Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 180940
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
340 AM MDT MON AUG 18 2014

.SHORT TERM...VALID FOR TDY AND TUE...

SHOULD BE A QUIET WEATHER DAY AS THE SLOW MOVING UPPER LOW THAT
BROUGHT SCATTERED THUNDERSTORMS THE LAST SEVERAL DAYS HAS SHIFTED
EAST OF THE FORECAST AREA. A FLAT UPPER RIDGE WILL TAKE OVER TODAY
AND PROVIDE A MAINLY DRY DAY. THE EXCEPTION WILL BE THE MOUNTAINS
AND FOOTHILLS AS SHORTWAVE ENERGY AND MOISTURE SPIN OFF AN UPPER
LOW OVER WESTERN OREGON INTO THE MOUNTAINS.

CONVECTION CHANCES INCREASE TUESDAY AFTERNOON AND EVENING AS A
STRONGER PIECE OF ENERGY SWINGS ACROSS THE GREAT BASIN AND INTO
SOUTHERN MONTANA. RAISED POPS A BIT AS A COUPLED JET MOVES INTO
WESTERN ZONES TUESDAY AFTERNOON. STABILITY DOES NOT LOOK THAT
GREAT AND WARN 700MB TEMPERATURES MAY HOLD THE BEST CHANCE OF
ACTIVITY OFF UNTIL THE EVENING. INVERTED V SOUNDINGS SUGGEST GUSTY
WINDS MORE THAN HEAVY RAIN WITH THIS CONVECTION. A SECOND STRONGER
PIECE OF ENERGY IS PROGGED TO WORK INTO SOUTHEAST MONTANA TUESDAY
NIGHT. RETURN SOUTH TO SOUTHEAST LOW LEVEL WINDS SHOULD ALLOW FOR
MOISTURE TO RETURN QUICKLY TO THE SOUTHEAST...SO RAISED POPS TO
SCATTERED THERE.

TEMPERATURES WILL BE SEASONAL TODAY...BUT WARMING TEMPERATURES AT
700MB WOULD SUPPORT LOWER 90S ON TUESDAY. THIS LOOKS TO BE THE
WARMEST DAY OF THE WEEK AS TROUGHING WILL SETTLE INTO THE NORTHERN
ROCKIES TO END THE WEEK. TWH

.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...

THE EXTENDED FORECAST REMAINS ON TRACK TODAY...WITH WEATHER
PATTERN TURNING COOLER AND WETTER BY MID TO LATE WEEK. GLOBAL
MODELS REMAIN IN GOOD AGREEMENT WITH THE DEVELOPMENT OF A LARGE-
SCALE TROUGH OVER THE WESTERN CONUS. THIS WILL SET THE STAGE FOR
THE COOLER AND WETTER CONDITIONS...WITH EMBEDDED SHORTWAVES
ROUNDING THE PARENT TROUGH HELPING TO ORGANIZE PERIODS OF
PRECIPITATION.

TEMPERATURES WILL START THE COOLING TREND ON WEDNESDAY AFTER AN
INITIAL WEAK SHORTWAVE PASSAGE AS THE MAIN TROUGH CONTINUES TO
BUILD INTO THE WEST. SCATTERED SHOWER AND THUNDERSTORM ACTIVITY
WILL INCREASE WEDNESDAY WITH THAT SHORTWAVE PASSAGE AS WELL WITH
SOME SOME ENHANCEMENT FROM THE MONSOONAL MOISTURE. THE MAIN TROUGH
WILL CONTINUE TO BUILD IN TO OUR WEST ON THURSDAY... WITH
SOUTHWESTERLY FLOW ALOFT BRINGING CONTINUED MONSOONAL FLOW INTO
THE FORECAST AREA. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
COMMON AGAIN ON THURSDAY. THE STRONGEST PUSH OF QC FORCING WITH THE
MAIN TROUGH AXIS PASSAGE LOOKS SET FOR FRIDAY / FRIDAY EVENING AS
AGREEMENT REMAIN GOOD BETWEEN THE GLOBAL MODELS. TEMPERATURES WILL
ALSO BOTTOM OUT ON FRIDAY AND SATURDAY WITH THE PASSAGE OF THE
TROUGH. EC MOS GUIDANCE CONTINUES TO ADVERTISE A HIGH OF 68 ON
SATURDAY IN BILLINGS...WITH THE GFS SLIGHTLY MORE CONSERVATIVE AT
74. HAVE ELECTED TO KEEP THE FORECAST A COMPROMISE BETWEEN THE
MODELS...WITH LOW 70S IN THE FORECAST. TEMPERATURES WILL REMAIN
COOL THROUGH THE REMAINDER OF THE WEEKEND AS THE LARGE-SCALE
TROUGHING STAYS OVER THE WESTERN CONUS. THIS HAS ALSO PROMPTED
CHANCE TYPE POPS THROUGH THE WEEKEND AS THE CYCLONIC FLOW REMAINS
IN PLACE.

