Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 282050
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
250 PM MDT TUE JUL 28 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
THE VERY STRONG AND VERTICALLY STACKED LOW THAT BROUGHT STRONG
WINDS...AND SOAKING RAINS TO NORTHEAST MONTANA OVER THE LAST 24
HOURS WILL CONTINUE TO LIFT OUT TOWARD HUDSON BAY THIS EVENING. AS A
RESULT PRECIPITATION AND WINDS WILL QUICKLY TAPER OFF FROM WEST TO
EAST THROUGH THE EVENING HOURS...ALLOWING FOR MUCH QUIETER
WEATHER. SOME CLEARING OF SKIES WILL ALSO BUILD IN FROM THE WEST
OVERNIGHT TONIGHT. THIS CLEARING COULD ALLOW FOR SOME PATCHY FOG
DEVELOPMENT OVER AREAS THAT SAW SIGNIFICANT RAINFALL OVER THE LAST
36 HOURS.

WEDNESDAY AND THURSDAY FLATTENED UPPER RIDGING WILL
BUILD IN FROM THE WEST. THIS WILL RESULT IN SUNNY SKIES...WARMING
TEMPERATURES...DRY CONDITIONS...AND GENERALLY WEST-NORTHWEST WINDS
AT 10-15 MPH. GILCHRIST


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

HOT DESERT AIR WILL ANCHOR THE HIGH PRESSURE RIDGE IN THE WEST
WHILE THE PERSISTENT HUDSON BAY LOW CONTINUES THROUGH THE EXTENDED
PERIOD. THIS MOSTLY UNCHANGING PATTERN WILL ESTABLISH A NORTHWEST
FLOW ALOFT FOR NORTHEAST MONTANA. THE THERMAL BOUNDARY BETWEEN
THESE DIFFERING AIR MASSES WILL MOSTLY REMAIN NW TO SE ACROSS
NEMONT...KEEPING THE HOT DESERT AIR CONFINED TO THE SOUTH AND
WEST. LOCAL TEMPERATURES WILL STAY AROUND NORMAL.

THIS WILL ALSO BE A DRY PATTERN FOR THE MOST PART. HOWEVER
BEGINNING SUNDAY NIGHT THROUGH MONDAY NIGHT AN UPPER DISTURBANCE
IN CANADA WILL BUMP THE BOUNDARY TO THE SOUTH WHICH WILL BRING IN
A CHANCE FOR RAIN SHOWERS AND THUNDERSTORMS. BEYOND THAT TIME GFS
AND THE EC FALL OUT OF PHASE FOR THE NEXT FEATURE.

EXCEPT FOR NUDGING UP POPS FOR MONDAY...FEW CHANGES WERE MADE TO
THE FORECAST. SCT

PREVIOUS DISCUSSION...
SYNOPTIC SET UP...A LARGE TROUGH RUNS THROUGH NUNAVUT NORTHERN
MANITOBA AND INTO ONTARIO. A LARGE HOT HIGH PRESSURE RIDGE HAS
DEVELOPED OVER THE WESTERN THIRD OF THE CONUS. NORTHEAST MONTANA
WILL BE WEDGED BETWEEN THESE TWO FEATURES IN SEMI ZONAL TO
NORTHWESTERN FLOW. FARTHER NORTHWEST A LARGE TROUGH SETS OVER THE
GULF OF ALASKA WHICH COULD LET A SHORTWAVE OR TOW FLY OVER THE
ROCKIES INTO HIGH PLAINS.

THURSDAY NIGHT THROUGH FRIDAY NIGHT.... MODELS ARE IN GOOD
AGREEMENT WITH MOSTLY CLEAR SKIES AND DRY... WARM CONDITIONS.

SATURDAY TO MONDAY... WEAK SHORTWAVES INT EH FLOW WILL EXIT THE
SOUTHERN ALBERTAN FRONT RANGE. TIMING IS UNKNOWN FOR EACH OF THESE
PASSAGES AND THEY QUICKLY KNOCK THE MODELS OUT OF FULL ALIGNMENT
DUE TO THEIR SUBTLY. POPS RISE BACK UP BUT DO NOT QUITE HIT
MENTION YET... DUE TO MOST OF THE ENERGY STAYING NORTH OF THE BORDER.
CONFIDENCE IS AVERAGE DURING THESE PERIODS.

