Office: BOI
FXUS65 KBOI 190931
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
330 AM MDT WED JUN 19 2013
.SHORT TERM...TODAY THROUGH THURSDAY...A NARROW N-S ORIENTED BAND OF
RAINFALL WAS SITUATED ACROSS FAR SOUTHWESTERN IDAHO THIS MORNING
WITH LIGHT RAIN OCCURRING AT THE BOISE AIRPORT. HEAVIER RAINFALL AS
INDICATED BY RADAR WAS LOCATED JUST NORTH OF BOISE AND ACROSS THE
UPPER WEISER BASIN. MODELS DEPICT THIS BAND OF RAINFALL WILL SHIFT
TO THE NORTHEAST AND EXIT THE AREA BY MID-MORNING. MEANWHILE...A
DEEP UPPER LOW CENTERED OFF THE WA/OR COAST WAS STILL MOVING INLAND
AND WAS SPREADING SHOWERS INTO OREGON. THE LEADING EDGE OF THE
SHOWERS HAS REACHED HARNEY COUNTY AND WESTERN MALHEUR COUNTY. THE
LOW WILL CONTINUE TO MOVE INTO THE PACNW TODAY WITH SHOWERS
SPREADING INTO THE REMAINDER OF SE OREGON AND MOST OF SW IDAHO BY
MIDDAY. INSTABILITY ACCOMPANYING THE COLD LOW WILL RESULT IN
ISOLATED THUNDERSTORMS BY LATE MORNING AND LASTING THROUGH THE
AFTERNOON. WHILE WE ARE NOT ANTICIPATING ANY SEVERE STORMS...HEAVY
RAIN AND SMALL HAIL ARE POSSIBLE. THE UPPER LOW WILL GRADUALLY LIFT
TO OUR NORTH TONIGHT WITH SHOWERS DECREASING FROM SOUTH TO NORTH.
THE LOW IS EXPECTED TO STALL JUST TO OUR NORTH ON THURSDAY.
THUS...SHOWERS WILL LINGER ACROSS BAKER COUNTY AND THE BOISE/WEST
CENTRAL MOUNTAINS. SNOW LEVELS WILL LOWER TO AROUND 6500 FEET SO THE
NORTHERN MOUNTAINS COULD RECEIVE LIGHT SNOW ACCUMULATIONS TONIGHT.
WINDS WILL REMAIN GUSTY TODAY THEN DIMINISH TONIGHT AND THURSDAY.
TEMPERATURES WILL BE RATHER COOL TODAY AS HIGHS WILL ONLY BE IN THE
50S AND 60S. TEMPS WILL BE A LITTLE WARMER ON THURSDAY BUT STILL
10-15 DEGREES BELOW NORMAL.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...GOOD MODEL AGREEMENT
THAT AN UPPER LOW WILL STILL BE MEANDERING OVER THE NORTHERN ROCKIES
LATE IN THE WEEK AND THEN FINALLY MOVING EAST SATURDAY. MODELS
SUGGEST MULTIPLE LOW CENTERS WITH A SPOKE OF ENERGY ROTATING ACROSS
CENTRAL AND SOUTHERN IDAHO FRIDAY AND FRIDAY NIGHT BEFORE THE SYSTEM
DEPARTS. THIS WILL KEEP A CHANCE OF SHOWERS IN THE FORECAST MAINLY
FOR EAST CENTRAL OREGON AND THE WEST CENTRAL AND BOISE MOUNTAINS IN
IDAHO THROUGH FRIDAY NIGHT. DRYING AND TEMPERATURES WARMING TO NEAR
NORMAL FOR THE WEEKEND UNDER A TRANSIENT SHORTWAVE RIDGE. A CHANCE
OF SHOWERS BACK IN THE FORECAST SUNDAY NIGHT THROUGH MONDAY...
