Weather Service Report


774 
FXUS65 KBYZ 291616
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT 
916 AM MST THU JAN 29 2015

.UPDATE...
NO SIGNIFICANT CHANGES TO THE INHERITED FORECAST. I EXTENDED THE
PATCHY FOG OUT EAST UNTIL NOON AND ADJUSTED SKY GRIDS A BIT.
OTHERWISE THE WEATHER LOOKS RATHER BENIGN TODAY. BT

&&

.SHORT TERM...VALID FOR TDY AND FRI...

A QUIET SHORT TERM FORECAST WITH VERY PLEASANT TEMPERATURES FOR
THIS TIME OF YEAR ABSENT THE USUAL GUSTY WINDS. 

STRONGER NORTHWEST FLOW WILL EXIST JUST TO THE EAST OF THE AREA
THE NEXT COUPLE OF DAYS WITH SOME WEAK RIDGING TRYING TO BUMP INTO
THE AREA FROM THE WEST. THIS WILL KEEP PLENTY OF SUN AND ABOVE
NORMAL TEMPERATURES OVER THE AREA...BUT HOLD DOWN THE GUSTY WINDS
THAT WOULD NORMALLY ACCOMPANY SUCH TEMPERATURES THIS TIME OF YEAR.
HIGHS TODAY WILL RANGE FROM THE MID 30S EAST TO THE MID 40S
WEST...CLIMBING JUST A FEW DEGREES WARMER ON FRIDAY. 

A STRONG DISTURBANCE DROPS INTO THE AREA FROM THE NORTHWEST ON THE
NOSE OF A STRONG NW-SE ORIENTED JET STREAK LATE FRIDAY NIGHT. THIS
WILL USHER IN COLDER AIR FOR SATURDAY. LATEST OPERATIONAL MODEL
RUNS HAVE SLOWED DOWN THE ARRIVAL OF THIS FEATURE SOME AND DON'T
BRING IN STRONGER DYNAMICS FOR PRECIPITATION UNTIL SOMETIME DURING
THE DAY SATURDAY. THIS RESULTS IN A DRY FORECAST FOR FRIDAY NIGHT.
HOWEVER THE ENSEMBLE SPREADS FOR FRIDAY NIGHT AND SATURDAY REMAIN
HUGE AS FAR AS TEMPERATURES GO INDICATING THAT THE MODELS ARE
STILL NOT SET ON AN ARRIVAL TIME FOR THIS SYSTEM AND IT COULD
ARRIVE OVERNIGHT FRIDAY NIGHT SO WILL HAVE TO KEEP AN EYE ON THIS
FEATURE. 

WITH A LACK OF WIND AND CONTINUED SNOW MELT COULD SEE SOME PATCHY
FOG IN LOW LYING AREAS EACH OF THE NEXT FEW NIGHTS. ONLY OTHER
CONCERN CONTINUES TO BE ICE JAMS ON AREA STREAMS AND RIVERS.
COOLER WEATHER OVER THE NEXT SEVERAL DAYS SHOULD SLOW DOWN SNOW
MELT BUT IT WILL TAKE SOME TIME FOR WATER TO WORK THROUGH TO THE
LARGER STREAMS. ICE HAS BECOME UNSTABLE AND IS MOVING IN SOME
LOCATIONS SO THE THREAT OF ICE JAMS AND LOCALIZED FLOODING IS
PRESENT. ITS NEARLY IMPOSSIBLE TO PREDICT WHERE ICE JAMS WILL
OCCUR AND WHETHER FLOODING WILL RESULT. THOSE LIVING NEAR AREA
WATERWAYS SHOULD BE AWARE OF THE THREAT AND ALERT FOR ICE JAMS
AND FLOODING. MOVE EQUIPMENT AND LIVESTOCK TO HIGHER GROUND.
CHAMBERS

