textproduct: NWS Phoenix

UPDATE

Updated 12Z Aviation Discussion.

KEY MESSAGES

- As high pressure builds over the region, temperatures will warm back to near normal this weekend and eventually slightly above normal by the middle of next week.

- Periods of breezy to locally windy conditions can be expected across southcentral and southwestern AZ through this weekend with gusts reaching 20-30 mph at times.

- Dry weather with zero rain chances will persist through this weekend and into much of next week.

SHORT TERM /TODAY THROUGH SUNDAY/

Latest GOES mid-lvl wv imagery and 500 mb streamline analysis reveals a ridge of high pressure building over SoCal and the Great Basin region while a weak area of low pressure is beginning to cutoff over W TX and SE NM. Dry NE flow is present over AZ which will keep skies clear over the forecast area today. Ridging aloft is expected to be the predominant weather pattern over the Desert Southwest through this weekend which will continue to to result in dry weather with essentially zero chances for rain anywhere in the state. Due to an increased pressure gradient between the high to our north and low to the SE of our region, elevated easterly flow is expected to develop today and persist into this weekend. Winds will become gusty each morning and last into the early afternoon, reaching up to 20-30 mph at times with gusts up to 35 mph possible across the higher terrain of southcentral AZ.

Positive hght anomalies will be most pronounced over SoCal and into northern AZ where 500 mb hghts will reach upwards of 588-590 dam which is in the 90th percentile of climatology this time of year. This will result in high temperatures reaching slightly above normal in the upper 90s to low 100s along and west of the Colorado River Valley through this weekend. Elsewhere across southcentral AZ, elevated easterly winds and higher dewpoints in the low to mid 50s will keep high temperatures in a near normal range, mainly in the low to mid 90s. Overnight lows will be noticeably warmer in the mid to upper 70s across the lower deserts over the next few nights due to breezy conditions developing prior to sunrise.

LONG TERM /SUNDAY THROUGH THURSDAY/

Deterministic and ensemble guidance shows the 500 mb ridge axis flattening as a weak trough passes through the Intermountain West early next week before rebuilding over SoCal and the Great Basin region again by mid- week. As this pattern evolves, there may be a brief dip in temperatures on Monday before significant warming occurs from Tuesday into Thursday. Highs across the western deserts will likely remain in the low 100s Monday and Tuesday before topping out around 100-105 degrees as early as Wednesday. The lower deserts of southcentral AZ will also see temperatures gradually rise from the low to mid 90s Monday and Tuesday to around 100 degrees by mid-week. Overnight lows will also be warm, generally remaining in the low to mid 70s. Overall, daily temperatures are expected peak around 4-8 degrees above normal mid to late next week. Subsidence aloft and dry air in the mid lvls should keep a lid on any potential convective, even over the AZ higher terrain and thus rain chances will remain near zero each day next week.

AVIATION

Updated at 1120Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation weather concerns under clear skies can be expected throughout the TAF period. Overall wind directions throughout the period will be out of the east. Light speeds under 10 kts will prevail through early this morning before gusts upwards of 20 kts materialize by the mid/late morning (15-16Z for KIWA and KPHX and around 19Z for KDVT and KSDL) through the afternoon hours, subsiding around sunset. Winds will remain elevated this evening and overnight with speeds around 7-12 kt expected. Another period of gusty winds (upper teens to around 20 kt) will then start to materialize early tomorrow morning, around or shortly after sunrise.

Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather issues under clear skies can be expected throughout the TAF period. Winds through most of this morning will generally be light and variable with periods of calm conditions before a more easterly direction materializes by the late morning hours with overall speeds aob 10 kts. Another period of light and variable with periods of calm conditions is then expected for this evening and overnight into tomorrow morning.

FIRE WEATHER

Dry conditions with near normal temperatures are anticipated through this weekend with a steady warming trend expected from the beginning to middle of next week. MinRHs will mostly range from 15-25% over the western districts to 25-35% for the eastern districts with good to excellent overnight recoveries. A persistent breezy easterly gradient wind will develop across the region today and persist for the next several days. Morning to early afternoon wind gusts in the 20-30 mph range will become common.

PSR WATCHES/WARNINGS/ADVISORIES

AZ...None. CA...None.