textproduct: NWS Phoenix

UPDATE

Updated 18Z Aviation Discussion.

KEY MESSAGES

- Lingering showers and running washes and streams should clear out and dry up this morning with no additional rain expected heading into this afternoon.

- Very dry conditions will develop by this weekend with near to slightly above normal temperatures continuing each day through early next week.

- A low pressure system early next week may bring a return of moisture and rain chances to Arizona.

SHORT TERM /TODAY THROUGH FRIDAY/

The tropical low that moved through over the past 24 hours produced quite a soaker for a good portion of central AZ. There was a large area of 1-3 inches of rain that fell from Apache Junction and East Mesa through Fountain Hills and North Scottsdale to Anthem and New River, which led to significant running washes and lots of street flooding. Just after midnight, early this morning, satellite and radar showed the southern end and last of the stretched out low circulation was moving up through Pinal County toward Gila County, with moderate showers gradually shifting off to the north and east. The risk for additional flash flooding from very heavy rain has diminished. However, the Flood Watch was extended through 5 AM MST for areas east of Phoenix, including all of southern Gila County, where a few hours of moderate rain may add up to cause some flooding impacts. Some washes and flood control systems across south- central AZ may also continue to see flow through this morning.

Dry air will begin working into the region, initially just aloft, rather quickly today as the remnant tropical circulation lifts through the Four Corners by noon. The environment will also be overworked. Rain chances will come to an end early this morning for the lower deserts of south-central AZ and the higher terrain to the east not long after, with little to no chance for additional rain after noon for all areas. Drying will continue through Friday with mostly clear skies expected. There will be another shortwave trough that will clip through southeast AZ Friday morning, but this wave will not have any influence on the local weather.

Temperatures today will remain slightly below normal across south-central AZ and near normal to the west. Highs are forecast to reach the mid-90s across Maricopa and Pinal Counties and around 100 degrees out west. Highs Friday will then be around 100 degrees across all lower desert locations and it will still feel a bit muggy in south-central AZ where surface moisture will still be holding on with dew point temperatures still in upper-50s to mid-60s.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

A more significant total column push of dry air is expected this weekend, coinciding with a mid-level front moving through at the base of the trough moving through the West. This will finally scour out the lingering PBL moisture across south-central AZ. PWATs are forecast drop as low as 0.4-0.7" across the southern deserts by Sunday. With this dry of air you can count out any chance at rain and count on plenty of sun. This trough will also help moderate temperatures, keeping them near to slightly above normal. There is good confidence that the trough moving through the West will continue on into the Plains by Monday and another Pacific low moves to the CA coast. What this next Pacific low does once reaching the CA coast Monday is a little less certain, but it may be what helps eventually drive moisture back up in the deserts and drive the next chance at rain in the AZ deserts. Latest NBM shows slight PoPs (10-30%) returning by Tuesday. Average to slightly above average temperatures are forecast to continue this weekend through the first half of next week with this outlook, with afternoon highs around to slightly above 100 degrees. With the drier air coming in, the morning lows will finally be more pleasant, consistently dropping into the 70s for most lower desert locations.

AVIATION

Updated at 1725Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation concerns are expected during the next 24 hours. Initially, some lingering low level moisture producing occasional ceilings at BKN035, but this moisture will scatter out early this afternoon. Otherwise skies will become clear this evening and into tomorrow. Winds will be light with overall easterly component, not expecting the typical westerly switch this afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation concerns are expected during the next 24 hours. At KIPL, current southeasterly winds will go southwesterly this evening and then northwesterly overnight. Some low level moisture through early afternoon producing occasional bkn035. At KBLH, general light south/southwest component to winds.

FIRE WEATHER

Overall there are no fire weather concerns through the next week. Lingering wet grounds and elevated surface moisture will continue into Friday, but a drying trend will begin today, initially aloft, followed by a more significant drying this weekend. After showers dissipate/move out of the area this morning, no additional rain is expected through at least the start of next week. Minimum RH values this afternoon will be around 25-45%, with driest conditions in southeast CA. As drying continues, min RHs will dip as low as 10-20% Saturday. Overnight recoveries across south- central AZ will be good the next couple nights at 45-75% and then dry slightly over the weekend. Winds will mostly follow typical diurnal patterns with modest afternoon upslope/upvalley gustiness (15-25 mph).

PSR WATCHES/WARNINGS/ADVISORIES

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