amplified flow currently has us between a deep
trough near the west coast, and strong high pressure from northern
Mexico through the southern plains. A dry southwesterly to
westerly flow for SE AZ, with temperatures near seasonal averages
for June today and tomorrow.

Some flow reconsolidation off the pacific northwest coast and
southern Canada will see the ridge build into the desert southwest
with a vengeance this weekend. High confidence in near record to
record heat Sunday through Tuesday with record high 700mb temps
suggested by the NAEFS ensemble. Even as the high center slowly
shifts northward into northeastern and northern Arizona,
thicknesses continue to support record heat through the week. The
only thing that will affect that is a moisture increase.

As the blocking high position shifts northward, both GEFS and
ECMWF ensembles continue to show a decent moisture increase
through Sinaloa and up the Sierra Madres into Sonora. Pressure
differentials and convection forming further north should help
push lower level moisture up from the south, although it isn't
supported as a deep push at this point with limited larger scale
forcing and continued dry conditions in Durango. In addition, as
the mid level high reconsolidates further north, we'll gain an
easterly component to our mid level flow which will probably draw
some moisture back westward and shift the H7 theta-e ridge back
into at least eastern New Mexico. The question is how much and
how fast?

Both the GFS and ECMWF ensembles show the 50 percent line for
1 inch precipitable water probabilities crossing the southern
border Tuesday night or Wednesday. In addition, showing the 30
percent line approaching our eastern border from eastern New
Mexico. In between there's a relatively drier wedge through
Chihuahua and western New Mexico. Also, the NBM has been
consistent in pushing surface dew points into the 40s by
Wednesday. So, it looks like moisture will be above average for
mid June, but should still be well below an average monsoon day.

The bottom line is that the atmosphere will likely support record
heat through the entire week. However, some moisture increase is
very likely next week. It may be sufficient to create enough cloud
cover and thunderstorm chances to mitigate some of the heat,
mainly the second half of the week.

&&

.AVIATION...Valid through 11/00Z.
VFR conditions with FEW-SCT clouds above 20k ft MSL. SFC winds
SWLY/NWLY 10-15 kts with gusts 20-25 kts this afternoon and early
evening. Expect similar speeds Thursday afternoon. Sfc winds then
diminish to light and variable once again aft 10/03Z. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Dry and hot weather is expected through this
weekend as temperatures gradually climb to well above normal levels.
Some increased mid level moisture is possible early next week which
could increase the dry lightning threat, but confidence in this is
low at this time. Otherwise, typical afternoon breezes with gusts to
around 20-25 mph are expected each day this week due to strong
daytime heating. Minimum humidities will generally be in the single
digits in the valleys and 6-12% in the mountains with poor overnight
recoveries. Lowest humidities look to be during the Friday-Monday
timeframe.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 10 AM Sunday to 8 PM MST Wednesday
for AZZ503-504-509.

Excessive Heat Watch from Wednesday evening through Friday
evening for AZZ503-504-509.

Excessive Heat Warning from 10 AM Sunday to 9 PM MST Friday for
AZZ501-502-505-506.

&&

Public...Meyer
Aviation...Hardin
Fire Weather....Hardin

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