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 191511
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
911 AM MDT FRI SEP 19 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY...

MORNING UPDATE...
CHANGES FOR THIS MORNING FOCUSED AROUND DIFFERENCES IN MODELS FOR
SHOWERS DEVELOPMENT THIS AFTERNOON. RADAR TRENDS IN SOUTHERN
SASKATCHEWAN SHOW ECHOS SLOWLY PROGRESSING SOUTHEAST TOWARD THE
BORDER. ALL MODELS HAVE SOME FORM OF SHOWERS MOVEMENT ACROSS THE
NORTHEAST CORNER OF THE CWA THIS AFTERNOON. HOWEVER... THE EXTENT
SOUTH IS IN QUESTION. HAVE SPREAD SLIGHT CHANCE POPS FARTHER SOUTH
AND RAISED POPS ACROSS THE FAR NORTHEAST. HI-RESOLUTION MODELS
ALSO SHOW SOME REMNANT SHOWERS AFTER 6PM ALONG THE MT/ND BORDER.
THEREFORE... RAISED POPS TO SLIGHT CHANCE DURING THIS TIME. GAH


PREVIOUS SHORT TERM DISCUSSION...
COLD FRONT WILL MOVE THROUGH EASTERN MONTANA THIS MORNING TURNING
WINDS TO THE NORTHWEST. ISOLATED SHOWERS AND THUNDERSTORMS HAVE
OCCURRED AT TIMES OVERNIGHT ALONG THIS FRONT. WILL MAINTAIN A
SLIGHT CHANCE IN THE EAST THIS MORNING. EXPECT NORTHWEST WINDS TO
INCREASE ENOUGH THIS MORNING TO WARRANT KEEPING THE LAKE WIND
ADVISORY IN EFFECT.

WSW FLOW ALOFT WILL TURN WNW TODAY AS A SHORTWAVE TROUGH MOVES
THROUGH THE AREA THIS MORNING. A SECOND SHORTWAVE MOVES THROUGH
THE FORECAST AREA THIS AFTERNOON. MOISTURE AND UPPER LEVEL
DYNAMICS WILL BE FOCUSED IN THE NE CORNER OF THE STATE WITH THIS
WAVE. THERE WILL ALSO BE ENOUGH INSTABILITY THAT A FEW
THUNDERSTORMS ARE POSSIBLE. WILL MENTION A CHANCE OF SHOWERS AND
THUNDERSTORMS THAT WILL EXTEND THROUGH TONIGHT AS MODELS WANT TO
BRING A THIRD SHORTWAVE THROUGH THE SAME AREA LATE TONIGHT AND
SATURDAY MORNING.

SURFACE HIGH PRESSURE BUILDS INTO THE AREA ON SATURDAY WITH COOLER
TEMPERATURES. EXPECT DRY WEATHER AFTER THE SHORTWAVE DEPARTS IN
THE MORNING. NORTHWEST MAY BE STRONG ENOUGH AGAIN FOR ANOTHER
LAKE WIND ADVISORY. WILL NOT EXTEND THE LAKE WIND INTO SATURDAY
FOR NOW AS WIND SPEEDS ARE FORECASTED TO BE MARGINAL.

SURFACE HIGH WILL DIMINISH THE WINDS SATURDAY NIGHT AND REMAIN
OVER THE AREA ON SUNDAY KEEPING WINDS LIGHT AND SKIES MOSTLY
CLEAR. FORRESTER


.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...

THE EXTENDED PERIOD BEGINS MONDAY NIGHT WITH AN AMPLIFIED LONG-
WAVE RIDGE IN PLACE OVER WESTERN CONUS AND CANADA. A CLOSED OFF
LOW CENTERED OVER THE NORTHERN REACHES OF THE GREAT BASIN WILL CUT
ACROSS THE RIDGE AS THE RIDGE AXIS SHIFTS EAST. THE LOW WILL
GENERALLY CUT UNDER NORTHEAST MONTANA...MAINLY AFFECTING SOUTHERN
MONTANA. THE RIDGE IN PLACE WILL BRING MORE WARMING TO THE REGION
WITH TEMPERATURES RAMPING UP ABOVE NORMAL AGAIN.

MONDAY NIGHT THE LOW OPENS AND MOVES ACROSS A SURFACE TROUGH. THIS
COULD LEAD TO SOME INSTABILITY THAT COULD PRODUCE A FEW SHOWERS
AND ISOLATED THUNDERSTORMS INTO TUESDAY. ON WEDNESDAY THE RIDGE
REESTABLISHES ITSELF AS A DEEP TROUGH/EASTERN PACIFIC STORM PUSHES
UP AGAINST THE CASCADE RANGE. THERE IS A VERY DISTINCT COLD FRONT
ASSOCIATED WITH THIS STORM SYSTEM. THE MAIN QUESTION IS IF IT HAS
ENOUGH STRENGTH TO BREAK DOWN THE RIDGE OVER EASTERN MONTANA. HERE
IS WHERE THE MODELS DIFFER. THE EC HAS THE FRONT STALLING OUT TO
OUR WEST...WHILE THE GFS PUSHES THE FRONT ACROSS EASTERN MONTANA
FRIDAY NIGHT AND SATURDAY. THE SIGNIFICANCE OF THE STRONG FRONT IS
THE WARM TEMPERATURES IN PLACE. SO WHERE THE FRONT HITS THERE WILL
BE RAIN AND THUNDER FROM THE CANADIAN BORDER TO THE MEXICAN
BORDER. MODEL DIFFERENCES ADD TO THE UNCERTAINTY AFTER MID WEEK. SCT


&&

.AVIATION...
A WEAK COLD FRONT WILL DROP OUT OF SASKATCHEWAN TODAY AND COULD
BRING A FEW SHOWERS OR EVEN A THUNDERSTORM TO THE NORTHEAST CORNER
OF MONTANA TODAY. VFR CONDITIONS ARE GENERALLY EXPECTED...BUT
FLIGHT CONDITIONS COULD DROP WHERE SHOWERS OCCUR. ANOTHER WEAK
FRONT WILL CLIP THE REGION SATURDAY MORNING WITH SIMILAR
CONDITIONS.


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR FORT PECK
LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.


&&

$$

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.