Area Forecast Discussion
Issued by NWS Billings, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
000
FXUS65 KBYZ 192238
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
338 PM MST WED NOV 19 2014

.SHORT TERM...VALID FOR THU AND FRI...

A WARMING TREND IS EXPECTED THE NEXT FEW DAYS AS FLOW ALOFT SHIFTS
TO A MORE WESTERLY DIRECTION AND ALLOWS MILD PACIFIC AIR TO SPREAD
EASTWARD INTO THE REGION.

TONIGHT...THE STRATUS /LOW CLOUDS/ IN SOUTHEASTERN MT HAS ACTUALLY
BEEN BREAKING UP THIS AFTERNOON PER RECENT SATELLITE IMAGERY...BUT
WE FEEL THAT IT WILL REDEVELOP AGAIN OVERNIGHT. THAT IDEA HAS GOOD
SUPPORT FROM RECENT HRRR RUNS AND THE 12 UTC NAM AS WEAK LOW-LEVEL
FLOW PERSISTS. WE ALSO ADDED PATCHY FOG INTO THE FORECAST AFTER 06
UTC OVER SOUTHEASTERN MT AND AS FAR WEST AS HYSHAM AS THE EDGES OF
A STRATUS FIELD LIKE THE ONE WE EXPECT ARE TYPICALLY FAVORABLE FOR
THE FORMATION OF FOG. THAT NOTION TOO HAS STRONG SUPPORT IN THE 12
UTC NCEP WRF-ARW AND WRF-NMM AS WELL AS RECENT HRRR RUNS. IT LOOKS
LIKE AN UNEVENTFUL NIGHT OVER THE REST OF THE AREA.

THURSDAY...IF LOW CLOUDS AND/OR PATCHY FOG DOES INDEED FORM ACROSS
SOUTHEASTERN MT TONIGHT...IT WILL LIKELY LINGER THROUGH THE MIDDAY
HOURS AS LIGHT LOW-LEVEL WINDS BECOME SOUTHERLY AND BOUNDARY LAYER
MIXING REMAINS VERY WEAK. WE LEANED ON THE SLIGHTLY COOLER...RAW 2
METER TEMPERATURES FOR HIGHS IN THOSE AREAS WITH WARMING DEPENDENT
ON HOW WIDESPREAD OR LONG-LASTING STRATUS IS /OR IS NOT/. HIGHS IN
GENERAL WILL WARM OVER THE REST OF THE AREA THOUGH AND THE BLENDED
12 UTC MODEL GUIDANCE WE USED TO BUILD THE FORECAST CALLS FOR HIGH
TEMPERATURES IN THE LOWER TO MIDDLE 40S F IN MOST AREAS.

FRIDAY...SEASONABLY MILD WEATHER WILL CONTINUE WITH HIGHS EXPECTED
TO BE IN THE 40S F ONCE AGAIN IN AN AIR MASS CHARACTERIZED BY 850-
MB TEMPERATURES OF +4 TO +6 C. THE LEE-SIDE PRESSURE TROUGH SHOULD
DEEPEN FRIDAY NIGHT IN ADVANCE OF AN ENERGETIC SHORTWAVE TROUGH SO
WINDS SHOULD INCREASE IN THE FOOTHILLS. LIVINGSTON AND NYE WILL BE
CANDIDATES FOR A WIND ADVISORY GIVEN THE EXPECTED PLACEMENT OF THE
SURFACE PRESSURE FALL MAXIMUM TO THEIR NORTHWEST LATE FRIDAY NIGHT
AS A MOUNTAIN-TOP STABLE LAYER STRENGTHENS. SCHULTZ

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

MILD AND WINDY WEATHER SATURDAY WILL TRANSITION TO SEASONABLY COOL
AND UNSETTLED WEATHER BEGINNING SUNDAY. THE 12 UTC GUIDANCE STAYED
IN RELATIVELY GOOD AGREEMENT WITH REGARD TO A STRENGTHENING SHORT-
WAVE TROUGH THAT WILL CROSS THE REGION AROUND SATURDAY NIGHT. SNOW
SHOULD FALL IN THE HIGH COUNTRY AS THE WAVE PASSES AND THERE IS AT
LEAST A CHANCE OF LOWER-ELEVATION SHOWER ACTIVITY TOO. WINDS COULD
BE AT THEIR PEAK IN THE FOOTHILLS DURING THE DAY SATURDAY WITH 60+
MPH GUSTS POSSIBLE AT LIVINGSTON AND NYE.

