Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 300944
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
344 AM MDT SAT APR 30 2016

.SHORT TERM...TODAY THROUGH SUNDAY...A BROAD UPPER TROUGH IS
SITUATED OVER THE WESTERN STATES EARLY THIS MORNING WITH AN UPPER
RIDGE JUST OFF THE COAST. THE MAIN ENERGY WITHIN THE TROUGH WILL
SHIFT SOUTH AND EAST AWAY FROM THE FORECAST AREA TODAY WHILE A
WEAK CIRCULATION LOCATED ALONG THE MONTANA AND IDAHO BORDER MOVES
SOUTH ACROSS THE FORECAST AREA. THIS WILL BRING A CHANCE OF
SHOWERS TO THE AREA THROUGH THIS EVENING BUT MAINLY OVER THE HIGH
TERRAIN ON THE IDAHO SIDE. THERE MAY BE JUST ENOUGH INSTABILITY
FOR AN AFTERNOON OR EARLY EVENING THUNDERSTORM SO KEPT A SLIGHT
CHANCE MENTION IN THE FORECAST. SURFACE PRESSURE GRADIENT REMAINS
FAIRLY TIGHT TODAY AND WILL AGAIN PRODUCE BREEZY CONDITIONS THIS
AFTERNOON AND EVENING...ESPECIALLY ACROSS EASTERN OREGON THE UPPER
TREASURE VALLEY AND OWYHEE COUNTY.

THE UPPER RIDGE RIDGE JUST OFF THE COAST WILL BUILD INLAND ACROSS THE
PACIFIC NORTHWEST AND NORTHERN ROCKIES THROUGH THE WEEKEND WHILE
A TROUGH REMAINS OVER THE SOUTHWEST STATES. THIS WILL BRING A
WARMING AND DRYING TREND TO THE FORECAST AREA UNDER EASTERLY FLOW
ALOFT. SURFACE GRADIENT RELAXES ON SUNDAY WITH DOWNSLOPE EASTERLY
FLOW AT THE SURFACE AIDING THE WARMING TREND FOR THE TREASURE
VALLEY.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...AN UPPER RIDGE OVER THE
NORTHERN ROCKIES WILL DOMINATE ON MONDAY. SOUTHERLY FLOW ALOFT WILL
DRAW SOME LIMITED MOISTURE NORTHWARD FROM NEVADA FOR A SLIGHT CHANCE
OF AFTERNOON SHOWERS ALONG THE NEVADA BORDER AND IN THE WEST CENTRAL
MOUNTAINS. OTHERWISE...SKIES WILL BE MOSTLY CLEAR WITH TEMPERATURES
ABOVE NORMAL. THE RIDGE WILL SLOWLY SHIFT EAST AS THE NEXT PACIFIC
TROUGH ENTERS THE WEST TUESDAY AND WEDNESDAY. THE SHOWER CHANCES
WILL INCREASE FOR THE REMAINDER OF THE WEEK AS THE TROUGH
SPLITS...FORMING A LARGE UPPER CLOSED LOW WHICH IS PROGGED TO MOVE
INTO THE SOUTHWESTERN U.S. AND GREAT BASIN BY FRIDAY. THE WARMING
TREND WILL CONTINUE THROUGH MIDWEEK /NEAR 80F IN THE LOWER VALLEYS
ON WEDNESDAY/...THEN COOL SLIGHTLY BY THE END OF THE WEEK.

&&

.AVIATION...MAINLY VFR. ISOLATED TO SCATTERED SHOWERS /MAINLY OVER
THE HIGHER TERRAIN/ OF SOUTHWEST IDAHO AND BAKER COUNTY IN SOUTHEAST
OREGON. SLIGHT CHANCE OF THUNDERSTORMS AFTER 18Z. SHOWERS WILL
DECREASE IN COVERAGE AND BECOME ISOLATED AFTER 03Z. SURFACE
WINDS...NORTHWEST 10 KNOTS OR LESS INCREASING TO 10-20 KNOTS WITH
GUSTS TO 30 KNOTS AFTER 18Z...DIMINISHING AFTER 03Z. WINDS ALOFT
NEAR 10K FEET MSL...NORTH 10-20 KNOTS BECOMING EAST AFTER 03Z.

OUTLOOK FOR SUNDAY...ISOLATED SHOWERS OVER THE HIGHER TERRAIN OF
CENTRAL IDAHO AND ALONG THE NEVADA BORDER AFTER 18Z...OTHERWISE VFR
WITH PARTLY CLOUDY SKIES.

&&

.HYDROLOGY...THE BRUNEAU AND JARBIDGE RIVERS CONTINUE TO RUN HIGH
IN OWYHEE COUNTY WITH SOME SMALLER TRIBUTARIES LIKELY RUNNING
BANKFULL. DIURNAL PEAKS FOR THE EAST FORK OF THE JARBIDGE RIVER
AND THE EAST FORK OF THE BRUNEAU RIVER TRENDED UP AGAIN COMPARED
TO THE PREVIOUS DAY. THIS WILL KEEP THE BRUNEAU RIVER AT HOT
SPRINGS RUNNING HIGH WITH THE LATEST OBSERVATION A LITTLE MORE
THAN A FOOT BELOW FLOOD STAGE. NO FLOODING IS EXPECTED ON THE
MAINSTEM OF THE BRUNEAU...BUT A GOOD HIGH ELEVATION SNOWPACK
REMAINS IN THE UPPER BASIN AND WARMING TEMPERATURES THROUGH THE
WEEKEND AND EARLY NEXT WEEK WILL KEEP STREAMFLOWS HIGH.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.

&&

$$

WWW.WEATHER.GOV/BOISE
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE

SHORT TERM...TL
LONG TERM....BW
AVIATION.....BW
HYDROLOGY...TL



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