National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS65 KGGW 210126
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
726 PM MDT MON MAY 20 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY...
THE RAIN HAS PRETTY MUCH PUSHED TO OUR SOUTH IN THE PAST COUPLE OF
HOURS BUT ANOTHER ROUND LOOKS TO MAKE ANOTHER DASH LATER TONIGHT...
SO HIGHER POPS IN THE EAST FOR LATE TONIGHT LOOK GOOD. LOWERED
TEMPS A TAD FOR TONIGHT AS DRY AIR FROM THE NORTH WILL CONTINUE TO
FLOW IN. OTHERWISE...LAKE WIND ADVISORY WAS CANCELLED AND WINDS
WERE DECREASED FOR THE EVENING HOURS. JAMBA

PREVIOUS DISCUSSION...
LARGE UPPER LOW OVER THE UPPER MIDWEST CONTINUES TO PUSH RAIN BACK
INTO EASTERN MONTANA THIS AFTERNOON. NOT MUCH MOVEMENT EXPECTED
WITH THE SYSTEM UNTIL TUESDAY NIGHT WHEN ANOTHER STRONG UPPER LOW
PUSHES INTO THE PACIFIC NORTHWEST. DRIER AIR WRAPPING INTO THE
NORTHWEST SIDE OF THE SYSTEM BEGINNING TO PUSH RAIN SOUTHWARD BUT
EXPECT SHOWERS TO CONTINUE IN THE VICINITY OF THE LOWER
YELLOWSTONE VALLEY THROUGH TUESDAY.

OMEGA BLOCK LIKE PATTERN DEVELOPS ON TUESDAY WITH THE LOW OVER THE
UPPER MIDWEST AND THE LOW OVER THE PACIFIC NORTHWEST AND PINCHED
RIDGE OVER MONTANA. THIS WILL RESULT IN DRY WEATHER WITH HIGH
PRESSURE PUSHING INTO THE NORTHERN PLAINS INTO WEDNESDAY. EBERT

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE PERIOD BEGINS WITH EASTERN MONTANA UNDER A NARROW RIDGE AND
MILD CONDITIONS BETWEEN TWO LOW PRESSURE SYSTEMS. THE SYSTEM TO
THE WEST...A CLOSED LOW SPINNING OVER WASHINGTON/OREGON WILL BEGIN
TO LIFT INTO WESTERN CANADA THURSDAY. THIS MOVEMENT WILL SEND A
COLD FRONT OVER THE MONTANA PRAIRIE THURSDAY NIGHT. FRIDAY THE
FRONT SWINGS ACROSS EASTERN MONTANA WHERE IT WILL MEET UP WITH
UNSTABLE AIR. MODELS SEEM TO INDICATE EARLY THAT A LINE OF
THUNDERSTORMS COULD DEVELOP FRIDAY AFTERNOON AND DUMP RAIN AND
POSSIBLY HAIL. THE SOUTHWEST FLOW ALOFT WILL KEEP DIRECTING MOIST
WARM AIR INTO THE REGION TO CREATE MORE INSTABILITY FOR SATURDAY
AND SUNDAY. SO THE WEEKEND LOOKS STORMY WITH POSSIBLE STRONG
THUNDERSTORMS. A SECONDARY TROUGH WILL SEND MORE SHOWERS OUR WAY
INTO EARLY NEXT WEEK.

INHERITED GRID MATCH UP WITH MODEL TRENDS FOR THUNDERSTORMS
THROUGH THE WEEKEND...SO FEW GRID EDITS NEEDED...MAINLY TO
ADJUST WX GRIDS BASED ON INSTABILITY PEAKS. WITH SOUTHWEST FLOW
ALOFT...TEMPERATURES MIGHT TREND SLIGHTLY ABOVE NORMAL...BUT BIAS
ADJUSTED TEMPERATURES ARE LIKELY TO CHANGE. SO LEFT TEMPERATURE
GRIDS AS IS FOR NOW. SCT

...PREVIOUS DISCUSSION...
THE EXTENDED FEATURES MORE SOUTHWEST FLOW THROUGH THE PERIOD. MOST
DAYS SLIGHT CHANCES OF THUNDERSTORMS SLIDING OFF THE CENTRAL
MONTANA MOUNTAINS INTO THE PLAINS FOR HIGHER POPS WEST AND LOW
POPS EAST. FOR THE WEEKEND THE UPPER LOW BREAKS A GOOD WAVE OFF
AND DRIVES IT THROUGH NORTHEAST MONTANA FOR A BETTER CHANCE OF
THUNDERSTORMS THEREFORE BUMPED UP POPS A TAD FOR THOSE PERIODS.

TEMPERATURES WILL HOLD IN NEAR NORMAL THROUGH THE PERIOD.

MODEL TRENDS ARE SHOWING LOWERING HEIGHTS ON THE GFS FOR NORTHEAST
MONTANA WHICH LEADS TO THE UPPER LOW MOVING TOWARDS THE EAST. IF
THE TREND CONTINUES THEN LIKELY POPS ARE A GOOD BET FOR THE
WEEKEND WITH ELEVATED CONFIDENCE. RMOP/ENSEMBLES ARE SHOWING THAT
ITS A GOOD BET THAT AT SOME POINT THIS UPCOMING WEEKEND FOR A
STRONG THUNDERSTORM EVENT ACROSS EASTERN MONTANA. PROTON


&&

.AVIATION...
AS THE LOW CENTER MOVES INTO THE EASTERN DAKOTAS...HIGH PRESSURE
MOVES INTO NORTHEASTERN MONTANA FROM THE WEST TONIGHT. THIS WILL
BRING CLEARING TO KGGW AND POSSIBLY KOLF...PLUS ALL AREAS TO THE
WEST. THE LOW STRATUS DECK WILL LINGER TONIGHT AND TUESDAY MORNING
OVER ALL OF THE DAKOTAS AND FAR EASTERN AREAS OF NORTHEAST
MONTANA. SO SHOWERS AND LOW STRATUS ARE STILL POSSIBLE AT KOLF
BUT LIKELY OVER KSDY AND KGDV WHERE CEILINGS COULD REMAIN MVFR.

THE STRONG NORTHERLY WIND OF 15G25KTS WILL ALSO LINGER OVER KSDY
AND KGDV THIS EVENING...WITH LESSER STRENGTHS TO THE WEST. LATE
TONIGHT NORTH WIND WILL DIMINISH TO 10-15KTS. TUESDAY WIND WILL
VEER TO THE NORTHEAST...THEN EAST. SCT


&&

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

&&

$$

WEATHER.GOV/GLASGOW