Blizzard and Flooding in Montana, May 9 to 15, 2016

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
907 AM MDT MON MAY 9 2016

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

AFTERNOON UPDATE...
CHANGE TO THE FORECAST REVOLO9VED AROUND UPDATING POPS FOR PLACES
WHERE CURRENT RADAR ECHO ALREADY ARE AND ARE PLANNED TO MOVE. TWO
AREAS OF FOCUS STAND OUT AMONG THE REST THE FIRST IS ACROSS THE
FAR WEST WERE A STATIONARY FRONT IS CURRENTLY GENERATING SHOWERS
WHILE THE SECOND IS ACROSS THE EASTERN MOST ZONE WHERE A BROAD
AREA OF SURFACE INSTABILITY WILL BE OVER TOPPED BY A UPPER LEVEL
LIFT ZONES THIS AFTERNOON. THIS WILL SPARK OFF RAIN SHOWERS AND
THUNDERSTORMS WHICH WILL INCREASE IN COVERAGE THROUGH THE EVENING
HOURS UNTIL THE STATIONARY FRONT MOVES FORWARD AND THE LOW CLOSES
UP COMPLETELY ACROSS THE CWA. GAH

PREVIOUS SHORT TERM DISCUSSION...
THERE IS AN ENERGETIC TROUGH DROPPING INTO THE NORTHERN ROCKIES
THIS MORNING WHILE A SEPARATE TROUGH IS MOVING EAST OUT OF THE
CENTRAL ROCKIES INTO THE CENTRAL PLAINS. THESE TWO LOW CENTERS
WILL SLOWLY SPIN AROUND EACH OTHER AND MERGE BY TONIGHT. THIS
MOVEMENT WILL HAVE THE EFFECT OF THE STORM STALLING OVER NORTHEAST
MONTANA THROUGHOUT MOST OF THE SHORT TERM PERIOD...TODAY THROUGH
WEDNESDAY. THIS STORM HAS HAD FAIRLY GOOD MODEL CONSISTENCY AND
IS EXPECTED TO DUMP FROM 1 TO 2 INCHES ACROSS ALL OF NORTHEAST
MONTANA. THE TWO STORMS WILL MERGE INTO A COMPACT CYCLONE LATE
MONDAY NIGHT OR TUESDAY MORNING.

RADAR IMAGERY THIS MORNING CLEARLY SHOWS A SLOW MOVING FRONTAL
BOUNDARY MOVING FROM CENTRAL MONTANA INTO NORTHEAST MONTANA. FOR
TODAY...MOST PRECIPITATION WILL CONTINUE OVER CENTRAL MONTANA AND
OUR WESTERN COUNTIES. THE CENTRAL PLAINS STORM WILL RETROGRADE
INTO OUR EASTERN ZONES TODAY.

WITH THE SURFACE TROUGH IN OUR EAST...STRONG NORTHERLY WINDS WILL
ACCOMPANY THE WESTERN FRONTAL BOUNDARY. SO WILL ISSUE AN NPW FOR
FOR PECK LAKE. THIS ADVISORY WILL LIKELY NEED TO CONTINUE THROUGH
WEDNESDAY EVENING. WITH WIDESPREAD WEAK TO MODERATE INSTABILITY...
GENERAL THUNDERSTORMS WILL BE POSSIBLE TODAY.

TONIGHT THROUGH TUESDAY NIGHT...THE MEETING OF THE TWO AIR-MASS
WILL FORM A TIGHT LOW ALOFT WHICH WILL QUICKLY GENERATE A TROWAL
ON THE BACK SIDE OF IT TUESDAY MORNING. AT THIS POINT THE EASTWARD
PROGRESSION OF THE LOW WILL SLOW DOWN LEAVING A WELL MOISTEN AND
CONSISTENTLY FUELED TROWAL TO DUMP COPIOUS AMOUNTS OF RAIN ACROSS
THE CWA. QPF TOTALS LASTING ALL THE WAY INTO WEDNESDAY WILL LIKELY
BE AROUND 1 INCH FOR MOST LOCATIONS WITH NEARLY 2 1/2 INCHES
POSSIBLE IN ISOLATED AREAS.

WEDNESDAY...WILL SEE THE STORM SYSTEM MOVING NORTHEAST INTO
MANITOBA. SHOWERS WILL TAPER OFF RAPIDLY...ENDING IN THE
AFTERNOON. THE GFS IS SHOWING 850MB TEMPERATURES THROUGH THE
PERIOD REMAINING ABOVE 0C. SO DO NOT EXPECT SNOW...ALTHOUGH SOME
COOLER AIR COULD BE ENTRAINED IN THE CIRCULATION AND PRODUCE A FEW
FLAKES.