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

ONLY MINOR CHANGES TO THE EXTENDED FORECAST AT THIS
TIME...LARGELY BASED ON IN-BRIEFING OF SOMEWHAT INCONSISTENT MODEL
PROGGS OF APPROACHING UNSETTLED WEATHER. OVERALL THE MODELS
CONTINUE TO FAVOR A COOLER AND UNSETTLED PATTERN. THERE ARE
HOWEVER SIGNIFICANT DIFFERENCES IN THE DETAILS BETWEEN
MODELS...FROM RUN TO RUN OF EACH MODEL...AS WELL AS WITHIN THE
ENSEMBLE MEMBERS OF THE MODELS. THESE ISSUES MAKE IT VERY
DIFFICULT TO BE CONFIDENT IN MAKING ANY CHANGES TO THE FORECAST.
TEMPS DO APPEAR TO BE TRENDING A BIT COOLER THAN INHERITED...BASED
ON THE MODEL SPECTRUM AND TEMPS POISED JUST TO THE NORTH.

A STRONG JET IS STILL PROGGED TO DRIVE BACKDOOR FRONT AND
SHORTWAVE INTO THE REGION ON SATURDAY...WHICH SHOULD BRING A
CHANCE FOR PRECIP AND MUCH COOLER TEMPS ACROSS THE AREA...BUT
MODELS CONTINUE TO VARY GREATLY ON WHAT AREAS RECEIVE PRECIP. GFS
DRIVES THE ENERGY ALL THE WAY WEST INTO THE MOUNTAINS...WHILE EC
KEEPS QPF MAINLY IN THE EASTERN MOST COUNTIES. 

THE NEXT SYSTEM IS PROGGED TO PUSH INTO THE REGION
SUNDAY...POINTING TOWARD AND EXTENDED PERIOD OF PACIFIC MOISTURE
OVERRUNNING THE SURFACE BOUNDARY. MODELS CONTINUE TO DIFFER ON
QPF LOCATION...BUT ARE CONSISTENT WITH PRECIP...SO RAISED POPS
SOME SUNDAY NIGHT AND MONDAY. A SHORTWAVE REINFORCES THE COLD AIR
OVER THE REGION ON MON AND TUE...AND PACIFIC MOISTURE CONTINUES
TO STREAM INTO THE REGION.

THE REGION APPEARS TO GET INTO SOME WRAP AROUND ENERGY FROM THE
HUDSON BAY LOW THROUGH THE REMAINDER OF THE PERIOD. THIS WILL ALSO
BRING A REINFORCING SHOT OF COLD AIR INTO THE REGION. LEFT POPS IN
PLACE...AS MODELS CANNOT SEEM TO QUITE GET A HANDLE ON HOW MUCH
MOISTURE REMAINS AVAILABLE. THE EC IS MUCH WETTER AT THIS TIME.
AAG

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL OVER MOST OF THE AREA TODAY WITH THE
EXCEPTION OF THE KBHK AREA WHERE IFR/LIFR CONDITIONS WILL LAST
INTO EARLY AFTERNOON. CONDITIONS ARE EXPECTED TO LIFT LATE IN THE
DAY TO VFR. AREAS OF MVFR TO LIFR CONDITIONS ARE POSSIBLE AGAIN
TONIGHT INTO FRI MORNING FROM KMLS E AND SE. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    TDY FRI     SAT     SUN     MON     TUE     WED     
-------------------------------------------------------
BIL 047 029/047 026/035 019/030 022/041 022/036 019/032
    0/U 00/U    13/W    33/J    43/W    32/J    23/J
LVM 048 026/046 021/037 020/036 025/045 028/040 024/038
    0/U 00/U    13/W    23/J    43/W    32/W    23/W
HDN 046 025/045 022/032 015/029 017/038 017/032 015/030
    0/U 00/U    13/W    32/J    43/J    33/J    23/J
MLS 044 027/043 022/029 011/023 014/032 016/025 011/025
    0/U 00/U    14/J    22/J    33/J    23/J    22/J
4BQ 046 026/046 022/034 015/029 018/039 019/032 016/030
    0/U 00/U    13/W    32/J    33/J    23/J    22/J
BHK 039 025/041 019/025 007/020 009/029 014/024 009/023
    0/B 00/U    15/J    32/J    22/J    23/J    22/J
SHR 044 022/044 019/034 015/029 016/040 019/035 017/032
    0/U 00/U    13/W    32/J    22/J    32/J    23/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS

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