870
FXUS66 KPDT 141800
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1100 AM PDT TUE JUL 14 2026
KEY MESSAGES
- ISOLATED TO WIDELY SCATTERED THUNDERSTORM CHANCES THIS
AFTERNOON ACROSS CENTRAL OR AND THE EASTERN MOUNTAINS, WITH
CHANCES SPREADING TO NORTH CENTRAL OR AND SOUTH CENTRAL WA
WEDNESDAY AND THURSDAY
- ABOVE NORMAL TEMPERATURES WITH DRY CONDITIONS WILL PERSIST
INTO EARLY NEXT WEEK
- UNCERTAINTY REMAINS AROUND SYNOPTIC PATTERN THURSDAY INTO
EARLY NEXT WEEK
DISCUSSION
TODAY THROUGH WEDNESDAY: SATELLITE IMAGERY TONIGHT SHOWS
INCREASING MID TO UPPER LEVEL CLOUD COVER EAST OF THE CASCADE
CREST, WITH RADAR IMAGERY SHOWING LIGHT TO MODERATE RETURNS
PUSHING ACROSS EAST CENTRAL OR. THIS ACTIVITY IS ASSOCIATED WITH
A SHORTWAVE IMPULSE CURRENTLY OVER SOUTHEAST OR, AND IS
ANTICIPATED TO PUSH NORTH ALONG THE OR/ID BORDER THEN ROTATE
NORTHWEST INTO ID/MT EARLY IN THE AFTERNOON. SHOWERS ASSOCIATED
WITH THIS IMPULSE WILL BE FOCUSED ALONG THE SOUTHERN BLUES INTO
WALLOWA COUNTY THROUGHOUT THIS MORNING, WITH SHOWER ACTIVITY
WANING MID TO LATE AFTERNOON. A SECONDARY IMPULSE RIDING UP THE
SOUTH-SOUTHWEST FLOW ALOFT WILL PRODUCE ANOTHER ROUND OF SHOWER
ACTIVITY ACROSS CENTRAL OR MID AFTERNOON INTO THE OVERNIGHT
HOURS. IN ADDITION TO OROGRAPHIC LIFT AIDING SHOWER DEVELOPMENT,
INCREASING MUCAPE BETWEEN 250-750 J/KG WILL ALLOW FOR ISOLATED
TO WIDELY SCATTERED THUNDERSTORMS TO DEVELOP.
WEDNESDAY, ANOTHER SHORTWAVE IMPULSE IS ANTICIPATED TO PUSH
NORTH ALONG THE CASCADE EAST SLOPES, PRODUCING SHOWERS FROM
CENTRAL OR TO THE CENTRAL WA CASCADES THROUGH WEDNESDAY NIGHT,
WITH ISOLATED SHOWER CHANCES (20-35%) ACROSS WESTERN PORTIONS
OF THE COLUMBIA BASIN. MUCH LIKE THIS AFTERNOON, MARGINAL
INSTABILITY COMBINING WITH OROGRAPHIC ASCENT WILL RESULT IN
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ACROSS THE CASCADE
EAST SLOPES FROM CENTRAL OR TO CENTRAL WA.
INCREASING NEAR-SURFACE MONSOONAL MOISTURE WILL ALLOW FOR
PRECIPITABLE WATER VALUES TO INCREASE TO BETWEEN 0.75 TO ABOUT
1.2 INCHES BOTH TUESDAY AND WEDNESDAY. THIS WILL ALLOW FOR
MODERATE TO LOCALLY HEAVY RAIN CORES TO DEVELOP WITHIN
SHOWERS/THUNDERSTORMS. THAT SAID, ELEVATED FIRE WEATHER
CONDITIONS WILL REMAIN PRESENT FOR THE THREAT OF LIGHTNING
OUTSIDE OF THE RAIN CORES AS WELL AS FOR THE POTENTIAL OF
OUTFLOW BOUNDARIES.
THURSDAY THROUGH MONDAY: THURSDAY INTO EARLY NEXT WEEK,
UNCERTAINTY REMAINS IN THE EVOLUTION OF THE SYNOPTIC PATTERN,
ESPECIALLY IN REGARDS TO AN UPPER LEVEL LOW OFFSHORE THE PACNW.
