Area Forecast Discussion
Issued by NWS Boise, 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 44 45 46 47 48 49 50
000
FXUS65 KBOI 081623
AFDBOI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
923 AM MST MON FEB 8 2016

.DISCUSSION...
SATELLITE...WEBCAMS AND SFC OBS SHOWING LOW CLOUDS FOG EXTENDING
FROM EASTERN IDAHO THROUGH TWIN FALLS TOWARDS GLENNS FERRY AND
POTENTIALLY INTO THE CAMAS PRAIRIE. THIS SHOULD LINGER THROUGH
NOON THEN START TO DIMINISH. FORECAST SOUNDINGS FOR THE BOISE AREA
DIFFERENT THAN YESTERDAY IN THAT THE LOWER AIRMASS IS NOT
SATURATED LIKE IT WAS INDICATING YESTERDAY...SO BASED ON THAT AND
FULL SUN THIS MORNING...DONT EXPECT IT TO MOVE INTO THE UPPER
TREASURE VALLEY. RIDGE CONTINUE TO AMPLIFY AND WARMER AIR STILL
EXPECTED TO MOVE IN AROUND 700MB KEEP INVERSION IN PLACE. CURRENT
FORECAST HAS THIS TREND...SO NO CHANGES EXPECTED. OUTSIDE OF THE
ST/FOG...TEMPS REMAINING ABOVE NORMAL.

&&

.AVIATION...
MAINLY VFR. SURFACE BASED TEMPERATURE INVERSION WILL
PERSIST THROUGH AT LEAST WEDNESDAY NIGHT DUE TO HIGH PRESSURE ALOFT
OVER THE INTERMOUNTAIN WEST. FOR THE NEXT FEW DAYS EXPECT AREAS OF
IFR/LIFR FOG AND LOW STRATUS IN THE SNAKE RIVER VALLEY DURING THE
NIGHT AND THROUGH EARLY AFTERNOON...WITH PATCHY VALLEY FOG IN THE
KBNO...KBKE AND KMYL AREAS. DAYTIME HEATING WILL PROVIDE ENOUGH
MIXING TO DISSIPATE THE FOG AND STRATUS BY 21Z...BUT WILL REDEVELOP
AGAIN IN THE EVENING. SURFACE WINDS VARIABLE 10 KTS OR LESS. WINDS
ALOFT NORTHWEST 10-20 KNOTS UP THROUGH 10K FT MSL.

&&

.AIR STAGNATION...
INVERSION TO CONTINUE TO STREGTHEN AT LEAST THROUGH MIDWEEK WITH
WARMING TEMPERATURES AT 700MB. TRANSPORT WINDS REMAINING LIGHT
EASTERLY AT THE SFC AT UNDER 10 MPH THEN SHIFTING LIGHT NORTHERLY
5-10KFT. MIXING HGTS EXPECTED AROUND 1000-1500 FT THROUGH TUESDAY.

&&

.PREV DISCUSSION...
SHORT TERM...UPPER RIDGE STILL BUILDING...AND STRENGTHENING THE
INVERSION.  SEVERAL WX DIFFERENCES FROM LAST NIGHT AT 09Z.  AN AREA
OF FOG/STRATUS HAS FORMED IN THE MAGIC VALLEY AND SLOWLY EXPANDING
WEST.  FAIRFIELD/ID IS MUCH COLDER THAN LAST NIGHT...NEAR ZERO THIS
MORNING VS MID 20S LAST NIGHT WHEN WINDS WERE NEAR 15 MPH.  WINDS
HAVE BECOME NE AT JEROME/ID DRAINING FROM THE COLD CAMAS PRAIRIE.
WITH MOS GUIDANCE CONTINUING TO FORECAST NE WIND WE CAN ALSO EXPECT
A CONTINUATION OF COLD TEMPS IN THE CAMAS PRAIRIE THROUGH TUESDAY.
AS FOR THE FOG/STRATUS...WE SEE THAT NAM AND NAMBC ARE THE ONLY
MODELS THAT KEEP MAX TEMPS DOWN THROUGHOUT THE SNAKE BASIN TODAY AND
TUESDAY. THAT SUGGESTS COLD FOGGY AIR WILL SPREAD OVER NEARLY ALL OF
THE LOWER SNAKE BASIN.  BUT THOSE TWO MODELS ALSO SHOW IDAHO CITY
COLDER THAN THE UPPER TREASURE VALLEY TODAY WHICH IS PROBABLY
INCORRECT.  NO OTHER MODELS DO THIS.  YESTERDAY IDAHO CITY HAD A
HIGH OF 52 VS ONLY UPPER 40S IN THE TREASURE VALLEY...AND SIMILAR
TEMPS ARE EXPECTED TODAY. NO PCPN THROUGH TUESDAY.  LIGHT EAST WINDS
TODAY AND TUESDAY...EXCEPT MODERATE NE NEAR JEROME/ID.

LONG TERM...TUESDAY NIGHT THROUGH MONDAY...INVERSION WILL REMAIN IN
PLACE THROUGH FRIDAY UNDER A HIGH AMPLITUDE UPPER LEVEL RIDGE. DID
ADJUST TEMPERATURES A BIT HIGHER ESPECIALLY ON WEDNESDAY AS MODEL
SOUNDING ARE SHOWING THE STRATUS DECK BREAKING UP. INCREASING EAST-
SOUTHEASTERLY FLOW ACROSS THE REGION ON THURSDAY/FRIDAY AHEAD OF THE
NEXT UPPER LEVEL TROUGH OFF THE COAST WILL ALSO LIMIT FOG/STRATUS
COVERAGE. TEMPERATURES WILL REACH THE LOWER 40S WEDNESDAY THROUGH
FRIDAY EXCEPT IN THE LOWER TREASURE VALLEY. HIGH TEMPERATURES ABOVE
THE INVERSION WILL BE IN THE 40S AND LOWER 50S. THE UPPER TROUGH
MOVES INLAND FRIDAY NIGHT/SATURDAY BUT WEAKENS SIGNIFICANTLY BY THE
TIME IT REACHES THE INTERMOUNTAIN WEST. 00Z GFS DOESN/T EVEN HAVE THE
TROUGH MAKING IT THAT FAR INLAND. 00Z ECMWF DOES BRING IN THE THOUGH
THOUGH BUT WITH VERY LITTLE PRECIPITATION. THE UPPER RIDGE REBUILDS
OVER THE WESTERN CONUS BEGINNING SUNDAY WHICH LOOKS TO LAST THROUGH
THE MIDDLE OF NEXT WEEK. TEMPERATURES WILL CONTINUE TO BE ABOVE
NORMAL FRIDAY THROUGH MONDAY.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
OR...NONE.

&&

$$

WEATHER.GOV/BOISE

DISCUSSION...CR
AVIATION.....JA
AIR STAGNATION...CR
PREV SHORT TERM...LC
PREV LONG TERM....JDS


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