Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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395 FXUS65 KPSR 050911 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 211 AM MST Sun May 5 2024 .SYNOPSIS... A dry weather system passing across the northern portion of the region today will help to bring fairly widespread windy conditions by this afternoon as well as dropping temperatures to slightly below normal. The weather pattern for the rest of the week will keep dry conditions in place while temperatures will warm back into a normal range through at least mid week. && .DISCUSSION... A mostly dry Pacific low pressure system is currently moving eastward across northern California into Nevada with the base of the trough reaching into our region. IR satellite shows considerable high cloudiness currently moving through our region and this will continue into the afternoon hours before skies begin to clear out. A dry cold front is also starting to push through the area with objective analysis showing the front now mostly through southeast California. The front will eventually make its way through most of Arizona later this morning, but it will also be washing out as it does leaving the coolest air to the west of the Phoenix area. Forecast highs today show readings only in the upper 70s across southeast California to the mid to upper 80s across Phoenix and other lower desert areas in south-central Arizona. The main forecast concerns for today will be the gusty winds which will likely result in areas of elevated fire weather conditions. Winds early this morning continue to occasionally gust to between 30-40 mph across southeast California and this will expand into much of Arizona by late morning or early afternoon. The rest of this afternoon into early this evening should see winds gusting to between 25-35 mph across the south-central Arizona lower deserts, including the Phoenix area, to as high as 35-45 mph across southeast California into the higher terrain north and east of Phoenix. Starting Monday, the center of the Pacific trough will quickly lift to the northeast through Colorado into the Northern Plains leaving drier west northwesterly flow across the Desert Southwest. Winds will be considerably lighter over our area on Monday, while temperatures remain a few degrees below normal. The trough is then expected to deepen again as it becomes nearly stationary centered over the Northern Plains while the western fringes of the trough stays over the Great Basin into northern portions of our region through at least mid week. This synoptic set-up should bring more breezy conditions over our area into the middle part of the week, while temperatures slowly warm back into a normal range with highs back to around 90 degrees or the lower 90s by Tuesday or Wednesday. Eventually the influence of this trough will begin to wane later this week as a ridge tries to build over portions of the Western U.S. Ensemble guidance is still unsure when this ridge will be able to fully displace the remnant trough from our region, but either way it seems our temperatures will mostly likely warm further by next weekend with the NBM indicating highs into the mid to possibly upper 90s by Friday or Saturday. && .AVIATION...Updated at 0552Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Westerly winds will continue at all terminals through 08-10Z before shifting E to SE. E to SE, 5-8 kt, winds will prevail between 10-15Z. By 15-16Z Sunday, S to SW winds increase with speeds initially around 8-12 kts. W to SW winds further increase by 20Z, with sustained speeds up to 15-20 kts and gusts to around 25-30 kts. Between ~22-02Z, occasional gusts may reach 30-35 kts. A cold front will move through around 3-4Z, which may also lead to a brief spike in winds. Following the front winds should gradually subside. SCT to BKN high clouds around 20 kft will pass over the region throughout the period with lower bases to around 8 kft expected Sunday afternoon. Southeast California/Southwest Arizona including KIPL and KBLH: Winds will be the primary aviation weather concern through the TAF period. There will be a small reprieve from the winds tonight through early Sunday, more so at KBLH. Slightly stronger winds than Saturday are then expected during the day at the terminals, with westerly to southwesterly gusts mostly to 30-35 kts. Occasion gusts may reach up to 40 kts. The strong winds will be capable of generating blowing dust which will likely lead to slantwise visibility reductions at a minimum, but could also briefly reduce surface visibility as well. A cold front will eventually pass through KBLH around 01Z and shift winds to the NW. Winds subside at both terminals after sunset. Expect to see fluctuating coverage of high clouds throughout the period. && .FIRE WEATHER... A weather system moving just to the north of the region today will bring breezy to windy conditions areawide. Wind gusts of 25-35 mph are likely in many areas this afternoon with upwards of 40-45 mph possible across portions of southeast California and over the high terrain north and east of Phoenix. The strong winds and dry conditions with humidities as low as 20% today could lead to elevated fire weather conditions. Lighter winds are expected by Monday with MinRHs lowering to around 10%, with fair to good overnight recoveries. Weak high pressure will then remain over the region through much of the coming week as temperatures return to slightly above normal by late week. Seasonably dry conditions are expected this week with MinRHs dropping to around 10% each day starting Monday. Winds this week will be fairly light most days, except for Tuesday and Wednesday when winds will be more elevated with afternoon gusts between 20-30 mph in some areas. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...Wind Advisory until 9 AM PDT this morning for CAZ560. Wind Advisory until 8 PM PDT this evening for CAZ563>567. Wind Advisory until 11 PM PDT this evening for CAZ562. && $$ DISCUSSION...Kuhlman AVIATION...Benedict FIRE WEATHER...Kuhlman