000
FXUS65 KBOI 172103
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
303 PM MDT SAT MAY 17 2008
.SHORT TERM...TONIGHT THROUGH MONDAY...RECORD HEAT ON TRACK WITH
BOISE AIRPORT REACHING 90 AS JUST BEFORE 21Z WITH A MAX EXPECTED
AROUND 24Z. A MILD NIGHT IS STILL ON TRACK. ON SUNDAY A LITTLE
MORE WINDS WAS FORECAST AS AN UPPER LEVEL WAVE ON THE SW CANADIAN
COAST PUSHES THROUGH THE IDAHO PANHANDLE AND BUILDS A TIGHTER NW-
SE PRESSURE GRADIENT SUNDAY MORNING AND SW AND S CENTRAL IDAHO IN
THE MID TO LATE AFTERNOON. THIS WILL DROP HIGHS FROM TODAY A FEW
DEGREES AS ALREADY ANTICIPATED IN THE FORECAST. ABOVE NORMAL BUT
NOT AS HOT OR DRY WEATHER IS EXPECTED MONDAY AS THE UPPER LEVEL
RIDGE RETROGRADES SLIGHTLY SOUTHWESTWARD.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...MODELS ARE QUITE CLOSE
BRINGING THE TROUGH INTO OUR AREA TUESDAY AFTERNOON. THE GENERAL
TREND IS TO SLOW THE PROGRESS OF THE COLD FRONT DELAYING IT UNTIL
AFTERNOON OR EVENING AT THE TIME OF MAX HEATING. BECAUSE OF THIS WE
HAVE A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS ON THE
IDAHO SIDE. BOTH GFS AND NAM SHOW INSTABILITY IN THOSE AREAS FOR
THAT TIME. A PROBLEM EXISTS WITH MAX TEMPERATURES TUESDAY. BOTH
ANALOG AND BC BLENDS HAVE MAXS AT LEAST 5 DEGREES ABOVE OUR
FORECAST. AFTERNOON CLOUD COVER AND SHOWERS OVER OUR NORTHERN
MOUNTAINS ARE EXPECTED TO HOLD DAYTIME TEMPERATURES BACK. FOR
TUESDAY NIGHT THROUGH THURSDAY CONFIDENCE IS GOOD THAT THE UPPER
TROUGH WILL DEEPEN OVER THE INTERMOUNTAIN REGION WITH HIGHS AND LOWS
5-8 DEGREES BELOW NORMAL AND POPS NEAR CLIMATOLOGY. FRIDAY AND
SATURDAY...CONFIDENCE DECREASES BEYOND FRIDAY AS MODELS BEGIN TO
STRUGGLE WITH STRENGTH AND LOCATION OF UPPER LEVEL TROUGH. ECMWF AND
GFS ENSEMBLE MEAN HOLD ON TO THIS SYSTEM THROUGH LATE SATURDAY...FOR
A CONTINUATION OF UNSETTLED WEATHER. TEMPERATURES WILL REMAIN BELOW
NORMAL ON FRIDAY/SATURDAY AS A STRENGTHENING PAC NW RIDGE FAILS TO
PROGRESS INLAND OVER THE CWA.
&&
.AVIATION...VFR CONDITIONS WILL CONTINUE TONIGHT THROUGH SUNDAY. SKIES
WILL BE MOSTLY CLEAR WITH SCATTERED HIGH CLOUDS. SURFACE WINDS WILL
BE LIGHT. WINDS ALOFT WILL BE LIGHT TO MODERATE FROM THE WEST.
&&
.HYDROLOGY...RIVERS ARE EXPECTED TO CONTINUE TO RISE IN RESPONSE
TO RECORD HOT TEMPERATURES TODAY AND HOT TO NEAR RECORD
TEMPERATURES AGAIN TONIGHT AND SUNDAY. SO FAR NO FLOODING HAS
BEEN OBSERVED. THE BOISE RIVER BELOW LUCKY PEAK IS EXPECTED TO RUN
AT BANKFULL THIS EVENING THROUGH SUNDAY SO RVSBOI/FGUS85KBOI WAS
UPDATED. THE PAYETTE RIVER IS EXPECTED TO RUN HIGH OR NEAR
BANKFULL AS MOUNTAIN SNOWMELT INCREASES THROUGH SUNDAY. THE WEISER
IS EXPECTED TO CREST BELOW FLOOD STAGE WITH THIS EVENT. MANY OR
EVEN MOST SMALL STREAMS AND CREEKS ABOVE 5 KFT ARE EXPECTED TO BE
AT BANKFULL TONIGHT AND SUNDAY.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...VM
LONG TERM....JT/MT
AVIATION.....JT
HYDROLOGY...VM
