textproduct: NWS Phoenix

UPDATE

00Z Aviation Discussion

KEY MESSAGES

- Slightly above normal temperatures will persist through Friday with gradual drying across the region.

- Temperatures will warm again by early next week with readings returning to around 10 degrees above normal.

SHORT TERM /Today through Friday/

A vigorous, compact shortwave was propagating across the four corners early this afternoon dragging a weakening cold front through the region. Both ascent mechanisms and a deep moisture pool have already exited the forecast area, however lingering cyclonic flow with troughing still evident over the Great Basin will prevent stronger subsidence and drying from entering the region for the next 48 hours. While midlevel height falls associated with this shortwave haven't been particularly robust, they have been sufficient to allow temperatures to retreat somewhat closer to the seasonal normal (albeit, still remaining several degrees above normal). Models are in very good agreement that H5 heights will generally hover in a 570- 576dm range through Friday, and narrow numerical guidance spread yields excellent forecast confidence of nearly steady temperatures 3F-6F above normal. Otherwise, some enhanced gusty sundowner winds are likely in parts of SE California this evening, though height falls, fropa, and positioning of the jet core are mistimed and misaligned for more intense speeds and impacts. At this time, advisory level wind speeds appear too temporally and spatially limited to justify any headlines.

LONG TERM /Saturday through Tuesday/

A quiet weather pattern is expected through the weekend and at least the first part of next week. A modest ridge will move into the region over the weekend quickly boosting temperatures as highs top out around 90 degrees Saturday and into the low to mid 90s on Sunday. This ridge will somewhat stick around into early next week, but it will likely be undercut by a very weak shortwave on Monday before another Pacific trough potentially moves into the Western U.S. on Wednesday. Dry conditions are likely to prevail the entire time with the only chances (5-10%) for any showers across the far eastern Arizona high terrain. NBM forecast temperatures look quite stable for the first half of next week with highs hovering around 95 degrees, or roughly 10 degrees above normal.

AVIATION

Updated at 2310Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation concerns are expected during the TAF period. Familiar diurnal trends are favored through Thursday afternoon with some lingering breeziness through about sunset this evening. FEW-SCT low bases will disperse with SCT high clouds moving in later in the forecast window.

Southeast California/Southwest Arizona including KIPL and KBLH: Breezy to windy conditions will be the main aviation concern over the next 24 hours, especially at KIPL where gusts may near 30 kt this evening. At KBLH, gusts will also be observed, but readings should only reach around 20 kt. Winds are expected to relax early tonight. Clear skies will give way to SCT high clouds.

FIRE WEATHER

A weak cold front pushing through the area this morning will bring scattered light showers with little measurable rainfall. Breezy westerly winds will also affect the area today with gusts as high as 25-35 mph with the frontal passage and again this afternoon across southeast California and the Arizona high terrain. MinRHs today will mostly be between 20-30% before drier air gradually moves in lowering MinRHs to 15-25% Thursday and 10-15% starting Friday. Afternoon breezy conditions will be possible on both Thursday and Friday focused more across the western districts. Lighter winds, temperatures rising to well above normal, and low humidities are then anticipated for the weekend.

PSR WATCHES/WARNINGS/ADVISORIES

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