SCT

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...

UPPER LOW MOVING THROUGH THE REGION EARLY IN THE WEEK EXPECTED TO
PUSH INTO THE WESTERN GREAT LAKES BY WEDNESDAY NIGHT. A FEW SHOWER
MAY LINGER ALONG THE NORTH DAKOTA BORDER DURING THE EVENING BUT
SHOULD CLEAR AS COOLER AND DRIER AIR IS PULLED SOUTH BY THE
DEPARTING SYSTEM.

UPPER RIDGE BEGINS BUILDING INTO THE NORTHERN ROCKIES FOR THE END
OF THE WEEK. PROGRESS WILL BE STALLED BRIEFLY BY A SHORTWAVE
ZIPPING ALONG THE CANADIAN BORDER ON THURSDAY AND DROPPING A COLD
FRONT THROUGH MONTANA. SOME SHOWERS POSSIBLE WITH THE FRONT
THURSDAY INTO THURSDAY NIGHT.

NORTHWEST FLOW EXPECTED FOR THE THE REMAINDER OF THE PERIOD WITH
RIDGE TO THE WEST AND DEEP LOW DEVELOPING OVER ONTARIO. HIGH
PRESSURE EXPECTED OVER THE NORTHERN PLAINS FOR DRY CONDITIONS AND
A LITTLE BELOW NORMAL TEMPERATURES. EBERT

&&

.AVIATION...
AN UPPER LEVEL LOW WILL MOVE OVER THE REGION WHICH WILL BRING A
CHANGE IN THE WEATHER PATTERN.

SURFACE LOW OVER EASTERN MONTANA TODAY WILL BRING A MIX OF
SOUTHEAST... EAST AND NORTHEAST WINDS AROUND 10 KNOTS THIS
MORNING. SLOW MOVING COLD FRONT WILL TURN WINDS TO THE NORTH 15 TO
25 KNOTS AT KGGW THIS AFTERNOON AND NORTHEAST 10 TO 15 KNOTS AT
KOLF THIS EVENING WHILE KGDV AND KSDY MAINTAIN LIGHT AND VARIABLE
WINDS INTO TUESDAY MORNING. CLOUDS AND PRECIPITATION WILL MOVE
INTO THE TAFS SITE AFTER 21Z TODAY AND FLIGHT CONDITIONS GRADUALLY
LOWER FROM VFR TO MVFR DURING THE EVENING. IFR CONDITIONS ARE
POSSIBLE LATE TONIGHT AND TUESDAY MORNING AS RAIN BECOME
WIDESPREAD ACROSS NORTHEAST MONTANA.

&&

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

&&

WEATHER.GOV/GLASGOW

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
308 AM MDT MON MAY 9 2016

MTZ016>027-059>062-100915-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
DANIELS-SHERIDAN-WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE-
RICHLAND-DAWSON-PRAIRIE-WIBAUX-NORTHERN PHILLIPS-
SOUTHWEST PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT-
308 AM MDT MON MAY 9 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TODAY AND TONIGHT

A LAKE WIND ADVISORY FOR FORT PECK LAKE IS IN EFFECT FROM NOON
TODAY THROUGH 9 PM WEDNESDAY EVENING. EXPECT NORTH TO NORTHWEST
WINDS OF 25 TO 35 MPH WITH GUSTS TO 50 MPH THROUGHTOUT THE PERIOD.

A SLOW MOVING LOW PRESSURE SYSTEM WILL BRING WIDESPREAD RAIN TO
NORTHEAST MONTANA TODAY...CONTINUING THROUGH WEDNESDAY. MANY
AREAS WILL RECEIVE ONE TO TWO 1/2 INCHES OF RAIN FROM THIS SYSTEM.
STRONG...GUSTY NORTH TO NORTHWEST WINDS WILL DEVELOP TODAY AND
CONTINUE STRONG THROUGH WEDNESDAY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A LAKE WIND ADVISORY FOR FORT PECK LAKE WILL LIKELY CONTINUE
THROUGH EARLY WEDNESDAY EVENING.

THE STRONG STORM SYSTEM WILL LIKELY CONTINUE THROUGH WEDNESDAY
BEFORE EXITING THE REGION BY WEDNESDAY EVENING.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.