Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 220901
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
301 AM MDT FRI MAY 22 2015

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

THE FORECAST BEGINS WITH NORTHEAST MONTANA STILL UNDER THE HIGH
PRESSURE THAT HAS BROUGHT SEVERAL DAYS OF CLEAR SKIES AND SEASONAL
TO SLIGHTLY ABOVE SEASONAL TEMPERATURES TO THE AREA. BUT A CHANGE
IS OCCURRING. A CLOSED UPPER LOW CENTERED OVER SOUTHERN CALIFORNIA
WILL BE PICKING UP PACIFIC MOISTURE AND EJECTING IT INTO THE
CENTRAL ROCKIES AND PLAINS. THIS LOW WILL SLOWLY LIFT NORTHEAST
THROUGH SUNDAY...ENDING UP OVER THE LOCAL REGION. THE MOVEMENT OF
THIS TROUGH WILL BE NOTICED LOCALLY TODAY AS MID TO HIGH CLOUDS
DRIFT NORTH ACROSS THE AREA...ENDING THE CLEAR SKIES.

TODAY/TONIGHT...AREAS OF INSTABILITY WILL DEVELOP OVER CENTRAL
MONTANA. WEAKER INSTABILITY SPREADS INTO OUR SOUTHWEST ZONES.
THERE IS NOT MUCH TO INITIATE CONVECTION EXCEPT FOR LIFT OVER THE
HILLS. SPC HAS PLACED THAT AREA IN ITS GENERAL THUNDERSTORM AREA.
SO ALTHOUGH NOT EXPECTING MUCH IN THE WAY OF THUNDER OR
SHOWERS...WILL MAINTAIN THE SLIGHT CHANCE THAT HAS BEEN IN PLACE.
A SURFACE GRADIENT IN PLACE WILL AGAIN SET UP A BRISK SOUTHEAST
WIND. MODELS SUGGEST A BIT STRONGER WIND THAN THURSDAY. A LWA IS
IN EFFECT FOR FORT PECK LAKE.

SATURDAY...THE LOW CENTER LIFTS FURTHER INTO THE CENTRAL ROCKIES
WHERE THE MOISTURE FINDS TRIGGERS FOR SHOWERS AND GENERAL
THUNDERSTORMS. BUT WITH NORTHEAST MONTANA REMAINING IN AN AREA
BETWEEN STORMS...ONLY ISOLATED RAIN AND THUNDER IS EXPECTED. BRISK
EAST WINDS WILL CONTINUE.

SATURDAY NIGHT AND SUNDAY...THE LOW LIFTS SUFFICIENTLY NORTH TO
BEGIN AFFECTING THE LOCAL AREA WITH A GREATER CHANCE FOR
SHOWERS...ESPECIALLY IN THE SOUTHEAST ZONES...WITH GREATER QPF ON
SUNDAY AFTERNOON. THE COOLER AIR FROM THE TROUGH WILL TEMPER
TEMPERATURES CLOSER TO NORMAL. SCT

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
MODELS HAVE THEIR DIFFERENCES WITH THE UPPER TROUGH/LOW LIFTING
NORTH INTO MONTANA AND THE DAKOTAS SUNDAY NIGHT AND MONDAY. ECMWF
MAINTAINS AN OPEN TROUGH AND KEEPS MOST OF THE MOISTURE TO THE
EAST WHILE THE GFS HAS A CLOSED LOW AND PUSHES MOISTURE FURTHER
WEST INTO EASTERN MONTANA. WILL SPLIT THE DIFFERENCE FOR NOW AND
MAINTAIN HIGHER POPS IN THE EAST.

THE REST OF THE PERIOD...MODELS TIME SYSTEMS DIFFERENTLY BUT EACH
ONE HAS FREQUENT SHORTWAVE TROUGHS GOING THROUGH MONTANA WHICH
WOULD LEAD TO SHOWERS AND THUNDERSTORMS AT TIMES THAT WOULD BE TOO
DIFFICULT TO TIME. WILL MAINTAIN CHANCE/SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGH THE WEEK. FORRESTER

&&

.AVIATION...
VFR.

MOSTLY CLEAR SKIES THIS MORNING WILL GIVE WAY TO INCREASING HIGH
CLOUDS THIS AFTERNOON. SOUTHEAST WINDS WILL INCREASE TO 10 TO 20
KNOTS BY AFTERNOON. CLOUDS WILL CONTINUE TO INCREASE TONIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE AREA FROM THE WEST. LOOK FOR
EAST WINDS TO CONTINUE AS AROUND 10 KNOTS.


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM MDT THIS
EVENING FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...
CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW





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