Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
117 FXUS65 KPSR 210816 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 116 AM MST Tue May 21 2024 .SYNOPSIS... Typical dry late-May weather will persist through the remainder of this week and this weekend, with near normal temperatures each day as lower desert highs reach the nineties. Typical daily breeziness in the afternoons can be expected. A weak disturbance late this week will bring a slight enhancement to the winds and cool temperatures slightly. By early next week temperatures will warm to above normal as high pressure develops. && .DISCUSSION... Global ensemble models maintain strong agreement in the persistence of a longwave trough pattern across the Western CONUS through the remainder of this week and this weekend, with a few embedded dry shortwave troughs, but no substantial weather impacts. H5 heights are expected to remain around 576-580dm over the area which is typical for this time of year. So, for the 6 days fairly typical dry Spring weather is expected across the Desert Southwest. This will include daily widespread Minor HeatRisk, with afternoon lower desert high temperatures in the 90s, right at seasonal normals, plenty of sun, and overnight lows in the 60s. Typical afternoon breeziness can be expected, with most days gusting into the 15-30 mph range across the southern deserts. Slight enhancements to the wind are possible with passing shortwaves. Currently, the strongest/deepest wave looks to impact the region Friday and Saturday, with potential for stronger wind gusts, including in excess of 35 mph in Southeast CA. Following the shortwave late this week and this weekend, global ensembles are strongly in favor of a high-amplitude ridge developing across the Western CONUS heading into early next week, with H5 heights climbing up to the 585-590dm range. This will lead to 100 degree afternoon temperatures again and potentially the hottest temperatures of the year so far. && .AVIATION...Updated at 0530Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Winds have substantially calmed across all the terminals, now exhibiting speeds aob 6 kt. Some light, erratic behavior will be possible through the next several hours before winds definitively establish out of their typical E/SE drainage directions. Going forward, wind directions will generally follow diurnal tendencies. Expect southwest winds to establish by the afternoon across the terminals with occasional gusts into the mid teens through early tomorrow evening. Clear skies will prevail through the period, aside from a thinly scattered deck to the SE based around 8-10 kft lingering for another hour or so. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns will exist through the next 24 hours under clear skies. Winds will lessen and turn out of the NW overnight at KIPL and are expected to pick up again out of the W tomorrow evening, but with speeds mostly aob 12 kt sustained and gusts potentially into the low 20s. An extended period of light wind speeds (aob 6 kt sustained) and variability can be anticipated at KBLH after southerly winds subside tonight. && .FIRE WEATHER... Very typical mid/late May weather will prevail the remainder of the week highlighted by seasonably warm temperatures, dry conditions, and frequently breezy afternoon/early evenings. Minimum afternoon humidity levels will mostly fall into the single digits with some modest improvement into a 10-20% level towards the end of the week. This will follow generally poor to fair overnight recovery of 20- 40%. Wind gusts 15-25 mph will be common through the week. A slight enhancement is anticipated during the late-week timeframe as a dry system moves through. Wind gusts with the late-week system may increase up to 25-30 mph, to as high as 30-40 mph near terrain features, and the Imperial Valley, resulting in an elevated, to perhaps locally critical, fire danger. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Benedict AVIATION...Whittock FIRE WEATHER...18/Benedict