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 190248 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
748 PM MST THU DEC 18 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
UPDATE...
GOING TO CONTINUE THE DENSE FOG ADVISORY OVER PHILLIPS-NORTHERN
VALLEY COUNTIES FOR NOW. THE STRATUS-FOG LINE RUNS FROM DODSON TO
SAINT MARIE TO WOLF POINT TO FAIRVIEW ACROSS THE FORECAST AREA.
FOG/IR SAT IS GETTING OBSCURED BY MID-HIGH CLOUDS ZIPPING THROUGH.
A FEW FLURRIES WERE ADDED TO THE FORECAST UNDER MID CLOUD MOVING
BY MAINLY SOUTH OF THE MISSOURI RIVER. AREA CAMERAS CONFIRM FOG
ACTIVITY THIS EVENING. DID BRING TEMPS UP IN THE NORTHEAST UNDER
THE THICK STRATUS DECK...AND DECREASED THEM ALONG THE EDGE OF THE
STRATUS DECK BASED ON CURRENT TRENDS. 00Z SOUNDING SHOWS WARMING
AROUND 850 MB/S WITH A SLIGHT INVERSION AT KGGW...DO EXPECT THE
INVERSION TO STRENGTHEN OVERNIGHT AND THE CHANCE FOR THE STRATUS
AND FOG TO RETURN LATER IN THE PERIOD.      PROTON

PREVIOUS DISCUSSION...
TONIGHT INTO FRIDAY THE FORECAST CHALLENGE REMAINS THE EXTENT OF
STRATUS AND FOG. PHONE CALLS TO SPOTTERS AND SATELLITE IMAGERY REVEALS
SOME DECREASE IN THE EXTENT OF FOG COVERAGE IN PHILLIPS
COUNTY...WHILE NORTHERN VALLEY COUNTY HOLDS STRONG. WITH THE MAJOR
POPULATION CENTERS IN PHILLIPS COUNTY REMAINING IMPACTED...HELD
ON TO THE DENSE FOG ADVISORY FOR CENTRAL AND NORTHERN PHILIPS
COUNTY. WITH NORTHERN VALLEY COUNTY REMAINING STEADFAST IN THE FOG
FOR SEVERAL DAYS NOW...RIME ICE BUILDUP ON POWER LINES COULD START
CAUSING POWER ISSUES. THUS MADE MENTION OF THIS IN THE DENSE FOG
ADVISORY. MODELS DEPICT SOME POSSIBLE EROSION OF THE FOG AND
STRATUS BY SUNRISE AS A SHORTWAVE FEATURE PUSHES THROUGH...THUS
EXTENDED THE ADVISORY THROUGH 6 AM.

FRIDAY SHOULD BRING A SOUTHERLY SURFACE FLOW WHICH WILL AGAIN HELP
SCOUR OUT ANY LINGERING STRATUS AND OR FOG AND WARM TEMPERATURES
NORTH OF THE MISSOURI RIVER. UPPER RIDGING WILL KEEP CONDITIONS
DRY INTO FRIDAY EVENING.

LATE FRIDAY NIGHT INTO SATURDAY ANOTHER SHORTWAVE FEATURE WILL
PUSH THROUGH FROM WEST TO EAST. MOISTURE LOOKS A BIT LACKING BUT
CONFIDENCE IN THE FEATURE WAS HIGH ENOUGH TO INCREASE POPS TO MORE
CHANCE CATEGORY WHILE IT PASSES. PRECIP TYPE CONTINUES TO LOOK
MIXED IN NATURE...WITH FREEZING RAIN A GOOD POSSIBILITY. GIVEN THE
HIGH IMPACT NATURE OF -FZRA WILL CONTINUE TO HIGHLIGHT THE THREAT
ON SOCIAL MEDIA...THROUGH OUR WEATHER STORIES...AND THROUGH OUR
HAZARDOUS WEATHER OUTLOOK. GILCHRIST


.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
THE 12Z MODEL GUIDANCE IS NOW MORE INDICATIVE OF PRECIPITATION
STARTING A BIT EARLIER THAN PREVIOUS THINKING. DECIDED TO INCLUDE
POPS ACROSS THE WESTERN ZONES FOR SATURDAY NIGHT. EXPECT
PRECIPITATION TO EVOLVE FROM WEST TO EAST DURING THE DAY SUNDAY
BEFORE TAPERING OFF SUNDAY NIGHT AS THE UPPER LEVEL WAVE EXITS THE
REGION.

