Tornado Warning 16, NWS Glasgow, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
306 PM MDT FRI AUG 6 2010

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
THINGS ARE COMING TOGETHER FOR THUNDERSTORM ACTIVITY FOR TONIGHT.
SURFACE HIGH PRESSURE HAS SHIFTED TO THE EAST AND ALLOWED A RETURN
FLOW FROM THE SOUTHEAST TO KEEP A RELATIVELY MOIST AIRMASS IN PLACE
FOR ALL BUT THE SW ZONES THIS AFTERNOON. UPPER LEVELS ARE WORKING IN
TANDEM WITH A FLOW FROM THE SOUTHWEST AND INTERJECTING VORT MAXES
ACROSS THE AREA TONIGHT. STORM PREDICTIONS CENTER/S SLIGHT RISK AREA
FOR THE ENTIRE CWA IS LOOKING GOOD ATTM.

THE UPPER LEVEL DISTURBANCES ARE SEEN ON SATELLITE WITH CONVECTION
OVER THE CENTRAL ROCKIES. INHERITED FORECAST WITH SCATTERED COVERAGE
FOR TONIGHT LOOKED GOOD FOR THE MOST PART BUT IT LOOKS A BIT BETTER
FOR THE NE ZONES LATER TONIGHT WITH MODELS SHOWING CAPE AND MOISTURE
HANGING IN THIS AREA INTO SATURDAY MORNING. WITH PRECIP WATERS OVER
AN INCH...WILL KEEP THE MENTION OF HEAVY RAIN FOR THE CENTRAL AND
EASTERN ZONES.

THINGS QUIET DOWN A BIT SATURDAY AS THE SURFACE FRONT SWEEPS TO OUR
EAST. THE JET WILL BE MORE WEST THAN SOUTHWEST TOO WITH THE BEST
ENERGY WELL TO OUR SOUTH EJECTING FROM THE DEVELOPED TROUGH OVER THE
WESTERN GREAT BASIN.

SATURDAY NIGHT AND SUNDAY...THE BOTTOM PORTION OF THE TROUGH BEGINS
TO LIFT TOWARD THE AREA AND TRIGGERS STORMS THAT MOVE INTO THE CWA
BY LATE SATURDAY NIGHT. HOWEVER THEY LOOK TO BE ISOLATED WITH THE
SURFACE THROUGH MID-LEVEL FRONT ABSENT. JAMBA

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
EXTENDED MODEL SOLUTIONS INITIALLY AGREE ON THE WESTERN US TROUGH
QUICKLY EJECTING NORTHEASTWARD THROUGH THE INTER-MOUNTAIN WEST AND
MONTANA MONDAY THROUGH TUESDAY. AFTER THAT...THE GFS AND EC
EXTENDED MODELS DIVERGE SIGNIFICANTLY. THROUGH THE REMAINDER OF
THE EXTENDED FORECAST PERIOD...THE EC BRINGS DOWN ANOTHER DEEP
TROUGH AND CLOSED UPPER LOW AND TRACKS IT UP THE SNAKE RIVER
VALLEY WHILE THE GFS HOLDS A MORE NORTHERN OPEN TROUGH PATTERN.
THESE DIFFERENCE LOWER THE CONFIDENCE IN THE EXTENDED FORECAST
AFTER TUESDAY...ESPECIALLY WITH MORNING LOW TEMPERATURES. AS A
RESULT...TRIED TO BLEND AND BROADBRUSH A GENERAL LOW SLIGHT CHANCE
POPS. BMICKELSON

PREVIOUS LONG TERM FORECAST DISCUSSION...SOUTHWEST FLOW ALOFT
WILL BRING A FAIRLY STRONG SHORTWAVE ACROSS EASTERN MONTANA MONDAY
AND MONDAY NIGHT. GFS SOMEWHAT FASTER THAN THE ECMWF WITH THIS
SYSTEM. VERY UNSTABLE AIRMASS IS EXPECTED AHEAD OF THIS WAVE AND
COLD FRONT. WILL INCREASE THE CHANCE OF THUNDERSTORMS FOR MONDAY
AND MAINTAIN THE 30 PERCENT CHANCE OF THUNDERSTORMS FOR MOST AREAS
FOR MONDAY NIGHT.

