Area Forecast Discussion
Issued by NWS Glasgow, MT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KGGW 051537 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
937 AM MDT TUE MAY 5 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
UPDATES HAVE BEEN SENT.

HIGHER RESOLUTION MODELS COMING IN AND TRIMMED BACK ON QPF IN A FEW
AREAS FOR TOMORROW AS INQUIRIES HAVE COME IN ABOUT INCOMING SYSTEM.
REST OF FORECAST LOOKED TO BE IN GOOD SHAPE. TFJ

PREVIOUS DISCUSSION...
UPPER LOW/TROUGH OFF THE BRITISH COLUMBIA COAST WILL DIVE SOUTH
THIS MORNING INTO THE PACIFIC NW. THE TROUGH WILL ELONGATE AND
SPLIT TODAY WITH THE SOUTHERN BRANCH DIVING SOUTH TO CALIFORNIA
TONIGHT AND FORMING A NEW UPPER LOW WHILE THE NORTHERN BRANCH
TROUGH MOVES TO THE CANADIAN PRAIRIES

THE CURRENT ZONAL FLOW ALOFT WILL TURN TO THE SOUTHWEST TODAY OVER
MONTANA AS THE BC UPPER LOW/TROUGH DIVES TO THE SOUTH. THIS WILL
BRING A WARM DAY TO THE FORECAST AREA. MEANWHILE...SURFACE LOW
WILL DEVELOP OVER CENTRAL MONTANA WHILE SHORTWAVE TROUGH OVER
DESERT SW MOVES NORTH. SOUTHEAST WINDS AHEAD OF THE SURFACE LOW
WILL LIKELY BE STRONG ENOUGH TODAY THAT A LAKE WIND ADVISORY WILL
BE NEEDED FOR FORT PECK LAKE. THE SW FLOW ALOFT WILL START TO
BRING MOISTURE OFF THE PACIFIC INTO MONTANA TODAY. THE MOISTURE
COMBINED WITH UNSTABLE AIRMASS WILL ALLOW SHOWERS AND THUNDERSTORMS
TO DEVELOP AHEAD OF THE COLD FRONT BY EVENING.

A COLD FRONT WILL MOVE THROUGH EASTERN MONTANA LATE TONIGHT AND
WEDNESDAY. AT THE SAME TIME...THE SHORTWAVE TROUGH THAT IS
CURRENTLY IN THE DESERT SW WILL MOVE NORTH ACROSS EASTERN MONTANA
AND THE DAKOTAS. THIS WAVE WILL BRING GULF OF MEXICO MOISTURE
NORTH INTO THE FORECAST AREA AND ALL SHOWERS TO BE COME WIDESPREAD
ACROSS THE FORECAST AREA LATE TONIGHT AND WEDNESDAY.

THE WAVE AND COLD FRONT WILL MOVE TO THE EAST WEDNESDAY NIGHT AND
HIGH PRESSURE SYSTEM WILL BUILD INTO THE AREA FROM ALBERTA WHICH
WILL DIMINISH THE SHOWERS FROM WEST TO EAST. A FEW SHOWERS COULD
LINGER IN THE EAST THURSDAY MORNING. OTHERWISE...SURFACE HIGH
PRESSURE COMBINED WITH SHORTWAVE RIDGE IN THE SW FLOW ALOFT WILL
ALLOW FOR MAINLY DRY WEATHER. NW WINDS WILL LIKELY BE STRONG
ENOUGH FOR A LAKE WIND ADVISORY AND WILL KEEP TEMPERATURES ON THE
COOL SIDE. FORRESTER

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

THE EXTENDED FORECAST PERIOD BEGINS THURSDAY EVENING WITH
NORTHEAST MONTANA BETWEEN A SPLIT TROUGH PATTERN. THE SOUTHERN
WAVE WILL BE A CLOSED LOW SPINNING OVER CENTRAL CALIFORNIA AND A
LONG-WAVE TROUGH CENTERED OVER NORTHERN SASKATCHEWAN AND MANITOBA.
LOCALLY CONDITIONS WILL BE DRY OVERNIGHT. THEN BY FRIDAY EVENING
THE SOUTHERN LOW WILL HAVE MOVED INTO THE SOUTHWEST DESERT WHILE
THE NORTHERN WAVE BEGINS TO DEVELOP A TROUGH EXTENSION REACHING
SOUTH OVER MONTANA. THIS NORTHERN LOW WILL BEGIN TO PUSH COOLER
TEMPERATURES SOUTH INTO OUR AREA FOR THE WEEKEND. A WEAK FRONT
COULD PRODUCE SOME SHOWER ACTIVITY THROUGH THE WEEKEND. HOWEVER
MOST OF THE ENERGY AND QPF WILL REMAIN SOUTH TIED UP WITH THE
SOUTHERN TROUGH. 850MB TEMPERATURES WILL HOVER NEAR 0C WHILE 700MB
TEMPERATURES TREND CLOSE TO -10C. SO EXPECT HIGHS IN THE 50S AND
LOWS IN THE 30S.

EARLY NEXT WEEK THE SOUTHERN TROUGH RETROGRADES AND MOVES TO THE
NORTHWEST TO KEEP THOSE COOL TEMPERATURES GOING WITH ISOLATED
SHOWERS. THE PATTERN BECOME LESS CERTAIN AFTER THE WEEKEND...BUT
THE WARMER AIR WILL HAVE A HARD TIME REACHING NORTH INTO THE
REGION. SO OVERALL...EXPECT BELOW NORMAL TO NEAR NORMAL
TEMPERATURES INTO MID-WEEK. SCT


&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL THROUGHOUT THE TAF CYCLE WITH RAIN
SHOWERS AND NEAR MVFR CONDITIONS POSSIBLE...INCLUDING A FEW
THUNDERSTORMS...TOWARD THE END OF THIS TAF PERIOD.

TODAY WILL BE A REPEAT OF MONDAY WITH HIGH PRESSURE
IN PLACE. A SURFACE TROUGH OVER ALBERTA AND CENTRAL MONTANA WILL
AGAIN DEVELOP BRISK SOUTHEAST WINDS ACROSS NORTHEAST MONTANA.

AN ENERGETIC CLOSED LOW MOVING OVER WASHINGTON STATE WILL PUSH
HIGH CLOUDS OVER THE DIVIDE AND THE NORTHERN HIGH PLAINS LATER
TODAY. THEN LATE TONIGHT...A NORTH- SOUTH ORIENTATED COLD FRONT AND
OVERRUNNING MOISTURE ALOFT FROM THE SOUTHWEST WILL DEVELOP RAIN
SHOWERS AND POSSIBLY A FEW LIGHTNING STRIKES. BMICKELSON


&&

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

&&

$$

WEATHER.GOV/GLASGOW





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.