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 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
141
FXUS65 KPIH 101031 CCA
AFDPIH

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE POCATELLO ID
331 AM MST WED FEB 10 2016

.SHORT TERM...TODAY THROUGH FRIDAY. UPPER RIDGE REMAINS IN PLACE
TODAY WITH STRONG VALLEY INVERSIONS TO START THE DAY. SAT IMAGERY
EARLY THIS MORNING SHOWING POCKETS OF FOG THAT ARE VERY LOCALLY
DENSE...CONFIRMED VIA SURFACE OBSERVATION AND AREA WEB CAMS. FOG
IS NOT WIDESPREAD...BUT EDGES FLUCTUATING ENOUGH TO MAKING
DROPPING THE DENSE FOG ADVISORY DIFFICULT. WEAK SHORTWAVE ALOFT
PROVIDING JUST ENOUGH MIXING TO ERODE SOME OF THE FOG IN PLACES AS
WELL WHICH FURTHER COMPLICATES THE ISSUE. WILL KEEP THE ADVISORY
IN PLACE SINCE THE POCKETS OF FOG THAT REMAIN ARE QUITE DENSE.

RIDGE CONTINUES THROUGH TONIGHT...AND HAVE TRENDED FORECAST
STRONGLY WITH PERSISTENCE. KEPT PATCHY FOG INCREASING THE COVERAGE
OVERNIGHT. WILL HOLD OFF FOR NOW ON ANY KIND OF DENSE MENTION IN
LIGHT OF CURRENT CONDITIONS. WEAK SHORTWAVE TOPS RIDGE LATE
THURSDAY INTO THURSDAY DAY. MODELS HAVE BEEN INCONSISTENT IN
SPREADING PRECIP INTO THE NORTHERN ZONES AND KEPT FORECAST TRENDED
DRY PER LATEST RUNS. AT THE VERY LEAST HOWEVER...ENOUGH MIXING MAY
BE PRESENT TO MITIGATE OVERNIGHT INVERSIONS AND HAVE AGAIN TRENDED
TOWARD LESS FOG COVERAGE INTO THURSDAY NIGHT. OTHERWISE...RIDGE
AXIS REMAINS IN PLACE FRIDAY BUT HEIGHTS DO CONTINUE TO FALL
SLIGHTLY AHEAD OF APPROACHING PACIFIC SYSTEM POISED TO REACH EAST
IDAHO DURING THE EARLY PORTIONS OF THE EXTENDED PERIOD. DMH

.LONG TERM...FRIDAY NIGHT THROUGH NEXT WEDNESDAY. MINIMAL CHANCES
FOR SOME SNOW SHOWERS LATE FRIDAY INTO SATURDAY FOR OUR NORTHERN
AREAS WITH POSSIBLE WEAK WAVE PASSING EASTWARD. MODELS NOT QUITE IN
AGREEMENT ON SATURDAYS FORECAST BUT GENERALLY IN AGREEMENT ON
SUNDAYS. DID NOT CHANGE OUR POP FORECAST SATURDAY...HOWEVER ONE
ELEMENT OF CHANGE WAS TO INCREASE WINDS SATURDAY BETWEEN 10-20MPH
THROUGH THE SNAKE PLAIN. BY SUNDAY WIDESPREAD ISOLATED TO SCATTERED
POPS ACROSS IDAHO WITH A FEW UPPER TROUGHS PASSING SOUTHEASTWARDS
UNTIL EARLY MONDAY. THEREAFTER GENREALLY DRY AND MILD CONDITIONS
EXPECTED. NP/DMH

&&

.AIR STAGNATION...HIGH PRESSURE REMAINS IN PLACE THIS MORNING.
WEAK SHORTWAVE PASSING PROVIDING JUST ENOUGH MIXING TO KEEP FOG
FROM BECOMING WIDESPREAD...BUT INVERSIONS ARE REMAINING IN PLACE
WITH POOR AIR CIRCULATION. ANOTHER WEAK DISTURBANCE WILL SLIP
NORTH OF THE DIVIDE THURSDAY NIGHT INTO FRIDAY WHICH MAY ALSO
SLIGHTLY WEAKEN THE INVERSION. A STRONGER SYSTEM IS EXPECTED TO
ARRIVE DURING THE WEEKEND WITH A CHANCE OF SHOWERS AND INCREASED
WINDS...ERODING MOST IF NOT ALL OF THE REMAINDER OF THE
INVERSIONS. DMH

&&

.AVIATION...MAIN FORECASTING CHALLENGE IS THE FOG AT PIH AND IDA
TODAY AND IF IT WILL REAPPEAR THIS EVENING AND OVERNIGHT. IT APPEARS
TO BE AT PRESENT WITH VARYING VISIBILITY THIS MORNING WITH LIFR
CEILINGS. WE`D EXPECT THIS TREND THIS LATE MORNING WITH IT VERY
LIKELY TO BE DOMINANTLY FZFG BETWEEN 12Z-16Z OR SO WITH LESS THAN
1SM VISIBILITY. GREATER LIKELIHOOD FOR FOG TO REDEVELOP TONIGHT AT
IDA THAN PIH BUT CANNOT BE RULED OUT AT EITHER SITE. BYI IS LOOKING
MORE LIKELY TO BRIEFLY BE UNDER A MIST/FOG EARLY THIS MORNING
OTHERWISE DO NOT EXPECT MUCH IMPACTS HERE. SUN VFR CONDITIONS
THE NEXT 24 HOURS. NP/DMH


&&

.PIH WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON MST TODAY FOR IDZ017-019>021.

&&

$$



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