Severe Thunderstorm Warning 47, NWS Glasgow, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
211 PM FRI JUL 16 2004

.SHORT TERM...FOR NORTHEAST MONTANA TONIGHT THROUGH SUNDAY...
A STRONG UPPER RIDGE EXTENDING NORTH INTO MONTANA FROM THE FOUR
CORNERS REGION WILL REMAIN FIRMLY IN PLACE FOR THE DURATION OF THE
SHORT TERM FORECAST PERIOD. ABOVE NORMAL TEMPERATURES ARE EXPECTED
THROUGH THE WEEKEND WITH THE FIRST 100 DEGREE DAY POSSIBLE BY
SUNDAY. ALTHOUGH THERE WILL BE THE CHANCE OF CONVECTION IT IS NOT
EXPECTED TO BE ORGANIZED...AND CHANCES ARE LOOKING GOOD THAT MOST
WILL HAVE A DRY WEEKEND.

TONIGHT...THE UPPER RIDGE CONTINUES TO BUILD NORTH WITH THE RIDGE
AXIS JUST TO THE WEST OF THE CWA. A SURFACE RIDGE NOW ACROSS THE
DAKOTAS WILL CONTINUE TO SLIDE SOUTH AND EAST INTO THE CENTRAL
PLAINS AND UPPER MISSISSIPPI VALLEY. A SOUTHEAST RETURN FLOW IS
EXPECTED AROUND THE SURFACE HIGH WHICH WILL CONTINUE TO KEEP THE LOW
LEVELS MOIST WITH HIGH DEW POINTS. A LEE SIDE SURFACE TROUGH WILL
EXTEND FROM ALBERTA AND INTO CENTRAL MONTANA. THERE ARE NO
DISCERNIBLE SHORTWAVES VISIBLE ON SATELLITE TO TRIGGER CONVECTION
TONIGHT...AND THE SPC HAS REMOVED ALL OF THE CWA FROM THE SLIGHT
RISK AREA. STILL DO HAVE SOME CONCERN THAT AN ISOLATED STORM COULD
POP UP WITH THE SURFACE TROUGH TO OUR WEST AND OLD BOUNDARIES LEFT
FROM EARLIER CONVECTION. HOWEVER...WITHOUT ANY CLEAR TRIGGERING
MECHANISM WILL KEEP IT DRY OVERNIGHT. PLAN FOR NOW IS TO KEEP SOME
ISOLATED POPS THIS EVENING ACROSS ALL OF THE CWA. ANY STORMS THAT
FIRE THIS EVENING WOULD HAVE THE POTENTIAL TO BE STRONG OR EVEN
SEVERE WITH LARGE HAIL AND DAMAGING WIND.

SATURDAY...THE UPPER RIDGE REMAINS ACROSS THE AREA WITH 590DAM
HEIGHTS POKING INTO CENTRAL MONTANA. 850H TEMPERATURES ARE PROGGED
TO BE AS WARM AS 30C ACROSS SOUTH CENTRAL MONTANA. THE HEIGHTS AND
850H TEMPERATURES ARE NOT PROGGED TO BE AS HIGH AS THEY WERE LAST
YEAR WHEN IN LATE JULY THERE WERE WIDESPREAD 100+ TEMPERATURES.
ANOTHER INHIBITING FACTOR WILL BE THAT OUR SURFACE WINDS WILL BE
OUT OF THE SOUTH TO SOUTHEAST ACROSS MOST OF THE CWA. ALSO A A GOOD
DEAL OF SURFACE MOISTURE AROUND AND SOME OF THE ENERGY WILL NEED TO
GO INTO EVAPORATING THE SURFACE MOISTURE POSSIBLE THAT THE WIND MAY
TURN INTO THE WEST ACROSS OUR WESTERN ZONES DURING THE AFTERNOON AND
THE DOWNSLOPE MAYBE ENOUGH FOR A COUPLE OF ISOLATED 100 DEGREE
READINGS THERE. ALTHOUGH THE ATMOSPHERE WILL BE MARGINALLY UNSTABLE
AND RELATIVELY MOIST IN THE LOW LEVELS NO TRIGGERS ARE SEEN TO
INITIATE CONVECTION.  THERE IS A GOOD FEED OF MOISTURE EVIDENT OFF
THE CALIFORNIA COAST...BUT WITH STRONG SOUTHWEST FLOW ACROSS THIS
AREA WOULD SUSPECT THAT ANY SHORTWAVES IN THE FLOW WOULD BE MORE OF
A CONCERN FURTHER TO OUR WEST. BOTH THE ETA AND GFS DO SHOW SOME
SHORTWAVE ENERGY TOMORROW AFTERNOON WORKING UP ALONG THE BACKSIDE OF
THE RIDGE AND INTO WASHINGTON STATE (ETA AND UKMET) OR WESTERN
MONTANA (GFS).  GIVEN THE UPPER PATTERN AND BY THE LOOK OF THINGS ON
SATELLITE IT APPEARS THAT THE ETA/UKMET LIKELY HAVE A BETTER HANDLE
ON THIS FEATURE WITH THE GFS BEING TO FAR EAST. GIVEN THE ABOVE PLAN
TO KEEP IT DRY ACROSS ALL OF THE CWA.

