Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 012040
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
140 PM MST MON FEB 1 2016

.SHORT TERM...SATELLITE IMAGERY SHOWS A LOW PRESSURE DISTURBANCE
WELL TO OUR SOUTH NEAR THE COLORADO AND NEW MEXICO BORDER WITH
CLOUDS REACHING BACK TO SOUTHEAST IDAHO FROM BEAR LAKE TO ABOUT
DRIGGS. KEPT A SLIGHT CHANCE OF SNOW IN THAT AREA TONIGHT WHILE
THE DISTURBANCE MOVES FURTHER EAST. TUESDAY...COLD NORTHWESTERLY
FLOW REMAINS OVER THIS AREA FAVORING THE CARIBOU AND SOUTH CENTRAL HIGHLANDS
FOR A CONTINUED SLIGHT CHANCE OF SNOW. THE UPPER SLOPES COULD SEE
A HALF TO ONE INCH ACCUMULATION OVER A 24 HOUR PERIOD.
TEMPERATURES REMAIN COLD TONIGHT /TUESDAY IF NOT 1 OR 2 DEGREES
COLDER THAN MONDAY MORNING. FOCUS SHIFTS ALONG THE IDAHO AND
WYOMING BORDER ON WEDNESDAY WITH MORE WESTERLY WINDS ALOFT AHEAD
OF THE NEXT APPROACHING DISTURBANCE. THIS DISTURBANCE RACES ACROSS
SOUTHEASTERN IDAHO LATE WEDNESDAY AFTERNOON THROUGH THURSDAY
AFTERNOON. SNOW ACCUMULATION OF AROUND ONE INCH EXPECTED IN THE
LOWER VALLEYS...AND 2 TO 5 INCHES POSSIBLE IN THE MOUNTAINS.
HIGHEST ACCUMULATIONS WILL BE NEAR GALENA SUMMIT ON THE WEST SIDE
AND BETWEEN PALISADES AND DRIGGS ON THE EAST SIDE. THIS COULD BE A
LITTLE LESS BY THE TIME IT GETS HERE SINCE MODELS ARE IN AGREEMENT
ON SOME SPLITTING/STRETCHING OF THE TROUGH NORTH AND SOUTH AS IT
MOVES THROUGH THE GREAT BASIN. THIS STRETCHING HAS ALREADY
RESULTED IN FORECAST WINDS FOR THURSDAY LIGHTER THAN PREVIOUSLY
FORECAST. RS

.LONG TERM...THU NIGHT THROUGH NEXT MON NIGHT. THE 500MB LONGWAVE
FORECAST IS FAIRLY SIMPLE. AN UPPER LEVEL LONGWAVE RIDGE IS IN PLACE
OVER THE GREAT BASIN AND AMPLIFIES DURING THE LAST COUPLE OF DAYS.
THIS INDICATES A BETTER CHANCE FOR AN EARLY WETTER PERIOD AND THE
LAST TWO DAYS OF A VERY DRY PERIOD. ADDING IN THE DETAILS IS VERY
MUCH HOW THAT PANS OUT. THE STORM OCCURRING LAT IN THE SHORT TERM
WRAPS UP ON THU NIGHT...THEN A SHORTWAVE IS ABLE TO RIDE THROUGH THE
LONG WAVE RIDGE ON SAT/SAT NIGHT. BUT AFTER THIS...THE LONG WAVE
PATTERN AMPLIFIES STRONGLY...FOR LITTLE CHANCE IN PRECIPITATION
OCCURRING. SO HAVE CLEARED UP THE END PERIOD A LITTLE IN TERMS OF
POP. HOWEVER...THE RISK OF FOG AND STRATUS DURING THIS TIME IS
HIGH...SO HAVE ADDED AREAS OF FOG FOR THE EASTERN MAGIC VALLEY/SNAKE
RIVER PLAIN/TETON VALLEY...MOSTLY AT NIGHT. COULD BE WINDY WITH THE
SAT/SAT NIGHT STORM...AND ENOUGH WARM AIR ADVECTION AHEAD OF THIS
STORM TO MAKE FOR A MOUNTAIN SNOW AND VALLEY RAIN/SNOW EVENT. IT
DOES NOT SEEM TO BE MAKING ANY SORT OF SUBTROPICAL CONNECTION...SO
RIGHT NOW IT LOOKS LIKE ONLY A LIGHT SNOW EVENT.  MESSICK
&&

.AVIATION...HIGH PRESSURE STRENGTHENING ONLY MEANS THE CHANCE OF FOG
AND STRATUS WILL INCREASE...UNLESS THE NORTHERLY AIR FLOW BRINGS IN
SOME SUPER-DRY AIR. AT THIS POINT...THE INDICATIONS ARE NO. THUS
HAVE PUT IN IFR STRATUS OR WORSE WITH SOME MIST TO SLIGHTLY HAVE AN
IMPACT ON VISIBILITY FOR THE UPCOMING LATE NIGHT AND MORNING HOURS
FOR THE THREE VALLEY AIRDROMES. FOR KSUN...EXPECT SEVERE CLEAR
CONDITIONS WITH THE NORTHERLY AIRFLOW KEEPING OUT STRATUS AND FOG.
MESSICK
&&

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

&&

$$


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