ONE AREA OF UNCERTAINTY WITH THIS FORECAST REMAINS THE HANDLING OF
THE CUT-OFF LOW OFF THE CALIFORNIA COAST...WITH GLOBAL MODELS
CONTINUING TO OFFER VARYING IDEAS ON HOW THIS LOW WILL EVOLVE.
WHILE THIS DOES HAVE SOME IMPACT ON THE CHARACTER OF THE NORTHERN
STREAM TROUGH...IT DOES NOT SIGNIFICANTLY DETRACT FROM THE
CONFIDENCE IN COOLER AND WETTER CONDITIONS FOR THE FORECAST AREA.

MODELS ARE STARTING TO COME INTO BETTER AGREEMENT ABOUT ANOTHER
MORE ORGANIZED SHORTWAVE DIGGING INTO THE MEAN TROUGH BY EARLY
NEXT WEEK. THE GFS REMAINS ON THE FAST END OF THE GUIDANCE...WITH
THE SHORTWAVE PASSAGE THROUGH THE FORECAST AREA BY SUNDAY NIGHT.
THE EC REMAINS SLOWER AND DOESN`T BRING IT INTO PLAY UNTIL MONDAY
INTO TUESDAY. EITHER WAY THE FORECAST WILL CONTINUE ADVERTISE
COOLER AND WETTER CONDITIONS THROUGH AT LEAST THE START OF NEXT
WEEK. ALSO TO NOTE WITH THIS SECOND SHORTWAVE...THE GFS CONTINUES
TO SHOW 700 MB TEMPERATURES TO AROUND 0 C BY MONDAY MORNING...WHICH
COULD EVEN MEAN A LITTLE SNOW IN THE HIGH PEAKS OF THE BEARTOOTH
ABSAROKA AND CRAZY MOUNTAINS BY MONDAY MORNING. CHURCH

&&

.AVIATION...

VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS THE FORECAST AREA
TODAY...WITH GENERALLY LIGHT WINDS. SOME ISOLATED/SCATTERED
SHOWERS AND THUNDERSTORMS MAY DEVELOP OVER THE MOUNTAINS NEAR KLVM
BY THIS AFTERNOON...AND WILL LIKELY NOT VENTURE FAR OFF THE
MOUNTAINS. LOCALIZED MVFR/IFR CONDITIONS ARE POSSIBLE WITH ANY
STRONG CELLS THAT DEVELOP ALONG WITH MOUNTAIN OBSCURATIONS. CHURCH

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY TUE     WED     THU     FRI     SAT     SUN
-------------------------------------------------------
BIL 087 061/092 063/085 058/079 057/074 053/071 051/073
    1/B 12/T    33/T    34/T    45/T    54/T    33/T
LVM 089 053/091 053/082 051/076 049/072 047/070 048/072
    2/T 22/T    34/T    45/T    55/T    54/T    43/T
HDN 089 058/093 059/086 054/083 056/078 054/073 052/076
    1/B 12/T    33/T    33/T    45/T    54/T    33/T
MLS 087 061/092 064/085 058/083 059/078 055/074 053/074
    1/B 11/U    23/T    34/T    45/T    54/T    33/T
4BQ 086 059/091 061/085 058/085 059/079 057/074 054/075
    1/B 11/B    33/T    23/T    45/T    54/T    32/T
BHK 083 055/088 059/082 054/081 055/076 056/073 055/071
    1/B 11/U    33/T    33/T    45/T    53/T    33/T
SHR 086 054/091 055/083 052/082 053/077 051/072 049/074
    1/B 12/T    33/T    33/T    44/T    44/T    33/T

&&

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

&&

$$
WEATHER.GOV/BILLINGS



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