FXUS65 KBYZ 261640
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT 
940 AM MST SAT DEC 26 2009

.SHORT TERM...VALID FOR TDY AND SUN...

SNOW CONTINUES OVER THE BIG HORN MOUNTAINS AND ACROSS THE FAR
EASTERN COUNTIES THIS MORNING WITH GUSTY WINDS AND BLOWING SNOW
ALSO CONTINUING IN THESE AREAS. CALLS TO ALL OTHER AREAS IN THE
ADVISORIES AND WARNINGS INDICATE GOOD CONDITIONS WITH NOT MUCH
WIND AND NO SNOW FALLING. SO WILL CANCEL MOST HIGHLIGHTS THIS
MORNING. SNOW WILL CONTINUE TO DECREASE THROUGH THE DAY. ALSO
LOWERED WIND SPEEDS ACROSS THE EAST THROUGH THE DAY BASED ON
CURRENT TRENDS AND LATEST MODEL GUIDANCE. UPDATE COMING OUT
SHORTLY. SOLUM

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

CONFIDENCE A BIT HIGHER TONIGHT FOR A POSSIBLE ARCTIC FRONTAL 
INTRUSION IN THE WED/WED NIGHT TIME FRAME. LATEST GFS WAS MORE IN 
LINE WITH LATEST ECMWF RUNS IN BRINGING A SHORTWAVE SE IN NW FLOW 
ALOFT INTO NE MT/NW ND DURING THIS PERIOD. THE WAVE WILL PUSH A COLD 
FRONT INTO THE AREA BRINGING COLDER CONDITIONS THROUGH THU NIGHT. 
HAVE ADJUSTED POPS BASED ON EXPECTED MOISTURE...AND LOWERED 
TEMPERATURES DURING THIS PERIOD. MOISTURE BEGINS PUSHING E INTO THE 
WESTERN ZONES ON FRI AHEAD OF THE NEXT PACIFIC SYSTEM...BRINGING A 
LOW CHANCE OF PRECIPITATION TO WESTERN SECTIONS OF THE AREA.

FOR EARLY IN THE PERIOD...UPPER RIDGING WILL PUSH OUT OF THE AREA 
DURING MON WHILE THE NORTHERN BRANCH OF A SPLITTING PACIFIC TROUGH 
PUSHES INTO THE AREA THROUGH TUE NIGHT. HAVE LOWERED POPS MON AND 
MON NIGHT DUE TO EXPECTED DRYNESS OF THE AIRMASS. DOWNSLOPE FLOW 
WILL KEEP PRECIPITATION CHANCES LOW FOR TUE AND TUE NIGHT WHILE THE 
SHORTWAVE TROUGH MOVES ACROSS THE AREA. INHERITED POPS LOOKED 
REASONABLE. BASED ON RECENT TEMPERATURE TRENDS...AND 850 MB 
TEMPERATURES FORECAST TO BE AROUND ZERO DEGREES C...HAVE RAISED HIGH 
TEMPERATURES FOR MON AND EXPECT READINGS TO BE AROUND NORMAL FOR 
THIS TIME OF YEAR. ALSO RAISED TEMPERATURES ON TUE. ARTHUR

&&

.AVIATION...

DRIER AIR WILL MOVE INTO THE WESTERN 2/3 OF THE FORECAST AREA
TODAY WITH A CLEARING TREND AT THE TERMINAL SITES. OCCASIONAL MVFR
CONDITIONS CAN STILL BE EXPECTED AT KMLS AND KSHR UNTIL 2000UTC
WITH LOWERED CEILINGS AND ISOLATED SNOW SHOWERS. EXPECT MOSTLY
CLEAR SKIES TONIGHT. BORSUM 

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY SUN     MON     TUE     WED     THU     FRI     
-------------------------------------------------------
BIL 023 004/028 008/032 013/031 014/025 009/019 004/028
    0/U 00/U    00/B    02/S    21/B    23/S    21/B
LVM 027 005/031 011/034 015/031 016/027 013/025 016/029
    0/U 00/U    00/B    02/S    21/B    23/S    22/S
HDN 021 903/023 000/030 005/031 007/026 003/022 901/026
    0/E 00/U    00/B    01/B    11/B    22/S    11/B
MLS 017 905/019 901/022 004/025 005/018 901/013 901/017
    2/S 00/U    00/B    01/B    11/B    22/S    11/B
4BQ 020 902/021 003/025 004/029 006/022 901/018 903/018
    3/S 00/U    00/B    02/S    12/S    22/S    21/B
BHK 015 904/018 902/022 004/020 002/018 908/010 907/014
    9/S 00/B    00/B    02/S    11/B    22/S    11/B
SHR 025 003/028 004/028 003/032 006/028 004/022 006/026
    2/S 00/U    00/B    02/S    11/B    23/S    21/B

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 5 PM MST THIS AFTERNOON
      FOR ZONES 33-37.
WY...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 PM MST THIS
      AFTERNOON FOR ZONE 98.

&&

$$
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