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 300235
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
835 PM MDT FRI APR 29 2016

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

EVENING UPDATE...
CHANGES TO THE FORECAST WERE MINOR. ECHOS ON RADAR ACROSS THE CWA
ARE LIKELY NOT HITTING THE GROUND AND RAPIDLY DISSIPATING. POPS
WERE TWEAKED DOWNWARD TO ACCOUNT FOR THIS. WINDS ARE EXPECTED TO
REMAIN LIGHT BUT WERE TWEAKED TO HAVE SLIGHTLY HIGHER TEMPORAL
RESOLUTION. GAH


PREVIOUS SHORT TERM DISCUSSION...
AN UPPER LEVEL LOW SPINNING OVER THE NORTHERN ROCKIES WILL FILL
IN TONIGHT...ALLOWING PRECIPITATION THERE TO WIND DOWN. HOWEVER
ANOTHER CLOSED LOW SPINS UP OVER EASTERN COLORADO AND MOVES EAST.
THIS WILL SEND PRECIPITATION NORTH INTO SOUTHERN MONTANA ON
SATURDAY...AND SETS UP A SIMILAR PATTERN TO TODAY OF A HIGH IN
SOUTHERN SASKATCHEWAN ATTEMPTING TO CLEAR SKIES FROM THE NORTH AND
OVERRUNNING MOISTURE OVER OUR SOUTHWESTERN ZONES BRINGING CLOUD
COVER AND A SLIGHT CHANCE FOR SHOWERS.

SATURDAY NIGHT AND SUNDAY...THE SURFACE HIGH SLIDES FURTHER SOUTH
INTO NEMONT WHILE AN UPPER LEVEL HIGH FLOPS OVER INTO SOUTHWEST
CANADA AND OUR NORTHWEST TO INITIATE A WARMING TREND AND CLEARING
SKIES.

OVERALL...DIMINISHING CHANCES FOR PRECIPITATION AND STRONG
WINDS...AND WARMING TREND BY SUNDAY. EXPECT SLIGHTLY BELOW HIGHS
ON SATURDAY AND SLIGHTLY ABOVE HIGHS ON SUNDAY.

SCT


.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
UPDATE...THE GOING FORECAST AS DESCRIBED BELOW STANDS...WITH
ONLY A FEW TWEAKS...NONE OF WHICH WERE NOTEWORTHY.

HOWEVER...THE USUALLY GOOD PERFORMING ECMWF MODEL IS NOW DROPPING
A WEAK LOW PRESSURE SYSTEM SOUTHWARD OUT OF CANADA SUNDAY NIGHT
INTO MONDAY...WHICH IN TURN BRINGS LIGHT PRECIPITATION TO PORTIONS
OF NORTHEAST MONTANA. OTHER EXTENDED MODELS ARE WEAKER AND FURTHER
EAST WITH THIS FEATURE...RESULTING IN DRY CONDITIONS. OVERALL
CONFIDENCE IN THE ECMWF SOLUTION IS LOW GIVEN THE TROUBLES ALL
MODELS HAVE IN A WEAK FLOW ENVIRONMENT LIKE WE WILL SEE ON
MONDAY. BUT...IF LATTER RUNS CONTINUE WITH THIS TREND WE MAY NEED
TO ADJUST THE FORECAST. GILCHRIST

PREVIOUS LONG TERM DISCUSSION...SYNOPTIC SETUP... A TROUGH
RUNS FROM THE GREAT LAKES INTO THE CENTRAL PLAINS AND COLORADO. A
LARGE RIDGE IS DEVELOPING OVER THE WESTERN HALF OF THE NORTH
AMERICAN CONTINENT AND RUNS FROM SOUTHERN CALIFORNIA THROUGH IDAHO
AND INTO ALBERTA AND THE NORTHWEST TERRITORIES. NORTHEAST MONTANA
LIES BETWEEN THESE TWO LARGE FEATURES UNDER THE WARMER SIDE OF
NORTHEASTERN FLOW ALOFT. FARTHER WEST... A HIGHLY AMPLIFIED LONG
WAVE TROUGH SETS JUST OFF THE COAST OF BRITISH COLUMBIA AND THE
PACIFIC NORTHWEST.

SUNDAY NIGHT THROUGH TUESDAY... RIDGE TO THE WEST WILL GROW IN
STRENGTH AND SLOWLY RAMP UP TEMPERATURES WHILE KEEPING CONDITIONS
DRY.

TUESDAY NIGHT THROUGH THURSDAY... CORE OF THE RIDGE/HIGH PRESSURE
TO THE WEST WILL MOVE ACROSS THE CWA, FURTHER INCREASING
TEMPERATURES TO ABOVE SEASONAL NORMS. CONDITIONS SHOULD REMAIN
DRY.

THURSDAY NIGHT ONWARD... RIDGE WILL TOPPLE OVER AND ALLOW
SOUTHWEST FLOW TO ENTER MONTANA DURING THIS TIME. THIS SHOULD
BEGIN PUSHING US INTO A MORE UNSTABLE PATTERN WITH ENHANCED JETS,
GIVING RISE TO AFTERNOON AND EVENING RAIN SHOWERS WITH OCCASIONAL
THUNDERSTORMS.   GAH


&&

.AVIATION...
AN UPPER LEVEL RIDGE WILL BRING GOOD FLYING WEATHER WITH VFR
CONDITIONS AND MID LEVEL CLOUDS PREVAILING ACROSS THE AREA.
SKIES WILL BEGIN TO CLEAR FROM THE NORTHEAST SATURDAY MORNING.

WINDS WILL BE 10 KTS OR LESS TONIGHT GENERALLY FROM THE EAST.

AEH/TFJ


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.


&&

$$

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.