THERMAL PROFILES ARE STILL SUGGESTIVE OF A TRICKY FORECAST
WHEN IT COMES TO PRECIPITATION TYPE. THERE IS UNCERTAINTY
REGARDING THE THICKNESS OF THE WARM LAYER ABOVE THE SURFACE.
BUFKIT SOUNDINGS ARE SUPPORTIVE OF A WINTRY MIX SATURDAY NIGHT. AS
SURFACE TEMPERATURES WARM ON SUNDAY MUCH OF THE CWA COULD SEE A
SWITCH TO RAIN BEFORE ENDING AS A WINTRY MIX SUNDAY NIGHT. AS
MODEL CONSENSUS CONTINUES TO IMPROVE...BUT FOR NOW WILL CARRY
MENTION OF SNOW...SLEET...FREEZING RAIN...AND/OR RAIN LATE THIS
WEEKEND. MALIAWCO

PREVIOUS LONG TERM DISCUSSION...
A SHORTWAVE TROUGH MOVES THROUGH THE AREA SATURDAY NIGHT AND
SUNDAY WITH A FRONTAL SYSTEM THAT WILL BECOME QUASI-STATIONARY IN
EITHER NORTHEAST MONTANA OR NEARBY WESTERN NORTH DAKOTA. LOOK LIKE
THERE MAY BE ENOUGH MOISTURE FOR MIXED PRECIPITATION. THERE IS A
CHANCE THAT TEMPERATURES FOR AT LEAST PART OF SUNDAY WILL BE WARM
ENOUGH ALOFT WHILE THE SURFACE IS STILL COLD ENOUGH FOR FREEZING
RAIN.

THAT FRONT MOVES BACK SOUTH SUNDAY NIGHT AND MONDAY AS A COLD
FRONT. LIMITED MOISTURE EXPECTED AT THIS TIME. WILL MAINTAIN A
SLIGHT CHANCE FOR A MIX OF RAIN AND SNOW DEPENDING ON
TEMPERATURES.

FLOW ALOFT TURNS TO THE NORTHWEST ON MONDAY AS AN UPPER TROUGH
DEEPENS OVER THE MIDWEST AND RIDGE REMAINS TO THE WEST.
SHORTHWAVES AND COLD FRONTS ARE EXPECTED ACROSS THE FORECAST AREA
BOTH TUESDAY...WEDNESDAY AND THURSDAY WITH LIMITED MOISTURE AND
TEMPERATURES TURNING COLDER WITH EACH SYSTEM. FORRESTER


&&

.AVIATION...
SYNOPSIS: LIGHT FLOW ALOFT WILL CONTINUE OVERNIGHT...THEN BY 18Z
AN UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE REGION FOR A
CHANGE IN THE WEATHER PATTERN.

FLIGHT CATEGORY: LIFR-IFR NORTH AND EAST OF A KM75-KGGW-KGDV LINE...VFR
SOUTH AND WEST.

CIGS AND VSBY: CIGS WILL CONTINUE FROM SFC-010 UNDER THE STRATUS
DECK OVER THE NORTHEASTERN SECTION OF THE FLYING AREA WITH
ISOLATED VSBY DOWN TO 1/2 SM WITH FZFG AT TIMES. ELSEWHERE...MID-
HIGH VFR CIGS AND EXTREMELY ISOLATED BCFG AT TIMES OVERNIGHT.

WIND: LIGHT AND VARIABLE.

PROTON

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 6 AM MST FRIDAY FOR CENTRAL AND
SOUTHEAST PHILLIPS...NORTHERN PHILLIPS...NORTHERN VALLEY.

&&

$$

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.