Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 020322
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
922 PM MDT FRI AUG 1 2014

.UPDATE...THUNDERSTORMS LEFT THIS EVENING IN CENTRAL MOUNTAINS AND
PORTIONS OF SOUTHERN/EASTERN HIGHLANDS. ACTIVITY HAS DIMINISHED
PAST COUPLE HOURS AND EXPECT TREND TO CONTINUE OVERNIGHT.
SHORTWAVE MOVING NORTHEAST FROM NEAR RENO/TAHOE SHOULD PUSH ACROSS
THE REGION LATE TONIGHT. LATEST HRRR SHOWING EVIDENCE OF
CONVECTION REFORMING IN SOUTHWEST IDAHO LATE TONIGHT AND REACHING
SOUTHWEST PORTIONS OF FORECAST AREA AROUND SUNRISE. GIVEN THE
AMOUNT OF OUTFLOW BOUNDARY INTERACTIONS THE PAST FEW NIGHTS THIS
SCENARIO DOESNT SEEM TOO FARFETCHED. EARLY LOOK AT NAM SUPPORTS
THIS IDEA AS WELL THOUGH SLIGHTLY SLOWER THAN HRRR WHICH KEEPS
MUCH OF EAST IDAHO DRY. ANOTHER SHORTWAVE EJECTING NORTHEAST
THROUGH PACNW COULD PROVIDE ENOUGH OF A TAIL TO KEEP WEAK THREAT
GOING IN CENTRAL MOUNTAINS OVERNIGHT. HAVE LEFT 06-12Z POPS AS
THEY ARE WITH VERY WEAK POPS CENTRAL MOUNTAINS /ENOUGH FOR
ISOLATED THUNDER MENTION OVERNIGHT/ AND WEAK SINGLE DIGIT POPS
HIGHER ELEVATIONS ELSEWHERE. OTHERWISE ONLY EDITS THIS EVENING
WERE TO ADJUST EVENING POP/WX GRIDS TO FIT CURRENT RADAR/SATELLITE
TRENDS. DMH



&&

.PREV DISCUSSION... /ISSUED 153 PM MDT FRI AUG 1 2014/

SHORT TERM...LOW PRESSURE DISTURBANCE MOVING FROM OREGON INTO
NORTHERN CALIFORNIA THIS AFTERNOON. THUNDERSTORMS ALREADY GETTING
STARTED IN CLOSE PROXIMITY TO THE BEAVER CREEK BURN SCAR FROM LAST
YEAR...WHICH REMAINS SUBJECT TO SLIDES AND QUICK RUN OFF WITH LITTLE
PRECIPITATION. MAIN DIFFERENCE TODAY IS STEERING WINDS ARE MORE
SOUTHWESTERLY RATHER THAN NORTHERLY AS THEY WERE YESTERDAY.
SATURDAY...SOUTHERLY WINDS WILL BRING A LIMITED SURGE OF MONSOON
MOISTURE UP FROM NEVADA TO PROVIDE ADDITIONAL MOISTURE FOR ISOLATED
AFTERNOON THUNDERSTORMS. THAT MOISTURE LINGERS ON SUNDAY UNDER VERY
LIGHT FLOW PATTERN SO MORE ISOLATED AFTERNOON SLOW MOVING
THUNDERSTORMS THAT PUT DOWN SOME GOOD RAIN WILL REPEAT.

LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY...THE PAST FEW MODEL RUNS
ARE SHOWING SOME CONSISTENCY WITH A DEVELOPING LOW CROSSING
CALIFORNIA TO NEVADA AND THEN TO IDAHO. THE INITIAL UPPER LEVEL
FRONT OFF THE LOW REACHES THE SOUTH CENTRAL HIGHLANDS CLOSE TO
MONDAY MORNING. THERE ARE SLIGHT VARIATIONS BETWEEN MODELS BUT
OVERALL THEY HINT AT THIS LOW BRING SOME FAIRLY NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS ALL OF SOUTHEAST IDAHO BETWEEN MONDAY
AND WEDNESDAY. POSSIBLY .5 TO 1 INCH OF PRECIPITATION OVER MOST OF
THE MOUNTAINS THROUGH THAT TIME PERIOD. MAYBE SOME WETTER SPOTS. GFS
MODEL SHOWING SOME CONVECTIVE FEED BACK THAT NEEDS TO BE TAKEN IN
STRIDE WITH THE FORECAST. GFS IS ALSO SLOWER TO CLEAR PRECIPITATION
OUT OF THE AREA EVEN ON THURSDAY. RS

AVIATION...NO CHANGES IN THIS ONGOING MONSOON PATTERN ACROSS
EASTERN IDAHO. WE ARE CARRYING VCTS FOR ALL TAF SITES WITH VFR
WEATHER EXPECTED. REDUCED CONDITIONS ARE POSSIBLE WITH STORMS
PRODUCING HEAVY RAIN AND/OR WINDS. KEYES

FIRE WEATHER...MONSOON MOISTURE WILL CONTINUE TO AFFECT EASTERN
IDAHO WELL INTO NEXT WEEK. SHOWERS AND THUNDERSTORMS WILL REMAIN A
PROBLEM. WE SHOULD SCATTERED STORMS TOMORROW ACROSS THE CENTRAL
MOUNTAINS WITH ISOLATED/WIDELY SCATTERED STORMS. BASED ON RECENT
HEAVY RAIN IN THE AREA...SIMILAR FORECASTS AND SOME COORDINATION WE
WILL NOT BE ISSUING A RED FLAG WARNING FOR THOSE ZONES. THUNDERSTORM
COVERAGE WILL BE A BIT LESS ON SUNDAY BUT STILL LOOK FOR LOCALLY
HEAVY RAINFALL. FOR MONDAY ONWARD...WE ARE LOOKING AT MULTIPLE DAYS
OF POTENTIALLY HEAVY RAIN AS A SLOW MOVING STORM FROM BAJA MOVES
THROUGH THE REGION. THE QUESTION WILL BE HOW MUCH THUNDERSTORM
COVERAGE. RIGHT NOW...WE MAY BE LOOKING AT TOO MUCH EARLY CLOUD
COVER THAT WOULD MAKE THINGS TOO STABLE FOR WIDESPREAD THUNDER. THIS
IS ESPECIALLY THE CASE ON MONDAY. EVEN IF THAT IS THE
CASE...PREDICTED RAINFALL PER DAY COULD EXCEED 0.50 INCHES IN THE
MOUNTAINS. STAY TUNED.  KEYES

&&

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

$$







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