Area Forecast Discussion
Issued by NWS Glasgow, 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 47 48 49 50
000
FXUS65 KGGW 302044
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
244 PM MDT MON MAR 30 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...

FORECAST FOCUS IN THE SHORT TERM PERIOD IS ON FIRE WEATHER
CONCERNS BEGINNING TUESDAY AMID THE APPROACHING STORM SYSTEM AND
STRONG WIND SHIFT BEHIND THE COLD FRONT ON WEDNESDAY. SEE FIRE
WEATHER DISCUSSION BELOW.

WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOW A STRONG BUILDING
UPPER-LEVEL RIDGE OVER THE WESTERN STATES WITH NW FLOW OVER NE
MONTANA. BEAUTIFUL AND WARM CONDITIONS ARE EXPECTED TO PREVAIL
UNDER THIS RIDGE TODAY THROUGH TUESDAY WITH NO PRECIP AND DRYING
SURFACE CONDITIONS.

BY MID DAY TUESDAY...FLOW ALOFT TURNS ZONAL WITH INCREASING
CLOUDS. A SW FLOW ALOFT AND RAIN SHOWERS BEGIN TO EMERGE OVER
CENTRAL MONTANA BY TUESDAY AFTERNOON AND THUNDERSTORMS BECOME
POSSIBLE. SHOULD BE FAIRLY LOW THREAT AND ISOLATED IN
NATURE...BARELY REACHING OUR WESTERN ZONES BEFORE 00Z THAT
EVENING. AFTER 00Z...SHOWERS AND THUNDERSTORMS BECOME MORE CERTAIN
THROUGH THE REMAINDER OF OUR CWA ON A GENERAL SW TO NE PATH. MAY
NOT BE MUCH OUTSIDE OF A MAIN CORRIDOR FROM WINNET THROUGH GLASGOW
TO SCOBEY. SUPPORT FOR THUNDERSTORM ACTIVITY SHOULD WANE AFTER
SUNSET. COLD FRONTAL PASSAGE...OR INITIAL WIND SHIFT IS EXPECTED
THROUGH ZORTMAN TUESDAY EVENING...THROUGH GLASGOW TUESDAY
MIDNIGHT...AND THROUGH SIDNEY BY EARLY WEDNESDAY MORNING.

FOR WEDNESDAY...NE MONTANA WILL BE MAINLY IN A DRY SLOT WITH
WIDESPREAD DOWNSLOPE ENHANCED STRONG AND GUSTY WINDS SPREADING
ACROSS THE ENTIRE CWA. ALTHOUGH NOT QUITE AS STRONG AS THE LAST
STORM SYSTEM...EXPECTING SUSTAINED WEST WINDS OF 25 TO 35 MPH WITH
GUSTS AS HIGH AS 50 MPH AMID A SLIGHT CHANCE OF RAIN SHOWERS
NEAR THE PERIMETER OF THE CWA...ESPECIALLY NORTH. A LAKE WIND
ADVISORY WILL LIKELY BE NEEDED...BUT SINCE THAT WOULD LINGER
THROUGH DAY 3 IN THE FORECAST...WILL LET NEXT SHIFT LOOK CLOSER AT
TIMING THAT OUT BEFORE ISSUING AT THIS TIME. BMICKELSON

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...

THE GOING FORECAST AS DESCRIBED BELOW. THE ONLY TWEAK WAS AN
OVERALL TREND TOWARDS THE LATEST CONSENSUS OF THE EXTENDED
MODELS...A TWEAK WHICH RESULTED IN VERY MINOR CHANGES. GILCHRIST

PREVIOUS DISCUSSION...EXTENDED PERIOD OPENS WITH UPPER TROF
PUSHING ACROSS THE NORTHERN PLAINS AND WELL DEVELOPED CYCLONE OVER
SOUTHERN MANITOBA. TIGHT GRADIENT AND COLD AIR ADVECTION INTO
EASTERN MONTANA BEHIND THIS SYSTEM WILL KEEP WINDY CONDITIONS OVER
THE REGION WEDNESDAY NIGHT BEFORE SLOWLY DIMINISHING ON THURSDAY.
MOISTURE ALSO WRAPPING SOUTH WITH THE COLD AIR TO PRODUCE SOME
MIXED PRECIPITATION SHOWERS.

SOMEWHAT UNSETTLED WEATHER CONTINUES INTO FRIDAY AS A SECOND TROF
PUSHES THROUGH THE GREAT BASIN...THEN SLIGHT RIDGING WILL BRING
DRIER WEATHER BY SATURDAY. CONFIDENCE LOW FOR THE END OF THE
FORECAST PERIOD WITH SIGNIFICANT MODEL DIFFERENCES. GFS REMAINS
PROGRESSIVE AND BRINGS THE NEXT SHORTWAVE TROF INTO THE REGION
EARLY NEXT WEEK FOR COOL AND WET WEATHER. THE ECMWF DEVELOPS A
BLOCKING PATTERN BY DIGGING THE TROF DOWN THE WEST COAST PUMPING
WARM AND DRY AIR INTO REGION BEFORE PUSHING THE TROF EAST BY
MIDWEEK. WILL TREND A LITTLE MORE TOWARD THE PROGRESSIVE SOLUTION
AND CLIMO VALUES FOR SUNDAY AND MONDAY. EBERT

&&

.AVIATION...

VFR CONDITIONS EXPECTED FOR THE TAF CYCLE AS HIGH PRESSURE BUILDS
OVER THE REGION.

&&

.FIRE WEATHER...

FIRE WEATHER CONCERNS THIS WEEK SPAN BOTH TUESDAY AND WEDNESDAY
FOR DIFFERENT COMBINATIONS OF REASONS. A STRONG RIDGE OF HIGH
PRESSURE AND SUNNY SKIES WILL ALLOW TEMPERATURES TO CLIMB WELL
ABOVE NORMAL AND RH VALUES TO DROP EASILY INTO THE
TEENS...ESPECIALLY SOUTH OF THE MISSOURI RIVER. THIS WILL BE IN A
PRE-FRONTAL ENVIRONMENT AND COULD SEE EVEN HIGHER TEMPS OR LOWER RH
VALUES THAN CURRENTLY FORECASTED. EXPECT WINDS ON TUESDAY FROM THE
SOUTH AND SOUTHWEST IN THE 15 TO 20 MPH RANGE.

A STRONG COLD FRONT IS CURRENTLY PROGGED TO PUSH THROUGH THE
REGION TUESDAY NIGHT WITH SOME SHOWERS AND AND ISOLATED TO
SCATTERED THUNDERSTORMS POSSIBLE WITH SOME RECOVERY IN RH VALUES.
MID DAY WEDNESDAY THROUGH THE AFTERNOON HOURS...RH VALUES DROP DOWN
NEAR 20 PERCENT SOUTH AND 25 TO 30 PERCENT NORTH WITH WIDESPREAD
STRONG AND GUSTY WEST WINDS IN THE 30-35 MPH RANGE WITH GUSTS UP
TO 50 MPH. RATHER THAN GET TOO DETAILED WITH COVERAGE AND START
AND STOP TIMING...FELT IT WAS BEST TO SIMPLY SET THE RED FLAG
WARNING FOR THE ENTIRE FORECAST AREA EVEN THOUGH A RESPITE IS
EXPECTED DURING THE OVERNIGHT HOURS BETWEEN THESE TWO CONCERNS.
BMICKELSON

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TUESDAY TO 9 PM MDT WEDNESDAY FOR
MTZ120-122-134>137.

&&

$$

WEATHER.GOV/GLASGOW




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