259
FXUS66 KPDT 200510
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1010 PM PDT TUE MAY 19 2026
KEY MESSAGES
- ISOLATED SHOWERS TODAY AND WEDNESDAY, MAINLY OVER THE
MOUNTAINS
- BREEZY TO LOCALLY WINDY WESTERLY WINDS THROUGH THE CASCADE
GAPS TODAY
- WARMING THROUGH THE WEEK
DISCUSSION
THROUGH SATURDAY, WARMING TEMPERATURES AND MOSTLY DRY CONDITIONS
ARE FORECAST REGION-WIDE AS AN UPPER-LEVEL RIDGE OF HIGH
PRESSURE WILL LIKELY (95 PERCENT CONFIDENCE) BUILD INTO THE
REGION FROM THE PACIFIC AND DOMINATE THE WEATHER. A COUPLE WEAK
SHORTWAVES COUPLED WITH MODEST DIURNALLY INDUCED INSTABILITY
(SURFACE-BASED CAPE OF A UP TO A COUPLE HUNDRED J/KG FROM
FORECAST SOUNDINGS) MAY FACILITATE SOME ISOLATED SHOWERS, MAINLY
OVER THE MOUNTAINS THROUGH THURSDAY, BUT POPS ARE LOW (15
PERCENT OR LESS).
BREEZY TO LOCALLY WINDY WESTERLY WINDS ARE FORECAST THROUGH THE
CASCADE GAPS TODAY, BUT NOT ANTICIPATING A NEED FOR ANY WIND
HEADLINES. LATE WEDNESDAY THROUGH THURSDAY, A REVERSAL TO MOSTLY
LIGHT EASTERLY TO NORTHEASTERLY (OFFSHORE) WINDS IS FORECAST AS
A SHORTWAVE TROUGH DIGS SOUTH ACROSS THE NORTHERN PLAINS AND
ROCKIES, JUST CLIPPING THE EDGE OF OUR FORECAST AREA.
CONSIDERABLE UNCERTAINTY IN THE 500-HPA PATTERN IS PRESENT IN
ENSEMBLE SOLUTIONS BY THE WEEKEND AND EARLY NEXT WEEK, WITH THE
MAJORITY OF THE VARIANCE IN SOLUTIONS EXPLAINED BY TIMING AND
MAGNITUDE DIFFERENCES REGARDING THE ARRIVAL OF A TROUGH OR
CLOSED LOW FROM THE PACIFIC. ENSEMBLE TRENDS HAVE BEEN TOWARDS A
CLOSED LOW FOR THE PACIFIC NORTHWEST SOMETIME BETWEEN MONDAY
AND TUESDAY, BUT RUN-TO-RUN AND ENSEMBLE-TO-ENSEMBLE
DIFFERENCES ARE STILL QUITE SIGNIFICANT AND FORECAST CONFIDENCE
IS LOWER THAN AVERAGE. ENSEMBLE CLUSTERING TOOLS DID NOT RUN
TODAY, SO CAN'T PROVIDE ANY MORE DETAILS ABOUT SCENARIOS AT
THIS TIME.
THE NBM HAS WESTERLY WINDS RETURNING TO THE REGION BY LATE
FRIDAY, PERSISTING THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.
THERE ARE LOW CHANCES (10-40 PERCENT) OF REACHING ADVISORY-
LEVEL WINDS SATURDAY AND SUNDAY THROUGH WIND-PRONE AREAS OF THE
LOWER ELEVATIONS, PRIMARILY THE EASTERN COLUMBIA RIVER GORGE,
NORTH-CENTRAL OREGON, THE FOOTHILLS OF THE BLUE MOUNTAINS, AND
THE KITTITAS VALLEY. BY MONDAY, CHANCES INCREASE TO 20-60
PERCENT ACROSS THE SAME AREAS. OF COURSE, THE MAGNITUDE OF WINDS
WILL BE TIED TO THE SYNOPTIC PATTERN, AND GIVEN THE UNCERTAINTY
(SEE PARAGRAPH ABOVE), CAN'T REALLY TALK ABOUT MUCH CONFIDENCE
IN FORECAST DETAILS YET.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
VFR CONDITIONS TO
PREVAIL THROUGH THE PERIOD. BREEZY WINDS CONTINUE AT SITES
DLS/PDT/PSC FOR THE NEXT COUPLE HOURS TONIGHT, WITH LIGHT AND
DIURNALLY DRIVEN WINDS DEVELOPING AFTER 07-08Z. OTHERWISE, LIGHT
WINDS AT ALL OTHER SITES THROUGH THE PERIOD. LAWHORN/82
PRELIMINARY POINT TEMPS/POPS
PDT 46 73 46 76 / 0 0 0 0
ALW 50 73 49 76 / 0 0 0 0
PSC 49 78 51 81 / 0 0 0 0
YKM 47 79 50 80 / 0 0 0 0
HRI 48 76 49 79 / 0 0 0 0
ELN 43 73 45 75 / 0 0 0 0
RDM 37 73 39 77 / 0 0 0 0
LGD 40 70 41 73 / 0 0 0 0
GCD 39 73 39 75 / 0 0 0 0
DLS 50 77 51 83 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...86
AVIATION...82
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page