411
FXUS65 KTWC 042107
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
207 PM MST Thu Jul 4 2024

.SYNOPSIS...Chances of showers and thunderstorms will diminish
into the weekend as drier air pushes down from the north. With
high pressure building in from the northwest, daytime temperatures
will be trending hotter into much of next week. Temperatures are
expected to approach record levels in some locations.

&&

.DISCUSSION...Our main story is going to turn to the heat over the
next several days with strong high pressure driving near record
heat as the monsoon temporarily dips into lower grade activity.

The moisture gradient is tightening as high pressure building in
from the northwest brings a flow reversal and pushes the deeper
moisture further south. Precipitable water values from around 1 to
1.2 inches north of Tucson and 1.2 to 1.4 inches from Tucson
southward; ramping up to 1.7 inches just south of the border.
Plenty of room for dewpoints in the 50s to mix lower this
afternoon. Any storms should be south and southeast of Tucson
today as the mid level drying eats away our convective potential,
with increasing chances as you near the international border.

Overall that will be the trend over the next several days, however
don`t expect our corner of the state to scour all of the moisture
out. Some days will be busier than others, but in general not much
activity expected north of Tucson.

As high pressure builds in from the northwest and we see lower
levels of moisture, heights and thicknesses will support near
record heat for areas from Tucson into the lower deserts. Right
now we just have an excessive heat warning for Friday and Saturday
as we continue to evaluate a possible moisture return, but it`s
looking more and more likely we`ll have to add at least Monday and
Tuesday to the excessive heat headlines.

Ensemble means continue to suggest the high center will
eventually reconsolidate into a more favorable position by the
middle of next week and into the following weekend. Keeping an
eye on the tropics we now have TS Aletta off the southwest Mexican
coast. At this point it doesn`t look like it will remain too far
south to even provide much of a moisture push as it drifts
westward and dissipates over the weekend.

&&

.AVIATION...Valid through 06/00Z.
SCT- BKN clouds at 7k-10k ft AGL and ISOLD TSRA/SHRA mainly south
of KTUS. MVFR conditions near TSRA, with mountain obscurations,
VSBY restrictions and gusts to 40+ kts. Aft 05/05Z, gradual
clearing with ISOLD TSRA possible again after 05/20Z. Outside of
TSRA outflows, SFC wind WLY/NWLY at 8-15 kts and gusts to 15-25
kts, diminishing after 05/04Z. Aviation discussion not updated
for TAF amendments.

&&

.FIRE WEATHER...There will be the daily chance for isolated to
scattered showers and thunderstorms mainly from Tucson east and
south into early next week. High pressure aloft will build to our
northwest through the weekend into early next week, which will
result in hot conditions. With the hotter temperatures and some of
the deeper moisture getting pushed to the south and east of the
region, min RH values will lower into the 10-18% range across the
lower elevations and 15-30% in the higher elevations through early
next week. Hot high temperature are expected into early next week,
with highs 106-113 degrees from Tucson westward and in the Gila
River Valley, and in the upper 90s to 105 degrees across Santa Cruz
and Cochise counties. Excessive Heat will be an issue during this
time frame. Outside of any thunderstorm outflow winds, 20-foot winds
will generally be 15 mph or less each afternoon with occasional
gusts to 20-25 mph through the weekend. Early next week there will
be the potential for more elevated wind speeds in the 15-20 mph
range, especially east of Tucson.

&&

.CLIMATE...
Record or near record high temperatures tomorrow and Saturday

Date                         Jul 05           Jul 06
                          FCST RCD/YR      FCST RCD/YR
Tucson Intl Airport       110 111/2018     110 110/2023
Organ Pipe Cactus         112 115/1983     110 113/2018
Picacho Peak              112 113/2007     112 113/2005
Safford Ag Station        107 109/2007     106 109/2023

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Warning from 11 AM Friday to 8 PM MST Saturday
for AZZ501-502-504-505.

&&

$$


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