PRIMARILY FOR NORTHERN AREAS WITH A LOW AMPLITUDE WESTERLY FLOW
PROGGED TO TRANSPORT MOISTURE ACROSS THE FORECAST AREA. TOWARD THE
MIDDLE OF NEXT WEEK MODELS ARE HINTING AT THE SUBTROPICAL RIDGE
BUILDING OVER THE FOUR CORNERS VICINITY WHICH WOULD BRING DRIER
SUMMER LIKE TEMPERATURES TO THE FORECAST AREA.
&&
.AVIATION...A BAND OF SHOWERS EXTENDING FROM NEAR KMYL THROUGH KBOI
TO THE NEVADA BORDER...WILL LIFT NORTHEAST ACROSS THE WEST CENTRAL
AND BOISE MOUNTAINS THROUGH 15Z. A BIT OF A DRY SLOT BETWEEN THIS
BAND AND THE NEXT BATCH OF SHOWERS AND ISOLATED THUNDERSTORMS WHICH
WILL SPREAD ACROSS SOUTHEAST AND EAST CENTRAL OREGON THROUGH EARLY
MORNING...AND INTO SOUTHWEST IDAHO 14-15Z TIMEFRAME. GREATEST
COVERAGE WILL BE ACROSS BAKER COUNTY AND THE WEST CENTRAL MOUNTAINS.
LOCAL MVFR CONDITIONS IN HEAVIER SHOWERS. SHOWERS SHIFTING MAINLY TO
BAKER COUNTY AND WEST CENTRAL AND BOISE MOUNTAINS AFTER 06Z
TONIGHT.
WESTERLY SURFACE WINDS INCREASING TO 10-20KTS GUSTS TO 30KTS...
MAINLY FROM KBKE TO KJER AND SOUTH...DIMINISHING AFTER 03Z.
WINDS ALOFT WILL BE WESTERLY 20-25KTS UP THROUGH 10K FEET MSL.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...BW
LONG TERM....TL
AVIATION.....TL
Office: PIH
FXUS65 KPIH 190839
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
239 AM MDT WED JUN 19 2013
.DISCUSSION...UPPER LOW CONTINUES TO SPIN OFF THE COAST OF WA/OR
THIS MORNING. INITIAL SHORTWAVE TROUGH IS PRODUCING BAROCLINIC BAND
OVER WESTERN IDAHO WHILE A SECOND SHORTWAVE ROUNDS THE BASE OF THE
TROUGH IN CALIFORNIA. NEGATIVE ORIENTATION OF THE UPPER TROUGH WILL
BE CONDUCIVE TO SOME STRONG FORCING LATE THIS MORNING AND EARLY
AFTERNOON. MODELS KEEP HEAVIEST PRECIP IN THE CENTRAL MOUNTAINS AND
AREAS NORTH...BUT 00Z NAM AND EVEN THE 00Z WRF RUNS ARE PRODUCING
CONVECTION STARTING AROUND 18Z OVER THE SOUTHEAST HIGHLANDS. CENTRAL
MOUNTAINS MAY SEE MUCAPE VALUES OF 900-1000 J/KG THIS AFTERNOON.
COUPLED WITH THE 45-50 KTS 0-6KM SHEAR...THIS COULD LEAD TO SOME
RIGOROUS CONVECTION WHICH MAY PRODUCE HAIL. A COOLER AIRMASS WILL
QUICKLY MOVE INTO THE AREA LATE TONIGHT BRINGING SNOW LEVELS DOWN TO
AROUND 6500-7000 FT.
CONTINUING WITH CURRENT WIND HEADLINES WITH TIGHTENING SFC GRADIENT
LATER THIS MORNING INTO THE AFTERNOON. BOUNDARY LAYER WINDS INCREASE
THIS MORNING TO AROUND 30-35 KTS IN SOME AREAS. KSFX VAD WINDS
ALREADY SHOWING 35KTS JUST OFF THE DECK.
