textproduct: NWS Phoenix

KEY MESSAGES

- Well above normal temperatures will be seen across the region through at least the weekend with some locations flirting with record highs.

- Dry and tranquil conditions will prevail through at least next week.

SHORT TERM /TODAY THROUGH MONDAY/

An unseasonably strong upper level ridge remains positioned over and just to the west of our region with H5 heights easily into the 90th percentile of climatology. The high heights have allowed for a gradual warming of the boundary layer with most lower desert locales reaching into the upper 70s yesterday to as warm as the lower 80s across portions of Imperial County. Little to no change in the atmospheric pattern is seen through Sunday with temperatures remaining stable at between 10-15 degrees above normal. Daily records could be reached or broken for Phoenix, Yuma, and El Centro, especially those of which that are only around 80 degrees. For the Phoenix area, NBM forecast highs show a peak on Sunday with highs between 80-82 degrees, despite some expected higher level clouds. Monday's highs are not likely to change much despite a very weak and dry shortwave trough beginning to cut through the upper level ridge. Overnight lows through the weekend will mostly range from the mid 40s in more rural desert areas to the mid 50s within urban areas.

LONG TERM /TUESDAY THROUGH NEXT FRIDAY/

Very little will change as far as the weather pattern is expected for next week with any weather systems staying across the northern tier states. The very weak shortwave trough cutting through the ridge later Monday into Tuesday should knock temperatures down a couple of degrees for Tuesday and Wednesday, but another ridge will already be rebuilding to our west. This next ridge should maintain H5 heights of 580-584dm over our region through the rest of next week with dry westerly flow persisting under generally clear skies. Depending on the strength of the ridge later next week, we may again see highs at or just over 80 degrees at some point later next week into the following weekend. Long range guidance is starting to allude to a potential pattern shift by around Christmas which may bring a larger trough farther to the south along the West Coast. If this were to occur, it could bring an end to our unseasonably warm and dry conditions.

AVIATION

Updated at 0855Z.

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 Friday night. Light winds (generally AOB 7 kts) will follow a familiar diurnal pattern, with extended periods of variability to nearly calm conditions. Clear skies will be followed by FEW-SCT high cirrus decks moving over the region later this afternoon and evening.

FIRE WEATHER

Strong high pressure will continue to dominate across the region through at least the weekend bringing unseasonably warm and dry conditions. High temperatures in the upper 70s to the lower 80s will be common across the lower deserts, or at least 10 degrees above normals. Winds will continue to follow familiar diurnal trends with occasional afternoon upslope breeziness. Daily MinRHs will be between 20-25% while overnight recoveries run generally between 45-75%.

CLIMATE

Daily Record Highs

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

PSR WATCHES/WARNINGS/ADVISORIES

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