textproduct: NWS Phoenix

UPDATE

Updated 06Z Aviation Discussion.

KEY MESSAGES

- Well above normal temperatures will prevail across the entire region through next week.

- Record setting highs and warm lows will be possible across the lower deserts including Phoenix on Sunday and Monday.

- Dry and tranquil weather will continue for the next several days.

SHORT TERM /TODAY THROUGH MONDAY/

An unseasonably strong ridge of high pressure continues to be the dominate the weather feature over the Desert Southwest. This ridge has brought several days of abnormally warm temperatures and benign weather conditions to our area. The 500 mb ridge will reach peak strength on Sunday before a weak shortwave trough replaces the ridge on Monday. 500 mb hghts will rise up to 580-583 dam across the forecast area on Sunday, resulting in sfc highs reaching the upper 70s to lower 80s across the lower deserts. Record warm lows/highs will be threatened Sunday morning/afternoon. For Phoenix Sky Harbor, the latest NBM probabilities of at least tying the record warm low Sunday morning is around 60% and the probability of tying or reaching a new record high is up to 90-95% Sunday afternoon. Although temperatures will cool by a degree or two on Monday due to the arrival of the shortwave trough, highs are still expected to reach near daily records around 80 degrees in locations including Phoenix, Yuma, and El Centro.

LONG TERM /TUESDAY THROUGH NEXT FRIDAY/

Very little will change as far as the weather pattern is expected for next week with the large scale ridging remaining the dominant feature. The very weak disturbance currently off the southern California coast will eventually cut through the ridge later Monday and Monday night, likely knocking temperatures down a degree or two for Tuesday and possibly Wednesday. However, the ridge will quickly rebuild to our west and is forecast to shift back into our region by Wednesday. We should maintain H5 heights of 580-584dm over our region through the rest of next week with dry westerly flow persisting under clear to mostly clear skies. Depending on the strength of the ridge later next week, we may again see highs topping 80 degrees in some spots later next week into next weekend. Long range guidance is still pointing toward a potential pattern shift by around Christmas which may bring a larger trough farther to the south along the West Coast. If this occurs, it could bring an end to our unseasonably warm and dry conditions.

AVIATION

Updated at 0541Z.

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

No aviation weather concerns will exist through the TAF period. Light winds (generally AOB 10 kts) will continue through the TAF period with some elevated winds through the overnight period. East to northeast winds will dominate the period with a westerly shift looking unlikely for tomorrow afternoon. The western terminals will be mostly light and VRB, however KBLH will see a NNW shift by tomorrow afternoon. Otherwise FEW-SCT high clouds will be passing the region.

FIRE WEATHER

A strong ridge of high pressure will continue to encompass the region, resulting in warm and dry conditions persisting well into next week. High temperatures in the upper 70s to the lower 80s will be common across the lower deserts, or around 10 to 15 degrees above daily normals. Winds will follow typical diurnal trends with occasional afternoon and overnight breeziness across the AZ high terrain. Daily MinRHs will range between 15-25% while overnight recoveries run generally between 40-70%.

CLIMATE

Daily Record Highs

Phoenix ------- 12/13 82 (2010) 12/14 78 (2010) 12/15 79 (1969)

PSR WATCHES/WARNINGS/ADVISORIES

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