textproduct: NWS Phoenix

UPDATE...Updated 12z Aviation Discussion

KEY MESSAGES

- Well above normal temperatures will continue into early next week, with lower desert highs reaching the lower to middle eighties, resulting in Minor Heat Risk across the lower deserts.

- A pattern change next week will cool temperatures somewhat and may eventually bring rain chances into the following weekend.

SHORT TERM /TODAY THROUGH SUNDAY/

Ridging that has been over much of Western CONUS the past several days is now to our east into the Plains. Meanwhile the cut off low that developed earlier yesterday off the SW coast of CA continues to move southeastwards and is expected to continue down the Baja Coast through today and tomorrow. The cut off low will be too far south to really affect H5 heights over our region, resulting in afternoon high temperatures to remain 8F-14F degrees above normal as readings top out in the low to mid 80s across the lower deserts. Early morning low temperatures will also remain above normal with most areas bottoming out in the mid 40s to mid 50s, with the potential for near record warm lows to be achieved in Phoenix. With the very warm afternoons in place, it is encouraged to stay hydrated and take breaks as needed, especially for travelers who may not be accustomed to these temperatures at this time of year as Minor HeatRisk is in effect for the lower desert areas.

LONG TERM /MONDAY THROUGH FRIDAY/

Ensembles continue to show good agreement that the cut off low will continue to dive down the Baja Coast through the weekend before beginning its travel eastwards over Northern Mexico starting Monday. While this cut off low moves another troughing feature can be seen diving down the West Coast starting Tuesday and throughout the rest of the week, brining an increase in upper level cloud coverage across the CWA with it. By mid next week, temperatures are expected to cool into the mid 70s across the lower desert areas as H5 heights will lower as this system approaches the region. However, some uncertainty remains in the strength of this trough, but does show good agreement in being positively tilted with the bulk of the associated PVA remaining remain to the north of the region, severely limiting precipitation chances mid to late next week. It is not until next weekend that another troughing feature looks to favor our region in regards of precipitation chances, but it is too far in advance to get a clear picture. Additional monitoring of how ensembles trend will need to take place over the next week.

AVIATION

Updated at 1100Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation weather concerns under some passing high clouds can be expected throughout the TAF period. Winds will follow light and diurnal tendencies with speeds aob 7 kts along with extended periods of variable to calm conditions.

Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns under some passing high clouds can be expected through the TAF period. At KIPL, winds will generally be light and variable while at KBLH, winds will fluctuate between the northwest to northeast. Wind speeds at both terminals will remain light aob 5 kts.

FIRE WEATHER

Well above normal temperatures and dry conditions will continue into early next week. Afternoon MinRHs will range from 15-25% areawide through Monday, with overnight recoveries generally in a 40-65% range. Winds will remain light, generally below 15 mph through Monday, with a northerly fetch this weekend then becoming southwesterly Monday afternoon. By mid next week a pattern change is expected which will help cool temperatures several degrees but remaining above normal. While rain chances late next week are slim humidities are expected to increase slightly, and bring periods of increased breeziness.

PSR WATCHES/WARNINGS/ADVISORIES

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