Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 290154 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
754 PM MDT THU AUG 28 2014

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

SENT AN EARLY UPDATE TO THE FORECAST TONIGHT AS STRONG TO SEVERE
THUNDERSTORMS ARE APPROACHING THE CWA FROM THE NORTHWEST. THESE
STORMS ARE SUSTAINED AND SUPPORTED BY THE LEADING COLD FRONT
DESCENDING FROM THE CANADIAN ROCKIES. COMMUNICATION FROM THE
CANADIAN STORM PREDICTION CENTER INDICATES THAT THE LEADING
SUPERCELL IS IN FACE SEVERE WITH LARGE HAIL AND DAMAGING WINDS.
UPDATED THE GRIDS INTO 3-HOURLY SECTIONS TO ACCOUNT FOR THE SPEED
OF THESE STORMS AND TO INCLUDE SEVERE WORDING. EXPECT THE SEVERITY
TO DIMINISH AFTER MIDNIGHT AS A LESS-FAVORABLE SHEAR PROFILE IS
FOUND NEAR AND SOUTH OF THE MISSOURI RIVER. BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...UPPER FLOW IS RATHER PROGRESSIVE
WITH A COUPLE OF DISTURBANCES MOVING THROUGH DURING THIS PERIOD.
THE FIRST ONE WILL MOVE THROUGH TONIGHT BRINGING SHOWERS/ISOLATED
THUNDERSTORMS. UPPER LEVEL VORT MAX COMBINED WITH LOW-LEVEL
INSTABILITY SHOULD GIVE AT LEAST SCATTERED PRECIPITATION TO MOST
AREAS TONIGHT.

A SHORTWAVE RIDGE MOVES ACROSS THE AREA FRIDAY WITH AN UPPER TROUGH
MOVING INTO THE PACIFIC NW. THIS TROUGH WILL THEN MOVE INTO THE AREA
SATURDAY AND WORK IN TANDEM WITH A SURFACE TROUGH. AGAIN...UPPER
LEVEL ENERGY WILL WORK WITH LOW-LEVEL INSTABILITY TO BRING A RAPID
INCREASE IN SHOWERS/TSTORMS FROM THE WEST/SOUTHWEST. THIS
DISTURBANCE SHOULD HAVE A BIT BETTER COVERAGE WITH THE NE ZONES
LIKELY TO RECEIVE THE MOST QPF (WHERE THEY TAP INTO DEEPER
INSTABILITY).

TEMPERATURES WILL BE COOLER FRIDAY AS A COLD FRONT DROPS SOUTH INTO
THE CWA TONIGHT. CLOUDS AND RAIN SHOWERS WILL KEEP A LID ON
TEMPERATURES SATURDAY DESPITE HIGHER THICKNESSES. TFJ


.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...

FEW CHANGES WERE NECESSARY AS THE 28/12Z GUIDANCE IS PRETTY MUCH
IN LINE WITH THE 28/00Z SUITE. WILL EXPECT A BROAD TROUGH ACROSS
THE WESTERN U.S. OVER THE LATTER HALF OF WEEKEND TO GRADUALLY FLATTEN
AND LIFT INTO EASTERN CANADA DURING THE UPCOMING WEEK. THIS TROUGH
WILL PROVIDE DYNAMIC SUPPORT FOR SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS NORTHEAST MONTANA THROUGH SUNDAY ALONG WITH
TEMPERATURES BELOW SEASONAL NORMALS. AS THE TROUGH TRANSLATES OUT
OF THE REGION THERE MAY BE A SLOW UPTREND IN TEMPERATURES. MALIAWCO

PREVIOUS LONG TERM DISCUSSION...
BROAD TROF OVER THE WESTERN STATES THIS WEEKEND EXPECTED TO
FLATTEN AS IT LIFTS TOWARD EASTERN CANADA NEXT WEEK AND ANOTHER
TROF DIGS TOWARD THE PACIFIC NORTHWEST. UPPER FLOW OVER MONTANA
WILL THUS GRADUALLY BACK FROM NORTHWEST EARLY IN THE WEEK TO
SOUTHWEST BY THE END OF THE FORECAST PERIOD.

LINGERING SHOWERS OR THUNDERSTORMS EXPECTED AT THE BEGINNING OF
THE PERIOD AS THE UPPER TROF MOVES FROM THE NORTHERN ROCKIES INTO
THE PLAINS. MUCH COOLER AIR UNDER THE TROF WILL RESULT IN MAX
TEMPERATURES OF 5 TO 15 DEGREES BELOW NORMAL FOR SUNDAY AND
MONDAY. AS THE UPPER FLOW BACKS TEMPERATURES WILL WARM...RETURNING
TO NEAR NORMAL VALUES BY WEDNESDAY.


&&

.AVIATION...

MAINLY VFR CONDITIONS ARE EXPECTED TONIGHT. EXPECT CIGS TO LOWER
TO ABOUT 8000 FT BY FRIDAY MORNING. SCATTERED SHOWERS AND PERHAPS
A THUNDERSTORM COULD TEMPORARILY RESTRICT VISIBILITIES BUT
CONFIDENCE IS LOW FOR ANY SPECIFIC TAF SITE. WEST WINDS AROUND 10
KTS WILL SHIFT NORTH OVERNIGHT AS A COLD FRONT SWEEPS THROUGH THE
REGION. MALIAWCO

&&

.HYDROLOGY...

FLOOD WARNINGS REMAIN IN EFFECT FOR THE LOWER MILK RIVER AND
BEAVER CREEK IN EASTERN PHILLIPS AND WESTERN VALLEY COUNTY. GAUGES
THAT ARE STILL RISING ARE THE MILK RIVER AT TAMPICO AND THE BEAVER
CREEK SOUTH OF SACO. THE AREAL FLOOD WARNING FOR THE BEAVER CREEK
WAS EXTENDED UNTIL 245 PM FRIDAY AS THE GAUGE SOUTH OF SACO HAS
RECENTLY CRESTED AND FLOODING CONTINUES TO BE REPORTED.

&&

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

&&

$$

WEATHER.GOV/GLASGOW





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