Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 290241
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
841 PM MDT MON JUL 28 2014

.DISCUSSION...SHOWERS AND STORMS CONTINUE ACROSS PORTIONS OF THE
AREA...NAMELY...OVER BOISE AND ELMORE COUNTIES...OWYHEE
COUNTY...AND VALLEY COUNTY. THE STRONGEST STORMS AS OF 830 PM MDT
WERE IN SOUTHEAST BOISE COUNTY MOVING SE INTO ELMORE COUNTY. AN
OUTFLOW BOUNDARY WAS MOVING ALONG WITH THE CONVECTION...HELPING TO
STRENGTHEN AND INITIATE CONVECTION. SOME PORTION OF THIS OUTFLOW
BOUNDARY WILL BE HEADED TOWARD BOISE THROUGH 9 PM MDT. GUSTS TO 30
MPH ARE ANTICIPATED.

THE CONVECTION WILL DIMINISH WITH THE SETTING SUN AND WE EXPECT
ALMOST ALL THE ACTIVITY WILL BE GONE BY 11 PM MDT. THIS IS HANDLED
WELL BY THE CURRENT FORECAST AND NO CHANGES ARE PLANNED AT THIS
TIME.

&&

.AVIATION...VFR...MOSTLY CLOUDY MID AND HIGH LEVEL CLOUDS. AFTER
18Z WEDNESDAY...ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP
WITH LOCALLY GUSTY WINDS 30 TO 40 MPH VICINITY OF THUNDERSTORMS.
SURFACE WINDS LESS THAN 10 KTS...AFTER 16Z WESTERLY 10 KTS. WINDS
ALOFT VARIABLE 5 TO 10 KTS UP THRU 10K FT MSL.

&&

.PREV DISCUSSION...
SHORT TERM...MONSOON MOISTURE IS MAINLY AT MID AND HIGH LEVELS.
INSTABILITY AND SHEAR HAVE BEEN WEAK SO FAR AND THE AIR MASS HAS
BEEN SLOW TO GENERATE THUNDERSTORMS.  INSTABILITY WILL INCREASE
TUESDAY /BUT SHEAR WILL REMAIN WEAK/ FOR A BETTER CHANCE OF
THUNDERSTORMS TUESDAY AFTERNOON...ESPECIALLY IN THE MOUNTAINS.
NAM IN PARTICULAR HAS INCREASED INSTABILITY WITH LIFTED INDEX
NEAR MINUS 4 OVER ABOUT HALF OUR CWA INCLUDING SRN HARNEY AND
MALHEUR COUNTIES...THE OWYHEE MOUNTAINS...TREASURE VALLEY...AND
THE BOISE MOUNTAINS.  OUR NWRN ZONES WILL HAVE LESS MOISTURE...
WHILE OUR SERN ZONES MAY BE TOO CLOUDY AND NOT AS UNSTABLE.  DUE
TO CLOUDS...DAYTIME TEMPS WILL BE A LITTLE COOLER TUESDAY AND
COOLER AGAIN WEDNESDAY.  NIGHTTIME TEMPS WILL CONTINUE WARM.

LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...LITTLE CHANGE IN THE
POSITIVE PNA PATTERN IS FORESEEN BY THE MODELS...WITH THE VERY WARM
UPPER LEVEL RIDGE ANCHORED OVER WESTERN NORTH AMERICA. SOUTHWEST
IDAHO AND SOUTHEAST OREGON WILL REMAIN UNDER SOUTHWEST FLOW ALOFT
..A FAVORABLE TRAJECTORY FOR ADVECTING MONSOON MOISTURE OVER OUR
AREA. FORECAST SOUNDINGS SHOW FAVORABLE CONDITIONS FOR CONVECTION
THROUGH THE PERIOD...ESPECIALLY SUNDAY AND MONDAY. THUNDERSTORMS
WILL BE SUPPORTED BY SURFACE HEATING...PLUS ANY SHORTWAVES EMBEDDED
IN THE SOUTHWEST FLOW...ALTHOUGH CONFIDENCE IN TIMING THESE
DISTURBANCES IS BELOW AVERAGE. AS USUAL THE BEST CHANCE OF
THUNDERSTORMS WILL BE AFTERNOONS AND EVENINGS OVER THE HIGHER
TERRAIN. TEMPERATURES ARE EXPECTED TO CONTINUE A FEW DEGREES ABOVE
AVERAGE FOR LATE JULY AND EARLY AUGUST.

&&

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

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...SP
AVIATION.....RD
PREV SHORT TERM...LC
PREV LONG TERM....JT/WH


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