Flash Flood Warning 1, NWS Boise, ID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
242 PM MDT WED JUL 8 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY...
AN UPPER LEVEL LOW CENTERED NEAR SAN FRANCISCO WILL BE THE MAIN
WEATHER FEATURE OVER THE NEXT COUPLE OF DAYS. THE LOW WILL
GRADUALLY MOVE INLAND OVER CALIFORNIA TONIGHT AND THURSDAY...THEN
GRADUALLY TRANSITION INTO AN OPEN WAVE AND MOVE NORTHEAST FRIDAY.
SOUTHERLY FLOW AHEAD OF THE LOW WILL CONTINUE TO ADVECT MOISTURE
ACROSS THE FORECAST AREA WITH PRECIPITABLE WATER AROUND ONE INCH.
DIFLUENCE ALOFT WILL AID IN LIFT AND WATER VAPOR IMAGERY SUGGESTS
A COUPLE SHORTWAVES ROTATING AROUND THE EAST SIDE OF THE LOW...ONE
OF WHICH WILL MOVE ACROSS THE FORECAST AREA TONIGHT AND HELP DRIVE
SOME NOCTURNAL SHOWERS AND THUNDERSTORMS. WEAK STEERING FLOW ALOFT
WILL YIELD SLOW MOVING STORMS AND A HEAVY RAIN THREAT. OUTFLOW
WINDS OF 45 TO 50 MPH WERE OBSERVED WITH STORMS YESTERDAY AND
EXPECT SIMILAR GUSTS WITH SOME STORMS LATE THIS AFTERNOON AND
EVENING. LOW CONFIDENCE IN TIMING SPECIFIC WAVES AND RELATED
BOUTS OF SHOWERS AND THUNDERSTORMS...BUT THURSDAY AND FRIDAY
APPEAR A HIGHER THREAT FOR HEAVY RAIN AND FLASH FLOODING...
ESPECIALLY IN STEEP TERRAIN AND ON BURN SCARS. NEAR NORMAL DAYTIME
HIGH TEMPERATURES FOR THURSDAY WITH INCREASED CLOUDS AND
PRECIPITATION ON FRIDAY EXPECTED TO KEEP MAX TEMPERATURES BELOW
NORMAL. MOISTURE AIRMASS AND CLOUDS WILL KEEP TEMPERATURES RATHER
MILD DURING OVERNIGHT PERIODS.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY. AS UPPER LEVEL TROUGH
MOVES INLAND FRIDAY NIGHT INTO SATURDAY...IT IS EXPECTED TO SLOWLY
GET ABSORBED INTO A LARGER UPPER LOW OFF OF THE BRITISH COLUMBIA
COAST. NONETHELESS...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
CONTINUE THROUGH SUNDAY WITH SHORTWAVES MOVING THROUGH IN THE
UNSTABLE SOUTHWESTERLY FLOW. PWAT VALUES ARE STILL EXPECTED TO
REMAIN IN THE 80TH TO 90TH PERCENTILE THROUGH THE WEEKEND. FOR
MONDAY AND BEYOND...UPPER LOW LOOKS TO ELONGATE ALONG THE WESTERN
COAST WHILE WEAKENING AND DRYING CONDITIONS OUT. PWAT VALUES DROP
ACROSS THE AREA AND ANY SHOWERS AND THUNDERSTORMS LOOK TO BE MUCH
MORE TERRAIN DRIVEN. TEMPERATURES LOOK TO REMAIN BELOW NORMAL
THROUGH THE WEEKEND...THEN A SLIGHT WARMING TREND TO NORMAL FOR
NEXT WEEK.

&&

.AVIATION...VFR. SHOWERS AND THUNDERSTORMS THROUGH THE DAY...AND
SOME ISOLATED THUNDERSTORMS LINGERING OVERNIGHT. VARIABLE GUSTY
OUTFLOW WINDS AROUND 45 KTS POSSIBLE NEAR THUNDERSTORMS...ALONG WITH
HEAVY RAIN. OTHERWISE...SURFACE WINDS GENERALLY 10 KTS OR
LESS...EXCEPT SOUTHEAST GUSTS IN THE TREASURE VALLEY. WINDS ALOFT
NEAR 10KFT MSL...VARIABLE 5-10KTS...THEN AFTER 09/06Z EAST AT 10-15
KTS.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...RED FLAG WARNING UNTIL MIDNIGHT MDT TONIGHT IDZ423-426.
OR...RED FLAG WARNING UNTIL MIDNIGHT MDT /11 PM PDT/ TONIGHT
     ORZ636-637.

&&

WEATHER.GOV/BOISE

SHORT TERM...TL
LONG TERM....EP/WH
AVIATION.....EP