Flash Flood Warning 2, NWS Boise, ID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
1000 AM MDT FRI JUL 10 2015

.DISCUSSION...A WEAKENING SHORTWAVE MOVING NORTH BY NORTHWEST OVER
SOUTHERN IDAHO THIS MORNING HAS ALREADY TRIGGERED A THUNDERSTORM
OVER THE MOUNTAINS NORTHWEST OF JEROME. THE SHORTWAVE WILL HAVE
MOVED NORTH OF OUR CWA BY THIS EVENING SO CONVECTIVE DEVELOPMENT
WILL NEED TO RELY ON OROGRAPHIC LIFT AND SURFACE HEATING...WHICH
WILL BE DELAYED OVER SOUTHWEST IDAHO BY CLOUD COVER. HOWEVER BUFFER
SOUNDINGS DO INDICATE THE CONVECTIVE TEMPERATURES WILL BE REACHED BY
LATE AFTERNOON. THE HRRR SHOWS CONVECTION DEVELOPING OVER THE HIGHER
TERRAIN THIS AFTERNOON AND MOVING NORTHWEST WITH THE STEERING FLOW.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO MOVE DOWN THE
SNAKE RIVER VALLEY REACHING THE TREASURE VALLEY LATE THIS AFTERNOON.
WITH SLIGHTLY FASTER FLOW COMPARED TO THIS PAST WEDNESDAY...STORM
PRECIPITATION TOTALS ARE NOT EXPECTED TO BE QUITE AS MUCH...BUT WITH
PW STILL CLOSE TO AN INCH LOCAL HEAVY RAIN IS STILL POSSIBLE. THE
BROAD UPPER LEVEL TROUGH CENTERED OVER THE CALIFORNIA-NEVADA BORDER
THIS MORNING IS STILL FORECAST BY ALL MODELS TO WEAKEN AS IT MOVES
OVER THE NORTHWEST STATES TONIGHT AND SATURDAY...LEAVING INCREASING
SOUTHWEST FLOW ALOFT OVER OUR AREA AND NOT AS MUCH DYNAMIC
SUPPORT... BUT MOISTURE AND INSTABILITY WILL BE ADEQUATE FOR
CONTINUING SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND.

&&

.AVIATION...VFR. EXPECTING NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS THIS AFTERNOON...THEN ISOLATED SHOWERS AND
THUNDERSTORMS OVERNIGHT. PERIODS OF VARIABLE GUSTY WINDS UP TO 40
KTS AND BRIEF IFR CONDITIONS IN IN HEAVY RAIN ASSOCIATED WITH
THUNDERSTORMS. OTHERWISE...SURFACE WINDS GENERALLY 12 KTS OR LESS.
WINDS ALOFT UP THROUGH 10K FEET MSL...SOUTHERLY 10-20 KTS.

&&

.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH SATURDAY...SHOWERS AND THUNDERSTORMS
WILL MOVE THROUGH THE UPPER WEISER BASIN TOWARDS BAKER COUNTY
THROUGH 5 AM PDT AS WELL AS ACROSS CENTRAL IDAHO THIS MORNING. THE
UPPER LOW TO OUR SW WILL SEND A PIECE OF ENERGY ACROSS SW IDAHO
THIS AFTERNOON AND EVENING WHILE AN ARC OF WIDESPREAD SHOWERS AND
EMBEDDED THUNDERSTORMS IS EXPECTED ON THE NORTH SIDE OF THE LOW
FROM BURNS TO STANLEY NORTHWARD...THIS AFTERNOON AND EVENING. PWAT
REMAINS HIGH AND DDFT CAPE TOO SO GUSTY WINDS AND BRIEF HEAVY RAIN
ARE EXPECTED. TONIGHT LOOKS TO HAVE A LULL IN THE ACTIVITY
ESPECIALLY OVER SW IDAHO WITH SHOWERS AND ISOLATED THUNDERSTORMS
MAINLY OVER HARNEY BAKER AND ADAMS COUNTIES. THEN SATURDAY THERE
IS A TRANSITION TO MORE SHEAR AND WIND ALOFT THOUGH PWAT AND
INSTABILITY REMAIN HIGH SO STORMS WILL BE FASTER MOVERS BUT STILL
HAVE GUSTY WINDS.

LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...UPPER LEVEL TROUGH
OVER THE PACIFIC NORTHWEST WILL BRING A SERIES OF SHORTWAVES
THROUGH THE AREA SUNDAY THROUGH MONDAY. THE FIRST SHORTWAVES MOVES
THROUGH SUNDAY AFTERNOON FOLLOWED BY A SECOND SHORTWAVE MONDAY
MORNING. BOTH WILL BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS
BOTH DAYS WITH DEVELOPMENT FAVORING THE HIGHER TERRAIN. DYNAMICS
IS BETTER ON THE MONDAY /AOA 30 KTS 0-6KM SHEAR/ BUT INSTABILITY
REMAINS LIMITED WITH WIDESPREAD CLOUD COVER. HEAVY RAIN AND GUSTY
WINDS WILL LIKELY ACCOMPANY THE STRONGER STORMS. TUESDAY THROUGH
FRIDAY...A DRIER WESTERLY FLOW WILL SET UP THROUGH AT LEAST
THURSDAY. THERE IS A LARGE DIFFERENCE IN HOW STRONG THE NEXT
TROUGH WILL BE LATE NEXT WEEK WITH THE 00Z ECMWF MUCH STRONGER AND
SLOWER THAN 00Z GFS. BOTH ARE SHOWING A TROUGH WHICH SHOULD KEEP
TEMPERATURES AT OR NEAR NORMAL. TEMPERATURES ARE EXPECTED TO
REMAIN BELOW NORMAL THROUGH TUESDAY THEN GRADUALLY WARM THROUGH TO
NEAR NORMAL BY FRIDAY.

&&

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

&&

WEATHER.GOV/BOISE

DISCUSSION...JT
AVIATION.....AB
PREV SHORT TERM...VM
PREV LONG TERM....JS