textproduct: NWS Phoenix

UPDATE

Updated 12Z Aviation Discussion.

KEY MESSAGES

- Above normal temperatures with afternoon highs in the nineties will be common through the middle of next week as high pressure prevails over the region.

- There is a chance of scattered showers and isolated storms, especially on Monday morning, across the Arizona high terrain.

- Another weather system is likely to affect the region late next week and weekend, leading to increased winds and cooling temperatures.

SHORT TERM /Today through Tuesday/

Current objective analysis shows ridging over Western CONUS with the core of the ridge centered over the Pacific NW, and a backdoor front being pushed into southern AZ. This backdoor front will cause easterly winds to pick up this morning, especially across south-central and southeastern AZ, where gusts between 15-25 mph will be common, and gusts up to 35 mph possible in the higher terrain areas. This front will also help PWATs increase to 170-200% of normal in eastern AZ, where the development of a few showers and isolated storms, mainly the Mogollon Rim and White Mountains will be possible starting late this afternoon. By the afternoon winds are expected to relax as ridging will build over the lower deserts with H5 heights between 580-582 dam today. This will lead to temperatures in the lower deserts to be in the low to mid 90s. Winds are expected to pick back up late tonight into Monday morning with similar speeds across south-central and southeastern AZ again.

Upper level moisture will linger into Monday which will help facilitate plenty of cloud coverage that will aid temperatures to cool to the upper 80s to low 90s. Afterwards going into Tuesday moderate ridging will continue to be dominate over the region, with dryer air filling back in causing skies to clear and temperatures climbing back into the mid to upper 90s across the lower deserts.

LONG TERM /Wednesday through Saturday/

Upper level ridging will continue through most of the workweek with afternoon highs in the lower deserts generally staying in the low to mid 90s. By Friday models are pointing towards a stronger upper-level low progressing into our region from the eastern Pacific. Unfortunately, at this time a lot of uncertainly can be seen on cluster analysis in the exact timing and potency of this system. However, even with the uncertainly, temperatures will most likely begin to trend back to near normal by Saturday, with afternoon highs in the mid 80s. Continued monitoring of this upcoming system will be needed, especially for increasing moisture and rain chances.

AVIATION

Updated at 1135Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:

E/NE continue early this morning with speeds generally around 10 kt or less. Upon daytime heating after sunrise this morning, around 15-16Z, easterly surface winds will increase up to 10-15 kts, with gusts up to 20-25 kts (20% chance for peak gusts >25 kts). The prospect of slantwise visibility impacts from lofted dust in the morning is there, but confidence in this occurring is low. Gustiness will subside by mid afternoon Sunday, with E/SE wind directions expected to persist through the rest of the TAF period. The gradient easterly wind will be a touch stronger tonight and likely will lead to elevated surface winds (up around 20-25 kt) most of the night and Monday morning. FEW to BKN mid and high clouds will continue to pass over the area.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather impacts are expected through the next 24 hours under FEW - BKN high clouds. Winds will favor a W/NW component through most of the TAF period at KIPL, while favoring N/NW at KBLH. Wind speeds will mostly stay below 8 kts, with periods of light variability and calm conditions.

FIRE WEATHER

Generally dry weather and above normal temperatures will persist during the next several days. Afternoon MinRHs will stay near 10-15% in the western districts, however increasing to 20-35% today and Monday as moisture increases. The increase in moisture will result in some shower and thunderstorm chances, mainly confined to northern and far eastern AZ, particularly on Monday. Easterly winds are expected to pick up this morning and again Monday morning, particularly across the higher terrain areas of south- central AZ where peak gusts upwards of 25-35 mph are possible. Lighter winds briefly return Tuesday and Wednesday before increasing once again towards the latter portion of next week with the approach of another weather system.

PSR WATCHES/WARNINGS/ADVISORIES

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