MONDAY NIGHT ONWARD... GULF OF ALASKA TROUGH BREAKS APART AND
TRAVELS ACROSS THE ROCKIES EXITING THE CANADIAN FRONT RANGE. THE
IMPACT HERE IS IN QUESTION DEPENDING ON MODEL. THE GFS FAVORS A
RIDGE ACROSS THE CWA WHICH BLOCKS THE MOVEMENT OF THIS TROUGH AND
ITS ENERGY INTO THE AREA. THE EC FAVORS THE TROUGH COMING ACROSS
AND DROPPING SOUTH INTO THE CWA. CONFIDENCE IS BELOW AVERAGE HERE
AND HAD TO SPLIT THE DIFFERENCE ON TEMPERATURES UNTIL SOME FORM OF
ALIGNMENT OCCURS. GAH


&&

.AVIATION...

THE LOW PRESSURE STORM SYSTEM THAT BROUGHT SEVERE THUNDERSTORMS TO
THE AREA ON MONDAY AND MORE RAIN AND WIND TODAY WILL MOVE OUT OF
THE AREA TONIGHT. THE LOWER AND UPPER LEVEL LOW PRESSURE CENTERS
WILL BE STACKED UP OVER SOUTHERN MANITOBA AT MIDNIGHT THAT WILL
RESULT LOCALLY IN RAIN ENDING AND WIND DIMINISHING.

AT 6 PM THIS EVENING THE STORM CENTER WILL BE LOCATED ON THE BORDERS
BETWEEN SASKATCHEWAN...MANITOBA AND NORTH DAKOTA. THE RAIN THAT
WRAPS AROUND THE LOW CENTER WILL THEREFORE MOVE MOSTLY TO OUR EAST.
RAIN AND WIND TAPER OFF IN LATE AFTERNOON AND RAIN MOSTLY ENDS BY
SUNSET WHEN CONDITIONS SHOULD BECOME VFR.

FLIGHT CATEGORY: LATE AFTERNOON MVFR/IFR...IMPROVING TO VFR THIS
EVENING AND WEDNESDAY.

AREA WINDS: WEST AT 20 TO 30 KTS GUSTING TO 40 THIS AFTERNOON THE
TAPERING DOWN THIS EVENING. WIND DIMINISHES SIGNIFICANTLY AFTER
MIDNIGHT TO WNW AROUND 10KT...THEN INCREASING TO AROUND 15KT ON
WEDNESDAY.

SCT

&&

.HYDROLOGY...
RISES ON AREA CREEKS AND STREAMS ARE BEING OBSERVED ACROSS
NORTHEAST MONTANA. THE HEAVIEST RAIN FELL ACROSS
PHILLIPS...VALLEY...DANIELS...AND WESTERN ROOSEVELT COUNTIES WITH
1-3+ INCHES OBSERVED. IT WILL TAKE SOME TIME FOR THIS RAINFALL TO
MAKE ITS WAY DOWNSTREAM INTO CREEKS...STREAMS...AND RIVERS. THUS
WILL CONTINUE THE GOING FLOOD WATCH FOR THESE AREAS INTO
WEDNESDAY. GILCHRIST

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR CENTRAL AND
SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS...
DAWSON...EASTERN ROOSEVELT...GARFIELD...MCCONE...NORTHERN
PHILLIPS...NORTHERN VALLEY...PETROLEUM...PRAIRIE...RICHLAND...
SHERIDAN...SOUTHWEST PHILLIPS...WESTERN ROOSEVELT...WIBAUX.

FLOOD WATCH THROUGH WEDNESDAY MORNING FOR CENTRAL AND SOUTHEAST
PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS...NORTHERN
PHILLIPS...NORTHERN VALLEY...SOUTHWEST PHILLIPS...WESTERN
ROOSEVELT.

&&

$$

WEATHER.GOV/GLASGOW





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