Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 020926
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
326 AM MDT SUN AUG 2 2015

.SHORT TERM...VALID FOR TDY AND MON...

A SURFACE LOW SCOOTED ACROSS NORTHEAST MONTANA SATURDAY EVENING
AND WAS SITTING IN SOUTHEAST NORTH DAKOTA THIS HOUR. THIS LOW
PULLED A COOL FRONT THROUGH THE AREA. THIS FRONT WILL WASH OUT
TODAY UNDERNEATH A STRONG RIDGE AND DRY NORTHWEST FLOW...BUT
EASTERLY LOW LEVEL WINDS WILL LINGER THROUGH THE DAY. THIS WILL
KEEP THE AREA A BIT COOLER AS THE 30C 850MB AIR WILL OF SATURDAY
WILL BE SUPPRESSED TO THE SOUTH AND WEST. HIGHS WILL STILL BE
ABOVE NORMAL...JUST NOT AS HOT AS THE LAST COUPLE OF DAYS. COOLER
TEMPERATURES WILL KEEP MINIMUM HUMIDITY VALUES A LITTLE HIGHER
TODAY BUT STILL HAVE READINGS FALLING INTO THE TEENS. SHOULD NOT
SEE SINGLE DIGITS TO AROUND 10 PERCENT. EASTERLY WINDS WILL KEEP
THE ATMOSPHERE CAPPED. THAT AND THE LACK OF ANY FORCING WITH A
SHORTWAVE...WILL KEEP THE IDEA OF A CONVECTION FREE DAY.

THE RIDGE AXIS...CURRENTLY OVER WESTERN IDAHO THROUGH UTAH...WILL
SHIFT OVER THE FORECAST AREA MONDAY. THIS WILL KEEP THE DAY DRY.
EAST TO SOUTHEAST LOW LEVEL WINDS WILL INCREASE THROUGH THE DAY.
THIS WILL PULL IN HIGHER DEWPOINTS AND KEEP HUMIDITIES FROM
BOTTOMING OUT IN THE AFTERNOON. SO DESPITE INCREASING WINDS...WILL
NOT ISSUE ANY FIRE WEATHER HIGHLIGHTS DUE TO THE IDEA OF MINIMUM
HUMIDITIES STAYING AROUND 20 PERCENT WITH HIGHER VALUES OVER THE
EAST WHERE THE STRONGEST WINDS SHOULD BE.

THE UPPER RIDGE WILL CONTINUE TO PROGRESS EAST MONDAY NIGHT. THIS
WAS DUE TO AN UPPER TROUGH PUSHING IT ALONG FROM THE WEST. MID
LEVEL MOISTURE WITH THE TROUGH APPROACHING WILL SPREAD OVER THE
FORECAST AREA AND SHOULD KEEP HIGHS IN CHECK. THE TROUGH IS
PROGGED TO ENTER SOUTHWEST MONTANA MONDAY NIGHT...WITH THE BULK OF
THE ENERGY NOT GETTING INTO OUR WEST UNTIL LATE EVENING. THIS WILL
DELAY THE ONSET OF CONVECTION OVER THE WEST...AS HAS BEEN THE
TREND WITH THE MODELS OF LATE. HAVE THEREFORE TRIMMED POPS BACK
OVER WESTERN AND CENTRAL ZONES. WILL NOT ISSUE ANY FIRE WEATHER
HIGHLIGHTS FOR CONVECTION WITH LATER ARRIVAL. TWH

.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...

MADE SEVERAL CHANGES TO THE EXTENDED FORECAST PERIOD...AS GOOD
MODEL AGREEMENT CONTINUES...AND DETAILS BECOME CLEARER.

