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
000
FXUS65 KBYZ 242140
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
340 PM MDT THU APR 24 2014

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

WEAK HIGH PRESSURE RIDGE WILL CONTINUE TO BE OVER THE FORECAST
AREA INTO FRIDAY MORNING. HOWEVER...AN UPPER LEVEL WAVE AS NOTED
ON WATER VAPOR IMAGERY CURRENTLY MOVING ACROSS WASHINGTON STATE IS
PROVIDING FOR INCREASING CLOUDS ALONG WITH SOME ISOLATED SHOWER
ACTIVITY ACROSS OUR AREA THIS AFTERNOON. TEMPERATURE/DEWPOINT
SPREADS ARE AROUND 25 TO 30 DEGREES SO THE MAJORITY OF ANY SHOWER
ACTIVITY IS CONSISTING OF A FEW SPRINKLES ALONG WITH SOME GUSTY
WINDS. IN ADDITION...WINDS ALOFT HAVE MIXED DOWN TO THE SURFACE
THIS AFTERNOON RESULTING IN A WINDY AFTERNOON ACROSS THE ENTIRE
AREA...BUT NOT NEARLY AS WINDY AS YESTERDAY. WILL CONTINUE TO KEEP
A SLIGHT SHOWER CHANCE IN THE FORECAST THROUGH THE EVENING EAST OF
BILLINGS...AS WELL AS OVER AND NEAR THE MOUNTAINS. AREAS IN
BETWEEN SUCH AS BILLINGS WILL SEE MORE OF A DOWNSLOPE EFFECT.

HIGH PRESSURE RIDGE WILL CONTINUE OVER THE FORECAST AREA FOR MOST
OF FRIDAY BUT THE AXIS GETS SHIFTED EAST IN RESPONSE TO A STRONG
UPPER LOW THAT MOVES ONTO THE CALIFORNIA COAST. THIS LOW WILL
PROVIDE FOR A SOUTHWEST FLOW ALOFT ALONG WITH SOME UPPER LEVEL
DIVERGENCE. SHOWER CHANCES WILL INCREASE FROM WEST TO EAST DURING
THE AFTERNOON INTO THE EVENING. AT THE SAME TIME...A SURFACE LOW
DEVELOPS ACROSS EASTERN WYOMING DURING THE AFTERNOON RESULTING IN
WINDS BECOMING EAST AND SOUTHEAST ADVECTING SOME LOW LEVEL
MOISTURE INTO THE AREA. THIS SURFACE LOW WILL PLACE A WARM FRONT
ACROSS OUR FORECAST AREA AND THIS WILL BE THE FOCUS AREA FOR THE
BEST PRECIP CHANCES. THE LOW DRIFTS A BIT NORTH FRIDAY NIGHT
TAKING THE BULK OF THE SHOWER ACTIVITY WITH IT.

THE 500MB LOW OVER CALIFORNIA MOVES INTO THE FOUR CORNERS REGION
SATURDAY AND INTO EASTERN COLORADO SATURDAY NIGHT. A DOUBLE-
BARRELED SURFACE LOW TAKES SHAPE ACROSS EASTERN WYOMING AND
NORTHEAST COLORADO PROVIDING FOR A TIGHT PRESSURE GRADIENT ACROSS
SOUTHEAST MONTANA. A STRONG EASTERLY FLOW WILL BE IN STORE ACROSS
OUR EASTERN ZONES WITH A NORTH TO NORTHWEST SURFACE WIND ACROSS
OUR CENTRAL AND WESTERN AREA. MODELS BRING INCREASING PRECIP INTO
THE AREA SATURDAY AFTERNOON AND EVENING. ENOUGH INSTABILITY WILL
BE ON TAP TO WARRANT AN ISOLATED THUNDERSTORM SATURDAY AFTERNOON
WITH THE BEST CHANCES BEING ACROSS SOUTHEAST MONTANA WHERE BETTER
SHEAR EXISTS. TEMPERATURES LOOK TO BE WARM ENOUGH SATURDAY NIGHT
FOR THE SHOWERS TO BE IN LIQUID FORM. HOWEVER...CAN`T RULE OUT A
RAIN/SNOW MIX OR WET SNOW FOR THE MOUNTAIN FOOTHILLS OF SHERIDAN
AND RED LODGE WHERE A COUPLE INCHES COULD OCCUR BUT MAINLY ON
GRASSY SURFACES. HOOLEY

