Sunrise 5:19 AM   Sunset 8:37 PM Moonrise 4:59 PM   Moonset 2:54 AM

  Print   HELP   Reset   Save   Recall  New

FXUS66 KPDT 200927 AFDPDT

Area Forecast Discussion National Weather Service Pendleton OR 227 AM PDT Mon May 20 2024

SHORT TERM
Today through Wednesday...Cool, breezy, and wet conditions continue across the forecast area as a series of upper- level lows trek through the region. This trend will unfortunately continue through most of the week, so those hoping for clear and warm late-spring weather will have to hold on for just a little bit longer.

The first of this series of lows is actually a departing trough that has been centered over western Canada over the last several days.
This trough has developed a positive tilt and will invite northerly flow into the forecast area, as well as weak instability. This northerly flow is quite dry, however, and latest guidance has actually backed off a bit on PoPs this afternoon as models pick up more on the dry incoming airmass. The ingredients are there for weak showers to develop over Wallowa County, and perhaps even some isolated thunderstorms, however confidence is low (30%) on anything substantial materializing as mid-level moisture just isn't there to support more widespread development. Bulk shear is also pretty weak, so convective cells would be weak and short in duration. Elsewhere, expect generally clear skies and mildly breezy conditions, except for the Cascade Gaps, where windy conditions will continue.

Widespread showers become more likely Tuesday into Wednesday as another upper-level low dives down from Canada and envelops the forecast area through most of the midweek. Showers are expected to become widespread more towards the latter half of Tuesday, with t- storms not being of particular concern due to the cold, northerly origin of this system. Guidance has actually backed off quite a bit on storm chances for the period, even for Wednesday, when the low is directly overhead and lift is maximized. Even then, NAM shows very unimpressive CAPE, and lapse rates are weak as well. Did leave chances for storms Wednesday afternoon for primarily the eastern mountains, where mechanical lift over the mountains may help trigger an isolated storm, but overall expect showers more than anything through the midweek.

This train of systems will unfortunately keep the ongoing breezy conditions ongoing, however headline-worthy winds are not anticipated at this time. Northerly flow will also invite colder air into the forecast area, with temps dropping to as much as 15 degrees below average by Wednesday as highs struggle to climb into the 60s even for our lowest elevations. Fortunately, freeze concerns appear to be limited, as moisture and cloud cover are expected to insulate the area from temps really bottoming out overnight. Evans/74

LONG TERM
Thursday through Sunday...Thursday looks to be mainly dry across the region in northwesterly flow. There could be some lingering showers over the eastern Oregon mountains, though the deterministic models are less supportive of this than the NBM. By later Thursday into THursday night, all of the guidance has dry weather everywhere.

By Friday, there continues to be uncertainty with regard to the next trough/low approaching the Pacific Northwest. The GFS is a bit stronger and considerably further south with the low position than the ECMWF. However, each model does bring some showers to the area into Saturday, but exactly where and how much will be dependent on the track and strength of the low. The good news is the precip does look less than yesterday. With the deeper low, the GFS does bring ridging in behind its passage on Sunday while the ECMWF has dry west to northwesterly flow followed by ridging. Wile uncertainty remains, at this point, the second half of the holiday weekend does look better than the first.

The ensemble clusters continue to support the ECMWF (more northern)
solution. On Friday and Saturday, the GFS solution is only preferred by 18% of the solutions, while the ECMWF is preferred by 39% and 46% respectively. Additionally, the ECMWF continues ensemble mean continues to be in better agreement with its deterministic run at 500 mb giving more confidence to its solution.

Depending on the ultimate low track, Friday afternoon into Friday evening could be breezy.

High temperatures look to be below normal in central Oregon Thursday and near normal elsewhere. Friday will see highs near normal.
Saturday's highs will be about 5 or so degrees normal everywhere with a return to near normal on Sunday.

AVIATION
12Z TAFS...High confidence (90-100%) in VFR conditions through the period. Gusty winds to around 25 kts are expected to redevelop at DLS and 15 to 20 kts at PDT, BDN, RDM and YKM. All winds should become 10 kts or less during the late afternoon/evening except at DLS where the decrease will happen later...during the late evening/overnight.

PRELIMINARY POINT TEMPS/POPS
PDT 68 42 65 45 / 0 0 20 80 ALW 70 47 67 49 / 0 0 30 80 PSC 76 49 68 51 / 0 0 20 50 YKM 75 42 66 42 / 0 0 30 20 HRI 75 46 67 48 / 0 0 20 50 ELN 68 45 62 42 / 0 0 30 20 RDM 64 34 63 42 / 0 0 20 40 LGD 62 37 65 44 / 10 0 20 90 GCD 63 35 64 44 / 10 0 20 90 DLS 71 47 64 49 / 0 0 40 40

PDT WATCHES/WARNINGS/ADVISORIES
OR...None.
WA...None.

Vancouver
Click for Map
Mon -- 01:05 AM PDT     0.35 feet Low Tide
Mon -- 04:02 AM PDT     Moonset
Mon -- 05:31 AM PDT     1.66 feet High Tide
Mon -- 05:33 AM PDT     Sunrise
Mon -- 01:45 PM PDT     -0.04 feet Low Tide
Mon -- 06:04 PM PDT     Moonrise
Mon -- 06:13 PM PDT     1.23 feet High Tide
Mon -- 08:41 PM PDT     Sunset
Mon -- 09:14 PM PDT     0.98 feet Low Tide
Mon -- 10:08 PM PDT     0.99 feet High Tide
Tide / Current data from XTide NOT FOR NAVIGATION

Vancouver, Columbia River, Washington (dubious accuracy), Tide feet

Full Color Weather Map

Link to Loop


Other links: GEOS-West     Contential US     Full GOES-East

Pendleton, OR,