061 FXUS65 KPSR 132349 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 449 PM MST Thu Jan 13 2022 .UPDATE...Updated Aviation Discussion. && .SYNOPSIS... Overall dry conditions, periods of clouds, and above normal temperatures will persist through at least early next week. A weak upper level disturbance passing by the region on Friday will bring thicker clouds followed by breezy conditions later Friday into Saturday. The weather pattern will essentially be stalled through early next week providing little day to day change in temperatures and highs mostly in the lower 70s across the lower deserts. && .DISCUSSION... Satellite and objective analysis this afternoon shows a ridge axis over the Gulf of California and up through Arizona. Deep southerly flow is seen on the west side of this ridge with high clouds continuing to stream north into the Southwest. The ridge has also led to another degree or two of tropospheric warming from yesterday, as indicated by aircraft soundings, and surface temperatures so far today have been warming slightly quicker than yesterday. Still anticipating highs today to top out in the low- 70s. The most identifiable feature on water vapor this afternoon, across the western CONUS, is the low that has rounded the north side of the eastern Pacific rex block and has now pushed inland into the PacNW. Satellite shows this low is currently transitioning to an open shortwave and has already taken on a positive tilt. This shortwave is expected to quickly dig southeast through the Great Basin and Four Corners area, clipping through Arizona, through Friday. With this trajectory, the overall sensible impact to the local area will be minimal. While 500 mb heights will lower, surface temperatures are not expected to lower much, if at all. NBM forecast still has highs near the 70 degree mark for the lower deserts through this weekend. The one impact worth mentioning is a strong north to northeast gradient wind Friday night into Saturday as strong high pressure develops in the Great Basin following the shortwave. This should lead to breezy conditions in Arizona on Saturday. Forecast soundings show the strongest winds, upwards of 40-45 mph, will be mostly in the 850-700 mb layer and during the overnight hours. This will likely limit the strongest surface gusts to the higher terrain/ridges north and east of Phoenix. The ECMWF EFI is showing the potential for a seasonably anomalous wind event in central Arizona and HREF is indicating lower desert surface gusts up to 20-30 mph will be common Saturday, especially in the morning, while ridges and mountain tops could see gusts up to 45-55 mph. Breezy north winds are also expected in SoCal beginning Friday afternoon. So, caution should be taken if planning to recreate outdoors Saturday, especially in mountainous areas of south- central Arizona Saturday morning. As far as precipitation chances over the next several days, there is not much to speak of. NBM probabilities of measurable precipitation anywhere in the CWA through early next week is under 10%. EPS and GEFS do show the best push of moisture into the region over the next 7 days will actually be tonight through Friday, with IVT peaking briefly around 250 kg/ms. Ensembles show great consensus on this, but also still keep higher moisture content to the south and maintain a very dry layer subcloud layer, below 700 mb, through this period. Increased cloudiness and lower clouds, along with virga radar echoes, are expected. Maybe some rogue rain drops, but again the chance of measurable rain is very low (under 5%). The mid-levels dry out following the passage of the trough from the northwest later Friday. .PREVIOUS DISCUSSION... The rest of the weekend into early next week should see the cut- off low weakening further as it most likely drifts from just off the southern CA coast through our region some time early next week. Model ensembles continue to trend drier with this most likely scenario with the NBM now showing less than 10% PoPs through the first half of next week. Likely the only impact with this weak system passing through our region will be another round of clouds. NBM forecast temperatures for the first half of next week change very little with highs generally ranging from the upper 60s to lower 70s, or a few degrees above seasonal normals. && .AVIATION...Updated 2345Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH: An upper low centered off the northern Baja peninsula will spread increasing cloudiness over the region today and tonight. Mid-level CIGs will lower to 10-15 kft late tonight from west to east. Periods of virga and sprinkles are also likely from late tonight through Fri afternoon. Clouds decrease Fri afternoon over the Phoenix area but linger over SE CA. Surface winds will remain light (AOB 7kts) and favor diurnal patterns through the daytime Friday. Otherwise gusty N winds are expected to develop at KBLH by mid Fri afternoon with gust of 20-25 kts likely. && .FIRE WEATHER... Saturday through Wednesday: Dry weather with warmer than normal temperatures are expected through the first half of next week. A couple weak upper level disturbances are likely to bring periods of clouds and maybe some isolated very light showers, but chances for wetting rains are generally less than 5%. Minimum afternoon humidity levels will mostly fall into a 15-25% range following fair to good overnight recovery around 30-55%. Winds will start off breezy on Saturday, but are expected to be fairly light through the rest of the period. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Benedict PREVIOUS DISCUSSION...Kuhlman AVIATION...Sawtelle/AJ FIRE WEATHER...Kuhlman