514
FXUS65 KTWC 041010
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
310 AM MST Thu Jul 4 2024

.SYNOPSIS...Chances of showers and thunderstorms will gradually
diminish into the weekend as drier air continue to move in. With
high pressure building in from the northwest, daytime temperatures
will be trending hotter Friday into at least early next week.
Temperatures are expected to approach record levels in some
locations.

&&

.DISCUSSION...Satellite imagery this morning showed plenty of
convective debris clouds from Sonoran storms moving across the
area. PW values on last evening Tucson sounding was down to just
above 1" as drier air continues to push in from the N as high
pressure aloft slowly builds in from the NW.

Main forecast theme for the next 5 to 7 days will be a low grade
monsoon pattern, with activity mainly S and E of Tucson, while
temperatures heat up with near record highs tomorrow and Saturday,
and possibly hotter the first half of next week with record to
near record highs. Forecast highs next week are using the
recommended initialization which may not be hot enough especially
when compared to deterministic GFS/ECMWF/Canadian and
GEFS/EPS/GEPS low-level thickness values. Thus left the current
Excessive Heat (EH) Warning for tomorrow and Saturday with later
shifts likely adding next week to the EH warning. There is a
slight, less than 10%, chance that Tucson may tie the all-time
July high temperature, which is 114 degrees, next Monday and/or
Tuesday.

&&

.AVIATION...Valid through 05/12Z.
BKN-OVC high cirrus clouds AOA 20k ft AGL thru 04/15Z, then
diminishing cloud cover. Between 04/18Z and 05/05Z, SCT-BKN clouds
at 7k-10k ft AGL and ISOLD-SCT TSRA/SHRA. MVFR conditions near TSRA,
with mountain obscurations, VSBY restrictions and gusts to 40+ kts.
Aft 05/05Z, gradual clearing thru the remainder of the forecast
period. Outside of TSRA outflows, SFC wind less than 10 kts and
variable in direction thru 04/18Z and again aft 05/04Z. SFC wind
between 04/18Z and 05/04Z WLY/NWLY at 8-15 kts and gusts to 15-25
kts. 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         111 115/1983     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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