THURSDAY INTO FRIDAY, AN ENSEMBLE CLUSTER SOLUTION (~30-40% OF
MEMBERS) DRIVEN MAINLY BY MEMBERS OF THE ECMWF ENSEMBLE FAVOR AN
UPPER LOW LIFTING ACROSS THE PACNW WITH COOLER AND WETTER
CONDITIONS AS WELL AS BREEZY TO LOCALLY GUSTY CASCADE GAP AND
LOWER ELEVATION WINDS. THE REMAINING CLUSTER SOLUTIONS FAVOR THE
LOW WEAKENING AND OPENING INTO A WEAK UPPER TROUGHING OFFSHORE
DURING THIS TIME, RESULTING IN CONTINUED ABOVE NORMAL
TEMPERATURES WITH DRY CONDITIONS AND LIMITED MOUNTAIN SHOWER
ACTIVITY.
SATURDAY INTO EARLY NEXT WEEK, UNCERTAINTY REMAINS WITH THE
OVERALL PATTERN. THE MAIN CLUSTERING SOLUTIONS ARE SPLIT BETWEEN
EITHER A WEAKENING UPPER TROUGH EXTENDING FROM BC TO OFFSHORE
THE PACNW (50-55% OF MEMBERS), OR UPPER LEVEL RIDGING BUILDING
INTO THE REGION FROM THE EAST(45-50% OF MEMBERS). THE LATTER
SOLUTION WOULD RESULT IN A MARKED WARMING TREND AND INCREASING
POTENTIAL OF HEAT IMPACTS ACROSS FORECAST AREA WHILE THE WARMING
OF THE FORMER SOLUTION WOULD BRING A MODEST WARMING TREND ACROSS
THE REGION. OTHER THAN WARMING TEMPERATURES, BOTH SOLUTIONS
WOULD RESULT IN A RETURN TO DRY CONDITIONS WITH LIGHT WINDS INTO
EARLY NEXT WEEK (CONFIDENCE 35-50%). LAWHORN/82
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
VFR CONDITIONS ARE FORECAST THROUGH THE PERIOD. WIDESPREAD
MID/HIGH CLOUD THIS MORNING IS ANTICIPATED TO THIN OR CLEAR
THROUGH AFTERNOON, ESPECIALLY FOR WESTERN SITES. THERE IS A LOW
CHANCE (10-20%) OF ISOLATED THUNDERSTORMS FOR BDN/RDM THIS
AFTERNOON AND EARLY EVENING, BUT CONFIDENCE WAS TOO LOW TO
INCLUDE MENTION IN THE 18Z TAFS. 12Z HREF AND REFS GUIDANCE BOTH
ADVERTISE ANOTHER ROUND OF HIGH-BASED SHOWERS OVERNIGHT INTO
WEDNESDAY MORNING, BUT CONFIDENCE IN MEASURABLE PRECIPITATION AT
ANY TAF SITE WAS TOO LOW (<30%) TO MENTION.
WINDS WILL BE DIURNALLY AND TERRAIN-DRIVEN, MOSTLY LIGHT WITH
A COUPLE EXCEPTIONS. PERIODS OF BREEZY WINDS ARE ANTICIPATED
DURING THE AFTERNOON/EVENING HOURS FOR DLS/BDN/RDM, AND ANY
CONVECTION THAT DEVELOPS WILL BE CAPABLE OF PRODUCING ERRATIC,
GUSTY OUTFLOW WINDS.
PRELIMINARY POINT TEMPS/POPS
PDT 93 62 96 61 / 10 0 0 30
ALW 95 65 99 66 / 10 0 0 20
PSC 96 63 100 64 / 0 0 0 30
YKM 98 65 98 66 / 0 0 0 50
HRI 96 65 99 65 / 0 0 0 30
ELN 94 62 96 63 / 0 0 10 50
RDM 93 56 91 54 / 0 10 40 30
LGD 90 59 95 60 / 60 0 0 20
GCD 91 58 93 58 / 40 20 20 30
DLS 97 66 98 65 / 0 0 10 60
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...82
AVIATION...86
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