270
FXUS66 KPDT 041736
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1036 AM PDT FRI JUL 4 2025
AVIATION...18Z TAFS
VFR CONDITIONS ARE FORECAST THROUGH THE VALID
PERIOD FOR ALL SITES, THOUGH BDN/RDM HAVE A 20-30% CHANCE OF
TEMPORARY SUB-VFR CIGS AND/OR VSBYS IN SHOWERS OR THUNDERSTORMS THIS
AFTERNOON AND EARLY EVENING. CONFIDENCE IN PRECISE TIMING/LOCATION
WAS TOO LOW TO MENTION BEYOND VCSH AT ISSUANCE TIME.
WINDS WILL BE PREDOMINANTLY 5-15 KTS FOR ALL SITES, WITH GUSTS OF 15-
25 KTS IN THE AFTERNOON AND EVENING HOURS, STRONGEST AT
DLS. PLUNKETT/86
MORNING UPDATE
AN UPPER-LEVEL LOW-PRESSURE SYSTEM CENTERED JUST
OFF THE OREGON COAST IS INDUCING WIDESPREAD CLOUDINESS AND
PRECIPITATION OVER CENTRAL AND EASTERN OREGON THIS MORNING AS THE
FIRST OF TWO SHORTWAVES EMBEDDED WITHIN THE BROADER LOW MOVES
INLAND. MEANWHILE, SOME CLEARING IS EVIDENT ON SATELLITE IMAGERY
OVER SOUTH-CENTRAL OREGON EXTENDING NORTH INTO SOUTHERN DESCHUTES
COUNTY.
ADDITIONAL CLEARING ACROSS CENTRAL OREGON AND THE OCHOCO-JOHN DAY
HIGHLANDS THROUGH MORNING AND EARLY AFTERNOON SHOULD FACILITATE
SOME MODEST (250-500 J/KG) SURFACE-BASED CAPE BY THIS AFTERNOON.
THE SECOND SHORTWAVE, CURRENTLY JUST OFFSHORE, IS EXPECTED TO
PROPAGATE ONSHORE AND MOVE INLAND OVER SOUTH-CENTRAL AND EASTERN
OREGON THIS AFTERNOON. COUPLED WITH FALLING HEIGHTS ALOFT AS THE
MAIN UPPER LOW MOVES OVERHEAD, THIS SHOULD AID ADDITIONAL
THUNDERSTORM DEVELOPMENT PRIMARILY FOR DESCHUTES, CROOK, WHEELER,
AND GRANT COUNTIES.
OF NOTE, 12Z HREF NEIGHBORHOOD PROBABILITIES ARE HIGHLIGHTING UP
TO A 70% CHANCE OF 3-HR PRECIPITATION EXCEEDING 1 INCH OVER LAST
YEAR'S BURN SCARS IN THE OCHOCO-JOHN DAY HIGHLANDS. THE MAIN BURN
SCARS OF CONCERN INCLUDE THOSE ASSOCIATED WITH THE WILEY FLAT,
RAIL RIDGE, CRAZY CREEK, AND FALLS FIRES. AFTER COLLABORATION
WITH BOI, HAVE ISSUED A FLASH FLOOD WATCH FOR THE AFOREMENTIONED
BURN SCARS, VALID THROUGH 8PM PDT. PLUNKETT/86
FIRE WEATHER
THROUGH THIS EVENING, A LOW-PRESSURE SYSTEM
MOVING OVER THE PACIFIC NORTHWEST WILL FACILITATE WIDESPREAD
PRECIPITATION CHANCES, HIGHEST FOR OREGON. ADDITIONALLY, A CHANCE
OF THUNDERSTORMS IS FORECAST FOR CENTRAL OREGON AND THE BLUE
MOUNTAINS. CHANCES OF WETTING RAIN THROUGH THE EVENING ARE MEDIUM-
HIGH (50-80 PERCENT FOR THE BLUE MOUNTAINS) WITH LOW-MEDIUM
CHANCES (30-60 PERCENT) FOR THE REST OF CENTRAL AND EASTERN
OREGON. NO RED FLAG WARNINGS HAVE BEEN ISSUED DUE TO THE
ANTICIPATED WETTING RAIN, BUT FREQUENT CLOUD-TO-GROUND LIGHTNING
IS EXPECTED. THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LOCALLY
HEAVY RAINFALL, SMALL HAIL, AND STRONG, GUSTY OUTFLOW WINDS IN
EXCESS OF 60 MPH ACROSS SOUTHEAST DESCHUTES, CROOK, AND GRANT
