Area Forecast Discussion
Issued by NWS Boise, ID

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000
FXUS65 KBOI 300253
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
853 PM MDT FRI APR 29 2016

.DISCUSSION...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
CONTINUE MAINLY OVER THE SOUTHWEST HIGHLANDS...BOISE MOUNTAINS AND
WESTERN MAGIC VALLEY THROUGH MIDNIGHT THOUGH MOST OF THESE WILL
DISSIPATE BY SUNSET. A TIGHT PRESSURE GRADIENT REMAINS OVER THE
FORECAST AREA THROUGH SATURDAY FOR BREEZY NORTHWEST WINDS.
NORTH-NORTHEAST WINDS ALOFT ON SATURDAY WILL KEEP MOISTURE OVER
THE MOUNTAINS OF SOUTHWEST IDAHO FOR SHOWERS AND THUNDERSTORMS.
SHOWER COVERAGE WILL BE FAR LESS ON SATURDAY THAN TODAY. LOWERED
POPS IN MOST PLACES FOR THE REST OF THE EVENING AND OVERNIGHT.

&&

.AVIATION...MOSTLY VFR WITH MID LEVEL CLOUDS. SHOWERS TAPERING OFF
BY 30/06Z. MORE SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED EAST OF
A LINE KMYL-KMUO-KREO AFTER 30/18Z. GUSTY SURFACE WINDS EXPECTED TO
CALM TO 12 KTS OR LESS AFTER SUNSET. OTHERWISE...SURFACE WINDS
GENERALLY WEST/NORTHWEST AND GUSTING UP TO 30 KTS AFTER 30/18Z.
WINDS ALOFT NEAR 10K FT MSL...NORTH AT 10-15 KTS...THEN AFTER 01/03Z
BECOMING EAST.

&&

.HYDROLOGY...SMALL STREAMS ACROSS SOUTHERN IDAHO CONTINUE TO RUN
NEAR BANK FULL THROUGH THE WEEKEND. THE BRUNEAU RIVER LOOKS LIKE
IT HAS CRESTED THIS AFTERNOON ABOUT 1 FOOT BELOW FLOOD STAGE AND
IS FORECAST TO SLOWLY RECEDE THROUGH THE WEEKEND. THE BASIN DID
RECEIVE ABOUT A 0.10 TO 0.20 OF PRECIPITATION TODAY WHICH WILL
LIKELY KEEP IT FROM RECEDING MUCH OVERNIGHT. TEMPERATURES NEAR
NORMAL A FEW DEGREES ABOVE BY SUNDAY AND NO SIGNIFICANT
PRECIPITATION EXPECTED FOR THE NEXT 4 DAYS...SNOW MELT IS NOT
EXPECTED TO BE ENOUGH TO CAUSE MUCH CONCERN FOR FLOODING.
WE WILL CONTINUE TO CAREFULLY MONITOR THE SITUATION IN CASE MORE
RAIN THAN IS EXPECTED OCCURS.

&&

.PREV DISCUSSION...
SHORT TERM...TONIGHT THROUGH SUNDAY...SCATTERED SHOWERS WILL
CONTINUE OVER MOST OF SOUTHWESTERN IDAHO AND EASTERN OREGON
THROUGH THIS EVENING. RADAR AND SURFACE OBSERVATIONS SHOW RAIN IN
THE VICINITY OF BAKER CITY OREGON AND MCCALL IDAHO LATE THIS AFTERNOON
AND THESE SHOWERS WILL GENERALLY MOVE TOWARDS THE SOUTH EAST. THERE
IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS IN IDAHO THROUGH THE
EARLY EVENING HOURS.  THE UPPER LEVEL LOW RESPONSIBLE FOR THIS
ACTIVITY IS CENTERED NEAR MISSOULA MONTANA BUT IS SLOWLY WEAKENING.
MEANWHILE THE SURFACE PRESSURE GRADIENT WILL STRENGTHEN AND CAUSE
BREEZY CONDITIONS DURING THE DAY ON SATURDAY IN EASTERN OREGON AND
IN THE TREASURE VALLEY OF IDAHO. SHOWER ACTIVITY WILL DECREASE
OVERNIGHT...BUT A FEW SNOW SHOWERS WILL REMAIN OVER THE IDAHO
MOUNTAINS INTO SATURDAY. SUNDAY LOOKS MOSTLY DRY WITH LESS WIND AS
AN UPPER LEVEL RIDGE BEGINS TO BUILD INTO THE WESTERN U.S.
TEMPERATURES WILL WARM TO A FEW DEGREES ABOVE NORMAL ON SUNDAY
UNDER MOSTLY SUNNY SKIES.

LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY...MODEL AGREEMENT IS
ABOVE AVERAGE. THE HIGH PRESSURE RIDGE ALOFT CENTERED OVER SOUTHWEST
CANADA WILL KEEP MOST OF OUR AREA DRY THROUGH TUESDAY NIGHT.
PRECIPITATION ASSOCIATED WITH A LOW PRESSURE SYSTEM OVER THE GREAT
BASIN AND COLORADO PLATEAU IS NOT EXPECTED TO COME ANY CLOSER THAN
THE NEVADA BORDER. ON WEDNESDAY THE CHANCE OF SHOWERS WILL INCREASE
ACROSS SOUTHEAST OREGON AND THE CENTRAL IDAHO MOUNTAINS AS A TROUGH
DEVELOPS OFF THE WEST COAST AND THE RIDGE SHIFTS EAST. INCREASING
SOUTHERLY FLOW ALOFT AND EASTERLY FLOW AT THE SURFACE WILL RESULT IN
A WARMING TREND. TEMPERATURES WILL RISE FROM AROUND 5 DEGREES ABOVE
NORMAL ON MONDAY TO AROUND 10 DEGREES ABOVE NORMAL ON WEDNESDAY.

WEDNESDAY NIGHT THROUGH FRIDAY...THE NEXT LOW SITS OFF THE
CALIFORNIA COAST WITH SOUTHERLY WINDS OVER THE REGION. OREGON ZONES
WILL START SEEING AN INCREASE IN MOISTURE THURSDAY WITH A STEADY
INCREASE THROUGH THE PERIOD. BY FRIDAY ALL ZONES WILL SEE MOISTURE.
INSTABILITY IS ENOUGH TO GENERATE SOME AFTERNOON
THUNDERSTORMS...MOSTLY FOR HIGHER ELEVATIONS. THE SOUTHERLY WINDS
WILL HELP KEEP TEMPERATURES WELL ABOVE NORMAL.

&&

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

&&

$$

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

DISCUSSION...JDS
AVIATION.....EP
HYDROLOGY...JDS/JB
PREV SHORT TERM...JB/MS
PREV LONG TERM....JT/JC



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