022
FXUS66 KPDT 070424
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
924 PM PDT MON JUL 6 2026
KEY MESSAGES
- WIDESPREAD MODERATE (LEVEL 2 OF 4) HEATRISK TUESDAY
- SLIGHT CHANCE TO CHANCE (15-35%) OF THUNDERSTORMS TODAY FOR
CENTRAL OREGON, THEN SLIGHT CHANCE (10-20%) OF THUNDERSTORMS
FOR CENTRAL OREGON AND THE BLUE MOUNTAINS TUESDAY AFTERNOON
AND EVENING
- BREEZY TO LOCALLY WINDY CONDITIONS COUPLED WITH LOW RELATIVE
HUMIDITY FOR THE COLUMBIA BASIN AND KITTITAS VALLEY TUESDAY.
RED FLAG WARNINGS IN EFFECT 1 PM TO 10 PM.
DISCUSSION
SATELLITE IMAGERY SHOWS A COMPACT MID-LEVEL LOW CHURNING OVER
THE BLUE MOUNTAINS, TRACKING SLOWLY NORTHEAST. WIDESPREAD PARTLY
CLOUDY TO OVERCAST CONDITIONS ASSOCIATED WITH THE LOW ARE
PRESENT FROM CENTRAL OREGON THROUGH THE BLUE MOUNTAINS, THOUGH
PARTIAL CLEARING HAS BEEN NOTED IN CENTRAL OREGON AS THE LOW
DEPARTS TO THE NORTHEAST. OVER THE OREGON CASCADE CREST, A CU
FIELD HAS DEVELOPED, AND ISOLATED THUNDERSTORMS HAVE FORMED,
MAINLY SOUTH OF DESCHUTES COUNTY. AMPLE SURFACE-BASED MOISTURE
(DEW POINTS IN THE UPPER 40S TO MID-50S) COUPLED WITH
SUFFICIENT INSTABILITY (SURFACE-BASED CAPE OF 500-1000 J/KG PER
12Z HREF GUIDANCE) WILL FACILITATE ADDITIONAL SHOWER AND
THUNDERSTORM DEVELOP WITH WIDESPREAD 25-35% CHANCES OF
THUNDERSTORMS FOR THE CENTRAL OREGON CASCADES AND CENTRAL
OREGON. HIGHEST CHANCES ARE FOR FIRE WEATHER ZONES OR705 AND THE
SOUTHERN HALF OF OR700. STORMS ARE EXPECTED TO BE PREDOMINANTLY
WET DUE TO THEIR SLOW-MOVING NATURE, SO NO RED FLAG WARNINGS
HAVE BEEN ISSUED. STORMS WILL BE CAPABLE OF PRODUCING FREQUENT
CLOUD-TO-GROUND LIGHTNING, SMALL HAIL, AND GUSTY OUTFLOW WINDS
UP TO 55 MPH. FARTHER EAST, PARTLY TO MOSTLY CLOUDY SKIES HAVE
INHIBITED SURFACE HEATING AND INSTABILITY, BUT FORCING FROM THE
AFOREMENTIONED CLOSED LOW COULD STILL PROVIDE ENOUGH LIFT TO
GENERATE AN ISOLATED THUNDERSTORM OR TWO ACROSS THE BLUE
MOUNTAINS (10-20% CHANCE).
CLEARING SKIES ARE FORECAST TUESDAY, SO AMPLE DAYTIME HEATING IS
EXPECTED (90% CONFIDENCE) ACROSS THE MAJORITY OF THE REGION.
WIDESPREAD MODERATE (LEVEL 2 OF 4) HEATRISK IS FORECAST FOR THE
LOWER ELEVATIONS. THERE IS A LOW (10-35%) CHANCE OF AFTERNOON
HIGH TEMPERATURES REACHING OR EXCEEDING 100 DEGREES FOR THE
LOWER COLUMBIA BASIN AND ADJOINING LOWER ELEVATIONS.
