Area Forecast Discussion
Issued by NWS Boise, ID

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000
FXUS65 KBOI 230254
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
854 PM MDT MON SEP 22 2014

.DISCUSSION...A LINE OF SHOWERS AND THUNDERSTORMS MOVING THROUGH
SE OREGON THIS EVENING IS IN ADVANCE OF AN UPPER LEVEL FEATURE AND
ACCOMPANYING WEAK FRONTAL BOUNDARY. THE UPPER LEVEL SYSTEM IS
MOVING TO THE N-NE AND WILL TRACK THROUGH NE OREGON INTO THE IDAHO
PANHANDLE WHILE THE SURFACE FRONT WILL FURTHER ERODE. THE BEST
CHANCE OF OVERNIGHT SHOWERS AND STORMS WILL REMAIN CLOSE TO THE
UPPER LEVEL AND INCLUDE NORTHERN MALHEUR AND BAKER COUNTIES IN
OREGON AND ADAMS AND WASHINGTON COUNTY IN IDAHO. ELSEWHERE ACROSS
SE OREGON AND SW IDAHO ANY ISOLATED SHOWER AND STORM ACTIVITY
WILL DIMINISH BY MIDNIGHT. AT THIS POINT THE BEST CHANCE FOR
ISOLATED SHOWERS IN THE SNAKE VALLEY REMAINS WEST OF BOISE. HAVE
MADE UPDATES TO DRY OUT SOUTHERN AND EASTERN ZONES FOR THE
REMAINDER OF THE NIGHT.

&&

.AVIATION...VFR EXCEPT ISOLATED MVFR IN SHOWERS AND THUNDERSTORMS.
AS OF 0245Z...A LINE OF SHOWERS AND THUNDERSTORMS WAS MOVING NE
ACROSS HARNEY AND EXTREME WESTERN BAKER COUNTIES IN ERN OREGON.
THIS LINE IS EXPECTED TO MOVE NE OVERNIGHT...IMPACTING KBKE
THROUGH 06Z AND POSSIBLY IMPACTING KMYL AFTER 06Z. SURFACE WINDS
WILL BE VARIABLE 10 KTS OR LESS EXCEPT GUSTING TO 20 KTS NEAR
SHOWERS AND STORMS. SFC WINDS WILL BECOME SE TO SW 10-15 KTS
TUESDAY AFTERNOON. WINDS ALOFT THROUGH 10KFT WILL BE SW 15-20 KTS.

&&

.PREV DISCUSSION...
SHORT TERM...UPPER LOW HAS MOVED AWAY AND SHOWERS HAVE DECREASED
OR ENDED.  ATTENTION TURNS TO THE OFFSHORE FRONTAL BAND THAT WILL
WEAKEN AND TURN NORTHEAST AS IT MOVES INLAND TONIGHT.  SYSTEM WILL
BRING SHOWERS AND ISOLATED THUNDERSTORMS TO OREGON ZONES...
ESPECIALLY ELKHORN MOUNTAINS IN BAKER COUNTY.  SERN-MOST OREGON
ZONES AND SRN IDAHO ZONES WILL STAY DRY.  INSTABILITY IS SUFFICIENT
FOR ISOLATED THUNDERSTORMS IN OREGON ZONES AND MOUNTAINS IN
IDAHO...BUT PROBABLY NOT IN THE SNAKE BASIN.  WEAKENING FRONTAL
BAND WILL EXIT NORTHEAST OF OUR CWA TUESDAY MORNING AS UPPER RIDGE
BUILDS FROM THE SOUTH.  RIDGING WILL BRING CLEARING AND WARMING
TO OUR ZONES TUESDAY AND ESPECIALLY WEDNESDAY WHEN WIDESPREAD 80S
WILL OCCUR...WITH LOWER 90S IN THE TREASURE VALLEY.

LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY...MODELS AGREE ON
KEEPING SOUTHEAST OREGON AND SOUTHWEST IDAHO UNDER WARM AND DRY
SOUTHWEST FLOW ALOFT THROUGH THURSDAY MORNING. THE CHANCE OF SHOWERS
WILL INCREASE ACROSS EASTERN OREGON THURSDAY AFTERNOON AND SOUTHWEST
IDAHO THURSDAY NIGHT AS A PACIFIC COLD FRONT CROSSES THE AREA.
FRIDAY WILL BE 10 TO 15 DEGREES COOLER THAN THURSDAY...AND COOL
WEATHER WITH SCATTERED SHOWERS WILL CONTINUE THROUGH SATURDAY AS AN
UPPER LEVEL TROUGH SETTLES OVER THE INTERMOUNTAIN REGION. EXPECT
WEST TO NORTHWEST WINDS 10 TO 20 MPH ON SATURDAY.

SATURDAY NIGHT THROUGH MONDAY...MODEL AGREEMENT DECREASES AS WE MOVE
INTO SATURDAY NIGHT. THE GFS MODEL RUNS ARE CONSISTENT IN DEEPENING
THE TROUGH AS IT PASSES THROUGH OUR REGION...AS WELL AS CONSISTENT
IN ITS TIMING...HOWEVER THE 12Z EC MODEL RUN NO LONGER DEEPENS THE
TROUGH AS IT HAD BEFORE AND MOVES IT MUCH FASTER TOWARDS THE EAST.
BOTH MODELS AGREE THAT WE WILL BE WET WITH BELOW NORMAL TEMPERATURES
THROUGHOUT MOST OF OUR REGION INTO MONDAY...THOUGH CONFIDENCE IS LOW
IN PRECIP INTENSITY AND LOCATION.

&&

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

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...DG
AVIATION.....SP
PREV SHORT TERM...LC
PREV LONG TERM....JT/AB



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