GFS ENSEMBLE HOLDS MEAN UPPER TROUGH OVER IDAHO/WESTERN MT THROUGH
SATURDAY NIGHT BEFORE IT LIFTS AND MOVES EASTWARD. MODELS HAVE
CONTINUED HOLDING THE STRONGEST POPS IN THE NORTHERN PORTIONS OF OUR
CWA. A TRANSIENT UPPER RIDGE WILL MOVE ACROSS THE AREA ON SUNDAY
FOLLOWED BY A SOUTH/SOUTHWESTERLY FLOW WHICH WILL BRING IN A WARMING
TREND THROUGH THE MIDDLE OF NEXT WEEK. EXTENDED PERIODS LOOK MAINLY
DRY...BUT HAVE INCLUDED SOME SLIGHT MOUNTAIN POPS IN THE CENTRAL
MOUNTAINS. HINSBERGER
&&
.AVIATION...A LOW PRESSURE SYSTEM WILL SHIFT INLAND TODAY WITH
BREEZY WINDS ANTICIPATED THROUGHOUT THE SNAKE RIVER PLAIN. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO SPREAD INTO THE
REGION BY MID-MORNING AND ADVANCE INTO THE ERN HIGHLANDS BY THIS
AFTERNOON WITH TEMPORARY IMPACTS ANTICIPATED AT TERMINAL
LOCATIONS...OTHERWISE VFR CONDITIONS SHOULD PREVAIL. WIND AND SHOWER
ACTIVITY WILL DIMINISH AFTER 2100 MDT THIS EVENING AS THE UPPER LOW
ADVANCES INTO THE IDAHO PANHANDLE AND SOUTHERN IDAHO REMAINS ON THE
SOUTHERN PERIPHERY OF THE MAIN SHOWER ACTIVITY. HUSTON
&&
.FIRE WEATHER...A LOW PRESSURE SYSTEM WAS POSITIONED ALONG THE
WASHINGTON/OREGON COASTLINE EARLY THIS MORNING AS A FAIRLY STRONG
DISTURBANCE WAS NOTED ROTATING THROUGH THE BASE OF THE LOW ACROSS
THE NRN SIERRA AND INTO NW NEVADA. IN ADDITION TO THE UPPER LOW
ALONG THE COAST...A DEEP SURFACE LOW WAS LIFTING ENE THROUGH SE
IDAHO EARLY THIS MORNING WITH AN ASSOCIATED DRY FRONTAL BOUNDARY
ADVANCING THROUGH THE AREA. MODELS SUGGEST THAT THE DISTURBANCE
ROTATING OUT OF THE BASE OF THE UPPER LOW WILL LIFT NE ACROSS THE
REGION TODAY WITH ACCOMPANYING SHOWERS/THUNDERSTORMS SPREADING EAST
THROUGH THE DISTRICT. THE BEST CHANCE FOR WETTING RAINS IS EXPECTED
ACROSS THE CENTRAL MOUNTAINS NEAR THE CORE OF THE UPPER LOW WHILE
ISOLATED ACTIVITY IS ANTICIPATED ACROSS THE SNAKE PLAIN AND SOUTHERN
HIGHLANDS FURTHER TO THE SOUTH. STRONG WINDS ARE ANTICIPATED
THROUGHOUT THE DAY UNDER THE ADVANCING STORM SYSTEM. THE UPPER LOW
IS EXPECTED TO ADVANCE SLOWLY EAST INTO THE IDAHO PANHANDLE THURSDAY
WITH ACCOMPANYING SHOWERS...COOLER TEMPERATURES AND LOCALLY BREEZY
CONDITIONS LINGERING THROUGH SATURDAY BEFORE THE LOW FINALLY PUSHES
EAST INTO THE DAKOTAS SUNDAY. A SECOND LOW PRESSURE SYSTEM IS
EXPECTED TO ADVANCE INTO THE NW COASTAL WATERS SUNDAY WITH EJECTING
DISTURBANCES POSING A THREAT FOR RENEWED SHOWERS AND COOLER
TEMPERATURES EARLY NEXT WEEK. HUSTON
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO 9 PM MDT THIS EVENING IDZ020-021.
WIND ADVISORY UNTIL 9 AM MDT THIS MORNING IDZ022.
&&
$$
