textproduct: NWS Phoenix

UPDATE

00Z Aviation Discussion.

KEY MESSAGES

- Slightly above normal temperatures will prevail throughout the week before retreating closer to normal over the weekend.

- Other than a slight chance of a thunderstorm in eastern AZ during the middle of the week, dry conditions under mostly sunny skies will prevail through the next several days.

SHORT TERM /Today through Wednesday/

Latest water vapor satellite imagery as well as streamline analysis show an omega blocking pattern centered over central Canada with troughing along the northeastern CONUS and over the northern Rockies. Meanwhile, over the Desert Southwest, southwesterly flow aloft prevails with weak troughing noted just off the southern CA coast. This weak troughing feature will continue to slowly progress east-southeastward into northern Mexico through midweek and thus will not have any significant sensible weather impacts for our region. Thunderstorm activity materializing across New Mexico through the middle of the week will likely send a westward propagating outflow boundary into far eastern Arizona, increasing low-level moisture somewhat. Thus, isolated thunderstorms are likely to materialize near the White Mountains Wednesday afternoon, potentially impacting far eastern Gila County. Otherwise, fairly tranquil weather under mostly clear skies will prevail throughout the majority of the region.

With 500 mb height fields ranging 582-585dm, lower desert highs today and tomorrow will generally be in the low 100s and will rise a couple of more degrees to around 105 degrees by midweek as 500 mb heights rise closer to 585-587dm. These temperatures will be around 3-5 degrees above normal for early June. The overall HeatRisk through Tuesday will remain in the minor category before increasing into the moderate category midweek as temperatures rise into the mid 100s. Therefore, if planning in any outdoor activities, make sure to take the necessary heat precautions to avoid any heat-related illnesses.

LONG TERM /Thursday through Sunday/

During the latter half of the week, NAEFS members are in fair agreement showing weak southern stream troughing slowly translating into the southern plains as deep negative height anomalies approach the western Conus. The primary uncertainty is the forward speed at which this occurs, and how quickly the forecast area falls under anti-cyclonic subsidence. The preponderance of ensemble output suggests the trough axis not passing into the southern Rockies until Friday, thus keeping modest ascent mechanisms into eastern Arizona Thursday with a continued slight chance of storms over mountainous areas. Regardless, the pattern evolution late in the week will promote height falls and dry westerly flow with H5 readings retreating closer to 580-582dm by the weekend (and possibly much lower early next week). While numerical guidance spread widens during the evolution, an increasing number of ensemble members indicate deeper troughing and more robust cooling arriving over the weekend such that temperatures should return to near normal, or even into a slightly below normal category.

AVIATION

Updated at 2330Z.

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

No aviation weather impacts are expected through the forecast period. Winds will remain westerly through this evening with intermittent gusts into the teens possible prior to sunset. Winds will shift back out of the E-SE at KIWA and KPHX late tonight with speeds remaining aob 7 kts. FEW to at times SCT high clouds will progress over the region tonight before clearing out early Tuesday morning.

Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather impacts are expected through the forecast period under mostly clear skies. Winds at KIPL will shift out of the W-SW this evening, with gusts up to 15-20 kts for a brief period around sunset. Otherwise, speeds should generally remain aob 10 kts. At KBLH, winds will favor a S-SW component through the period. Gusts up to 15-20 kts will be possible over the next few hours with winds becoming light after sunset.

FIRE WEATHER

The threat for a few lightning strikes with little rainfall in far eastern Gila County Wednesday and Thursday is the main fire weather hazard this week. With temperatures hovering slightly above normal, winds will maintain a diurnal upslope/nocturnal drainage pattern. Gusts will be limited the first half of the week, then increase later in the week, particularly across the lower Colorado River valley and over mountainous locations. Minimum afternoon humidity levels will generally fall in a 5-15% range following a widely ranging poor to fair overnight recovery of 15-45%.

PSR WATCHES/WARNINGS/ADVISORIES

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