textproduct: NWS Phoenix

UPDATE

00Z Aviation Discussion.

KEY MESSAGES

- Temperatures will warm up through the weekend, reaching a slightly above normal category by the beginning of this upcoming week.

- Lighter, more seasonable wind speeds with only modest afternoon breezes will be common this weekend and likely persist through much of this upcoming week.

SHORT TERM /TODAY THROUGH MONDAY/

Upper-level water vapor satellite imagery and 500mb RAP analysis show a closed low pressure system in the WY-UT-CO tri state area with quasi-zonal flow over AZ and southern CA. With the aforementioned low well north of our area, and moving N/NE, wind speeds across the area have returned to more typical light speeds with some occasional afternoon breeziness. These lighter wind speeds are expected to continue into the beginning of this upcoming week.

H5 heights, early this afternoon, are around 580 dm over most of the CWA, which is an increase of 3-4 dm from 24 hours earlier. This increase in H5 heights has resulted in warming temperatures, with afternoon high temperatures expected to top out in the low to mid 90s across the lower deserts and in the mid to upper 80s to around 90 degrees across the higher terrain areas. Despite these warming temperatures, today's forecasted highs are still around 4-6 degrees below normal.

For the end of the weekend and by the beginning of next week and omega block pattern will start to amplify with deep low pressure systems in the New England area and the Gulf of Alaska and an amplifying ridge centered over the Plains. As this pattern amplifies H5 heights will gradually rise across our region (going from 580 dm this afternoon to around 585 dm by Monday afternoon). This increase in heights will result in a warming trend across the region. Afternoon high temperatures will rise to near normal on Sunday (upper 90s to near 100 across the lower deserts and 90s across the higher terrain) and go slightly above normal on Monday (100-105 degrees across the lower deserts and the mid to upper 90s across the higher terrain). With temperatures returning to the above normal category on Monday, isolated areas of Moderate HeatRisk will develop across portions of the lower deserts (most notably across the Lower CO River region). As temperatures warm, remember to practice smart heat safety by drinking plenty of water and electrolytes and limiting your time outdoors (especially during the afternoons).

LONG TERM /TUESDAY THROUGH FRIDAY/

By Tuesday, upper level ridging will already be present centered over Central CONUS and will lead to temperatures 2F-4F degrees above normal for early June. Localized areas of moderate HeatRisk will persist throughout the week as high temperatures will remain very steady with only a 1F-2F degrees difference day to day. Otherwise, skies will be mostly clear throughout the week which will help cooling overnight, where lows will be near to 1F-2F degrees above normal. By Friday and heading into next weekend, temperatures will begin to cool by a degree or two in response to a cut off low developing over Northern Mexico.

AVIATION

Updated at 2330Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation concerns are anticipated through the forecast period under clear skies. Winds will follow typical diurnal trends at all terminals with speeds remaining generally less than 10 kts. There may also be extended periods of calm and VRB conditions overnight and particularly prior to the onset of any wind shifts.

FIRE WEATHER

Light winds will mainly follow their diurnal upslope/upvalley and nocturnal drainage patterns through most of this upcoming week. Some occasional breeziness is expected as well. Below normal temperatures continue today with temperatures returning to near normal tomorrow. Temperatures rise slightly above normal on Monday and will stay slightly above normal through at least the upcoming workweek. MinRHs will be around 10-20% today and decrease even further to 5-15% region wide tomorrow and remain in that range through the workweek. Overnight recoveries will will be around 25-50% tonight then lower to 15-30% tomorrow and continue through the workweek. The driest day, with lowest humidities, are expected during the middle of the week.

PSR WATCHES/WARNINGS/ADVISORIES

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