831
FXUS66 KPDT 022139
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
239 PM PDT THU JUL 2 2026
KEY MESSAGES
- BREEZY AFTERNOON WINDS CONTINUE THROUGH SATURDAY.
- FIRE WEATHER CONCERNS SATURDAY.
*FIRE WEATHER WATCH ISSUED*
- WARMING AND DRYING TREND PEAKS MONDAY-TUESDAY.
DISCUSSION
CURRENT RADAR AND VISIBLE SATELLITE IMAGERY SHOWS DRY CONDITIONS
UNDER CLEAR TO MOSTLY CLEAR SKIES. THIS IS IN RESPONSE TO THE
PRESENCE OF A TRANSIENT UPPER LEVEL RIDGE THAT IS BETWEEN TWO
SHORTWAVES, WITH ONE DEPARTING TO OUR EAST AND THE SECOND
APPROACHING THE COAST. THE PATTERN HAS ALLOWED FOR THE NORTHWEST
FLOW ALOFT, THAT BROUGHT BELOW NORMAL TEMPERATURES TO THE AREA,
TO BECOME MORE FROM THE WEST. WINDS WILL INCREASE THIS AFTERNOON
AND EVENING AS THE SHORTWAVE APPROACHES AND A PRESSURE GRADIENT
DEVELOPS ALONG THE CASCADES, ALLOWING WEST-NORTHWEST WINDS OF
17-22 MPH WITH GUSTS UP TO 37 MPH THROUGH THE COLUMBIA GORGE,
SIMCOE HIGHLANDS, AND KITTITAS VALLEY. THE SHORTWAVE STALLS AND
DISSIPATES ON FRIDAY, WHICH AGAIN LEADS TO A PRESSURE GRADIENT
DEVELOPING ALONG THE CASCADES, ALBEIT MUCH WEAKER. WEST WINDS
OF 15-20 MPH WITH GUSTS UP TO 32 MPH WILL BE POSSIBLE ACROSS THE
COLUMBIA GORGE, SIMCOE HIGHLANDS, AND KITTITAS VALLEY ON
FRIDAY.
A STRONGER UPPER LEVEL SHORTWAVE APPROACHES THE COAST ON
SATURDAY AS AN UPPER LEVEL RIDGE BUILDS INLAND. THESE FEATURES
WILL ENHANCE THE WARMING AND DRYING TREND, DROPPING AFTERNOON
HUMIDITIES INTO THE MID-TEENS AS SUSTAINED WEST WINDS OF 15 TO
25 MPH AND GUSTS UP TO 35 MPH ARE POSSIBLE. THESE VALUES, AND
THE ADDED CONFIDENCE OF GUIDANCE AGREEMENT, HAS WARRANTED THE
ISSUANCE OF A FIRE WEATHER WATCH OVER THE LOWER COLUMBIA BASIN
OF OREGON (OR691) ON SATURDAY BETWEEN NOON AND 10 PM. LOW
HUMIDITIES WILL BE WIDESPREAD ON SATURDAY, INCLUDING NEAR SINGLE
DIGIT VALUES ACROSS CENTRAL OREGON AND LOW 20S THROUGH THE
KITTITAS VALLEY, BUT WINDS LOOK TO SUBSIDE IN THESE AREAS -
UNLIKE ACROSS THE LOWER COLUMBIA BASIN OF OREGON. THESE AREAS
WILL CONTINUE TO BE ANALYZED AS THE EVENT NEARS, BUT ONLY A
10-25% CHANCE OF RED FLAG WIND AND HUMIDITY CONDITIONS ARE
CURRENTLY FORECAST. FIRE WEATHER CONCERNS MATERIALIZE MONDAY
AND TUESDAY ACROSS CENTRAL AND EASTERN OREGON DUE TO ABUNDANT
DRY LIGHTNING, BUT CURRENT CONFIDENCE IS LOW DUE TO THE
INCONSISTENCY IN GUIDANCE.
