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 192110
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
310 PM MDT SUN APR 19 2015

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

THE LOWER...THICKER CLOUD DECK CONTINUES TO SLOWLY MOVE EASTWARD...NOW
JUST CLEARING THE STATE LINE...WHILE A BROAD AREA OF MORE MID-
LEVEL FAIR WEATHER CUMULUS CLOUDS HAVE NOW SPREAD OVER THE WESTERN
HALF OF THE CWA.

MODEL AGREEMENT IS EXCELLENT THROUGH THIS FORECAST PERIOD KEEPING
A PERSISTENT NORTHWEST FLOW ALOFT OVER OUR REGION AS AN AMPLIFIED
UPPER-LEVEL RIDGE OF HIGH PRESSURE SLOWLY CLIMBS THE CONTINENTAL
DIVIDE FROM THE WEST.

THIS PREVAILING WEATHER PATTERN WILL RESULT IN A SLOW INCREASE IN
DAILY TEMPERATURES WITH STRONG NIGHTTIME RADIATIONAL COOLING AMID
MOSTLY CLEARING SKIES EACH NIGHT. COULD EASILY HAVE SOME LOCATIONS
DROPPING DOWN BELOW FREEZING TEMPERATURES EACH NIGHT. MODELS
CONTINUE TO INDICATE THE PRESENCE OF SOME BANDS OF FAIR WEATHER
CUMULUS CLOUDS DEVELOPING EACH AFTERNOON AND NOT RESULTING IN ANY
PRECIP OUTSIDE OF LIMITED VIRGA SHOWERS OVER VERY ISOLATED PORTIONS
OF OUR EASTERN CWA. EXPECTING TO SEE MORE CUMULUS CLOUD
DEVELOPMENT OVER OUR SW ZONES TOWARD THE END OF THIS FORECAST
PERIOD. BMICKELSON

.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...

FORECAST CONFIDENCE REMAINS LOW FOR THE MID TO LATE WEEK PERIOD
WITH SIGNIFICANT MODEL DIFFERENCES. GFS CONTINUES TO SHOW MORE
CONSISTENCY...HOLDING WITH THE BLOCKING PATTERN WHILE THE ECMWF
REMAINS MORE PROGRESSIVE MOVING SHORTWAVES OUT OF THE PACIFIC
NORTHWEST. MADE ONLY A FEW CHANGES TO THE GOING FORECAST...ALONG
THE LINE OF THE GFS. EBERT

PREVIOUS LONG TERM DISCUSSION...MODELS HAVE DIVERGED FROM EARLIER
RUNS ON THEIR SOLUTIONS FOR THE EXTENDED PERIOD. THEY BOTH START
THE EXTENDED PERIOD TUESDAY NIGHT AND WEDNESDAY WITH NW FLOW ALOFT
OVER THE FORECAST AREA BETWEEN AN UPPER RIDGE TO THE WEST (WESTERN
MONTANA) AND DEEP UPPER LOW TO THE EAST.

THE GFS BARELY MOVES THE RIDGE DURING THE ENTIRE FORECAST PERIOD
AND GENERALLY KEEPS IT IN MONTANA AND ALBERTA WITH A SURFACE
NEARBY TO THE EAST AND THE UPPER LOW TO THE EAST REMAINING QUASI-
STATIONARY OVER ONTARIO. THIS WOULD KEEP NORTHEAST MONTANA DRY FOR
THE MOST PART WITH TEMPERATURES EITHER NEAR NORMAL OR SLIGHT
COOLER THAN NORMAL. THE GFS DOES BRING A WAVE THROUGH THE PACIFIC
NW NEXT WEEKEND AND THROUGH WESTERN MONTANA AND WYOMING THAT COULD
BRING A CHANCE OF SHOWERS TO THE SOUTHWEST PART OF THE FORECAST AREA.

MEANWHILE...THE ECMWF TRIES TO BE MORE PROGRESSIVE AND SLOWLY
MOVES THE UPPER LOW TO THE EAST WHICH IN TURN NUDGES THE RIDGE
EAST TO THE DAKOTAS BY NEXT WEEKEND. THE EC EVEN HAS A SHORTWAVE
TROUGH UNDERCUTTING THE RIDGE ACROSS SOUTHERN ALBERTA AND
SASKATCHEWAN THURSDAY AND FRIDAY WHICH WOULD BRING ENOUGH MOISTURE
INTO THE FORECAST AREA FOR A CHANCE OF SHOWERS. THEN THE EC BRINGS
AN UPPER TROUGH AND COLD FRONT THROUGH EASTERN MONTANA NEXT
WEEKEND FOR ANOTHER CHANCE OF SHOWERS.

AT THIS POINT... IT LOOKS LIKE THE GFS HAS MORE RUN TO RUN
CONSISTENCY AND WILL LEAN TOWARDS ITS FORECAST FOR NOW. FORRESTER

&&

.AVIATION...

VFR. WIDESPREAD MID LEVEL CU FIELD WITH ISOLATED SHOWERS WILL
PERSIST INTO THE EARLY EVENING THEN SOME MID AND HIGH LEVEL CLOUDS
ARE EXPECTED TONIGHT. GUSTY NORTH NORTHWEST WINDS WILL DIMINISH
BY SUNSET. GENERALLY CLEAR SKIES AND LIGHT WINDS ARE EXPECTED FOR
MONDAY.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 10 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.