180
FXUS65 KTWC 162105
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
205 PM MST Sun Jun 16 2024

.SYNOPSIS...Hot today with an Excessive Heat warning in effect
for portions of southeast Arizona. Temperatures decrease a bit
early in the week before likely heating up again by Thursday.
Moisture may begin to increase late next week which would bring
the potential for high-based thunderstorms.

&&

.DISCUSSION...Clear skies, a little hazy on the edges, and a hot
day. Temperatures are on track to warm several more degrees this
afternoon. Excessive Heat Warning is still in effect for Eastern
Pima County, Pinal County, and portions of Graham and Greenlee
Counties through this evening.

A trough over Washington will be moving into the Idaho and it will
bring temperatures down on Monday and Tuesday. Plus, it will
bring breezy conditions on Monday which elevates fire weather
concerns. See the Fire Weather Discussion for more details.

Ensemble models shows the next shift in the pattern. High Pressure
will start to build to the east and boosting temperatures hotter
starting by Thursday and into Friday. The longer term ensembles
shows a signal for stronger sustained southeasterly winds in the
Gila River Valley on Thursday and Friday from a tighter pressure
gradient. Another factor occuring later in the week is the
moisture coming into Southeast Arizona from east to west. Dew
points will be trending up each day to the 50 degree range by the
weekend. There is still a wide range of moisture values among the
ensemble models, but the general trend has overall PWATs around 1
inch mark. Any way, thunderstorms chances will increase by the
end of the week for mainly in the eastern side of the state and in
the mountains. The storms will be generally dry and high based
which can lead to dry lighting threats (and fire weather concerns)
on Thursday (low confidence) and Friday (moderate confidence).
Thunderstorm chances can be elevated through the weekend depending
on how the moisture moves across the region and placement of the
ridge axis.

&&

.AVIATION...Valid through 18/00Z.
Clear skies/SKC conditions thru the forecast period. SFC wind
SWLY/WLY at 11-16 kts and gusts to 18-25 kts thru 17/04Z, then
SFC wind less than 10 kts and variable in direction til 17/15Z.
Aft 17/15Z, SFC wind SWLY at 12-18 kts and gusts to 22-30 kts
thru the end of the forecast period. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Hot and dry conditions rest of today and then a
few degrees of cooling early Monday and Tuesday. High temperatures
will then heat back up Thursday and Friday. Through the middle of
this week, expect min RH values of 4-9 percent in the lower
elevations and 8-15 percent in the mountains, along with overnight
recoveries between 25-40 percent in most locations. RH values
then increase 5-10 percent the latter half of the week. Sustained
20-foot wind speeds today will be 15 mph or less. Winds then
increase on Monday, with southwest winds of 15-20 mph and gusts to
30-35 mph. A few areas will be near critical fire weather
thresholds Monday, especially to the east/southeast of Tucson, but
at this time we not expecting it to be widespread enough for a
watch or warning. Elevated afternoon/early evening winds of 15-20
mph then continue for much of this week with an uptick in speeds
for the eastern zones (Safford area) on Thursday and Friday. By
the end of this week, models show an increase in mid-level
moisture, resulting in a slight chance mainly dry thunderstorms to
the east of Tucson Thursday and and as far west as Tucson Friday
and Saturday.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning until 8 PM MST this evening for
AZZ504>506-509.

&&

$$

KJS

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