Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 262044
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
145 PM MST MON JAN 26 2015

.SHORT TERM...TONIGHT THROUGH THURSDAY. EARLY AFTERNOON SATELLITE
IMAGERY WAS SHOWING A RIDGE OF HIGH PRESSURE ACROSS THE ERN GREAT
BASIN WHILE A LOW PRESSURE SYSTEM WAS LIFTING NORTH ALONG THE
BAJA/SRN CALIFORNIA COAST. THE MODELS HAVE REMAINED FAIRLY
CONSISTENT WITH THE IDEA THAT THE LOW WILL LIFT NORTH ACROSS SRN
CALIFORNIA TONIGHT AND THROUGH NEVADA TUESDAY WITH THE LEADING EDGE
OF THE ASSOCIATED PRECIPITATION SHIELD SPREADING INTO SE IDAHO
DURING THE AFTERNOON. AGAIN...THE MAIN FORECAST ISSUE APPEARS TO BE
SNOW LEVELS AS WARM TEMPERATURES SPREAD ACROSS THE REGION AHEAD OF
THE LOW WHILE LOWER VALLEY LOCATIONS REMAIN TRAPPED UNDER STUBBORN
INVERSIONS. SUSPECT THAT AT LEAST A BRIEF PERIOD OF FREEZING RAIN
MAY BE REALIZED ACROSS THE INL/MUD LAKE AREA LATE TUESDAY
NIGHT/WEDNESDAY MORNING WHICH CAN BE HANDLED WITH ADVISORIES IF IT
DEVELOPS. BY WEDNESDAY AFTERNOON...THE UPPER LOW BEGINS TO SHEAR
EAST INTO WYOMING WITH PARTIALLY CLEARING SKIES ANTICIPATED
WEDNESDAY NIGHT. STORM TOTAL ACCUMULATIONS LOOK TO REMAIN BELOW 5
INCHES IN THE MOUNTAINS...THUS NO HIGHLIGHTS ARE ANTICIPATED AT THIS
TIME. A WEAK SECONDARY DISTURBANCE LIFTS NE THROUGH CNTRL NEVADA
THURSDAY AFTERNOON AND INTO THE BEAR LAKE REGION THURSDAY NIGHT. FOR
NOW...THE IMPACT LOOKS TO BE FOCUSED ACROSS UTAH WITH ONLY A SLIGHT
CHANCE OF LIGHT SNOW ACROSS SE IDAHO. HUSTON

.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY. A WEAKER SPLIT-FLOW
SYSTEM WILL WORK ACROSS THE REGION AT THE END OF THE WEEK. THE
MODELS ARE SPLIT...NO PUN INTENDED...ON HOW MUCH OF A SPLIT OCCURS.
THE GFS IS MORE CONNECTED TO THE NORTHERN STREAM VS THE ECMWF. WE
SHOULD SEE SOME LIGHT RAIN AND SNOW ALONG/SOUTH OF THE SNAKE
RIVER...POSSIBLY AS FAR NORTH AS ISLAND PARK BUT THE REST OF EASTERN
IDAHO WILL LIKELY STAY DRY. AFTER THAT...HIGH PRESSURE BUILDS ONCE
AGAIN ACROSS THE WEST. IDAHO WILL BE ON THE NORTHERN END OF THE
RIDGE AND SUBJECT TO THE POTENTIAL OF THE FLOW BEING MORE WESTERLY
AT TIMES. THE MODELS ARE STILL WANTING TO WAVER A BIT FROM RUN TO
RUN...AND THE ENSEMBLE FORECASTS AREN`T SHOWING MUCH TO HELP TREND
THE FORECAST ONE WAY OR THE OTHER. BASED ON THE PREVIOUS
FORECAST...WE KEPT ANY RAIN AND SNOW CONFINED TO THE CENTRAL AND
EASTERN MOUNTAINS. IT DOES LOOK LIKE THAT WE COULD SEE INVERSION
CONDITIONS...EVEN IF BRIEFLY HEADING INTO THE WEEKEND. KEYES
&&

.AVIATION...THE FOG IS A BIT SLOW TO DISSIPATE ALONG THE INTERSTATE
CORRIDOR AND SOME OTHER SPOTS AS OF NOON. BY DINNERTIME...MOST IF
NOT ALL OF IT WILL BE OUT OF HERE LEAVING US WITH CLEAR SKIES AND
VFR WEATHER AT ALL TAF SITES. AS FOR TONIGHT...KSUN SHOULD REMAIN
VFR AS WELL AS KBYI. KIDA AND KPIH MIGHT BE A BIT MORE
TRICKY...ESPECIALLY THE LATTER AIRPORT. PREVIOUS TAFS AND THE LATEST
GUIDANCE SHOWS KIDA GOING BACK TO IFR/LIFR DUE TO FOG THIS EVENING.
SINCE THEY WILL SEE THE LEAST INFLUENCE FROM THE NEXT STORM ARRIVING
UNTIL LATER TUESDAY...WE WENT WITH THE MORE PESSIMISTIC FORECAST. IF
WE GET A BIT MORE WIND TONIGHT IN THE UPPER PLAIN...WE MAY END UP
WITH STRATUS INSTEAD OR POSSIBLY NOTHING AT ALL.  AT KPIH...THE
LATEST SHOWS WE COULD SEE FOG/STRATUS REDEVELOP FOR A FEW HOURS
BEFORE WE SEE POSSIBLE SOUTHERLY GAP WINDS TAKING SHAPE. THIS WOULD
CLEAR OUT THE AIRPORT MOST LIKELY. WE ARE GOING WITH THAT SCENARIO
AFTER MIDNIGHT. IT IS POSSIBLE THAT THE WINDS AREN`T STRONG ENOUGH
TO KEEP FOG OR LOW CLOUDS AWAY. CLOUDS GENERALLY INCREASE DURING THE
DAY. WE MAY SEE PRECIPITATION AND REDUCED CEILINGS AS EARLY AS 21Z
(2PM)...BUT IT APPEARS THINGS COULD HOLD OFF UNTIL VERY LATE
AFTERNOON OR EVENING. KEYES
&&

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

$$








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