FXUS65 KBYZ 061515
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
915 AM MDT MON OCT 6 2008
.MORNING UPDATE...
UPPER WAVE THAT MOVED OVER THE FORECAST AREA LAST NIGHT CONTINUES
TO PUSH EAST INTO THE NORTH CENTRAL PLAINS THIS MORNING. RADAR
SHOWING SOME SHOWERS OVER SOUTHERN BIG HORN AND SHERIDAN
COUNTIES...AS WELL AS A FEW SHOWERS APPROACHING NORTHERN ROSEBUD
COUNTY. ACTIVITY WILL CONTINUE TO MOVE EAST/SOUTHEAST THIS
MORNING AND IS EXPECTED TO BE OUT OF THE AREA BY AFTERNOON. WATER
VAPOR SHOWING SUBSIDENCE BEHIND THIS WAVE WITH SKIES CLEARING
ACROSS THE CENTRAL AND WESTERN ZONES. EXPECT BREEZY...DRY AND
PARTLY CLOUDY CONDITIONS FOR THE AFTERNOON WITH THE EXCEPTION OF A
FEW SHOWERS POSSIBLE OVER THE EXTREME NORTHEAST...AS WELL AS THE
BIG HORNS. AFTERNOON TEMPERATURES WILL BE A BIT COOLER THAN SUNDAY
BUT READINGS ARE STILL EXPECTED TO REACH INTO THE UPPER 50S TO
LOWER 60S. HOOLEY
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
COOL AND UNSETTLED PERIOD OF WEATHER COMING IN THE LONG TERM...
WITH THE COLDEST AIR OF THE SEASON BY LATE WEEK. DETAILS REMAIN
SKETCHY HOWEVER.
WED SHOULD BE A DRY DAY IN A FAST ZONAL FLOW BEHIND TUE NITE
FRONTAL PASSAGE. NEXT PACIFIC WAVE THEN SET TO COME INTO THE AREA
WED NITE INTO THU...AND THIS SYSTEM IS LOOKING MORE INTERESTING AS
IT INTERACTS WITH BAROCLINIC ZONE ACROSS OUR SOUTH. WAVE INDUCES
FAIRLY STRONG FRONTOGENESIS...WHICH AT THIS TIME APPEARS TO BE
STRONGEST ACROSS OUR S/SE...TO THE POINT TO WHERE MID LEVEL FLOW
TURNS SE-E EVENTUALLY. HAVE ADDED SOME CHANCE POPS TO COVER
THIS...AGAIN HIGHEST OVER OUR SOUTHERN MTNS/FOOTHILLS AND OUR SE.
WITH WET BULB TEMPS SETTING UP TO BE NEAR FREEZING COULD SEE SOME
SNOW EVEN AT LOWER ELEVATIONS WED NITE IF PCPN BECOMES HEAVY
ENOUGH. WILL HAVE TO WATCH TO SEE HOW THIS EVOLVES...PLENTY OF
ROOM FOR MODEL ERROR GIVEN THE FAST PACIFIC FLOW.
FLOW THEN AMPLIFIES AS STRONGER ENERGY COMES OUT OF THE GULF OF
ALASKA AND DIGS THROUGH THE AREA. HUGE DIFFERENCES REMAIN BETWEEN
THE 00Z GFS AND ECMWF RUNS...WITH THE GFS TAKING ENERGY TO THE
EAST AND ECMWF DEVELOPING AN ANOMALOUSLY DEEP CLOSED LOW IN THE
GREAT BASIN. UKMET/CANADIAN ARE SOMEWHAT OF A COMPROMISE...BUT
LEAN TOWARD THE GFS IN THAT A CLOSED LOW DOES NOT AFFECT US. WITH
SUCH A STRONG NORTHERLY JET AND BUILDING RIDGE IN THE GULF THINK
THE GFS WRONGLY TAKES ENERGY EAST TOO QUICKLY...WITH RIDGING OVER
US BY SAT NIGHT. THAT BEING SAID IT IS HARD TO BUY THE ECMWF...
