Hail in Montana, June 14, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
335 AM MDT WED JUN 14 2006

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
THUNDERSTORMS CURRENTLY IN FERGUS AND PETROLEUM COUNTIES WILL MOVE
NORTH TO NORTHEAST THIS MORNING ACROSS PHILLIPS AND VALLEY
COUNTIES. WHILE THE STORMS WILL MOVE INTO STABLE AIR THIS MORNING
THE MAY BECOME ELEVATED AS THE LIFT OVER THE FRONTAL BOUNDARY THAT
IS NEAR THE STORMS AT THIS MOMENT. WILL MAINTAIN ISOLATED TO
SCATTERED THUNDERSTORMS THIS MORNING.
AN UPPER LOW IN WASHINGTON AND OREGON IS FORECAST TO MOVE NE INTO
SOUTHEAST ALBERTA TONIGHT. A STRONG AND INTENSIFYING COLD FRONT
FORECAST TO MOVE ACROSS EASTERN MONTANA TONIGHT. WITH WEAKENING
OF THE EASTERLY LOW LEVEL FLOW AND COOLING ALOFT TAKING
PLACE...THE SUBSIDENCE CAPPING INVERSION ALOFT SHOULD DISAPPEAR
LATE THIS AFTERNOON AND EVENING. THIS WILL OPEN THE WAY TO A VERY
ACTIVE EVENING OF SEVERE THUNDERSTORMS. MODELS BRING DEW POINTS
INTO THE 60S...LIFTED INDEXES AS LOW AS -9...AND CAPES TO 4000
J/KG OVER OUR AREA. WILL MENTION NUMEROUS THUNDERSTORMS THIS
EVENING BECOMING SCATTERED OVERNIGHT. HEAVY RAINFALL IS POSSIBLE
AS PRECIPITABLE WATER IS FORECASTED TO REACH 2.2 INCHES WHICH
ABOUT AS HIGH AS IT GETS AROUND HERE.

BEYOND TONIGHT...MODELS HAVE CHANGED THEIR TUNE ON THE UPPER LOW
TRACKING TO FURTHER SOUTH THAN EARLIER RUNS HAVE HAD IT. THEY
SLOWLY MOVE TO EITHER SOUTHERN SASK (GFS) OR NORTHEAST MONTANA
(NAM) BY FRIDAY. THIS WILL WOULD BRING THE MAIN COLD POOL ALOFT
OVER NORTHEAST MONTANA ON FRIDAY WITH SOME
INSTABILITY...ESPECIALLY DURING THE DAY. WILL MENTION A MIX OF
CHANCE AND SLIGHT CHANCE OF SHOWERS FOR THURSDAY THROUGH FRIDAY.
WILL COOL FRIDAY HIGHS FROM GOING FORECAST WITH COLD POOL EXPECTED
OVER THE AREA. FORRESTER

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
MODELS AGREE TO THE EXTENT THAT UPPER FLOW PATTERN THROUGH MOST OF
PERIOD LIKELY TO BE DOMINATED BY LOW AMPLITUDE RIDGES AND TROUGHS.
FIND GOOD AGREEMENT AMONG GFS/ECMWF/CANADIAN BUILDING A SHALLOW
SHORT WAVE RIDGE ACROSS REGION FRIDAY NIGHT THROUGH SATURDAY NIGHT
AS SLOW MOVING CLOSED LOW...FROM SHORT TERM PERIOD...DRIFTS EASTWARD
INTO NORTHWEST GREAT LAKES BY SUNDAY. BEGINNING SUNDAY...A BROAD
AND SHALLOW UPPER TROUGH IS EXPECTED OVER PACIFIC NORTHWEST AND
SOUTHWEST CANADA...BACKING FLOW ACROSS FORECAST SOUTH OF WEST. GFS
IN PARTICULAR TRACKS A FEW SHORT WAVE TROUGHS THROUGH THIS SOUTHWEST
FLOW FROM SUNDAY ONWARD. LOW CONFIDENCE ABOUT TIMING AND STRENGTH
OF THESE FEATURES IN GFS...BUT WILL MAINTAIN INHERITED SLIGHT CHANCE
POPS DUE TO INHERENT INSTABILITY IN THIS FLOW PATTERN FOR EARLY SUMMER.
RELATIVE FLATNESS OF FLOW SUGGESTS MINIMAL TEMPERATURE FLUCTUATIONS
THROUGH PERIOD...WITH TEMPERATURES PRETTY CLOSE TO NORMAL. GFS
ENSEMBLE MOS GUIDANCE SHOWS LITTLE CHANGE FROM PREVIOUS RUN...HAVE
MADE FEW AND MINOR CHANGES TO TEMPERATURES AND HUMIDITIES. GFS WINDS
LOOK GOOD FOR FIRST FEW PERIODS...SHOW LITTLE CHANGE FROM INHERITED
FORECAST...BUT CONFIDENCE IN MODEL WINDS GREATLY DIMINISHES THROUGH
PERIOD DUE TO LITTLE CONTINUITY WITH EARLIER RUNS...HENCE MADE FEW
CHANGES TO WIND FORECAST BEGINNING MONDAY.

&&

.AVIATION...
MOSTLY VFR FOR THE TAF SITES NEXT 24 HOURS...BUT WILL HAVE SCATTERED
THUNDERSTORMS...ESPECIALLY LATE AFTERNOON THROUGH EVENING...THAT
WILL GENERATE LOCAL MVFR CONDITIONS. BY LATE AFTERNOON A STRONG COLD
FRONT WILL INITIATE THUNDERSTORMS...SOME OF WHICH MAY BECOME SEVERE
WITH LARGE HAIL AND STRONG GUSTY WINDS. EAST WIND WILL CONTINUE AT
15 TO 25 KTS TODAY...BUT WILL GRADUALLY DIMINISH BY LATE AFTERNOON.
SURFACE WINDS WILL SHIFT TO THE WEST AFTER THE FRONT MOVES THROUGH
TO THE EAST DURING THE EVENING.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 6 PM MDT THIS AFTERNOON FOR FORT PECK
LAKE.

&&

WEATHER.GOV/GLASGOW