Area Forecast Discussion
Issued by NWS Pocatello, ID

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
000
FXUS65 KPIH 230247
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
847 PM MDT TUE APR 22 2014

.SHORT TERM...SECOND UPDATE THIS EVENING TO EXPIRE/CANCEL THE WIND
ADVISORY ACROSS THE SE HIGHLANDS AS OBSERVATIONS SHOW WIND SPEEDS
WELL BELOW ADVISORY LEVELS. ELSEWHERE...A MARGINAL WIND ADVISORY
EVENT CONTINUES ACROSS INL WITH LIGHTER WINDS THROUGHOUT THE
REMAINDER OF THE SNAKE RIVER PLAIN/ERN MAGIC VALLEY. THE LATEST NAM
NUMERICAL GUIDANCE STILL SUGGESTS WINDS DIMINISHING ACROSS THE SNAKE
PLAIN THROUGH MIDNIGHT WHILE INCREASING ACROSS THE ERN MAGIC VALLEY
AS THE SURFACE PRESSURE GRADIENT STRENGTHENS IN THAT REGION. NO NEW
STATISTICAL GUIDANCE AS OF YET. NAM NUMERICAL GUIDANCE ALSO SUPPORTS
SUB-ADVISORY CONDITIONS THROUGHOUT THE SNAKE PLAIN DURING DAY
WEDNESDAY. WANT TO SEE GFS AND STATISTICAL GUIDANCE BEFORE DROPPING
HIGHLIGHT...SO WILL LEAVE IT OUT FOR NOW AND ALLOW MID-SHIFT TO
REEVALUATE THE HEADLINE. SEE PREVIOUS DISCUSSIONS BELOW. HUSTON

UPDATE THIS EVENING TO CLEAR SEVERE THUNDERSTORM WATCH FROM SE IDAHO
COUNTIES FOR THE REMAINDER OF THE EVENING. WIND ADVISORY STILL
VERIFYING ACROSS INL AND SELECT LOCATIONS ACROSS THE SE IDAHO
MOUNTAINS. SOME DIFFERENCES NOTED BETWEEN THE NUMERICAL AND
STATISTICAL GUIDANCE FROM EARLIER TODAY AS STATISTICAL GUIDANCE
SUGGESTS THAT WINDS WILL REMAIN ELEVATED OVERNIGHT AND INCREASE
AGAIN WEDNESDAY AFTERNOON WHILE THE NUMERICAL GUIDANCE HAS IT
DROPPING OFF ACROSS THE UPPER VALLEY AND SE HIGHLANDS WITH A
RESURGENCE ACROSS THE MAGIC VALLEY LATE THIS EVENING/TONIGHT. WILL
HOLD OFF ON ANY MODIFICATIONS WITH THE ADVISORY UNTIL I CAN GET A
LOOK AT THE NEWER 00Z DATA. SEE PREVIOUS DISCUSSION BELOW. HUSTON

TONIGHT THROUGH WEDNESDAY NIGHT...APPROACHING TROUGH ADVANCING
ACROSS THE NORTHERN ROCKIES AND GREAT BASIN THIS AFTERNOON. COLD
FRONT SWEEPING THROUGH IDAHO WITH UNSTABLE AIR IN PLACE ACROSS OUR
EASTERN ZONES. MODELS AND SATELLITE SHOW AREA OF LIFT AND POTENTIAL
FOR RAPID CONVECTIVE DEVELOPMENT IN THE NEXT FEW HOURS OVER THE
EASTERN PART OF OUR AREA. THIS IN LINE WITH SPC SLIGHT RISK. AS
FRONT SWEEPS THROUGH THIS EVENING...SEVERE THREAT DIMINISHES LEAVING
CWA WITH STRONG WINDS AND COLD ADVECTION. MUCH COOLER AND WINDY
WEDNESDAY WITH LINGERING MOUNTAIN PRECIPITATION TO FALL AS SNOW
ALBEIT LIGHT AMOUNTS DUE TO RAPID LOSS OF AVAILABLE MOISTURE.
DITTMANN

