590
FXUS66 KPDT 020504
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1004 PM PDT WED JUL 1 2026
KEY MESSAGES
- BREEZY WINDS TODAY, SUBSIDING SLIGHTLY THROUGH WEEK.
- WARMING AND DRYING TREND INTENSIFIES FRIDAY THROUGH MONDAY.
- FIRE WEATHER CONCERNS OVER HOLIDAY WEEKEND.
DISCUSSION
CURRENT RADAR AND VISIBLE SATELLITE IMAGERY SHOWS ISOLATED
THUNDERSTORMS ACROSS SOUTHERN WALLOWA COUNTY UNDER MOSTLY SUNNY
TO SUNNY SKIES. THIS IS IN RESPONSE TO A SLOWLY DEPARTING
SHORTWAVE THAT WILL KEEP THESE CELLS DEVELOPING THROUGH THE
AFTERNOON AND EARLY EVENING. SEVERAL CLOUD PULSES HAVE BEEN
OBSERVED VIA NLDN AND GLD DATA RELATED TO A CELL SOUTHEAST OF
JOSEPH, HOWEVER THE ECWMF AI ENSEMBLE INDICATES PRECIPITATION
WATER AMOUNTS OF 0.5-0.6" WHICH IS AROUND 100% OF NORMAL - SO
DEVELOPING STORM CELLS SHOULD BE ACCOMPANIED BY A WETTING RAIN
(>0.10"). THIS SHORTWAVE, COUPLED WITH SURFACE HIGH PRESSURE
OFFSHORE, HAS ALLOWED FOR A PRESSURE GRADIENT TO DEVELOP ALONG
THE CASCADES. THIS HAS PROVIDED ANOTHER DAY OF BREEZY
CONDITIONS THROUGH THE EASTERN GORGE, SIMCOE HIGHLANDS, AND
KITTITAS VALLEYS AS SUSTAINED WEST-NORTHWEST WINDS OF 15-25 MPH
WITH GUSTS OF 35-45 MPH ARE EXPECTED. CONFIDENCE IS HIGH IN
WINDS STAYING BELOW ADVISORY CRITERIA (<45 MPH) AS THE NBM
ADVERTISES A 15-25% CHANCE OF 45 MPH WIND GUSTS OR GREATER OVER
THE AFOREMENTIONED AREAS, AND A 35-55% CHANCE OF 40 MPH WIND
GUSTS OR GREATER. ANOTHER SHORTWAVE MOVES INTO THE AREA ON
THURSDAY, BRINGING SLIGHTLY LESS BREEZY WINDS TO THESE AREAS AS
A WEAKER GRADIENT DEVELOPS ALONG THE CASCADES. THE WEAKER
GRADIENT IS A RESULT OF OVERALL BROADENING OF THE TROUGH THESE
SHORTWAVES ARE PASSING THROUGH, WHICH ALSO LEADS TO A SHIFT IN
FLOW ALOFT FROM THE NORTHWEST TO MORE FROM THE WEST.
THE SHIFT IN FLOW ALOFT INTO FRIDAY WILL INTENSIFY THE GRADUAL
WARMING TREND THAT HAS BEEN EXPERIENCED EARLIER IN THE WEEK.
HIGH TEMPERATURES WILL TRANSITION FROM ABOUT 5 DEGREES BELOW
NORMAL TO 5 DEGREES ABOVE NORMAL THURSDAY THROUGH SATURDAY DUE
TO A SHIFT TO SOUTHWEST FLOW ALOFT. AFTERNOON HUMIDITIES WILL
ALSO TRANSITION INTO THE TEENS ACROSS MUCH OF THE AREA ON
SATURDAY, WITH PORTIONS OF CENTRAL OREGON DIPPING INTO THE
SINGLE DIGITS. OVERNIGHT HUMIDITY RECOVERIES WILL ALSO DEGRADE
FROM GOOD (60-80%) VALUES SATURDAY MORNING TO POOR/MODERATE
(30-50%) MONDAY MORNING. THESE HUMIDITY VALUES CONTINUE THROUGH
TUESDAY AS HIGH TEMPERATURES PEAK IN THE LOW TO MID-90S ACROSS
THE COLUMBIA BASIN, YAKIMA VALLEY, BLUE MOUNTAIN FOOTHILLS,
GRANDE RONDE VALLEY, JOHN DAY BASIN, AND CENTRAL OREGON. THERE
IS A LIKELIHOOD THAT THESE TEMPERATURES MAY TREND EVEN HIGHER AS
57% OF ENSEMBLE MEMBERS SUGGEST HIGHER AFTERNOON TEMPERATURES
THAN THE CURRENT FORECAST ON MONDAY WITH 46% OF MEMBERS
SUGGESTING WARMER TEMPERATURES THAN THE CURRENT FORECAST ON
TUESDAY. EVEN THOUGH THERE IS LESS CONSENSUS ON TUESDAY, THESE
MEMBERS ARE 3-5 DEGREES WARMER AS 20% HINT AT TRIPLE DIGITS
OVER THE TRI-CITIES AREA. DUE TO THESE HIGH TEMPERATURES, AND
LACK OF RELIEF WITH OVERNIGHT TEMPERATURES OF AROUND 60 DEGREES,
MODERATE HEATRISK IS EXPECTED ACROSS MUCH OF THE COLUMBIA
BASIN, YAKIMA VALLEY, AND NORTHERN BLUE MOUNTAIN FOOTHILLS BOTH
MONDAY AND TUESDAY.
THE TRANSITION FROM A BREEZY WEATHER PATTERN THROUGH FRIDAY TO A
HOTTER AND DRIER REGIME THROUGH THE WEEKEND, ELEVATED FIRE
WEATHER CONCERNS ACROSS THE COLUMBIA BASIN ON SATURDAY
AFTERNOON. CRITICALLY LOW MINIMUM HUMIDITY VALUES IN THE LOW TO
MID-TEENS COUPLED WITH SUSTAINED WEST WINDS OF 22-27 MPH WITH
GUSTS UP TO 35 MPH MAY PROVIDE ENOUGH CONCERN FOR FIRE WEATHER
PRODUCTS TO BE ISSUED OVER THE NEXT 36 HOURS FOR THE LOWER
COLUMBIA BASIN OF OREGON, FIRE WEATHER ZONE OR691. THESE
PARAMETERS MATERIALIZED IN THE LAST 24 HOURS, SO FURTHER
ANALYSIS OF THIS TREND WILL NEED TO BE CONDUCTED WITH UPDATED
GUIDANCE. STAY TUNED. 75
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
VFR CONDITIONS TO
PREVAIL THROUGH THE PERIOD. LIGHT WINDS WILL PREVAIL THROUGH THE
PERIOD, EXCEPT AT SITE DLS WHERE WINDS OF 12-20KTS AND GUSTS UP
TO 28KTS WILL IMPACT THE SITE AFTER 17Z TOMORROW. LAWHORN/82
PRELIMINARY POINT TEMPS/POPS
PDT 46 80 52 84 / 0 0 0 0
ALW 52 81 57 85 / 0 0 0 0
PSC 50 83 54 88 / 0 0 0 0
YKM 50 82 54 87 / 0 0 0 0
HRI 49 82 54 87 / 0 0 0 0
ELN 47 77 50 82 / 0 0 0 0
RDM 37 79 43 85 / 0 0 0 0
LGD 44 80 50 83 / 0 0 0 0
GCD 42 82 48 86 / 0 0 0 0
DLS 52 79 56 85 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...75
AVIATION...82
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