Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 041850
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
1250 PM MDT MON MAY 4 2015

.SHORT TERM...TONIGHT THROUGH WEDNESDAY AFTERNOON. MOISTURE
CONTINUES TO STREAM OVER IDAHO AS THE BIG LOW THE
WASHINGTON/BRITISH COLUMBIA INCHES CLOSER. ANOTHER ROUND OF
SHOWERS AND STORMS HAVE DEVELOPED THIS AFTERNOON. MOST OF THE
ACTIVITY WILL REMAIN OVER THE MOUNTAINS...BUT THERE WILL LIKELY BE
SOME STRAYS THAT PUSH OUT OVER THE PLAIN ESPECIALLY IF WE CAN GET
ANY CONVERGENCE OR OUTFLOW BOUNDARIES TO FORM. SMALL HAIL...WINDS
OVER 40 MPH AND BRIEF MODERATE TO HEAVY RAIN CAN BE EXPECTED. THE
MODELS OVERNIGHT HAVE SOME RESIDUAL CLOUDS AND POTENTIAL
SHOWERS AROUND AND SEEMS REASONABLE GIVEN THE MOISTURE STILL TO
OUR SOUTH. WE WOULDN`T BE SURPRISED IF A LIGHTNING STRIKE OR TWO
HAPPENS AS WELL. THE LOW SLOWLY CHURNS INLAND TUESDAY. WE WILL
SEE A FRONT MOVING ACROSS EASTERN IDAHO TOMORROW OUT AHEAD OF THE
MAIN STORM. WITH THE MOISTURE IN PLACE ALREADY AND THE STORM
FARTHER EAST...EXPECT MORE SHOWERS AND THUNDERSTORMS. THIS MAY BE
THE DAY WITH THE HIGHEST CHANCES FOR THE SNAKE PLAIN. WITH DRIER
AIR WORKING UP THE MAGIC VALLEY BEHIND THE FRONT...IT APPEARS THAT
AREA WILL ONLY SEE A BRIEF SHOT AT DEVELOPMENT. THUNDERSTORM
COVERAGE TOMORROW IS DEPENDENT ON CLOUD COVER...THE MODELS MIGHT
HAVE A BIT TOO MUCH BUT AGAIN THERE IS PLENTY OF MOISTURE IN
NEVADA AND UTAH. WE WILL HAVE PLAY THAT BY EAR. THE WINDS TOMORROW
WILL INCREASE ESPECIALLY ALONG AND BEHIND THE FRONT. OVERALL
SUSTAINED 10-20MPH WITH HIGHER GUSTS ARE IN THE FORECAST...SO WE
AREN`T EXPECTING ANY REAL IMPACTS FROM THAT UNLESS ENHANCED BY
THUNDERSTORMS. SPEAKING OF STORMS...IT LOOKS LIKE ANOTHER DAY WITH
THE POTENTIAL OF SMALL HAIL AND BRIEF HEAVIER RAIN WITH STRONGER
CELLS.

FOR TUESDAY NIGHT AND WEDNESDAY...THE MODELS QUICKLY DIVERGE. THE
FORECAST IS HEAVILY DEPENDENT ON THE PLACEMENT OF THE LOW TO OUR
WEST AND CONTINUING STREAMING OF MOISTURE FROM THE SOUTH. ALL
THREE HAVE AN ENLONGATED STORM OVER WASHINGTON AND OREGON...BUT
THERE DIFFERENCES IN THE DETAILS. THE NAM IS EXTREMELY DRY WITH
LITTLE DEVELOPMENT...THE GFS IS IN THE MIDDLE AND THE ECMWF IS THE
WETTEST. THE NAM SEEMED A LITTLE TOO EXTREME AT THE MOMENT...SO WE
LEANED MORE TOWARD THE GFS AND EC WHICH FOLLOWS ALONG WITH THE
PREVIOUS FORECAST. WINDS WILL BE DWINDLING AND TEMPERATURES WILL
FALL OFF 5-10 DEGREES FROM TUESDAY. SNOW LEVELS WILL BEGIN TO
SLOWLY DROP...RANGING FROM 7500FT OUT WEST TO AROUND 9000FT ALONG
THE WYOMING BORDER. KEYES

.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT MONDAY. MODELS CONSISTENT
IN DROPPING UPPER LOW SOUTHWARD INTO CALIFORNIA...THEN SLOWLY
DRAGGING IT EASTWARD THROUGH SOUTHERN NEVADA THURSDAY THROUGH
FRIDAY. SEE LITTLE NEED TO MAKE ANYTHING BUT MINOR TWEAKS TO CURRENT
FORECAST...IF ANYTHING JUST TO BOOST POPS A BIT AS WE HEAD INTO THE
WEEKEND. GFS/ECMWF SIGNAL SOMEWHAT DRIER CONDITIONS FOR SUNDAY
MORNING...ESPECIALLY ALONG OUR SOUTHERN BORDER...WITH CONVECTION
DEVELOPING AGAIN SUNDAY AFTERNOON AS A SPEED MAX ROUNDS A BROAD
UPPER RIDGE POSITIONED OVER IDAHO. MODELS FAVOR SOMEWHAT COOLER
TEMPS THURSDAY THROUGH SUNDAY...BUT REMAIN ONLY SLIGHTLY BELOW
NORMAL. HINSBERGER

&&

.AVIATION...INSTABILITY LINGERING OVER THE REGION WITH AMPLE
MOISTURE WILL LEAD TO ANOTHER ROUND OF AFTERNOON AND EVENING
THUNDER. VFR CONDITIONS WILL BE PREVALENT...BUT BRIEF HEAVY SHOWERS
MAY DROP VIS. STRONGER SOUTHWESTERLY FLOW WILL DEVELOP AHEAD OF A
COLD FRONT AND MAY PRODUCE SHOWERS EARLIER TOMORROW MORNING.
HINSBERGER

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$


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