Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 120916
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
316 AM MDT SAT APR 12 2014

.SHORT TERM...TODAY THROUGH MON NIGHT. APPROACHING TROUGH HAS
DECELERATED A LITTLE MORE AND BEST CHANCE OF PRECIPITATION OCCURS
MORE IN THE EVENING AND LATE NIGHT THAN THIS AFTERNOON. LOCAL
STUDY INDICATES HIGH CONFIDENCE IN A WIND ADVISORY FOR ZONES 17
AND 21. ALL THE UPPER LEVEL SUPPORT IS THERE WITH THE PROPER
SYNOPTIC PATTERN. THE ONLY WEAKNESS IS THAT 700MB WIND IS ONLY 10KT
TO 20KT. BUT THERE IS A STRONG NORTHWEST TO SOUTHEAST GRAIDIENT
FOR THE SEA LEVEL PRESSURE PATTERN. WITH THE PERSISTENT WEST TO
NORTHWEST WIND...THE STUDY INDICATES NOT MUCH CHANCE FOR ZONE 20
WHICH WOULD BE EXACERBATED BY BLOWING DUST. IN FACT WINDS ARE
INDICATING A SHIFT UP THERE TO THE NORTHEAST AS THE TROUGH COMES
THROUGH DUE TO ITS APPROACH FROM THE NORTH-NORTHWEST RATHER THAN
FROM THE WEST. TEMPERATURES COOLER THAN YESTERDAYS VERY MILD
PATTERN...AND EVEN COLDER FOR SUN AFTER THE FRONTAL PASSAGE. WINDS
WILL CALM DOWN AS THE UPPER LEVEL PATTERN SHIFTS FARTHER EAST AS
THE TROUGH DEPARTS. THE COLD AIR COULD PRODUCE SOME SNOW EVEN IN
THE NORTHERN END OF THE SNAKE RIVER PLAIN DUE TO THE COLD
NORTHERLY AIR FLOW...AS MUCH AS 1 TO 6 INCHES ABOVE 7000 FT
ELEVATION. WILL ISSUE SPECIAL WEATHER STATEMENT FOR THIS EVENT
SINCE IT HAS BEEN A WHILE SINCE SNOW OCCURRED THIS LOW IN
ELEVATION. THE REST OF SUN AND SUN NIGHT IS A LOW CONFIDENCE
FORECAST WITH SOME AREAS OF SHARP DISAGREEMENT AMONG GUIDANCE
PRODUCTS IN THE NORTHERLY FLOW ALOFT PATTERN BEHIND THIS. GFS IS
DEFINITELY WETTER...THE BULLS-EYE APPEARANCE OF THE PRECIPITATION
PATTERN INDICATES THERE COULD BE SOME CONVECTIVE FEEDBACK PROBLEMS
IN BOTH THE NAM AND GFS. HARD TO TELL AS IT WAS THIS WAY THU NIGHT
AS WELL. WENT MORE WITH NAM AMOUNTS AND MOST LOCATIONS WILL WARM
TO ABOVE FREEZING. DO NOT EXPECT WIND TO RETURN AND BY LATE SUN
NIGHT CLEARING SKIES WILL MAKE FOR A COLD MON MORNING. AN UPPER
LEVEL RIDGE RETURNS AND STRONG WARMING MEANS A 6 TO 10 DEG F WARM
UP FOR MON AFTERNOON AND WARMING TREND FOR OVERNIGHT LOWS DEVELOPS
MON NIGHT. MESSICK

.LONG TERM...UESDAY THROUGH SATURDAY. MODELS ARE CONTINUING TO SHOW
AN UPPER RIDGE PERSISTING UNTIL MID DAY TUESDAY WITH A SHORTWAVE
PASSING TO THE NORTH TUESDAY EVENING. BEYOND THAT...MODELS HAVE BEEN
EXTREMELY INCONSISTENT WITH EACH OTHER AND INCONSISTENT WITH
THEMSELVES RUN TO RUN. THE GFS KEEPS A CLOSED LOW IN THE FORECAST
FOR MID WEEK BUT ITS ORIGIN AND PATHS ARE VARYING GREATLY.  THE
ECMWF KEEPS US IN A FAIRLY ACTIVE WESTERLY FLOW WITH SHORTWAVES
PASSING THROUGH. DUE TO MUCH UNCERTAINTY...HAVE KEPT IN AROUND
CLIMO POPS FOR THE ENTIRE EXTENDED FORECAST. TEMPERATURES LOOK TO
REMAIN NEAR OR ABOVE NORMAL THROUGH THE PERIOD. EP

&&

.AVIATION...VFR CONDITIONS EXPECTED AT ALL TAF SITES THROUGH THE
PERIOD. WINDS WILL PICK UP ONCE AGAIN THIS AFTERNOON AND QUIET DOWN
NEAR SUNSET. EP

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 9 PM MDT THIS EVENING
IDZ017-021.

&&

$$







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