FXUS65 KBYZ 021642
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
942 AM MST WED DEC 2 2009
.SHORT TERM...VALID FOR TDY AND THU...
CYCLONIC NORTH FLOW SPREADING SOME LIGHT SNOW TO OUR EAST THIS
MORNING...WITH VISIBILITIES NEAR A MILE AT BAKER AND EKALAKA AT
TIMES. FLOW CONTINUES TO VEER AS ENERGY DROPS FROM THE NORTH...
AND AS A RESULT LATEST SATELLITE/RADAR TRENDS SHOW LOWER CLOUD AND
LIGHT ECHOES PUSHING WEST AND SOUTHWARD. ALREADY SOME ENHANCEMENT
IS NOTED SOUTH OF BILLINGS ALONG OUR NORTH SLOPES. WOULD EXPECT
STRATOCU WITH SOME LIGHT PCPN TO SPREAD THROUGH BILLINGS AND
AFFECT THE FOOTHILLS OF THE BEARTOOTHS/PRYORS/BIG HORNS THIS
AFTERNOON INTO TONIGHT. FORECAST SOUNDINGS INDICATE FAIRLY SHALLOW
MOISTURE AND INSTABILITY BUT THROUGH THE DENDRITIC LAYER...WHICH
SHOULD BE ENOUGH FOR LIGHT SNOW SHOWERS OR FLURRIES. FLOW ALSO
FAVORS THE BIG HORNS...BUT MOISTURE DOES NOT APPEAR DEEP ENOUGH
AND DENDRITIC LAYER DISAPPEARS ABOVE MTN TOP SO DO NOT THINK
ANYTHING MORE THAN LIGHT SNOW UP THERE.
OTHERWISE AFTER A COLD START TEMPS WILL MAX OUT IN THE TEENS TO
MID 20S TODAY.
HAVE ADJUSTED POPS/SNOW A BIT TO ACCOUNT FOR CURRENT TRENDS.
JKL
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
AREA STARTS OFF DRY ON FRIDAY BUT MOISTURE BEGINS INCREASING OVER
THE WESTERN ZONES AS AN UPPER LEVEL LOW MOVES SOUTHWARD THROUGH
IDAHO. THIS BRINGS A TEMPORARY INCREASE IN HEIGHTS OVER SOUTHERN
MONTANA AND NORTHERN WYOMING AND BRINGS A BIT OF MODERATION OF THE
COLD AIRMASS. PRECIPITATION SHOULD BE LIMITED TO THE WESTERN
MOUNTAINS LATE IN THE PERIOD. BY SATURDAY THIS UPPER LEVEL FEATURE
ELONGATES AND FILLS CAUSING A TROUGH AXIS TO BECOME STATIONARY
OVER MONTANA. REINFORCING COLD SURGE INTO THE AREA COMES INTO THE
AREA SOME TIME DURING THE DAY ON SATURDAY AND ENHANCES UPSLOPE
ACROSS THE AREA. LITTLE IN THE WAY OF DYNAMICS WILL EXIST EXCEPT
FOR THE UPSLOPE SO HAVE PRECIPITATION MAINLY OVER THE MOUNTAINS
AND FOOTHILLS...A PATTERN THAT WILL LINGER FOR A NUMBER OF DAYS.
TEMPERATURES ON SATURDAY WILL PROBABLY HAVE MORNING HIGHS AND
DESCEND INTO THE TEENS DURING THE AFTERNOON. A STRONGER ARCTIC
HIGH PRESSURE WILL PUSH INTO THE AREA AND TEMPERATURES WILL HAVE A
CHANCE TO BE 15 TO 20 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR.
EXPECT THE TEMPERATURES TO HAVE A CHANCE TO TREND SLIGHTLY
DOWNWARD SUNDAY AND MONDAY AS THE ARCTIC HIGH SETTLES INTO MONTANA
AND WYOMING. UPSLOPE DECREASES ON MONDAY AS THE HIGH PRESSURE
BECOMES TOO DEEP AND PRECIPITATION SHOULD START BECOMING SPARSE
OVER THE PLAINS. PATTERN BEGINS TO SHIFT ON TUESDAY AS A STRONGER
NORTHWEST FLOW ALOFT DEVELOPS WITH SOME DOWNSLOPING BECOMING
POSSIBLE. THIS FLOW CHANGE MAY INCREASE MOISTURE INTO THE REGION
BUT PATTERN DOES NOT LOOK ACTIVE SO ANY SNOWFALL WOULD BE LIGHT.
BORSUM
&&
.AVIATION...
MAINLY VFR CONDITIONS WILL PREVAIL ACROSS THE REGION...AND
NORTHERLY FLOW ALOFT WILL REINFORCE THE COLD AIR THAT ENTERED THE
REGION ON TUESDAY. MVFR FLIGHT CONDITIONS WILL BE POSSIBLE AROUND
KMLS AND EAST AND IN THE EASTERN FACING UPSLOPE REGIONS...AS WRAP AROUND
MOISTURE ROTATES INTO THE AREA AS THE UPPER LEVEL LOW MOVES FROM
CANADA INTO THE DAKOTAS. LIGHT SNOW AND STRATUS CLOUD CONDITIONS
WILL SPREAD FROM EAST TO WEST THROUGH THE DAY WITH THIS
SYSTEM...AS FAR WEST AS THE FOOTHILLS REGIONS BY THIS EVENING. GILSTAD
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 022 007/022 011/035 018/028 008/014 002/014 001/019
2/J 21/B 11/B 02/J 33/J 22/B 21/B
LVM 019 901/023 008/032 014/026 901/011 909/014 907/018
1/B 11/U 01/B 23/J 43/J 32/J 21/B
HDN 022 007/025 008/036 015/028 008/016 901/018 901/022
3/J 31/B 11/B 02/J 32/J 21/B 21/B
MLS 023 006/022 007/034 011/026 006/017 000/016 901/017
3/J 31/B 11/B 12/B 22/J 11/B 21/B
4BQ 022 007/020 004/034 010/028 008/018 003/018 003/019
4/J 32/J 11/B 12/B 22/J 21/B 22/J
BHK 021 004/018 001/029 007/026 006/018 000/017 003/016
6/J 32/J 11/B 12/B 22/J 11/B 22/J
SHR 020 005/022 003/037 014/032 006/016 001/017 004/017
4/J 32/J 11/B 12/J 33/J 32/J 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
