Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 012210
AFDSEW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
310 PM PDT SUN MAY 1 2016

.SYNOPSIS...HIGH PRESSURE ALOFT WILL BRING ONE MORE DRY AND WARM
DAY MONDAY. SOUTHERLY FLOW ALOFT AND LOW LEVEL ONSHORE FLOW WILL
RETURN TUESDAY AND PERSIST FOR MOST OF THE REST OF THE WEEK FOR A
CHANCE OF SHOWERS AND COOLER TEMPERATURES. AN UPPER RIDGE WILL
BRING DRIER AND WARMER WEATHER AGAIN LATE IN THE WEEK.

&&

.SHORT TERM...HIGH PRESSURE ALOFT WILL BRING SUNNY AND WARM
WEATHER AGAIN MONDAY. AT THE SURFACE...A THERMAL TROUGH ALONG THE
COAST WILL SHIFT OVER THE INTERIOR OF WESTERN WASHINGTON MONDAY.
THIS WILL TRANSLATE INTO MONDAY BEING THE WARMEST DAY FOR THE
INTERIOR. SOME COOLING WILL OCCUR AT THE COAST WHERE ONSHORE FLOW
WILL START TO DEVELOP.

AN UPPER TROUGH WILL MOVE TO NEAR 130W TUESDAY WITH INCREASING
MOIST AND SLIGHTLY UNSTABLE SOUTHERLY FLOW ALOFT FOR WESTERN
WASHINGTON. THIS WILL BRING A CHANCE OF SHOWERS. THE BEST CHANCES
WILL BE NEAR THE COAST AND OVER THE CASCADES. THERE WILL ALSO BE
A CHANCE OF AFTERNOON AND EVENING THUNDER FOR THE CASCADES WHERE
THE AIR WILL BE MORE UNSTABLE. INCREASING LOW LEVEL ONSHORE FLOW
WILL COOL HIGHS INTO THE 60S TO LOWER 70S.

WEDNESDAY WILL BE A RELATIVE REPEAT OF TUESDAY. MOIST AND
SLIGHTLY UNSTABLE SOUTHERLY FLOW ALOFT WILL CONTINUE FOR A CHANCE
OF SHOWERS. MODELS SUGGEST SHOWERS WILL BE A BIT MORE NUMEROUS IN
THE AFTERNOON. MODERATE LOW LEVEL ONSHORE FLOW WILL CONTINUE.
HIGHS WILL COOL A FEW MORE DEGREES WITH MOST AREAS IN THE 60S.
SCHNEIDER

.LONG TERM...A SPLIT UPPER TROUGH WILL SLOWLY SHIFT ONSHORE
THURSDAY WITH A DECREASING CHANCE OF SHOWERS. AN UPPER RIDGE WILL
BUILD OVER THE AREA FRIDAY...BRINGING AND END TO THE SHOWER
THREAT. THE RIDGE WILL BE IN CONTROL NEXT WEEKEND FOR DRY AND
MOSTLY SUNNY WEATHER. HIGH SHOULD WARM BACK INTO THE 70S FOR THE
WEEKEND. SCHNEIDER

&&

.AVIATION...UPPER LEVEL RIDGE CENTERED OVER SOUTHERN BRITISH
COLUMBIA AND ALBERTA WITH EASTERLY FLOW ALOFT. LOW LEVEL FLOW
REMAINING OFFSHORE TONIGHT BECOMING LIGHT ON MONDAY.

WITH THE UPPER LEVEL RIDGE AND LOW LEVEL OFFSHORE FLOW CLEAR
SKIES OVER THE AREA THROUGH MONDAY.

KSEA...CLEAR SKIES. NORTHERLY WINDS 8 TO 12 KNOTS EASING AND
BECOMING NORTHEAST AFTER 05Z. FELTON

&&

.MARINE...LOW LEVEL OFFSHORE FLOW THROUGH MONDAY MORNING WITH LOW
PRESSURE OVER THE COASTAL WATERS. A RETURN TO LOW LEVEL ONSHORE FLOW
WILL OCCUR MONDAY NIGHT INTO TUESDAY WITH VARYING DEGREES OF ONSHORE
FLOW THROUGH THE END OF THE WEEK. GALE FORCE WESTERLY WINDS ARE
POSSIBLE IN THE CENTRAL AND EASTERN STRAIT OF JUAN DE FUCA TUESDAY
NIGHT. FELTON

&&

.CLIMATE...APRIL 2016 WAS THE WARMEST APRIL ON RECORD ACROSS
WESTERN WASHINGTON. APRIL 2016 TEMPERATURES CRUSHED THE OLD RECORD
TEMPERATURES BY 1.5 DEGREES TO A LITTLE MORE THAN 3 DEGREES.
SEATTLE HAD THE BIGGEST DIFFERENCE WITH 56.7 DEGREES VERSUS THE OLD
RECORD OF 53.6 DEGREES SET IN 1977. OTHER RECORDS INCLUDE
BUT ARE NOT LIMITED TO...OLYMPIA 53.2...OLD RECORD 50.9
(1989)...BELLINGHAM 54.0...OLD RECORD 52.0 (1989)...HOQUIAM 53.8
DEGREES...OLD RECORD 52.3 (1987) AND QUILLAYUTE 51.9 DEGREES...OLD
RECORD 50.3 (1989).

WITH THE RECORD WARM APRIL SEATTLE HAS HAD 7 RECORD WARM MONTHS IN
THE LAST 19 MONTHS...OCTOBER AND DECEMBER 2014 AND FEBRUARY...MARCH...
JUNE AND JULY...2015. FELTON

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.
&&

$$

WWW.WEATHER.GOV/SEATTLE

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