TUESDAY AFTERNOON AND EVENING, ANOTHER SLIGHT CHANCE (10-20%)
OF THUNDERSTORMS IS FORECAST FOR THE REGION STRETCHING FROM
CENTRAL OREGON THROUGH THE BLUE MOUNTAINS. THERE ARE LOW (5-10%)
CHANCES FOR THE BLUE MOUNTAIN FOOTHILLS AND LOWER COLUMBIA
BASIN. CONFIDENCE IN EXACT LOCATION OF THUNDERSTORMS REMAINS
LOW, PARTLY DUE TO THE LATE AFTERNOON AND EVENING ARRIVAL OF
UPPER-LEVEL FORCING FROM AN INCOMING SHORTWAVE TROUGH THAT IS
EXPECTED TO PASS OVER SOUTHERN CANADA.
BREEZY TO LOCALLY WINDY WESTERLY TO NORTHWESTERLY WINDS COUPLED
WITH LOW RELATIVE HUMIDITY WILL LIKELY (70-90% CONFIDENCE)
RESULT IN AREAS OF RED FLAG CONDITIONS ACROSS THE LOWER COLUMBIA
BASIN OF OREGON AND WASHINGTON AS WELL AS THROUGH THE KITTITAS
VALLEY TUESDAY AFTERNOON AND EVENING. RED FLAG WARNINGS ARE IN
EFFECT FROM 1 PM TO 10 PM TUESDAY FOR OR691, WA691, AND WA690.
CONFIDENCE IN REACHING RED FLAG CRITERIA ELSEWHERE IS LOW (30%
OR LESS).
A QUASI-ZONAL MID-LEVEL PATTERN IS ADVERTISED BY ENSEMBLE
GUIDANCE THROUGH LATE WEEK. THIS SHOULD KEEP PERIODS OF BREEZY
TO LOCALLY WINDY CONDITIONS AND LOW RELATIVE HUMIDITY PRESENT,
BUT CONFIDENCE IN OVERLAP OF WIND AND RELATIVE HUMIDITY IS
CURRENTLY TOO LOW (50% OR LESS) TO HAVE ANY ADDITIONAL WATCHES
OR WARNINGS IN EFFECT.
ENSEMBLE CLUSTERS SUGGEST A HIGH PROBABILITY (70-90%) OF AN
AMPLIFYING MID-LEVEL PATTERN BY THE WEEKEND, WITH TROUGHING
OFFSHORE AND A BUILDING HIGH OVER THE FOUR CORNERS AND/OR
WESTERN CONUS.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
THERE WILL BE MORE GUSTY WINDS ON TUESDAY AS A STRONGER WESTELRY
COMPONENT DEVELOPS WITH GUSTS COMMONLY BETWEEN 20 AND 30 KNOTS
AT TERMINALS DLS/YKM/PDT. LIKEWISE RDM/BDN WILL ALSO SEE GUSTS
DEVELOPING BY HAVE MORE OF A NORTHWEST WIND THAN A WEST OR SW
LIKE THE OTHERS. VISIBILITY SHOULD BE GOOD EVERYWHERE 10SM OF
BETTER, WITH NO CEILINGS.
PRELIMINARY POINT TEMPS/POPS
PDT 89 57 96 59 / 0 0 0 0
ALW 91 62 98 65 / 0 0 0 0
PSC 93 58 100 63 / 0 0 0 0
YKM 95 61 99 60 / 0 0 0 0
HRI 92 59 98 63 / 0 0 0 10
ELN 92 59 93 58 / 0 0 0 0
RDM 85 53 92 51 / 10 20 0 10
LGD 87 56 95 59 / 10 0 20 10
GCD 82 53 95 55 / 60 10 10 10
DLS 96 64 94 62 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...RED FLAG WARNING FROM 1 PM TO 10 PM PDT TUESDAY FOR WAZ690-691.
OR...RED FLAG WARNING FROM 1 PM TO 10 PM PDT TUESDAY FOR ORZ691.
DISCUSSION...86
AVIATION...71
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