Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 041614
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1014 AM MDT MON MAY 4 2015

.DISCUSSION...UPPER TROUGH IS TRACKING SOUTH ALONG THE BC THIS
MORNING. UPPER FLOW IS SHIFTING TO THE SOUTH-SOUTHWEST WHICH IS
PULLING MOISTURE FURTHER INTO THE REGION THIS MORNING WITH A BROAD
FIELD OF ALTOCUMULUS OVER SE OREGON AND SW IDAHO. NO CHANGE TO
FORECAST FOR TODAY WITH SHOWER AND THUNDERSTORM INITIATION OVER
THE HIGHER TERRAIN SOUTH OF THE SNAKE RIVER AND ACROSS MTNS OF
EAST-CENTRAL OREGON AND WEST-CENTRAL IDAHO. WITH SOUTHWEST FLOW
ALOFT SHOWERS AND STORMS INITIATING OFF THE OWYHEES AND SW ID
HIGHLANDS COULD PUSH INTO THE SNAKE PLAIN...BUT WITH PULSE NATURE
OF STORMS EXPECT THEM TO QUICKLY DIMINISH IN THE TREASURE VALLEY.
FOR THE WESTERN MAGIC VALLEY WILL NEED TO WATCH A FEATURE TRACKING
THROUGH E-CENTRAL NV THIS MORNING /AS SEEN IN WATER VAPOR
SATELLITE PICS/. IF IT HOLDS TOGETHER THIS COULD INCREASE
COVERAGE AND DURATION OF THUNDERSTORM ACTIVITY OVER S-CENTRAL ID
BY LATE AFTERNOON.

&&

.AVIATION...VFR UNDER SCATTERED MID-HIGH CLOUDS.ISOLATED SHOWERS AND
THUNDERSTORMS OVER SOUTHERN SE OREGON/BAKER COUNTY/SOUTHERN SW
IDAHO/AND OVER THE WEST CENTRAL AND BOISE MTNS...ENDING BY 5/6Z.
ISOLATED SHOWERS WILL CONTINUE INTO THE MORNING ALONG THE ID/NV
BORDER AND IN THE BOISE/WEST CENTRAL MTNS. SURFACE WINDS...12 KTS OR
LESS. GUSTS EXPECTED NEAR THUNDERSTORMS AND REDUCED VISIBILITY DUE
TO BLOWING DUST...MOSTLY IN THE MAGIC VALLEY. WINDS ALOFT NEAR 10K
FT MSL...SW 5-15 KTS.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH TUESDAY...AFTER TWO DAYS OF CONVECTION
STAYING CONFINED ALONG THE NV BORDER...UPPER FLOW WILL BACK
SLIGHTLY TODAY...ALLOWING MOISTURE TO MOVE NORTHWARD INTO THE REST
OF THE AREA. INSTABILITY IS EXPECTED TO BE BETTER THIS AFTERNOON
AND EVENING...AND POPS WERE RAISED SLIGHTLY...ESPECIALLY IN FAR
SE OWYHEE COUNTY AND SRN TWIN FALLS COUNTY. THE UPPER FLOW WILL
BACK FURTHER MONDAY NIGHT INTO TUE AS A STRONG UPPER LOW MOVES
INTO WASHINGTON. AS THE DYNAMICS OF THE SYSTEM APPROACH...WE WILL
HAVE A SLIGHT CHANCE OF CONVECTION CONTINUING DURING THE OVERNIGHT
HOURS MONDAY NIGHT. THE SYSTEM WILL ADVECT DRY AIR FROM THE SW
INTO MOST OF THE AREA BY TUE AFTERNOON...BUT CONVECTION WILL
REMAIN IN THE FORECAST ALONG OUR EASTERN BORDER. FOR TODAY...THE
WSW FLOW ALOFT WILL BRING IN WARMER AIR...PUTTING OUR HIGHS A FEW
DEGREES ABOVE SUNDAY/S READINGS. THIS WILL RESULT IN MAX TEMPS
10-15 DEGREES ABOVE NORMAL TODAY. LOWS MONDAY NIGHT WILL BE MILD
OWING TO CLOUDS AND WIND...AVERAGING 5-10 DEGREES ABOVE NORMAL. ON
TUE...WITH HEIGHTS LOWERING IN ADVANCE OF THE INCOMING SYSTEM AND
A COLD FRONT MOVING THROUGH FROM LATE MONDAY NIGHT INTO EARLY
TUE...HIGHS WILL BE 7-15 DEGREES LOWER THAN TODAY. THE LARGEST
CHANGES COME BE IN BAKER COUNTY OREGON...AND THE SMALLEST ALONG
OUR EASTERN BORDER.

LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...MODELS REMAIN IN GOOD
AGREEMENT THROUGH THE EXTENDED PERIOD. A DEEP UPPER LEVEL LOW
WILL BRING UNSETTLED WEATHER AND COOL TEMPERATURES TO THE REGION
THROUGH THE REST OF THE WEEK AND INTO THE WEEKEND. THE DEEP LOW
WILL MOVE INTO THE PACIFIC NORTHWEST TUESDAY NIGHT THEN SPLIT
WEDNESDAY NIGHT. NORTHERN SECTION OF THE SPLIT WILL MOVE QUICKLY
TO THE EAST ACROSS SOUTHERN CANADA...BUT THE SOUTHERN SECTION OF
THE SPLIT WILL SLOWLY MOVE TO THE SOUTH. EVEN THOUGH THE MODELS
ARE IN GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN THERE ARE BIG
DIFFERENCES AS TO WHERE AND WHEN PRECIPITATION WILL OCCUR. WITH
UNCERTAINTY IN THE PLACEMENT AND TIMING OF PRECIPITATION THROUGH
THE EXTENDED WENT TOWARD A MODEL BLEND. TEMPERATURES WILL AVERAGE
5-10 DEGREES BELOW NORMAL.

&&

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

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...DG
AVIATION.....AB
PREV SHORT TERM...SP
PREV LONG TERM....JA



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