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
159 FXUS65 KPSR 060901 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 201 AM MST Thu Jun 6 2024 .SYNOPSIS... Unseasonably strong high pressure positioned over the region will help promote the hottest temperatures so far this year through the remainder of the week, resulting in an Excessive Heat Warning that will be in effect through Friday. Increased cloud cover and a slight relative cooldown in temperatures are anticipated by this weekend before another warming trend is expected early next week. && .DISCUSSION... Excessively hot temperatures will continue across the majority of the area through Friday as the unseasonably strong high pressure system sits over the Desert Southwest. H5 heights are currently analyzed at around 591-592dm over most of Arizona and New Mexico, or easily into the 90th percentile of climatology, and this will continue through tonight before gradually lowering into the weekend. The relative positions of the high center over northeast Arizona/western New Mexico and the cut-off low a few hundred miles west of southern Baja are starting to allow for weak southeasterly flow into Arizona. Current water vapor imagery is showing some weak moisture advection into Arizona, but guidance is still pointing at very minimal chances of showers and maybe an isolated thunderstorm or two well north and east of Phoenix today and Friday. Temperatures are likely to reach their peak today with highs anywhere from 108-113 degrees across the lower deserts. This should mark the first 110 degree day this year for Phoenix, five days earlier than the 30 year normal first occurrence. Much of the lower deserts and even portions of the higher terrain will see a Major HeatRisk today with the areal coverage shrinking some on Friday, but still remaining high enough to keep the Excessive Heat Warning in place. The increasing moisture starting later today, mostly above 20K feet, will bring some higher level cloudiness which will hang around into Friday. The clouds along with H5 heights beginning to lower starting Friday should shave a degree off the highs Friday, but the typically hotter lower desert locations should still top 110 degrees. The cut-off low will start to affect our region more starting Saturday as the low center reaches the northern Gulf of California later in the day. The increasing proximity of the low should also bring even more higher level clouds into the region for Saturday, lasting through Sunday when the weakening low moves through the area. Some modest cooling will be realized this weekend as NBM forecast temperatures lower to between 104-109 degrees Saturday and 103-107 degrees Sunday. The weather pattern for next week is looking very similar to what we are currently experiencing as another cut-off low is expected to develop off the southern California/northern Baja coast by Monday. Ensemble guidance heavily supports this solution, but there remains a good deal of uncertainty with the position of the low and how long it will meander off the coast before swinging northward later next week. For now, the most likely scenario calls for a ridge to build back into our region in response to the low to our west and this should lead to another round of hotter temperatures, potentially reaching Excessive Heat levels again by the middle of next week. && .AVIATION...Updated at 0520Z. South-Central Arizona including KPHX, KIWA, KSDL, KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH: Winds will follow typical diurnal tendencies for all terminals, with speeds generally aob 10 kt with some occasional gusts up to 15-20 kts in the Phoenix area late tomorrow afternoon through the early evening. High clouds will start to push into the region from the southeast during the early morning hours on Thursday. High cloud coverage will increase through the TAF period becoming SCT- BKN at towards the end of the TAF period. && .FIRE WEATHER... Hot and dry conditions will continue to support high fire danger across the area. Well above normal temperatures are forecast through Friday with highs at or just above 110 degrees for a good portion of the lower deserts. Winds will continue to be fairly light much of the time, but occasionally gusting upwards of 20 mph during the afternoon hours. MinRH values will hover around 10%, with poor to fair overnight recoveries as MaxRHs range between 20-40%. A weak weather system is then expected to move through the region this weekend allowing temperatures to start to lower, but remaining above normal. Winds will also increase a bit which could push afternoon gusts up to 25 mph in some locations. && .CLIMATE... Record high temperatures: Date Phoenix Yuma El Centro ---- ------- ---- --------- June 6 111 in 2016 114 in 1928 113 in 2002 June 7 115 in 1985 116 in 1985 113 in 1985 && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Excessive Heat Warning until 8 PM MST Friday for AZZ530>556- 559>562. CA...Excessive Heat Warning until 8 PM PDT Friday for CAZ561-563-566- 567-569-570. && $$ DISCUSSION...Kuhlman AVIATION...Berislavich FIRE WEATHER...Kuhlman CLIMATE...18