Area Forecast Discussion
Issued by NWS Boise, ID

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FXUS65 KBOI 221501
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
901 AM MDT FRI AUG 22 2014

.DISCUSSION...NUMEROUS SHOWERS ACROSS NORTHERN ELMORE AND EASTERN
BOISE COUNTIES ALSO HAVE A FEW THUNDERSTORMS POPPING UP. DUAL POL
RADAR IS PICKING UP A FEW HAIL CORES AS WELL. NEAR THE NV BORDER
INSTABILITY...MID LAYER WINDS AND WIND SHEAR WILL CONTINUE TO BE
STRONG ENOUGH TO SUPPORT STORMS WITH STRONG GUSTY WINDS AND HAIL.
MID LAYER WINDS NEAR THE ID NV BORDER WILL BE WEST AROUND 20 MPH
WHILE THEY WILL GO LIGHT AND VARIABLE ACROSS THE CENTRAL
MOUNTAINS. SO HAVE MADE A MINOR UPDATE TO ADD STORM ATTRIBUTES OF
HAIL AND HEAVY RAIN AS WELL AS GUSTY WINDS.

&&

.AVIATION...VFR. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MAINLY
NORTH AND EAST OF A LINE FROM KBNO-KONO-KEUL-KREO. LIGHT SURFACE
WINDS BECOMING GENERALLY NORTHWESTERLY THIS AFTERNOON 5-
15KT...EXCEPT VARIABLE WINDS AND GUSTS UP TO 50KT IN VICINITY OF
THUNDERSTORMS. WINDS ALOFT AT 10K FEET MSL...SW 15-25KT BECOMING
NORTHERLY 5-15KT BY 03Z SAT.

&&

.HYDROLOGY...A MOIST UPPER LOW WILL SETTLE IN OVER CENTRAL IDAHO
FOR LATER TODAY. SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE AS
A RESULT. STORMS WILL BE SLOW MOVING AND CAPABLE OF PRODUCING ONE
THIRD OF AN INCH OF PRECIPITATION IN 30 MINUTES...ESPECIALLY
ACROSS CENTRAL IDAHO UNDER THE UPPER LOW. RECENT WET CONDITIONS
HAVE BROUGHT CENTRAL IDAHO/S LAST 30 DAYS OF PRECIPITATION TOTALS
TO ABOUT AN INCH ABOVE NORMAL. RECENT BURN SCARS WILL ALSO BE
VULNERABLE TO FURTHER DAMAGE FROM STRONG SLOW MOVING THUNDERSTORMS
CONTAINING HEAVY RAIN.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH SATURDAY...A CLOSED UPPER LOW DROPPING
INTO THE PAC NW THIS MORNING WILL TRACK ACROSS THE REGION
THROUGH SATURDAY. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS
IS TODAY...OUT AHEAD OF THE LOW CENTER. THE COMBINATION OF ENERGY
FROM THE LOW...MOIST CONDITIONS PRECEDING THE LOW...AND DAYTIME
HEATING WILL FOCUS SHOWER AND STORM DEVELOPMENT OVER E-CENTRAL
OREGON AND SW IDAHO THROUGH THIS EVENING. FAVORABLE 0-6 KM
SHEAR...LOWER FREEZING LEVELS AND GOOD INSTABILITY WILL FAVOR
DEVELOPMENT OF STRONGER STORMS OVER S-CENTRAL IDAHO THIS AFTERNOON
..WHERE HAIL AND HEAVY RAIN IS AGAIN POSSIBLE. ALSO STORM LAYER
WINDS INCREASE TO 40-50 KTS TODAY INCREASING THE CHANCE OF
STRONGER SURFACE WIND GUSTS NEAR STORMS. DRIER AIR ON THE
BACKSIDE OF THE LOW WILL LIMIT CONVECTIVE POTENTIAL ACROSS HARNEY
AND SOUTHERN MALHEUR COUNTIES TODAY AND WORK INTO SW IDAHO THIS
AFTERNOON. BELIEVE THIS WILL CUT DOWN ON THE CONVECTIVE THREAT IN
THE TREASURE VALLEY THIS AFTERNOON FROM BOISE WESTWARD. COVERAGE
OF SHOWERS AND STORMS DECREASES TONIGHT...KEEPING ONLY A SLIGHT
CHANCE IN THE MTNS OVERNIGHT. BY SATURDAY MORNING THE LOW CENTER
IS IN EASTERN IDAHO WITH NORTHERLY FLOW FOCUSING WRAP AROUND
SHOWERS AND THUNDERSTORMS OVER THE WEST CENTRAL AND BOISE MTNS.
TODAY AND SATURDAY ARE COOL...WITH TEMPERATURES 8-12 DEGREES BELOW
NORMAL. GUSTY NW WINDS ON SATURDAY WILL ACCOMPANY THE COOLER
CONDITIONS.

LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...MODELS ARE IN
REASONABLY GOOD AGREEMENT THROUGH THURSDAY. AN UPPER LEVEL TROUGH
OVER THE INTERMOUNTAIN AREA WILL KEEP OUR WEATHER COOL AND UNSETTLED
THROUGH TUESDAY WITH MAX TEMPERATURES 3-8 DEGREES BELOW
NORMAL...MINS NEAR NORMAL...AND SCATTERED SHOWERS AND ISOLATED
AFTERNOON/EVENING THUNDERSTORMS MAINLY OVER THE CENTRAL IDAHO
MOUNTAINS. BY WEDNESDAY THE TROUGH WILL HAVE EXITED AND AN UPPER
LEVEL RIDGE WILL BRING DRY WEATHER WITH TEMPERATURES WARMING TO A
FEW DEGREES ABOVE NORMAL ON THURSDAY.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...FLASH FLOOD WATCH FROM NOON MDT TODAY THROUGH THIS EVENING
     IDZ011-013-028.
OR...NONE.

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...VM
AVIATION.....KA
HYDROLOGY...VM
PREV SHORT TERM...DG PREV LONG TERM....JT


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