textproduct: NWS Phoenix

UPDATE

Updated Aviation

KEY MESSAGES

- Aside from some light shower activity lingering across Joshua Tree National Park through this afternoon, mostly dry and quiet weather conditions are expected through the first half of this week.

- Thunderstorm chances will start to increase across central and eastern Arizona by the latter half of the week. - As high pressure builds over the region, temperatures will heat up to above normal levels through the middle of the week.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Heading into the latter half of the workweek, ensemble model guidance has come into slightly better agreement on the overall synoptic pattern. The models have come into better agreement on the placement of the features, but still differ on the overall strength of the features. Both the GEFS and the EPS show a shortwave trough across the northern CONUS and southern Canada, a broad subtropical ridge stretching across much of the lower 2/3 of CONUS, along with a closed low off the coast of northern California. The EPS continues to be the slightly stronger solution, with a stronger closed low in the Pacific and a slightly stronger subtropical high. This overall better agreement is reflected with the slightly smaller temperature spread in the NBM interquartile range, which has narrowed to less than 5 degrees. The GEFS show the high at peak strength (H5 heights of 594-597 dm) on Wednesday before weakening (H5 heights of 591-594 dm) by the latter half of the week. The high looks to continue to weaken (H5 heights of 588-592 dm) heading into the weekend. Therefore, temperatures are forecasted to remain about 5 degrees above normal during the middle of the week before beginning a slight cooling trend for the end of the workweek and into the weekend closer to near normal levels.

As for shower and storm chances, the ensemble members continue to show those chances starting to increase, for at least portions of the CWA, beginning on Wednesday. PWATs look to increase to around 1.5-1.9" for the latter half of the week, so moisture should not be a limiting factor. With the high forecasted to move overhead, rain chances will likely be limited to the higher terrain areas across eastern Arizona on Wednesday and Thursday. Rain chances may extend into the lower deserts of south-central Arizona heading into the weekend. However, the current WPC PoPs of 30-40%, for Friday into Saturday, seem rather aggressive, especially this far out. WPC's Saturday PoPs of 10-30% seem more reasonable.

AVIATION

Updated at 2300Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: A period of gusty NW winds this evening will be the greatest weather impact under occasionally thick mid/high cigs. Confidence is moderate that a prolonged period of NW gusts 20-30kt will be common through the evening before slowly weakening by midnight. This may create some lofted dust across the region affecting slantwise visibility. Similar to this morning, winds will be delayed making the typical easterly switch, and in some cases like KPHX, may never truly complete the transition. Winds should be noticeably weaker Monday afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH: Gusty winds with lofted dust and areas of sfc vsby restriction into MVFR category early this evening will be the main weather issue. Confidence is good that thick mid/high cigs with virga/sprinkles will persist through overnight with northerly gusts 25-35kt early this evening rapidly weakening by mid evening. However, lofted dust and areas with sfc vsby falling into MVFR category will be common for a few hours. Otherwise, a N/NW wind component will be favored through Monday though periods of nearly calm conditions will become more likely.

FIRE WEATHER

Temperatures will be slightly below normal across SE CA today. Otherwise, temperatures will warm to above normal levels through the middle of the week. Rain chances today will be confined to Joshua Tree National Park, with chances for wetting rainfall very low. MinRH's will generally be around 20-30% area wide through much of this upcoming week with good overnight recoveries. Some elevated afternoon/early evening breeziness out of the northwest can be expected this afternoon and evening with peak gusts of 20-30 mph. A more typical diurnal wind pattern with some occasional afternoon upslope breeziness can be expected through much of this coming week.

PSR WATCHES/WARNINGS/ADVISORIES

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