MODELS ARE NOW PROGGING TO THE UPPER LEVEL PACIFIC LOW THAT IS
RESPONSIBLE FOR WAVES OF ENERGY THROUGH THE REGION TO STALL OVER
OVER BRITISH COLUMBIA THROUGH WEDNESDAY. THIS RESULTS IN NEGATIVE
TILT TO SHORTWAVES RADIATING THROUGH THE REGION...AS WELL AS
APPEARS TO IMPROVE INFLUX OF PACIFIC AND MONSOONAL FLOW. TWO
SIGNIFICANT WAVES HAVE BECOME EVIDENT IN THE MODELS...THE FIRST ON
TUESDAY...WHICH APPEARS TO BRING A SIGNIFICANT COOL OFF AND
RAIN/THUNDER CHANCES ACROSS THE REGION. PWATS OF 1 INCH WEST TO
1.5 INCHES EAST SHOULD LEAD TO HEAVY RAIN POTENTIAL WITH THESE
STORMS. RAISED POPS SIGNIFICANTLY WITH THIS FIRST DISTURBANCE. THE
SECOND WAVE IS LATER WEDNESDAY INTO THURSDAY...AND COINCIDES WITH
LOW SHIFTING EASTWARD. THIS WAVE LOOKS A BIT WEAKER...WITH LESS
ORGANIZED...BUT CERTAINLY WILL BRING ANOTHER CHANCE FOR PRECIP TO
THE REGION. FLOW BECOMES ZONAL ACROSS THE REGION FOR FRIDAY AS LOW
WASHES OUT OVER SASKATCHEWAN...AND RIDGING BEGINS TO REBUILD.
TIMING INCONSISTENCIES BEGIN INCREASING AT THIS POINT...BUT
GENERALLY AGREE ON RIDGING BEING FAIRLY SHORT-LIVED OVER THE
CWA...AS ANOTHER PACIFIC TROF DEVELOPS OFF THE NORTHERN CALIFORNIA
COAST. THIS TROF PUSHES INTO THE REGION SATURDAY NIGHT THROUGH
SUNDAY...WITH ACCOMPANYING PACIFIC MOISTURE AND A STRONG
CONNECTION TO MONSOONAL FLOW...SO LOOKS QUITE WET.

AS FOR TEMPS...EXPECT HIGH TEMPS BELOW SEASONAL AVERAGE FOR THE
FIRST HALF OF THE PERIOD...WITH UPPER 70S AND LOW 80S THROUGH
THURSDAY. COOLED TEMPS SIGNIFICANTLY FOR THIS PERIOD. TEMPS RETURN
TO SEASONAL RANGE FOR THE LATTER HALF OF THE EXTENDED...WITH MID
TO UPPER 80S. AAG

&&

.AVIATION...

VFR CONDITIONS WILL CONTINUE TODAY...WITH MOSTLY CLEAR SKIES.
EASTERLY WINDS WILL PREVAIL ACROSS THE REGION TODAY...BUT ARE NOT
EXPECTED TO POSE ANY PROBLEMS FOR AVIATION. AAG

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY MON     TUE     WED     THU     FRI     SAT
-------------------------------------------------------
BIL 092 060/092 064/079 052/081 056/082 059/086 059/086
    0/U 01/B    25/T    44/T    43/T    22/T    12/T
LVM 093 054/090 058/077 050/083 051/082 052/085 052/083
    0/U 02/T    35/T    34/T    43/T    22/T    12/T
HDN 094 058/096 062/083 052/085 054/084 057/087 057/088
    0/U 01/B    36/T    43/T    33/T    22/T    12/T
MLS 091 061/094 065/085 057/076 055/077 059/086 058/088
    0/U 00/U    25/T    73/T    33/T    22/T    22/T
4BQ 092 059/092 062/081 057/078 054/077 058/085 058/087
    0/U 00/U    36/T    63/T    34/T    42/T    22/T
BHK 089 057/090 060/082 058/074 053/076 056/083 056/085
    0/U 00/U    13/T    73/T    34/T    42/T    22/T
SHR 094 056/091 058/075 049/082 051/079 053/084 053/085
    0/U 01/B    36/T    43/T    33/T    22/T    12/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS



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