THE UPPER LEVEL RIDGE CONTINUES TO BUILD THROUGH THE WEEKEND
INTO THE EARLY PART OF THE WEEK. WEEKEND HIGH TEMPERATURES IN
THE LOW TO MID-90S ACROSS THE LOWER COLUMBIA BASIN AND CENTRAL
OREGON WILL INCREASE INTO THE MID-TO UPPER 90S MONDAY AND
TUESDAY. THE NBM SUGGESTS A 50-60% CHANCE OF HIGH TEMPERATURES
BOTH DAYS REACHING 95 DEGREES OR ABOVE FOR THE TRI-CITIES AND
YAKIMA AREAS, AND A 35-45% CHANCE FOR HERMISTON. THE UPPER LEVEL
RIDGE SUPPRESSES AND SOUTHWEST FLOW ALOFT BECOMES MORE FROM THE
WEST WEDNESDAY AND THURSDAY, ALLOWING HIGH TEMPERATURES TO
SLOWLY COOL INTO THE LOW 90S. 75
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
VFR CONDITIONS ARE
EXPECTED (99 PERCENT CONFIDENCE) FOR THE NEXT 24 HOURS AT ALL
TAF SITES. WINDS WILL BE DIURNALLY BREEZY AT DLS WITH WINDS OF
MOSTLY 10 KTS OR LESS, ASIDE FROM PM GUSTS, ELSEWHERE.
FIRE WEATHER
DIURNALLY BREEZY CONDITIONS CONTINUE TODAY THROUGH SATURDAY AS
THE DRYING AND WARMING TREND PERSISTS. CRITICAL VALUES LOOK TO
BE REACHED ON SATURDAY ASSOCIATED WITH A BUILDING UPPER LEVEL
RIDGE FROM OUR SOUTH, BUT WINDS DO BEGIN TO SLACKEN DUE TO THE
PRESENT HIGH PRESSURE. HOWEVER, THE LOWER COLUMBIA BASIN DOES
HOLD ONTO THOSE INCREASED WINDS LONGER AS BOTH CRITICAL WINDS
AND AFTERNOON HUMIDITIES ALIGN, REACHING RED FLAG WARNING
CRITERIA. THUS, A FIRE WEATHER WATCH HAS BEEN ISSUED FOR OR691
ON SATURDAY BETWEEN 12 PM AND 10 PM. THERE ARE SOME PORTIONS OF
ISOLATED CONCERN OVER OR690 (KITTITAS VALLEY), BUT IS CONFINED
TO THE EAST SECTION OF THE ZONE BETWEEN 1700-1900.
THE PRESENCE OF THE UPPER LEVEL RIDGE WILL EFFECTIVELY DRY
CONDITIONS THROUGH THE WEEKEND AND INTO THE EARLY PART OF THE
WEEK. GUIDANCE SUGGESTS A COUPLE SYSTEMS APPROACHING FROM THE
SOUTHWEST AND PASSING THROUGH CENTRAL OREGON, WHICH MAY RESULT
IN ABUNDANT DRY THUNDERSTORMS ACROSS OR693, OR694, OR695,
OR697, PR698, OR699, OR700, AND OR705 BOTH MONDAY AND TUESDAY.
AT THIS TIME, MONDAY LOOKS TO HAVE BETTER DRY THUNDERSTORM
CHANCES (10-20%) THAN TUESDAY (10-15%), BUT THIS WILL HAVE TO BE
FURTHER ANALYZED AS THE EVENT NEARS. 75
PRELIMINARY POINT TEMPS/POPS
PDT 52 85 54 88 / 0 0 0 0
ALW 57 86 60 89 / 0 0 0 0
PSC 54 89 56 92 / 0 0 0 0
YKM 54 88 55 91 / 0 0 0 0
HRI 54 88 57 91 / 0 0 0 0
ELN 51 82 52 83 / 0 0 0 0
RDM 43 86 48 88 / 0 0 0 0
LGD 49 85 52 88 / 0 0 0 0
GCD 47 87 51 92 / 0 0 0 0
DLS 56 86 57 88 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR ORZ691.
DISCUSSION...75
AVIATION...77
FIRE WEATHER...75
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page