572
FXUS66 KPDT 190519
AFDPDT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1019 PM PDT SAT APR 18 2026
.UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- WARMING TREND THROUGH MONDAY, FOLLOWED BY COOLER AIR MOVING IN
MIDWEEK VIA A COLD FRONTAL BOUNDARY.
- CHANCES OF SHOWERS AND THUNDERSTORMS INCREASE TUESDAY THROUGH
WEDNESDAY.
- BREEZY CONDITIONS GOING INTO WEDNESDAY AS THE FRONTAL BOUNDARY
PASSES THROUGH.
DISCUSSION
MORE MILD OVERNIGHT TEMPERATURES ARE EXPECTED AS THE AIRMASS
MODIFIES AND THICKER CLOUD COVER OVERSPREADS THE INTERIOR NW
TONIGHT. LOWS IN THE UPPER 30S AND LOW 40S WILL WARM
EFFICIENTLY SUNDAY MORNING, REACHING HIGHS IN THE UPPER 60S TO
70S ACROSS ALL NON MOUNTAIN ZONES. AN AMPLIFYING UPPER LEVEL
RIDGE AND SW BOUNDARY LAYER FLOW WILL CONTINUE TO MODIFY THE
AIRMASS BY MONDAY WITH EVEN WARMER LOWS IN THE 40S AND LOW 50S,
REACHING HIGHS APPROACHING 80 DEGREES IN THE EASTERN COLUMBIA
RIVER GORGE, CENTRAL OREGON, LOWER COLUMBIA BASIN AND JOHN DAY
BASIN. THE DAYS 4 AND 5 LREF, CENTERED ON TUESDAY SEEM TO
INDICATE SLIGHTLY SLOWER AND SOUTHWARD (OFFSHORE) SOLUTIONS
SHARED BY THE CLUSTERS 1 THROUGH 4. BY WEDNESDAY GENERAL
AGREEMENT IN THE CLUSTERS SHOW THE LOW MOVING INLAND AS AN OPEN
500 MB TROUGH. ESAT SUGGESTS ABOUT A +2 TO 3 STANDARD DEVIATION
OF SPECIFIC HUMIDITY AS COMPARED TO MODEL CLIMATOLOGY AT 500 MB
BUT ONLY NORMAL TO ABOUT 1 SD AT 700 MB. A MARGINAL INCREASE IN
CONFIDENCE IN THUNDERSTORM CHANCES IS WITH RESPECT TO TIMING AS
THE NBM ENSEMBLE CONTINUES TO FOCUS AND INITIAL 10% CHANCE OF
THUNDERSTORMS ACROSS THE OREGON CASCADES LATE AFTERNOON AND
EARLY EVENING MONDAY FOLLOWED BY MORE BROAD CHANCES TUESDAY
AFTERNOON, WITH LESS THAN 10% CHANCES ACROSS THE LOWLANDS, ABOUT
10-15% CHANCES ACROSS THE CASCADES AND NORTHERN BLUES, AND A
MAXIMUM OF 25% CHANCES ACROSS THE REST OF THE EASTERN MOUNTAINS,
WITH SBCAPE VALUES BETWEEN 150-400 J/KG. INCREASING
EXPECTATIONS OF WETTING RAINS WITH THE CURRENT ENSEMBLES, AS
CHANCES FOR 0.10 OR HIGHER RAINFALL BY TUESDAY EVENING RANGE
FROM 60 TO 80% FOR THE OREGON CASCADES AND CENTRAL OREGON
(BEND/REDMOND) AND ACROSS THE JOHN DAY BASIN AND SOUTHERN BLUES.
THE WETTING RAIN CHANCES BECOME WIDESPREAD AT 60 TO 80% CHANCES
BY WEDNESDAY MORNING WITH THE EXPECTATION OF THE COLUMBIA RIVER
GORGE AND LOWER COLUMBIA BASIN AND YAKIMA KITTITAS VALLEYS
WHERE PROBABILITY IS AROUND 50-60% FOR WETTING RAINS.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
VFR CONDITIONS CURRENTLY AT ALL SITES, WHICH WILL STAY THE COURSE
THROUGH THE PERIOD. WINDS WILL STAY LIGHT AND BELOW 10KTS AS 25KFT
CEILINGS PERSIST. 75
PRELIMINARY POINT TEMPS/POPS
PDT 41 74 45 77 / 0 0 0 0
ALW 45 74 51 78 / 0 0 0 0
PSC 40 77 46 82 / 0 0 0 0
YKM 40 74 47 79 / 0 0 0 0
HRI 39 76 45 80 / 0 0 0 0
ELN 38 71 44 76 / 0 0 0 0
RDM 36 74 41 75 / 0 0 0 0
LGD 36 69 41 75 / 0 0 0 0
GCD 38 72 44 77 / 0 0 0 0
DLS 45 75 51 79 / 0 0 0 0
PDT WATCHES/WARNINGS/ADVISORIES
WA...NONE.
OR...NONE.
DISCUSSION...71
AVIATION...75
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