textproduct: NWS Phoenix

UPDATE

Updated 18Z Aviation Discussion.

KEY MESSAGES

- Weak high pressure will settle back into the region today into Wednesday leading to drier conditions and eventual warmer temperatures.

- Breezy to locally windy conditions are expected Thursday and Friday with elevated Fire Weather conditions focused across the Lower Colorado River Valley.

- Above normal temperatures should return by early next week with lower desert highs warming into the low to mid nineties.

SHORT TERM /TODAY THROUGH WEDNESDAY/

A weakening upper level trough is currently moving through the Desert Southwest with the low center across northwest Arizona moving northeastward into Utah. A trailing trough axis is also moving through central Arizona with isolated light showers lingering from north Phoenix into the Mogollon Rim. These showers should move out of our area by sunrise leaving clearing skies and plenty of sunshine for the rest of today. A cooler post-frontal air mass will help to keep daytime highs from reaching 80 degrees across the south-central Arizona lower deserts to at most the lower 80s across the western deserts.

Weak upper level ridging is then forecast to move through the region on Wednesday helping to boost temperatures back into at least the mid 80s, or within the normal range. Drying conditions later today and on Wednesday will also lead to surface dew points dropping back into the 20s for most locations.

LONG TERM /THURSDAY THROUGH MONDAY/

By Thursday, a large Pacific weather system is slated to move southeastward through the Pacific Northwest into the Great Basin leading to height falls over our region and an increasing pressure gradient. Breezy to locally windy conditions are likely to affect much of the area starting Thursday afternoon and again on Friday as the system moves by just to our north. Advisory level winds may also be possible, particularly across southeast California and the Colorado River Valley. Near normal temperatures Thursday are forecast to dip on Friday as the NBM/WPC shows highs back into a 80-85 degree range.

Stronger ridging is then favored to build across the Western U.S. over the weekend pushing daytime highs to near 90 degrees Saturday and then into a 90-95 degree range for Sunday and next Monday. The weather pattern through at least the first half of next week should support continued dry weather along with at least one more weather system passing by to our north creating breezy to windy conditions.

AVIATION

Updated at 1728Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation concerns are expected throughout the TAF period. Winds will begin to follow typical diurnal trends today with speeds aob 10kts through out the period. Easterly shift is expected around midnight tonight for the overnight period. Otherwise, clear skies will prevail through the rest of the TAF period.

Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation concerns are expected throughout the TAF period. Wind speeds will generally remain AOB 10 kts through the TAF period at both terminals. KIPL will stay out of the NW through the afternoon, going VRB by the evening hours then quickly settling back out of the west for the overnight hours, and KBLH will be mostly VRB with a period of NNE winds this afternoon. Clear skies will persist through the TAF period.

FIRE WEATHER

A weather system will exit the region today with only lingering chances for isolated light showers across the eastern Arizona high terrain this morning. Weak high pressure and drying conditions will prevail for the rest of today through Wednesday with overall light winds. MinRHs will dip to between 15-20% today and 10-15% on Wednesday as overnight recoveries become poor to fair starting tonight at 30-50%. Another passing weather system late week will likely bring increased winds and even lower RHs resulting in the potential for elevated fire weather conditions on Thursday and Friday.

PSR WATCHES/WARNINGS/ADVISORIES

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