IN THE WAKE OF THE WEEKEND SHORTWAVE...FLOW ALOFT WILL TURN NORTH-
WESTERLY AS A MEAN TROUGH DEEPENS IN THE CENTRAL UNITED STATES. WE
ARE CALLING FOR SEASONABLY COOL TEMPERATURES WITH A CHANCE OF SNOW
SHOWERS IN THIS PATTERN IN THE EARLY AND MIDDLE PART OF NEXT WEEK.
HOWEVER...THERE IS CONSIDERABLE UNCERTAINTY IN THE FORECAST BY THE
TIME NEXT WEDNESDAY ROLLS AROUND...WHICH IS TROUBLING SINCE THAT/S
A MAJOR TRAVEL DAY AHEAD OF THANKSGIVING. THE ISSUE IS THAT THE 00
AND 12 UTC ECMWF SOLUTIONS AMPLIFY RIDGING OFF THE WEST COAST MUCH
MORE THAN THEIR GFS COUNTERPARTS...WHICH ALLOWS ARCTIC AIR TO DUMP
SOUTHWARD AND A SO-CALLED SLIDER SHORTWAVE TO CUT UNDER IT. IF THE
ECMWF IDEA IS RIGHT THEN SNOW AND MUCH COLDER WEATHER WOULD RESULT
RIGHT NEAR THE HOLIDAY TRAVEL PERIOD. HOWEVER...THE GFS IS CALLING
FOR MUCH-LESS-AMPLIFIED RIDGING OFF THE COAST...WHICH IN TURN DOES
NOT OPEN THE DOOR TO NEARLY AS COLD OF AN AIR MASS. IT IS TOO SOON
TO SAY WHICH OF THESE IDEAS IS RIGHT AS EVEN THOUGH IT/S COMMON TO
SEE THE ECMWF PICK UP ON A SCENARIO LIKE THIS FIRST...ITS VERY OWN
ENSEMBLE MEMBERS SUGGEST IT COULD BE TOO COLD AND SNOWY OF A MODEL
SOLUTION. STAY TUNED. SCHULTZ

&&

.AVIATION...

EXPECT VFR CONDITIONS TO PREVAIL ACROSS MUCH OF THE AREA TONIGHT
INTO TOMORROW. SOME LOW CEILINGS AND MVFR CONDITIONS WILL BE
POSSIBLE AT MILES CITY. SOME FOG MAY BE POSSIBLE AROUND MILES
CITY...BUT ONLY HAVE VCFG IN THE TAFS. REIMER

&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 019/044 029/045 029/046 029/040 025/037 023/037 022/035
    00/B    00/B    13/W    32/J    22/J    33/J    33/J
LVM 019/044 028/043 031/042 023/034 020/033 017/033 023/034
    00/N    00/N    14/W    32/J    22/J    33/J    33/J
HDN 014/042 023/045 021/047 026/040 020/036 018/037 017/036
    00/B    00/B    03/W    32/J    22/J    33/J    33/J
MLS 009/032 020/041 020/040 025/034 014/029 013/033 014/031
    00/B    00/B    02/W    32/J    22/J    22/J    32/J
4BQ 010/037 020/043 020/043 025/036 017/031 016/033 015/032
    00/B    00/B    02/W    32/J    22/J    23/J    32/J
BHK 003/030 017/040 020/039 024/030 011/024 011/029 013/028
    00/B    00/B    01/B    33/J    22/J    23/J    22/J
SHR 016/045 021/045 020/045 022/036 016/033 014/035 016/034
    00/B    10/B    02/W    32/J    22/J    23/J    33/J

&&

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

&&

$$
WEATHER.GOV/BILLINGS



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.