COUNTIES THIS AFTERNOON AND EVENING. PLUNKETT/86
PREV DISCUSSION
/ISSUED 206 PM PDT THU JUL 3 2025/
SHORT TERM
THIS EVENING THROUGH SATURDAY. TWO DISTINCT
CIRCULATIONS ARE EVIDENT ON SATELLITE IMAGERY THIS AFTERNOON; THE
FIRST IS LOCATED OFF THE SOUTHWEST OREGON AND NORTHWEST CALIFORNIA
COAST, AND THE SECOND IS UPSTREAM IN THE NORTHEAST PACIFIC. THESE
TWO LOWS ARE EXPECTED (>95% CHANCE) TO MOVE ONSHORE TONIGHT
THROUGH FRIDAY NIGHT AND FACILITATE WIDESPREAD CHANCES OF
PRECIPITATION. WHILE THE BEST CHANCES (50-75%) OF SHOWERS WILL
REMAIN OVER CENTRAL OREGON AND THE BLUE MOUNTAINS, LOW (15-40%)
CHANCES WILL ENCOMPASS THE REST OF THE FORECAST AREA. A CHANCE
(25+%) OF THUNDERSTORMS IS FORECAST OVER CENTRAL OREGON AND THE
BLUE MOUNTAINS TONIGHT THROUGH FRIDAY EVENING, WITH THE MOST
ROBUST CONVECTION ANTICIPATED FRIDAY AFTERNOON ALONG THE SOUTHERN
PART OF OUR FORECAST AREA IN DESCHUTES, CROOK, AND GRANT COUNTIES.
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING SMALL HAIL, LOCALLY
HEAVY DOWNPOURS, AND STRONG OUTFLOW WINDS IN EXCESS OF 50 MPH.
DRIER CONDITIONS ARE FORECAST BY SATURDAY AS THE LOW EXITS TO THE
EAST AND A DRIER ZONAL FLOW MOVES OVERHEAD. PLUNKETT/86
LONG TERM...SUNDAY THROUGH WEDNESDAY
CONFIDENCE IS INCREASING
IN WARM TO HOT WEATHER MONDAY THROUGH WEDNESDAY AS AN UPPER-LEVEL
RIDGE OF HIGH PRESSURE BUILDS OVER THE PACIFIC NORTHWEST. WHILE
ENSEMBLE CLUSTERS DEPICT SMALL DIFFERENCES IN THE 500-HPA HEIGHT
FIELD OVER THE REGION, ROUGHLY 80% OF MEMBERS SHOW A ROBUST RIDGE
OVERHEAD. FORECAST HEATRISK PEAKS AT MODERATE (LEVEL 2 OF 4) TO
MAJOR (LEVEL 3 OF 4) FOR THE LOWER ELEVATIONS, AND WOULD SUPPORT
SOME FORM OF HEAT HIGHLIGHTS.
ENSEMBLE NWP IS LESS CONFIDENT IN PATTERN DETAILS TUESDAY THROUGH
THURSDAY. WHILE MOST MEMBERS SHOW A VORTICITY MAXIMUM DIVING
SOUTHEAST FROM THE GULF OF ALASKA AND DEVELOPING INTO A CLOSED
LOW OFF THE NORTHERN CALIFORNIA COAST SUNDAY THROUGH MONDAY, ITS
TRACK AS IT RIDES OVER THE RIDGE AND MOVES ONSHORE SOMETIME
BETWEEN TUESDAY AND WEDNESDAY WILL MODULATE SHOWER AND
THUNDERSTORMS CHANCES. PROBABILITIES OF SHOWERS AND THUNDERSTORMS
ARE CURRENTLY TOO LOW (<10%) TO HAVE IN THE FORECAST. PLUNKETT/86
PRELIMINARY POINT TEMPS/POPS
PDT 78 57 87 56 / 30 20 0 0
ALW 78 61 86 60 / 30 20 0 0
PSC 81 59 90 57 / 20 20 0 0
YKM 83 58 88 57 / 20 0 0 0
HRI 81 60 89 57 / 20 20 0 0
ELN 83 57 86 57 / 10 0 0 0
RDM 76 42 82 45 / 40 20 0 0
LGD 73 52 82 53 / 70 30 0 0
GCD 75 48 82 51 / 70 40 0 0
DLS 79 57 86 57 / 20 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
OR...FLASH FLOOD WATCH UNTIL 8 PM PDT THIS EVENING FOR ORZ506.
WA...NONE.
SHORT TERM...86
LONG TERM....86
AVIATION...86
FIRE WEATHER...86
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page