THURSDAY MORNING THROUGH FRIDAY AFTERNOON.  WEAK HIGH PRESSURE
BUILDS ACROSS THE AREA IN BETWEEN STORM SYSTEMS. WE WON`T TOTALLY
DRY OUT EXCEPT ACROSS SOUTHERN AREAS THURSDAY MORNING. SNOW LEVELS
SHOULD REMAIN ABOVE 5500FT IN THE MORNING...RISING TO 6500-7000FT BY
AFTERNOON. BY THEN...WE WILL RETURN TO SOUTHWEST FLOW AHEAD OF THE
NEXT SYSTEM MOVING TOWARD THE COAST. SHOWERS WILL SLOWLY SPREAD
SOUTHEAST...BUT THE HIGHEST CHANCES WILL STILL REMAIN OVER THE
CENTRAL MOUNTAINS AND UPPER SNAKE HIGHLANDS. THIS STORM CONTINUES TO
SHOW SIGNS OF SPLITTING BUT IT APPEARS WE ARE LOOKING AT A DECENT
SHOT OF MOISTURE HEADING INTO THURSDAY NIGHT AND FRIDAY. SNOW LEVELS
WILL RANGE FROM 6500FT IN THE WEST TO AROUND 8000FT AROUND BEAR
LAKE. THIS MEANS...THAT WE MAY BE LOOKING AT RAIN ON TOP OF SNOW IN
CONJUNCTION WITH SOME MELTING FOR MID SLOPES.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY NIGHT. A GOOD CHANCE OF
SHOWERS REMAINS OVER ALL OF EASTERN IDAHO HEADING INTO
SATURDAY...WITH A DWINDLING CHANCE ON SUNDAY AND MONDAY. BEYOND
THAT...A STRONG RIDGE OF HIGH PRESSURE BUILDS THE STATE...DRYING US
OUT AND ALLOWING FOR WARMER WEATHER TO PERSIST. THE MODELS ARE
SHOWING SOME REASONABLE AGREEMENT AND THE FORECAST LOOKS PRETTY
GOOD...SO WE ARE PRETTY MUCH LEAVING IT ALONE FOR TODAY. EVEN THOUGH
WE SHOULD SEE A BIT OF A COOL DOWN FOR SUNDAY AND MONDAY...THE
THREAT OF SNOW MELT AND WATER RISES WILL CONTINUE.  KEYES
&&

.AVIATION...SHOWERS AND A FEW STORMS WILL AFFECT ALL TAF SITES
THROUGH EARLY EVENING. WE MAY SEE MVFR CONDITIONS DURING HEAVIER
SHOWERS AND STORMS...ALONG WITH A THREAT OF HAIL AND WIND GUSTS
APPROACHING 50KTS. OUTSIDE OF THUNDERSTORMS...GUSTY SURFACE WINDS
HAVE DEVELOPED AND WILL KEEP GOING THROUGH TOMORROW AFTERNOON. THIS
WILL BE AN ISSUE FOR KBYI...KPIH AND KIDA. WE ARE ALSO KEEPING VCSH
IN FOR KIDA AND KPIH THROUGH TOMORROW MORNING AT LEAST AS MOISTURE
WILL REMAIN IN PLACE ACROSS EASTERN LOCATIONS. WE MAY NEED TO ADD
THIS FOR KSUN FOR LATER TAF ISSUANCE...BUT APPEARS KBYI SHOULD BE
DRY AFTER THIS EVENING.  KEYES
&&

.HYDROLOGY...EXPECT TO SEE IN-BANK RISES IN RIVERS AND STREAMS OVER
THE NEXT FEW DAYS DUE TO RUNOFF FROM PRECIP AND SNOW MELT. CURRENT
HYDROGRAPH PROJECTIONS ARE NOT INDICATING FLOODING AT THIS TIME.
HINSBERGER
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 9 PM MDT WEDNESDAY IDZ017-020-021.
&&

$$






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.