textproduct: NWS Phoenix

UPDATE

Updated Aviation Discussion.

KEY MESSAGES

- Above normal temperatures will prevail into next week with highs peaking at around 80 degrees this weekend.

- Occasional periods of breezy winds will affect the Lower Colorado River Valley today and Friday.

- Dry conditions will persist well into next week under clear to mostly clear skies.

SHORT TERM /TODAY THROUGH FRIDAY/

The weather pattern through the rest of this week and likely even most of next week will continue to support ridging over the Western U.S. and deep troughing over the Eastern U.S. This will keep our region dry with overall tranquil conditions in place. Although the large scale weather pattern will continue to dominate, guidance shows a couple of fast moving dry shortwave troughs brushing past our region to the north today and Friday. These features will essentially pass by without much notice, but they will tighten the pressure gradient across the region and lead to some breezy conditions focused down the Lower CO River Valley during the daytime hours today and Friday. The rest of the area will also see more of a northerly flow which will help to dry out the boundary layer further pushing surface dew points into the teens today. The northerly winds should also bring some downslope warming into the lower deserts with highs likely reaching near 80 degrees by Friday in the Imperial Valley to as warm as the upper 70s elsewhere.

LONG TERM /SATURDAY THROUGH NEXT FRIDAY/

Higher amplitude ridging is heavily favored to move eastward from off the West Coast by Saturday with H5 heights over our region rising to between 579-582dm, or well into the 90th percentile of climatology. The higher heights, continued dry conditions, and plenty of sunshine are expected to push daytime highs to around 80 degrees for a good portion of the lower deserts this weekend. Guidance also shows a weak cut-off low developing well west of Baja on Friday before drifting eastward over the weekend. The most likely track of this feature keeps it to our south passing across central Baja on Sunday as it becomes an open wave. Our region should see a slight uptick in moisture over the weekend and some higher level clouds on Sunday, but little if anything will come from this cut-off low.

For at least the first half of next week, our weather will remain quiet with dry conditions persisting. For Monday and Tuesday, heights aloft are expected to lower due to the lingering dying cut-off low as well as a passing shortwave trough well to our northeast. We are also likely to see a decent amount of high clouds early next week which combined with the lowering heights should knock a few degrees off of daytime highs. The latest NBM shows lower desert highs mostly in a 74-78 degree range for Monday and Tuesday.

Ensembles then show a Rex block developing Tuesday into Wednesday with the core of the ridge setting up over the Pacific Northwest into the Great Basin and another cut-off low developing somewhere to our southwest. Our region should continue to be dominated by the upper level ridge through at least Thursday and potentially longer depending on what happens with the cut-off low. Temperatures will at least remain above normal during the latter half of next week, but they may start to trail off by next weekend if the cut-off low shifts into our region. There is too much uncertainty at this point to know if and when the cut-off low may affect our region. Ensembles do show some small precip chances by around Friday or into next weekend, but so far only 5-10% of the members show QPF for Phoenix.

AVIATION

Updated at 1710Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation weather concerns are expected throughout the TAF period under clearing skies. The overall wind pattern will exhibit light and diurnal tendencies with speeds generally AOB 7 kts along with extended periods of variable to calm conditions. Confidence is low on wind directions overnight, with a period of VRB or even light SW winds possible at KPHX, though winds should increase out of the E/NE once again Friday morning. Confidence is moderate on a west shift occurring late Friday afternoon, with a few hours of variability before/around sunset possible instead.

Southeast California/Southwest Arizona including KIPL and KBLH: The primary aviation concern through the next 24 hours will be gusty north winds at KBLH under mostly clear skies. Anticipate gusts to 20-25 kts through this afternoon at KBLH, followed by lighter winds (AOB 10 kts) backing out of the NW this evening and continuing through much of Friday morning. Winds at KIPL will generally remain AOB 10 kts and vary between W and N.

FIRE WEATHER

Dry conditions and above normal temperatures will prevail for the rest of the week. Some breezy winds with gusts up to around 25 mph will develop late this morning and last through the afternoon across the Lower CO River Valley, with another round again during the same time on Friday. MinRH values will continue to range between 10-20% through Friday before improving slightly over the weekend. Overnight recoveries will remain poor to fair with humidities between 30-55%.

PSR WATCHES/WARNINGS/ADVISORIES

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