WSW FLOW ALOFT CONTINUES ON TUESDAY AHEAD OF AN UPPER TROUGH THAT
WILL MOVE THROUGH THE FORECAST AREA MIDWEEK. GFS IS ABOUT A DAY
FASTER AND WEAKER THAN THE ECMWF WITH THIS TROUGH ALTHOUGH BOTH
MODELS SEEM TO BRING THE COLD FRONT ACROSS SOMETIME ON WEDNESDAY.
WITH WEAK SHORTWAVES EXPECTED AHEAD OF THE TROUGH...WILL MAINTAIN
A SLIGHT CHANCE OF THUNDERSTORMS ON TUESDAY. THE FRONTAL SYSTEM ON
WEDNESDAY HAS LIMITED MOISTURE AT THIS POINT SO WILL KEEP POPS AT
A SLIGHT CHANCE FOR NOW. FORRESTER

THE EXTENDED PERIOD APPEARS TO BE DOMINATED BY AN UPPER LEVEL LOW
THAT STALLS OVER CENTRAL CANADA BETWEEN A RIDGE OVER THE GULF OF
ALASKA AND BEHIND A STRONG MIDWEST RIDGE THAT EXTENDS INTO THE
HUDSON BAY AREA. NEMONT WILL BE INFLUENCED BY A SPLIT UPPER LEVEL
JET DURING THIS TIME...INITIALLY A SOUTHWEST TO NORTHWEST ORIENTED
JET WILL PUMP IN WARM MOIST AIR BUT THE POLAR JET SLIDING THROUGH
BRITISH COLUMBIA AND THE PACIFIC NORTHWEST WILL PUSH IN A COOLER
AIRMASS.

SHOWER AND THUNDERSTORM ACTIVITY IS MORE LIKELY WITH THE DISTURBANCE
ON THURSDAY SINCE THE ENVIRONMENT IS RELATIVELY MOIST AND UNSTABLE.
CHANCES WILL DECREASE AFTER THURSDAY NIGHT AS THE AIRMASS WILL
BECOME MODIFIED BY THE POLAR AIRMASS. EVEN THOUGH THE MODELS
DISAGREE ON THE TEMPERATURES IN THE LONG TERM...THEY DO SHOW A
SLIGHT COOLING TREND AFTER TWO SHORTWAVES PASS THROUGH...ESPECIALLY
AFTER THE SECOND DISTURBANCE MOVES THROUGH ON FRIDAY. WITH THE RIDGE
PUSHED FAR TO THE EAST A RAPID REBOUND A TEMPERATURES IS NOT
EXPECTED.

AES

&&

.AVIATION...
WILL SEE AN INCREASE IN MID AND HIGH LEVEL CLOUDS TODAY AHEAD OF
SCATTERED THUNDERSTORMS THAT WILL AFFECT THE TAF SITES TONIGHT AND
THROUGH THE OVERNIGHT HOURS. ERRATIC GUSTY WINDS AND PERIODS OF MVFR
AND IFR CONDITIONS MAY OCCUR IN ANY STORMS THAT HAPPEN TO PASS
DIRECTLY OVER A TAF SITE. WINDS FROM THE EAST AND SOUTHEAST TODAY
WILL TURN FROM THE WEST OVERNIGHT AS A FRONTAL SYSTEM MOVES THROUGH THE
AREA. BMICKELSON

&&

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

&&

WEATHER.GOV/GLASGOW

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
335 PM MDT FRI AUG 6 2010

MTZ016>027-059>062-071200-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
DANIELS-SHERIDAN-WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE-
RICHLAND-DAWSON-PRAIRIE-WIBAUX-NORTHERN PHILLIPS-
SOUTHWEST PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT-
335 PM MDT FRI AUG 6 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

SCATTERED STRONG THUNDERSTORMS WILL BE ARRIVING FROM THE
SOUTHWEST THIS AFTERNOON AND EVENING. A FEW OF THE STORMS COULD
BECOME SEVERE...WITH LARGE HAIL AND DAMAGING WINDS TO 60 MPH A
POSSIBILITY. THE STRONGER STORMS WILL ALSO HAVE HEAVY SHOWERS...
WITH RESULTING RAPID RUNOFF AND POOR VISIBILITY FOR A SHORT TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL POSSIBLY MOVE
THROUGH NORTHEAST MONTANA MONDAY AFTERNOON AND EVENING. BRIEF
HEAVY RAIN...CLOUD TO GROUND LIGHTNING AND HAIL LOOK TO BE THE
MAIN THREATS AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GLASGOW MT
536 PM MDT FRI AUG 6 2010

MTZ016-059-070000-
PHILLIPS-
536 PM MDT FRI AUG 6 2010

THE NATIONAL WEATHER SERVICE IN GLASGOW HAS ISSUED A

SIGNIFICANT WEATHER ADVISORY FOR...
  NORTHERN PHILLIPS COUNTY IN NORTHEAST MONTANA...

UNTIL 600 PM MDT/700 PM CDT/.

AT 533 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM LORING TO 7 MILES
WEST OF MALTA...AND MOVING EAST AT 15 MPH.

HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THESE STORMS.

LOCATIONS IN THE ADVISORY INCLUDE...
   LORING...
   MALTA...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4900 10795 4900 10740 4826 10749 4826 10818
      4884 10828 4891 10827 4892 10825 4900 10825
      4901 10823
TIME...MOT...LOC 2336Z 270DEG 14KT 4882 10794 4835 10801

MICKELSON
WEATHER.GOV/GLASGOW

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