textproduct: NWS Phoenix

KEY MESSAGES

- Major waterways such as the Salt and Gila Rivers will continue to experience high volumes flows through at least the end of the week due to dam releases.

- With the exception of a slight chances of mountain showers to finish out the workweek, dry weather will be common through at least the next seven days.

- Temperatures a few degrees below normal will warm very close to seasonal readings by this weekend.

SHORT TERM /Today through Friday/

Afternoon objective analysis reveals a rather dynamic pattern over the CONUS with closed lows spinning near the Utah-Colorado border and upper Midwest. These disturbances are now in close enough proximity to where they have severed an omega block type setup that brought short-lived ridging to the Desert Southwest yesterday. However, the western most system will only flatten out heights aloft across Arizona and southern California, which will promote tranquil conditions through Thursday. The pattern will take on a bit more cyclonic curvature by Friday as a decaying shortwave dives south from the Pacific Northwest. Guidance points towards a slight dip in the height fields as a result of the associated ascent aloft, but, as mentioned in the previous discussion, confidence remains low on exactly where this potential trough will setup. Regardless of positioning, intensity will likely be lacking, which would result in only some minimal to minor impacts areawide. The most expected from this system as of now is breezy conditions for portions of the region Friday into Saturday and perhaps some terrain driven shower activity Friday afternoon.

Day-to-day temperatures the next few afternoons will run relatively steady thanks to the above-mentioned zonal flow. Lower desert highs will range generally in the mid to upper 70s with perhaps a few spots reaching into the lower 80s, around 3-5 degrees below normal for the start of November. Even with the above-mentioned disturbance, highs on Friday will actually trend upwards due to efficient lower troposhperic heating, hovering within a degree or two of seasonal levels by that point.

LONG TERM /Saturday through Tuesday/

During the weekend, some semblance of a Rex block (or omega block) will develop in the southern stream with weak troughing over northern Mexico and broad ridging across the Great Basin/central Rockies. While the precise orientation and positioning of salient features remain uncertain based on notable ensemble differences, the overall pattern will promote surface pressure rises over the intermountain West and dry N/NE boundary layer flow. Based on the pattern, periods of breezy northeast winds are likely at times over the weekend and early next week, though nothing particularly strong or unusual for this time of year. At some point early next week, the bulk of ensemble members eject the northern Mexico wave through the forecast area bringing enhanced mid/upper level moisture. It remains to be seen whether this process can overcome the dry boundary layer airmass, with the highest odds suggesting dry weather persisting. With H5 heights remaining nearly steady state in a 580-584dm range, temperatures should follow a near persistence trends with readings not terribly far from climatology.

AVIATION

Updated at 1740Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather concerns are expected through the forecast period under mostly clear skies. Winds will remain light (generally 7 kts or less) and follow typical diurnal patterns at the Phoenix Metro terminals. Wind directions at KBLH and KIPL will generally remain N-NW through tonight. Extended periods of calm and vrb conditions can also be expected at all terminals, especially during any diurnal wind shifts.

FIRE WEATHER

While a stray shower may affect mountains of eastern districts Friday, the area will remain dry with little to no chance of wetting rainfall through early next week. Minimum afternoon humidity levels will largely fall into a 20-30% range in western districts and 30- 50% in eastern districts. This will follow fair to good overnight recovery in western districts and good to excellent levels in eastern districts. Winds speeds will remain seasonably light for the majority of the period, albeit obtaining 20-30 mph northerly gusts through the lower Colorado River valley late in the week. Increased easterly winds will also be likely in eastern districts early next week.

PSR WATCHES/WARNINGS/ADVISORIES

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