Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 061532 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
932 AM MDT MON JUL 6 2015

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

SATELLITE IMAGERY AGAIN SHOWS DIFFUSE SMOKE SPREADING ACROSS THE
AREA. VISIBILITY IS LESS AFFECTED THIS MORNING THAN YESTERDAY...
BUT COULD STILL BE A HEALTH HAZARD TO SOME. ALSO SEEN ON THE
IMAGERY IS MUCH THICKER SMOKE MOVING FROM WASHINGTON STATE AND
BRITISH COLUMBIA. SO WILL CHANGE HAZE TO SMOKE IN THE WX GRIDS FOR
TODAY & TONIGHT SINCE SMOKE IS A HEALTH ISSUE...AND ALSO TO REMAIN
CONSISTENT WITH OUR NEIGHBORS IN THE TEXT WORDING.

OTHERWISE...MODELS SHOW THE POSSIBILITY OF A FEW RAIN SHOWERS THIS
MORNING...MAINLY ALONG THE STATIONARY FRONTAL BOUNDARY IN THE
NORTHEAST...SO LEFT POPS IN BUT REDUCED TO ISOLATED. AFTER THESE
FEW SHOWERS LEAVE THE REST OF THE DAY SHOULD STAY DRY.
TEMPERATURES STARTED OUT THIS MORNING IN THE MID 50S...AND THE
COOL BOUNDARY WILL RETREAT EAST TODAY. THEREFORE EXPECT HIGHS TO
BE SLIGHTLY WARMER THAN THOSE ON SUNDAY. WITH A SURFACE HIGH OVER
NEMONT...WINDS SHOULD RUN RELATIVELY LIGHT. SCT

PREVIOUS DISCUSSION...
SYNOPTIC SET UP...A LARGE TROUGH EXISTS OVER MONTANA THE NORTHERN
US PLAINS AND THE CANADIAN PRAIRIE PROVINCES. NORTH OF THIS A
REINFORCING SHOT OF COLD AIR LIES OVER THE NORTHWEST TERRITORIES
AND NUNAVUT. HOT HIGH PRESSURE RESIDES OVER THE DESERT SOUTHWEST
WITH A RIDGE RUNNING OUT OF THAT CENTER AND THROUGH THE PACIFIC
NORTHWEST AND UP ALONG THE COAST OF BRITISH COLUMBIA.

TODAY THROUGH TUESDAY...A FEW ISOLATED RAIN SHOWERS MOVING
THROUGH THE AREA SHOULD EXIT THE CWA BUT THE MID MORNING HOURS
LEAVING A DRY AFTERNOON WHICH SHOULD LAST THROUGH TUESDAY. AS THE
COLD AIR SHALLOWS A WEAK MESO RIDGE IN THE NORTHWEST FLOW WILL
HELP TO WARM CONDITIONS FURTHER AND BACK TO NEAR NORMAL TUESDAY.

TUESDAY NIGHT THROUGH WEDNESDAY...SECOND FRONT FROM THE COLD
AIR-MASS OVER THE NORTHWEST TERRITORIES SHOULD HIT AROUND THIS
TIME. HOWEVER AS THE RIDGE TO WEST THICKENS....THIS MAY ACT TO
COUNTER BALANCE THE COOLING AND PERHAPS PARTIALLY DEFLECT THE
FRONT TO THE EAST. ISOLATED POST FRONTAL SHOWERS WILL BE POSSIBLE
WITH THIS PASSAGE. GAH

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
BETWEEN WEDNESDAY NIGHT AND THURSDAY NIGHT...NORTHEAST MONTANA
TRANSITIONS FROM NORTHWEST FLOW ALOFT IN THE NORTHERN STREAM TO
SOUTHWEST FLOW ALOFT IN THE SOUTHERN STREAM OF A SPLIT FLOW ALOFT.
AT THIS POINT...THE ECMWF IS SOMEWHAT FASTER THAN THE GFS IN THIS
TRANSITION. IT OCCURS WITHIN A NORTHERN STREAM UPPER RIDGE WITH
MAINLY DRY WEATHER AND WARM SUMMER LIKE TEMPERATURES.

IN THE SOUTHERN STREAM...THERE IS AN UPPER TROUGH/LOW OVER
CALIFORNIA DURING THE MIDDLE OF THE WEEK. THE LOW WEAKENS INTO AN
UPPER TROUGH ON THURSDAY AND MOISTURE IN THE SW FLOW ALOFT STARTS
MOVING TOWARDS MONTANA. THIS MOISTURE ALONG SHORTWAVES IN THE SW
FLOW ALOFT WILL START IMPACTING NORTHEAST MONTANA FRIDAY AFTERNOON
WITH CHANCES OF SHOWERS AND THUNDERSTORMS. AT THIS POINT...IT
LOOKS LIKE THE STRONGEST OF THESE WAVES WILL BE SATURDAY AFTERNOON
AND EVENING.

AN UPPER RIDGE BUILDS OVER MONTANA ON SUNDAY AND REMAINS IN PLACE
FOR MONDAY. MODELS DIFFER ON WHETHER OR NOT THERE WILL BE
SHORTWAVES MOVING ACROSS THE RIDGE. WILL MAINTAIN A SLIGHT CHANCE
OF SHOWERS AND THUNDERSTORMS. FORRESTER

&&

.AVIATION...
FLIGHT CATEGORY: MAINLY VFR...BUT SOME MVFR MIXED IN AT TIMES DUE
TO SMOKE FROM CANADIAN FIRES.

SKY: SKIES WILL BE MOSTLY CLEAR BY AFTERNOON AND WILL REMAIN
MOSTLY CLEAR TONIGHT.

WINDS: LIGHT NORTH-NORTHWEST AT 5 TO 10 KTS TODAY TURNING TO THE
EAST THIS EVENING.


&&

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

&&

$$

WEATHER.GOV/GLASGOW




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