000
FXUS65 KPIH 130244
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
844 PM MDT SUN MAY 12 2013

.UPDATE...MOISTURE ROTATING AROUND UPPER RIDGE LINGERS OVER
EASTERN IDAHO THIS EVENING. SAT IMAGERY CONTINUES TO SHOW LINE OF
HIGH BASE CLOUD COVER MOVIGN ACROSS THE REGION. SOME EMBEDDED WEAK
CUMULUS OCCURRED EARLIER BUT LITTLE LEFT THIS EVENING. RADAR
MOSAIC SHOWS CONVECTION WITH LIGHTING OCCURRING OVER NORTHEAST
OREGON EXTENDING INTO THE IDAHO PANHANDLE THIS EVENING. UPPER FLOW
SHOULD PUSH TRAJECTORY OF THIS CONVECTION WELL NORTH OF THE
FORECAST AREA EVEN IF IT SURVIVES THROUGH THE REMAINDER OF THE
EVENING AS PER THE NAM. HAVE NUDGED POP DOWN FOR THIS EVENING MOST
AREAS PER SATELLITE AND RADAR TRENDS. NO OTHER UPDATES
ANTICIPATED. DMH



&&

.PREV DISCUSSION... /ISSUED 213 PM MDT SUN MAY 12 2013/

SHORT TERM...THE AXIS OF THE HIGH PRESSURE RIDGE IS CROSSING OVER
SOUTHEAST IDAHO THIS AFTERNOON. THE CHANGE TO A DRIER AIR MASS
THE PAST COUPLE OF DAYS HAS RESULTED IN CLOSE TO A 40 DEGREE
DIURNAL SPREAD IN TEMPERATURES. PARTS OF THE SNAKE PLAIN ARE
ALREADY PASSING 80F THIS AFTERNOON. THE WARM AIR SHOULD ACCELERATE
RUN OFF FROM REMAINING MOUNTAIN SNOW PACK. THIS CAN OFTEN TAKE A
DAY OR TWO TO SHOW UP AS INCREASED FLOWS ON LOCAL RIVERS...NOT TO
UNDERESTIMATE THE POWER OF COLD AND SWIFT WATERS FOR ANY ONE
VENTURING NEAR THE RIVERS. FLOODING IS NOT EXPECTED.

A PACIFIC COLD FRONT IS JUST ENTERING WASHINGTON STATE AND IS
EXPECTED TO PASS THROUGH IDAHO FALLS AND POCATELLO AROUND 7 PM
MONDAY EVENING. THE LATE TIMING OF THE FRONT WILL FAVOR WINDS
RAMPING UP LATER IN THE AFTERNOON AND PERSISTING INTO THE EVENING
HOURS. SOUTHWEST WINDS 25 TO 35 MPH GUST 45 MPH LOOKS REASONABLE.
THE STRENGTH OF THE SURFACE PRESSURE GRADIENT MONDAY EVENING
ALONG WITH MINUS 10 C/12HR COLD AIR ADVECTION ALOFT IS QUITE
RESPECTABLE FOR A MIDDLE OF MAY TIME PERIOD EVENT. A WIND ADVISORY
HAS BEEN ISSUED. MODELS THE PAST COUPLE OF DAYS HAVE INCREASINGLY
TAKEN THIS DISTURBANCE THROUGH THE IDAHO PAN HANDLE IN A CONFLUENT
FLOW WITH PROGRESSIVELY DRIER FORECASTS FOR SOUTHEAST IDAHO. LOOKS
LIKE WINDS WILL BE THE MAIN FACTOR. HOPEFULLY FIELDS ARE GREENING
UP ENOUGH TO LIMIT BLOWING DUST. A LITTLE BREEZY STILL
TUESDAY...MOST SHOWERS IN ZONAL FLOW OVER THE NORTHERN REACHES OF
THE STATE. RS

LONG TERM...WEDNESDAY THROUGH SUNDAY. MODELS CONTINUE ADVERTISING A
ZONAL FLOW THROUGH THURSDAY. GFS ENSEMBLE SHOWING MORE CONFIDENCE IN
DEVELOPING UPPER TROUGH OVER THE WEST BEGINNING THURSDAY NIGHT.
CONTINUED TRENDING FRIDAY AND SATURDAY POPS HIGHER AS A RESULT.
WINDS WILL REMAIN FAIRLY STRONG...BUT APPEARS THEY SHOULD NOT
REQUIRE HEADLINES AT THIS TIME. MEX AND ECE GUIDANCE KEEP SUSTAINED
WINDS IN THE MID TO UPPER TEENS...THEN INCREASE THEM TO THE LOW 20S
AS THE UPPER SYSTEM APPROACHES. EXPECT TO SEE LOWER POPS AND WINDS
HEADING INTO SATURDAY NIGHT AND SUNDAY AS THE UPPER TROUGH PASSES.
HINSBERGER

AVIATION...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH PERIOD
WITH UPPER RIDGE BUILDING IN AND DRY CONDITIONS IN THE LOW LEVELS.
SHOWERS MAY DEVELOP OVER THE CENTRAL MOUNTAINS...BUT SHOULD REMAIN
NORTH OF KSUN. MOS GUIDANCE KEEPS POPS/TS CHANCES LOW. WINDS WILL
BEGIN RAMPING UP JUST BEFORE 18Z TOMORROW AS A COLD FRONT
APPROACHES...BUT STRONGEST WINDS WILL BE LATER TOMORROW AFTERNOON
INTO THE EARLY EVENING.  HINSBERGER

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 1 PM TO 11 PM MDT MONDAY IDZ020-021.

&&

$$