Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 262134
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
234 PM MST THU FEB 26 2015

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

THE SHORT TERM FORECAST PERIOD BEGINS WITH AN ARCTIC AIR MASS
OCCUPYING EASTERN CANADA AND MODIFIED ARCTIC AIR SPREAD TO THE
WEST AS FAR AS THE ROCKY MOUNTAINS WHERE THE STATIONARY FRONTAL
BOUNDARY IS LOCATED. THIS PLACES NORTHEAST MONTANA ON THE COLD
SIDE OF THE BOUNDARY. THUS TEMPERATURES FELL WELL BELOW ZERO IN
MOST PLACES LAST NIGHT FOR A VERY COLD START TO THE DAY. WITH
HIGHS TODAY LIMITED TO AROUND 20 DEGREES BELOW NORMAL...EXPECT
ANOTHER COLD NIGHT TONIGHT. THE MAIN QUESTION WILL BE WIND CHILLS.
FOR NOW THE WIND STRENGTH WILL BE IN THE LIGHT AND VARIABLE RANGE
IN THE EAST AND AROUND 5-10KTS IN THE WEST...WHERE TEMPERATURES
WILL BE SLIGHTLY WARMER. FOR NOW...NOT GOING WITH ANY ADVISORY.
THE UPDATE SHIFT CAN REVISIT THE WIND SITUATION. A SHORT-WAVE
RIDGE TONIGHT WILL LEAD TO SOME TEMPERATURE RECOVERY FOR FRIDAY.
YET MAXIMUM TEMPERATURES WILL STILL RUN BELOW NORMAL...BY AROUND
10 DEGREES.

FRIDAY NIGHT AND SATURDAY...A SPLIT TROUGH DEVELOPS WITH THE
WESTERN PORTION SPREADING A SIGNIFICANT AMOUNT OF MOISTURE OVER
THE CALIFORNIA...THE GREAT BASIN AND THE SOUTHWEST DESERT. NEMONT
WILL BE INFLUENCED BY THE NORTHERN WAVE THAT WILL SEND ANOTHER
COLD FRONT INTO THE REGION. THIS WILL KNOCK DOWN TEMPERATURES
AGAIN...BY ABOUT ANOTHER 5-10 DEGREES. THE OTHER EFFECT FROM THE
FRONT WILL BE SPREADING MID TO LOW CLOUDS OVER WESTERN PORTIONS OF
THE CWA BY FRIDAY NIGHT. HOWEVER CONDITIONS ARE EXPECTED TO REMAIN
DRY. SCT


.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
LITTLE CHANGE IN THE THINKING HAS TAKEN PLACE WITH THE LONG RANGE
FORECAST WITH 12Z GUIDANCE LOOKING FAIRLY SIMILAR TO PREVIOUS
RUNS. EXPECT MODERATING TEMPERATURES THROUGH ABOUT MONDAY BEFORE A
COLD FRONT SWEEPS IN AS A SHORTWAVE DIVING SOUTH FROM BRITISH
COLOMBIA HELPS TO ENERGIZE A LARGE TROUGH DOMINATING THE WESTERN
CONUS. WHILE MOST OF THE DYNAMICS WILL BE WELL TO THE SOUTH AND
WEST OF THE CWA...ENOUGH FORCING FOR ASCENT WILL EXIST FOR MONDAY
NIGHT AND TUESDAY FOR A CHANCE FOR SNOW. OTHERWISE THE MAIN STORY
WILL BE A REINFORCING SHOT OF ARCTIC AIR WITH 850MB TEMPERATURES
EXPECTED TO BE -20C TO -25C ACROSS THE REGION BY TUESDAY
AFTERNOON. MALIAWCO

PREVIOUS LONG TERM DISCUSSION...
SHORTWAVE TROUGH MOVES THROUGH THE AREA ON SUNDAY WITH LIMITED
MOISTURE. WILL MAINTAIN DRY FORECAST FOR NOW. A SHORTWAVE RIDGE
SUNDAY NIGHT AND MONDAY WILL BRING SOMEWHAT WARMER TEMPERATURES
INTO THE AREA.

THEN... A SHORTWAVE TROUGH WILL BRING A COLD FRONT THROUGH THE
AREA MONDAY NIGHT WITH ENOUGH MOISTURE FOR A CHANCE OF SNOW. THE
CHANCE OF SNOW MIGHT LINGER INTO TUESDAY. COLD HIGH PRESSURE
BUILDS INTO THE AREA FOR TUESDAY NIGHT AND WEDNESDAY WITH UPPER
TROUGH OVER MONTANA. NORTHWEST FLOW ALOFT WILL PREVAIL ON THURSDAY
AS THE TROUGH MOVES TO THE EAST TAKING THE COLDEST AIR WITH IT.
THIS WILL ALLOW TEMPERATURES TO MODERATE. FORRESTER

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED TO CONTINUE TONIGHT WITH LIGHT AND
VARIABLE WINDS. MALIAWCO


&&

.HYDROLOGY...
THE RIVER GAGE AT SIDNEY ON THE YELLOWSTONE RIVER APPEARED TO READ
A RISE IN THE RIVER THIS MORNING. BUT OBSERVATIONS HAVE
INDICATED THAT THE GAGE MAY HAVE MALFUNCTIONED TEMPORARILY.

&&

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

&&

$$

WEATHER.GOV/GLASGOW




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