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
000
FXUS65 KPIH 090358
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
857 PM MST MON FEB 8 2016

.SHORT TERM...TONIGHT THROUGH THURSDAY. WE ARE SEEING A FEW AREAS
WITH DENSE FOG THIS EVENING...PRIMARILY AROUND IDAHO FALLS TO
INL...DRIGGS...AND AT THE I-86/84 INTERSECTION NEAR RAFT RIVER. WE
ARE CARRYING AREAS OF DENSE FOG IN THE FORECAST AND AT THIS POINT I
THINK IT IS SUFFICIENT TO COVER WHAT WE HAVE GOING ON THIS EVENING.
IF CONDITIONS DETERIORATE FURTHER...WE MAY NEED TO FOLLOW WITH AN
ADVISORY. SEE PREVIOUS DISCUSSION BELOW. HUSTON

SURFACE INVERSIONS IN THE LOWER VALLEYS AND SNAKE PLAIN WILL
INCREASE IN STRENGTH THE NEXT FEW DAYS UNDER A STRONG RIDGE OF HIGH
PRESSURE ALOFT. GENERALLY LIGHT WINDS ARE EXPECTED IN MOST AREAS
EXCEPT THE EASTERN MAGIC VALLEY WHERE AN EASTERLY SURFACE PRESSURE
GRADIENT WILL PRODUCE WINDS OF 5 TO 15 MPH EACH AFTERNOON. ABUNDANT
LOW STRATUS AND FOG AT TIMES WILL PERSIST IN THE SNAKE PLAIN. THE
EAST WINDS AROUND SHOSHONE AND GOODING AREA MAY SUCCEED IN NUDGING
SOME OF THE STRATUS OFF TO THE WEST TOWARDS BOISE. IN THE
MEANTIME...THE STRATUS COULD HELP LIMIT THE FORMATION OF DENSE FOG
AT THE GROUND. AN ADVISORY MAY BE NEEDED LATE THIS EVENING. AS LONG
AS THE STRATUS HOLDS...TEMPERATURES WILL RESIST ANY BIG WARM UP/COOL
DOWN. OUTSIDE OF THE STRATUS...TEMPERATURES ON THE MOUNTAIN SLOPES
WILL WARM INTO THE LOWER 40S...ESPECIALLY IN THE SAWTOOTH AND SOUTH
CENTRAL HIGHLANDS. LIMITED SNOW MELT AND RUN OFF WILL PROBABLY OCCUR
ON A FEW SMALL STREAMS...BUT THERE IS NO FORECAST RAIN ON THE SNOW
PACK TO GREATLY ACCELERATE RUN OFF. RS

.LONG TERM...THURSDAY NIGHT THROUGH NEXT MONDAY. STRONG UPPER RIDGE
OVER THE WEST WILL CONTINUE ACROSS THE AREA BUT WILL SLOWLY SHIFT
EASTWARD FRIDAY WHILE MODERATE SHORTWAVE PUNCHES THROUGH. THERE IS
ABOUT A 12 HOUR TIMING DIFFERENCE BETWEEN THE ECMWF AND GFS WITH THE
ECMWF BEING THE FASTER OF THE MODELS. THE SHORTWAVE MAY HELP ERODE
THE LOW-LEVEL INVERSION ALLOWING SOME MIXING TO OCCUR...BUT MOST OF
THE ENERGY WILL LIKELY RIDE INTO NORTHERN IDAHO. AFTER SUNDAY...GFS
RE-ESTABLISHES THE UPPER RIDGE OVER THE WEST WHILE THE ECMWF GIVES
US A FLATTER...NORTHWESTERLY FLOW WITH MORE MOISTURE TRANSPORT. NO
MAJOR CHANGES MADE TO ON-GOING FORECAST AND AM KEEPING LOW CHANCE
POPS OVER THE MOUNTAINS FOR SATURDAY. HINSBERGER
&&

.AIR STAGNATION...LOW LEVEL INVERSION CONDITIONS WILL INCREASE
UNDER THE HIGH PRESSURE RIDGE THROUGH ABOUT WEDNESDAY. AFTER
THAT...ADDITION OF SOME MIDDLE AND HIGH LEVEL CLOUDS WILL HELP
MODIFY THE INVERSION CONDITIONS. A WEAK DISTURBANCE EXPECTED TO
ARRIVE SATURDAY OR SATURDAY NIGHT SHOULD BRING SOME STRONGER WINDS
AND MIXING. RS
&&

.AVIATION...CHALLENGE FOR THE PERIOD WILL BE TRACKING THE
FOG/STRATUS FIELD IN THE SNAKE PLAIN THROUGHOUT THE DAY. UPPER
RIDGING WILL CONTINUE TO REMAIN IN PLACE AND A STRONG LOW-LEVEL
INVERSION PERSISTS. GUIDANCE CONTINUES IFR/LIFR CONDITIONS THROUGH
THE TAF PERIOD FOR PIH AND IDA. BYI MAY SEE VFR CEILINGS THIS
AFTERNOON WITH MOS GUIDANCE AND BUFR TIME-HEIGHTS SUGGESTING
SO...BUT EXPECT TO SEE STRATUS RETURN AGAIN LATE TONIGHT. SUN IS
EXPECTED TO REMAIN VFR BUT WITH UP-VALLEY WINDS EXPECTED THIS
AFTERNOON...SOME OF THE STRATUS MAY MAKE ITS WAY INTO THAT TERMINAL.
HINSBERGER
&&

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

&&

$$


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