SAT NIGHT...THE GFS IS THE ONLY ONE OF THE OPERATIONAL MODELS THAT
TAKES THE SHORTWAVE EAST AND ACROSS EASTERN MONTANA. THE OTHER
MODELS TAKE THE ENERGY MUCH FURTHER NORTH AND ACROSS SOUTHERN
CANADA. WITH THE UPPER RIDGE AXIS ACROSS THE AREA IT IS CERTAINLY
POSSIBLE THAT A SHORTWAVE COULD PUSH EAST UNDER THE RIDGE...BUT AT
THIS TIME THERE IS ONLY A MOISTURE PLUM EVIDENT ON WATER VAPOR OFF
THE CALIFORNIA COAST AND WILL KEEP IT DRY UNTIL SOMETHING MORE
DEFINITIVE CAN BE SEEN. IT WILL BE ANOTHER WARM AND MUGGY NIGHT WITH
LOWS IN THE 60S.

SUNDAY...THE UPPER RIDGE WILL BE MAINTAINED ACROSS THE AREA. AN
UPPER LOW/TROUGH NOW IN THE NORTHEAST PACIFIC SOUTH OF THE GULF OF
ALASKA INCHES CLOSER TO THE COAST. SOME DIFFERENCES BETWEEN THE
MODELS AS TO HOW FAR EAST THE TROUGH WILL BE BY LATE IN THE DAY. THE
ETA AND UKMET ARE FURTHER EAST THAN THE GFS. THE MOST UNSTABLE AIR
SHOULD BE WELL TO OUR WEST AND IT LOOKS LIKE ANY CONVECTION THAT
DEVELOPS WILL AGAIN BE ACROSS THE MOUNTAINS WELL TO OUR WEST AND
COULD DRIFT INTO CENTRAL MONTANA LATE IN THE DAY. LOOKS LIKE THE
GRIDS HANDLE THIS WELL BY KEEPING IT DRY THROUGH 00Z MONDAY. THE ETA
BEING FURTHER EAST WITH THE UPPER TROUGH HAS A SURFACE TROUGH ACROSS
CENTRAL MONTANA AND A STRONG THERMAL RIDGE ACROSS EASTERN MONTANA...
AND WOULD BE MUCH MORE FAVORABLE FOR WIDESPREAD 100 DEGREE
TEMPERATURES ACROSS THE AREA. THE INHERITED GRIDS ARE NOT QUITE AS
HOT AS THE ETA IS ADVERTISING THAT IT COULD BE...BUT DOES PAINT 100
TEMPERATURES ACROSS ALL BUT THE HIGHER ELEVATION SOUTH OF THE
MISSOURI. CB

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
MODELS AGREE IN KEEPING UPPER RIDGE IN PLACE TO IMMEDIATE WEST NEAR
110 MERIDIAN THROUGH DAY MONDAY...HENCE FEW IF ANY CHANGES MADE TO
QUIET EARLY FORECAST PERIOD. ALL MEDIUM RANGE MODELS BRING A STRONG
NORTHERN STREAM SHORT WAVE ACROSS SOUTHERN CANADA TO FLATTEN RIDGE
TO ZONAL FLOW...BEGINNING MONDAY EVENING...TRANSITION TO FULLY ZONAL
FLOW COMPLETE BY TUESDAY EVENING. UPPER RIDGE RETURNS LATE IN THE
WEEK WEST OF ROCKIES...ROUGHLY VICINITY OF EASTERN OREGON.

SUNDAY NIGHT AND MONDAY...WITH STRONG RIDGE IN VICINITY...EXPECT
TEMPERATURES TO BE WARMEST OF PERIOD WITH ISOLATED THUNDERSTORMS
DEVELOPING MONDAY AFTERNOON AS COOL FRONT APPROACHES.

MONDAY NIGHT AND TUESDAY...INFLUENCE OF SHORT WAVE FLATTENING RIDGE
AND CROSSING SOUTHERN CANADA EXPECTED TO PROMOTE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT ACROSS REGION MONDAY NIGHT.
TEMPERATURES EXPECTED TO COOL SLIGHTLY DUE TO LOWER...ALBEIT STILL
FAIRLY HIGH...THICKNESSES.

TUESDAY NIGHT THROUGH FRIDAY...DRY AND SEASONABLE TO SLIGHTLY ABOVE
NORMAL TEMPERATURES LIKELY UNDER ZONAL TO SLIGHTLY NORTH OF WEST
FLOW THROUGH PERIOD. ANTICIPATE SOME RISK OF LATE AFTERNOON AND
EVENING THUNDERSTORMS DEVELOPING FRIDAY AS FLOW VEERS MORE NORTHWEST
WITH AMPLIFYING UPPER RIDGE OVER INTERIOR FAR WEST...BUT NO DEFINED
JET FEATURES AT THIS TIME TO JUSTIFY MENTION OF PRECIPITATION. DNS

&&

.KGGW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
554 AM MDT FRI JUL 16 2004

MTZ016>027-059>062-171200-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-DANIELS-
DAWSON-EASTERN ROOSEVELT-GARFIELD-MCCONE-NORTHERN PHILLIPS-
NORTHERN VALLEY-PETROLEUM-PRAIRIE-RICHLAND-SHERIDAN-
SOUTHWEST PHILLIPS-WESTERN ROOSEVELT-WIBAUX-
554 AM MDT FRI JUL 16 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST MONTANA

.DAY ONE...
EXPECT ISOLATED THUNDERSTORMS ACROSS NORTHEAST MONTANA TODAY AND THIS
EVENING. A FEW OF THESE STORMS COULD BECOME SEVERE WITH LARGE HAIL
AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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