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
691
FXUS65 KBYZ 212102
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
302 PM MDT THU MAY 21 2015

.SHORT TERM...VALID FOR FRI AND SAT...

SOMEWHAT BENIGN FLOW OVER THE REGION TODAY AS UPPER LOW OFF
CALIFORNIA COAST TRACKS INTO SOUTHERN CALIFORNIA BY EVENING.
WE HAVE SOME MOISTURE THAT HAS ADVECTED INTO WESTERN MONTANA
WHILE THE EAST REMAINS GENERALLY DRY. SO ISOLATED TO SCATTERED
SHOWERS AND MAYBE SOME THUNDER IS EXPECTED THROUGH THE
EVENING...WITH A BIT LINGERING OVERNIGHT. FLOW IS WEAK SO WE DONT
EXPECT THOSE SHOWERS TO MAKE MUCH HEADWAY INTO THE PLAINS.
SOUTHERLY FLOW AND MAYBE AN INCREASE IN HIGH CLOUDS TONIGHT SO I
DO NOT THINK WE WILL GET QUITE AS CHILLY AS WE HAVE BEEN RECENTLY.

FRIDAY/FRIDAY NIGHT...UPPER LOW TRACKS INTO THE DESERT SOUTHWEST
WITH A PIECE OF ENERGY EJECTING OUT AHEAD OF IT IN THE SOUTH TO
NORTH FLOW ALOFT. THIS WILL PUSH INTO WYOMING BY AFTERNOON AND
SPREAD SOME SHOWERS AND PERHAPS SOME THUNDERSTORMS INTO OUR
FORECAST AREA. I LEFT THE HIGHEST POPS OVER THE HIGH COUNTRY TO
THE WEST...REDUCED THE POPS A BIT FOR THE NORTH CENTRAL ZONES
NORTH OF I-94 BASED ON CURRENT PROGGS TRACKING THIS SHORT WAVE
ENERGY. LOOK FOR TEMPS EQUAL TO OR A LITTLE HIGHER THAN TODAYS ON
FRIDAY AS WARMER AIR ADVECTS NORTHWARD THANKS TO THE SOUTHERLY
FLOW.

THAT UPPER LOW PUSHES INTO THE CENTRAL ROCKIES FOR THE START OF
THE WEEKEND. ITS INFLUENCE WILL CONTINUE TO PRODUCE INCREASING
PRECIPITATABLE WATERS ACROSS OUR FORECAST AREA. THUS THE
WIDESPREAD SHOWERS AND SOME THUNDERSTORMS WE ARE ADVERTISING FOR
SATURDAY AND SATURDAY NIGHT LOOKS ON TRACK. WEAK WIND FIELDS
SHOULD NOT SUPPORT ANY ORGANIZED SEVERE THREAT...THOUGH AS LAST
WEEK INDICATED...AN ISOLATED STORM WITH LARGER HAIL CANNOT BE
COMPLETELY RULED OUT. BT

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

OVERALL EXTENDED FORECAST APPEARS IN GOOD SHAPE...WITH BROAD
UPPER LEVEL TROF IN CONTROL OVER THE REGION THROUGHOUT THE
MAJORITY OF THE PERIOD. ONLY SMALL ADJUSTMENTS WERE MADE TO CLEAN
UP BORDERS AND CONTINUE TO SLOW TREND TEMPERATURES UPWARD TOWARD
NORMAL THROUGH THE PERIOD.

THE REGION CONTINUES TO BE IMPACTED BY NORTHERN PORTION OF A
STRETCHED OUT UPPER LOW INTO NORTHEAST WYOMING AS IT MOVES INTO
THE DAKOTAS ON SUNDAY. PERSISTENT EAST TO SOUTHEAST SURFACE FLOW
WILL SUPPORT PWATS INTO THE ONE INCH RANGE IN SOUTHEAST MONTANA.
DEEP MOISTURE AVAILABILITY SHOULD ALLOW FOR A GOOD CHANCE FOR
SHOWERS...ESPECIALLY EAST OF BILLINGS. ATMOSPHERE DOES NOT APPEAR
VERY UNSTABLE...SO EXPECT LESS CHANCE OF THUNDER. IMPACTS TO THE
EAST WILL SLOWLY DECREASE THOUGHT MONDAY.

THERE IS SOME INDICATION OF A SHORT PERIOD OF SHORTWAVE RIDGING
ACROSS THE REGION MONDAY NIGHT...AHEAD OF THE NEXT SYSTEM. THIS
WILL BRING A BREAK IN PRECIP OVERNIGHT...BUT TIMING OF THE NEXT
SYSTEM SHOULD KEEP SOME CLOUD COVER IN PLACE AS MOISTURE CONTINUES
TO FLOW INTO THE WESTERN MOUNTAINS.

THE NEXT UPPER LEVEL LOW PRESSURE SYSTEM WILL DROP INTO THE REGION
FROM BRITISH COLUMBIA ON TUESDAY OR WEDNESDAY DEPENDING ON WHICH
MODEL YOU FAVOR. THE EC IS CURRENTLY MUCH FASTER BRINGING THE
SYSTEM INTO THE REGION...AND KEEPING IT OVER THE REGION UNTIL
THURSDAY MORNING. THE GFS HOLD THE LOW TO THE WEST UNTIL
WEDNESDAY...BUT KEEPS IT OVER THE REGION THROUGH THE END OF THE
PERIOD. HAVE GOING POPS INTACT...AS GFS HAS MADE SIGNIFICANT
CHANGE THIS RUN...BUT WILL BE WORTH FURTHER ATTENTION ON LATER
SHIFT. AAG

&&

.AVIATION...

EXPECTED CONTINUED MOUNTAIN SHOWER POTENTIAL TODAY AND
TONIGHT...AS AS A WEAK DISTURBANCE APPROACHES FROM SOUTHERN IDAHO
AND WESTERN MONTANA. SHOWERS WILL BE PRIMARILY CONFINED TO HIGHER
TERRAIN...BUT MAY IMPACT LIVINGSTON AND THE PARADISE VALLEY.
LOCALIZED MVFR CONDITIONS ARE POSSIBLE IN HEAVIER PRECIP. AT LEAST
OCCASIONAL MOUNTAIN OBSCURATION IS EXPECTED THROUGH THE REMAINDER
OF TODAY AND TONIGHT. SHOWERS WILL SPREAD ACROSS THE REGION ON
FRIDAY AFTERNOON...WITH LOCAL MVFR CONDITIONS POSSIBLE IN HEAVIER
PRECIP. AAG
&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 044/071 046/064 046/063 045/070 048/070 048/072 047/068
    03/T    23/T    23/T    32/T    23/T    33/T    33/T
LVM 040/067 044/060 042/061 039/066 043/066 044/067 041/066
    24/T    35/T    43/T    33/T    34/T    44/T    43/T
HDN 044/073 045/066 046/064 045/072 047/073 048/075 047/071
    03/T    23/T    33/T    32/T    23/T    33/T    33/T
MLS 045/073 046/065 046/064 047/069 046/072 049/073 048/069
    01/B    12/T    34/T    43/T    22/T    23/T    33/T
4BQ 044/068 043/062 046/060 045/068 045/072 048/073 048/069
    02/T    25/T    36/T    43/T    23/T    33/T    34/T
BHK 041/069 042/060 044/061 044/065 043/069 046/069 045/066
    01/N    25/T    46/T    55/T    33/T    33/T    33/T
SHR 041/064 041/060 043/058 041/068 043/069 044/070 045/067
    13/T    25/T    44/T    32/T    24/T    43/T    33/T

&&

.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.