Weather Service Report


179 
FXUS65 KTFX 282039
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
239 PM MDT THU MAY 28 2015

.DISCUSSION...
TONIGHT THROUGH SATURDAY...AN UPPER TROUGH FROM NORTHWESTERN WYOMING 
THROUGH EASTERN MONTANA THURSDAY AFTERNOON WILL CONTINUE MOVING EAST 
AND THE FORECAST AREA WILL FALL UNDER THE INFLUENCE OF AN UPSTREAM 
UPPER RIDGE LATER TONIGHT. EXPECT SCATTERED SHOWERS AND A FEW
THUNDERSTORMS EARLY THIS EVENING TO GRADUALLY DIMINISH OVERNIGHT.
NOT SURE HOW MUCH CLEARING WILL GO ON IN THE NORTH BUT HAVE
DECIDED TO MENTION PATCHY FOG FOR LATE TONIGHT AND EARLY FRIDAY
MORNING. THE UPPER RIDGE JUST MENTIONED WILL MOVE OVER THE
FORECAST AREA BY FRIDAY AFTERNOON. THIS WILL LEAD TO LESS SHOWER
AND THUNDERSTORM ACTIVITY THAN ON THURSDAY BUT THERE WILL STILL BE
SOME AFTERNOON INSTABILITY SO WILL CONTINUE THE MENTION OF A
CHANCE OF SHOWERS OR THUNDERSTORMS OVER THE WESTERN MOUNTAINS.
SATURDAY A WEATHER DISTURBANCE ALOFT WILL MOVE TO CENTRAL MONTANA
BY LATE AFTERNOON. THIS DISTURBANCE COMBINED WITH GENERALLY
GREATER INSTABILITY WILL RESULT IN AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY. IN FACT THE ENVIRONMENT OVER CENTRAL
MONTANA AND TO A LESSER EXTENT OVER SOUTHWEST MONTANA LOOKS
FAVORABLE FOR STRONGER BUT NOT NECESSARILY SEVERE THUNDERSTORMS.
BLANK

SATURDAY NIGHT THROUGH WEDNESDAY...A WESTERLY FLOW ALOFT OVER 
MONTANA THIS WEEKEND RESULTS AS A GRADIENT BETWEEN A WESTERN 
CANADIAN TROUGH AND AN GREAT BASIN RIDGE. MINOR IMPULSES IN THIS 
FLOW...COMBINED WITH SURFACE DEWPOINTS IN THE UPPER 40S AND A NEARLY 
LINEAR SHEAR PROFILE WILL MAINTAIN SCATTERED SHOWERS AND 
THUNDERSTORMS SATURDAY NIGHT. WEAK RIDGING ALOFT ON SUNDAY WILL 
SUPPRESS ALL BUT ISOLATED AFTERNOON SHOWERS AS THE UPPER LEVEL FLOW 
TURNS MORE SOUTHWESTERLY. WIDESPREAD THUNDERSTORMS ARE INDICATED 
MONDAY AFTERNOON WITH A CLOSED UPPER TROUGH APPROACHING FROM THE 
PACIFIC. AN ACCOMPANYING SURFACE LOW FORMING IN SOUTHEAST MONTANA 
WILL SUPPORT A HUMID EASTERLY FLOW OVER THE NORTH CENTRAL PLAINS. 
DIVERGENT SOUTHWEST FLOW ALOFT WILL YIELD AN INCREASINGLY UNSTABLE 
ENVIRONMENT. CONVECTIVE PARAMETERS DO NOT SUPPORT SEVERE STORMS... 
BUT THE SETUP DOES WARRANT ATTENTION FOR A FEW STRONGER STORMS 
INCLUDING SMALL HAIL AND GUSTY WINDS. TIMING WILL BECOME AN 
IMPORTANT FACTOR TO CONSIDER. THE WAVE OPENS ON TUESDAY AND 
WEDNESDAY AS DIFFERENCES BEGIN TO APPEAR AMONG MODEL SOLUTIONS. 
HOWEVER THE OVERALL PATTERN REMAINS UNSETTLED THROUGH THE PERIOD 
WITH CONTINUING SHOWERS AND ISOLATED THUNDERSTORMS. TEMPERATURES 
TREND BELOW NORMAL THROUGH MIDWEEK. SNOW LEVELS COULD LOWER TO 
AROUND 7500 FT MSL WEDNESDAY MORNING ALONG THE CONTINENTAL 
DIVIDE...BUT AS YET VERY LITTLE CONFIDENCE IN THE POTENTIAL FOR ANY 
ACCUMULATION. NUTTER

&&

.AVIATION... 
UPDATED 1730Z. 

THIS IS A LOW CONFIDENCE FORECAST. THERE WILL BE SCATTERED TO 
NUMEROUS SHOWERS THIS AFTERNOON WITH A FEW THUNDERSTORMS. CONDITIONS 
WILL BE VFR BUT DO EXPECT MVFR CEILINGS AND VISIBILITIES IN SOME OF 
THE SHOWERS AND THUNDERSTORMS. SHOWERS AND THUNDERSTORMS WILL 
GRADUALLY DIMINISH THIS EVENING. THE LOW CONFIDENCE COMES INTO PLAY 
TONIGHT AND CONTINUES FRIDAY MORNING. SOME GUIDANCE DEVELOPS MVFR 
CEILINGS THIS EVENING WITH EVEN IFR CEILINGS AND MVFR VISIBILITIES 
POSSIBLE LATE TONIGHT THROUGH EARLY FRIDAY MORNING. OTHER GUIDANCE 
KEEPS CONDITIONS VFR. HAVE OPTED TO GO WITH THE FORMER SOLUTION AT 
MOST LOCATIONS. BLANK

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  44  70  50  73 /  50  20  10  50 
CTB  40  67  43  71 /  10  20  20  50 
HLN  47  74  51  75 /  60  20  20  40 
BZN  44  68  47  71 /  60  20  20  40 
WEY  35  63  39  65 /  50  30  20  30 
DLN  44  70  48  72 /  40  20  30  50 
HVR  38  69  45  76 /  10  10  10  30 
LWT  42  65  47  73 /  80  20  10  60 

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

WEATHER.GOV/GREATFALLS

Return to Home page


Western Regional Climate Center, wrcc@dri.edu