THOUGH IT IS THE MUCH MORE CONSISTENT MODEL AT THIS TIME. ONE
THING THAT DOES NOT FAVOR A CLOSED LOW OVER US IS THE FAST FLOW
WED/THU WHICH DRIVES THE BAROCLINIC ZONE SOUTHWARD...PER THE
GFS/CANADIAN/UKMET. THUS THE INITIAL WED NITE/THU WAVE IS ONE TO
KEEP AN EYE ON...IF IT IS STRONG ENOUGH IT MAY BEGIN TO AMPLIFY
THE FLOW BEFORE THE STRONGER ENERGY ARRIVES SHORTLY THEREAFTER.
WITH ALL OF THIS IN MIND IT IS TOO DIFFICULT TO PROVIDE ANY DETAIL
IN THE FORECAST BEYOND THU. WILL KEEP SLIGHTLY ABOVE CLIMO POPS
GOING FRI/SAT PER SOME SORT OF TROFFING...AND NEAR CLIMO POPS SUN.
HAVE RAISED MTN POPS A BIT MORE THU NITE THROUGH SAT AS WHETHER WE
SEE A DEEP LOW OR AN UNSTABLE NORTH FLOW...THERE IS A GOOD CHANCE
OF SNOW SHOWERS DURING THIS TIME...ESPECIALLY AS 700MB TEMPS FALL
BELOW -10C.
AS FOR TEMPS...HAVE COOLED EXPECTED HIGHS A BIT WED...AND
SUBSTANTIALLY THU AS COLDER AIR WRAPS DOWN BEHIND THE WED NITE/THU
WAVE. THIS COOLING TREND WILL OBVIOUSLY CONTINUE FRI/SAT.
INHERITED FORECAST IS BELOW MEX NUMBERS...BUT REASONABLE IF FLOW
REMAINS A DRIER NW-N....AND NOT AS COLD AS THE ECMWF SUGGESTS.
A GOOD CHANCE WE WILL SEE OUR FIRST OFFICIAL FREEZE IN BILLINGS
AT SOME POINT.
JKL
&&
.AVIATION...
A FEW SHOWERS PUSHING ACROSS SOUTHERN BIG HORN COUNTY THIS
MORNING. THESE SHOWERS WILL CONTINUE SOUTH AND EAST ACROSS SOUTH
EAST ZONES INCLUDING SHERIDAN COUNTY THROUGH THIS MORNING. MVFR
CONDITIONS WILL BE POSSIBLE IN THESE AREAS WITH THE SHOWERS.
ELSEWHERE VFR CONDITIONS ARE EXPECTED TODAY...SKIES SHOULD BECOME
PARTLY CLOUDY WITH CUMULUS LATER THIS MORNING INTO THE AFTERNOON.
RASCH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 062 042/070 042/061 035/049 033/044 029/040 028/045
1/U 00/B 00/U 22/R 23/O 33/O 22/W
LVM 062 038/070 032/060 029/049 027/042 022/042 022/047
1/U 00/N 21/B 22/R 33/O 32/O 22/W
HDN 064 037/074 041/063 033/050 032/045 029/041 027/047
1/B 00/U 00/U 22/R 22/O 33/O 22/W
MLS 063 039/073 042/063 035/054 032/048 031/044 029/046
2/W 00/U 20/U 11/B 22/O 22/O 22/W
4BQ 064 036/072 041/062 034/053 029/048 030/042 029/046
2/W 00/U 00/B 33/R 22/O 22/O 22/W
BHK 063 035/073 038/058 031/052 026/048 027/043 027/046
2/W 00/U 11/U 11/B 22/O 22/O 22/W
SHR 061 036/071 036/061 032/049 028/045 028/039 027/044
2/W 00/U 00/N 33/R 23/O 33/O 22/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
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