textproduct: NWS Phoenix

KEY MESSAGES

- Dry and tranquil weather conditions with near zero rain chances can be expected through Monday.

- Near to slightly above normal temperatures will persist through next week.

- A low pressure system and moisture return early next week will bring a return of rain chances to at least the high terrain of northern and eastern Arizona.

SHORT TERM /TODAY THROUGH SUNDAY/

Upper-level water vapor satellite imagery early this morning shows a low pressure system in the northern Great Basin and a high pressure system centered over eastern Texas. In between these two features there is dry southwesterly flow over the Southwest. With dry southwesterly flow still in place over our region moisture continues to decrease. PWATs have decreased another 0.1-0.3" from yesterday afternoon with PWATs currently ranging from around 0.4" across the western deserts increasing to around 0.8" across the higher terrain areas in southern Gila County. Dry southwesterly flow will continue across the region today before going more westerly tomorrow as the aforementioned low pressure system moves eastward into the northern Plains. As the drying continues PWATs are expected to bottom out late tonight around 0.3-0.6". We will finally see this drier air make its way to the surface today as dew points fall into the 30s and 40s by late this afternoon/early this evening. There will be some moisture return from the Gulf of California into far SW AZ and SE CA tomorrow with dew points going back into the 50s for them, otherwise dew points will generally be in the 40s for most other locations. Due to all the dry air across our region this weekend, there will be mostly clear skies with zero chances for showers or storms. Additionally H5 heights will remain largely unchanged (generally around 588 dm), so temperatures will also remain fairly steady through the weekend. Afternoon highs will be in the upper 90s to low 100s (upper 80s to mid 90s) with morning lows in the 70s to around 80 degrees (mid 60s to low 70s) across the lower deserts (higher terrain). This will result in widespread Minor HeatRisk across the CWA.

LONG TERM /MONDAY THROUGH FRIDAY/

Models are in good agreement that a Pacific low will move to the south-central coast of California by early Monday and then move eastward onshore throughout the day. If it weren't for the lack of moisture on Monday it would be a decent set up for a transitional severe weather event as there will be potential for some frontogenesis with upper-level jet support and higher shear. However, while PWATs will increase on Monday, they look to remain around or slightly below 1" (0.6-1.0").

Then on Tuesday the low will slowly weaken as it moves NE into NV/UT before getting swept up into the large scale flow on Wednesday as it moves into the northern Plains. At the same time a weak ridge will be in place over TX and will start to strengthen on Wednesday. This will result in southwesterly flow over our area. With the moisture return and some upper-level forcing from the aforementioned low, rain chances will return to the higher terrain areas in northern and eastern Arizona. Weak large scale troughing will remain across the eastern Pacific/West Coast through the end of next week and will be battling the ridge of high pressure over TX. By the end of the workweek the ridge will try to retrograde into NM/AZ. Additionally ensemble members bring a surge of moisture into our area from the SE pushing PWATs back into a 1.0-1.3" range. As a result NBM/WPC PoPs for the end of next week have 30-50% chance of showers and storms across the higher terrain in southern Gila County and around 10-20% across the lower deserts of south-central AZ.

Temperatures next week will remain largely unchanged and be in the upper 90s to low 100s across the lower deserts and in the upper 80s to mid 90s across the higher terrain. Morning lows will generally be in the 70s to to low 80s across the lower deserts and in the 60s across the higher terrain areas. Morning lows do look to start to creep up by the end of next week (more morning lows in the low 80s across the lower deserts). As a result widespread Minor HeatRisk will continue through the beginning of next week with Moderate HeatRisk returning to the lower deserts for the latter half of next week as the morning lows creep up and daily normals decrease.

AVIATION

Updated at 1015Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation weather concerns expected through Sunday morning under clear skies. Winds will continue to follow typical diurnal tendencies with speeds around 8 kts or less. There will likely be a period of light southerly cross-runway winds at KPHX for most of the afternoon ahead of prevailing W-SW winds by late afternoon/evening. Extended periods of calm and vrb conditions can also be anticipated during the overnight and morning periods.

Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns expected through Saturday night under mostly clear skies. Winds will follow seasonal diurnal patterns at both terminals with mainly a W component at KIPL and S-SW at KBLH. Wnd speeds should remain around 8 kts or less with limited gusts, and extended periods calm conditions to light vrb can be expected.

FIRE WEATHER

Overall there are no fire weather concerns through the next week. Conditions will continue to dry out today with no chances for rain continuing through Monday. Slight chances for showers and storms return to the higher terrain areas of southern Gila County beginning on Tuesday. MinRHs will be around 10-25% today and tomorrow before increasing to around 15-30% for the first half of next week. Overnight recoveries will range from fair to good across the region through the middle of next week. Besides a potential increase in breeziness early next week with a weather system, winds will mostly follow typical diurnal patterns with modest afternoon upslope/upvalley gustiness (15-25 mph).

PSR WATCHES/WARNINGS/ADVISORIES

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