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

A FAIR AMOUNT OF PRECIPITATION WAS IN STORE FOR AREAS E OF KBIL
FOR THE EXTENDED PERIOD PER THE LATEST MODEL RUNS. A STRONG
PACIFIC JET WILL CARVE OUT A POSITIVELY TILTED PACIFIC TROUGH OVER
THE WESTERN U.S. ON SUN. AN UPPER LOW OVER E CO WILL ROTATE NE
INTO THE CENTRAL PLAINS ON MON. THIS CUTOFF LOW WILL THEN PHASE
WITH A GREAT LAKES LOW ON TUE AND ROTATE OVER THE MIDWEST THROUGH
THU LEAVING THE FORECAST AREA UNDER CYCLONIC FLOW. GULF OF MEXICO
MOISTURE WILL BE DRAWN INTO THE SYSTEM AND THERE WILL BE AN
INVERTED TROUGH OVER EASTERN PORTIONS OF THE FORECAST AREA...EXTENDING
FROM THE SYSTEM/S SURFACE LOW...INTO MON.

THE ABOVE FACTORS WILL BRING HEAVY PRECIPITATION TO EASTERN
PORTIONS OF THE AREA...MAINLY E OF KBIL. THE CYCLONIC FLOW ALOFT
WILL THEN BRING SCATTERED SHOWERS TO THE AREA MON NIGHT THROUGH
THU. CONTINUED WITH THE HIGH POPS OVER THE E SUN THROUGH MON.
AROUND AN INCH OF PRECIPITATION WILL BE POSSIBLE OVER SE MT
THROUGH MON. IN ADDITION...THE SYSTEM WILL DRAW COLD AIR INTO THE
AREA FROM THE N WHICH WILL CAUSE A RAIN/SNOW MIX. A FEW INCHES OF
ACCUMULATION WILL BE POSSIBLE OVER SE MT...ESPECIALLY SUN NIGHT.
TRENDED TEMPERATURES DOWN SUN AND MON...ESPECIALLY OVER THE E.

OTHERWISE WENT WITH ISOLATED TO SCATTERED POPS MON NIGHT THROUGH
WED. THE MODELS HAD THU DRYING OUT. EXPECTING ONLY A SLOW WARMUP
THROUGH THE WEEK AS MODELS KEEP THE COLD 850 MB AIR OVER THE AREA
INTO WED. ARTHUR
&&

.AVIATION...

ISOLATED TO SCATTERED SHOWERS WILL OCCUR OVER THE AREA THROUGH
THIS EVENING. THERE WILL BE A SLIGHT CHANCE OF SHOWERS OVER AND
NEAR THE MOUNTAINS OVERNIGHT. EXPECT MOSTLY VFR CONDITIONS
ALTHOUGH BRIEF MVFR CONDITIONS WITH A SHOWER CANNOT BE RULED OUT.
A FEW OF THE SHOWERS MAY PRODUCE GUSTY WINDS TO 45 KT THROUGH THIS
EVENING. SURFACE WIND GUSTS OF 30 TO 40 KT OVER THE AREA WILL
DIMINISH THIS EVENING. WIDESPREAD MOUNTAIN OBSCURATION OVER THE
BEARTOOTHS/ABSAROKAS WILL DECREASE OVERNIGHT. OTHERWISE EXPECT
LOCALIZED MOUNTAIN OBSCURATIONS THROUGH TONIGHT. CHANCES FOR
SHOWERS WILL INCREASE OVER THE AREA FROM KLVM TO A KBIL TO KSHR
LINE ON FRI. MVFR CONDITIONS MAY ACCOMPANY THE SHOWERS. MOUNTAIN
OBSCURATION WILL INCREASE DURING THE DAY. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 039/063 041/059 041/052 034/052 034/052 036/058 036/062
    23/W    66/T    87/W    43/W    33/W    22/W    11/U
LVM 035/056 036/053 035/052 033/052 032/055 035/059 035/065
    26/W    68/T    85/W    32/W    22/W    11/U    11/U
HDN 036/064 039/064 040/051 032/051 030/051 032/057 032/063
    22/W    44/T    78/W    65/W    33/W    22/W    11/B
MLS 039/067 045/065 040/048 032/046 030/047 033/052 033/057
    21/B    63/T    78/W    86/W    43/W    22/W    11/B
4BQ 037/068 042/070 040/048 032/046 030/045 032/050 032/057
    11/B    33/T    78/W    86/W    53/W    22/W    11/B
BHK 037/066 043/063 038/046 032/043 028/043 030/048 031/055
    10/B    63/T    78/W    86/W    53/W    32/W    11/B
SHR 034/064 039/065 040/048 033/048 031/048 030/053 032/061
    23/W    43/T    68/W    65/W    33/W    22/W    11/B

&&

.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.