Tornadoes and Hail in Montana, July 14, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
150 PM MDT WED JUL 14 2004

.SHORT TERM...FOR NORTHEAST MONTANA...
BIG UPPER LEVEL HIGH PRESSURE PERCHED ABOUT OVER AMARILLO TEXAS WITH
ENERGY ASSOCIATED WITH SOUTHWEST MONSOON MOVING NORTH-NORTHWEST
ACROSS ARIZONA PRESENTLY. WATER VAPOR IMAGERY SHOWS RATHER DRY
ATMOSPHERE OVER MOST OF CENTRAL AND EASTERN MONTANA. SURFACE PATTERN
STILL WITH HIGH PRESSURE EAST AND LOW WEST...HOWEVER DUE TO HEATING
AND SOME MIXING DOWN OF WIND FROM ALOFT...WIND DIRECTIONS ACROSS THE
AREA ARE ALL OVER THE PLACE. AS THE EVENING NEARS AND HEATING IS
LOST...MORE OF A LOW LEVEL EASTERLY FLOW SHOULD RESUME. NEXT FEW
DAYS WILL SEE CENTER OF UPPER RIDGE EASE FARTHER WEST TOWARD FOUR
CORNERS REGION WITH RIDGE AXIS EXPECTED TO POKE NORTH THRU CENTRAL
MONTANA...LEAVING US ON THE EAST SIDE IN MORE WEST OT NORTHWEST FLOW
ALOFT. MORNING MODELS ALL OVER THE PLACE WITH RESPECT TO SHORTWAVE
ENERGY AROUND THE HIGH. TRYING TO FIGURE OUT WHERE THIS ENERGY WILL
GO...WHICH WILL OBVIOUSLY HAVE GREAT BEARING ON THUNDERSTORM
POTENTIAL WITH SUCH AN UNSTABLE ATMOSPHERE...LIKE TRYING TO STAB A
FLY WITH A NEEDLE. THIS EVENING APPEARS THAT A WEAK WAVE COULD CLIP
THE NORTHEAST AND PERHAPS SPUR A FEW STORMS THERE. NOTHING MUCH
AFTER THIS UNTIL TOMORROW AFTERNOON/EVENING WHEN AFOREMENTIONED
ENERGY IN THE DESERT SOUTHWEST NEARS THE AREA AS IT MOVES AROUND THE
HIGH. CURRENT SATELLITE IMAGERY INDICATES THIS TRAJECTORY SHOULD
TAKE THE ENERGY AROUND THE HIGH TO OUR SOUTH...WITH LITTLE OR
PERHAPS NO EFFECT HERE AS FAR AS CONVECTION GOES. FOR NOW WILL KEEP
IN SOME SLIGHT CHANCE POPS TOMORROW AFTERNOON/EVENING FOR THE
WESTERN AND SOUTHERN PARTS OF THE CWA. AS FRIDAY ROLLS AROUND RIDGE
AXIS STILL APPEARS TO BE WEST OF THE CWA...LEAVING NORTHWEST FLOW
ALOFT. AN EXPECTED WEAK WAVE IN THIS FLOW MAY STRAFE THE NORTHEAST
CORNER IN THE AFTERNOON AND EVENING...THUS MORE SLIGHT CHANCE POPS
THEN. TEMPERATURES TO STAY ON THE ROASTY-TOASTY SIDE WITH READINGS
GENERALLY FLIRTING AROUND THE 90 TO 95 DEGREES RANGE. NIGHTS ON THE
MILD SIDE AS WELL WITH READINGS GENERALLY 60 TO 65. SUDDENLY SOME OF
THOSE HIGHS WE HAD IN THE 50S IN JUNE DO NOT LOOK SO BAD.

.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
MEDIUM RANGE MODELS ARE IN ABOVE AVERAGE AGREEMENT WITH THE LONGWAVE
PATTERN THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK.  THE EXTENDED
PERIOD STARTS THIS WEEKEND WITH A LARGE UPPER RIDGE ACROSS THE FOUR
CORNERS REGION EXTENDING NORTH INTO MONTANA. THE NORTHERN PERIPHERY
OF THE RIDGE TO BREAK DOWN WITH THE UPPER FLOW BECOMING MORE ZONAL
EARLY NEXT WEEK. VERY WARM/HOT WEATHER THIS WEEKEND WILL GIVE WAY TO
SEASONABLE TO SLIGHTLY BELOW AVERAGES TEMPERATURES BY EARLY NEXT
WEEK.

FRIDAY NIGHT & SATURDAY...A LARGE UPPER RIDGE WILL COVER THE WESTERN
CONUS WITH AN ANOMALOUSLY DEEP TROUGH IN THE EAST. AN UPPER TROUGH
WILL REMAIN IN THE NORTHEAST PACIFIC INCHING TOWARD THE WEST COAST
OF NOAM THROUGH SATURDAY. TEMPERATURES WILL CONTINUE TO BE QUITE
WARM UNDER THE UPPER RIDGE...BUT NOT EXCESSIVELY SO AS THE 30C+ 850
TEMPERATURES WILL BE CONFINED TO THE GREAT BASIN. IN ANY CASE...
MOST SPOTS SHOULD SEE HIGH TEMPERATURES OF 90F OR ABOVE SATURDAY.
DID NOT MAKE ANY CHANGES TO THE MAXIMA SATURDAY...BUT DID BUMP OF
THE MINIMA A FEW DEGREES FRIDAY NIGHT.

FOR A FEW DAYS THE GFS HAS BEEN SHOWING THAT A SHORTWAVE WILL
TRAVERSE THE TOP OF THE RIDGE A CLIP OUR NORTHEAST ZONES. THE GFS
STILL SEEMS TO BE THE ONLY OPERATIONAL MODEL HITTING THIS FEATURE
FRIDAY EVENING. PER COORDINATION WITH KBIS WILL LEAVE THE POPS ALONE
AS THEY HAVE ALREADY BEEN ADJUSTED A COUPLE OF TIMES. ALSO APPEARS
THAT THERE MAY BE A WEAK FRONT ACROSS THE AREA SO WILL NOT MAKE ANY
CHANGES. AS WE GET CLOSER TO THE TIME PERIOD...AND IF THE FEATURE
FAILS TO DEVELOP WHERE IT CAN BE SEEN IN THE FLOW WOULD BE ABLE TO
PULL THE POPS.

SATURDAY NIGHT & SUNDAY...IT LOOKS A LITTLE MORE LIKELY THAN IT DID
24 HOURS AGO THAT THE UPPER RIDGE WILL HOLD AND KEEP IT DRY THROUGH
SUNDAY AND THUS THE ONGOING DRY FORECAST IS LOOKING GOOD.  HEIGHTS
AND THICKNESS VALUES DO NOT CHANGE MUCH AND WOULD EXPECT HIGH
TEMPERATURES TO BE SIMILAR TO SATURDAY AFTER A MILD NIGHT SATURDAY
NIGHT.

SUNDAY NIGHT & MONDAY...A COLD FRONT WORKS ACROSS NORTHEAST MONTANA
SUNDAY NIGHT AS THE UPPER TROUGH PUSHES INTO WESTERN CANADA. LOOKS
LIKE THERE WILL NOT BE MUCH MOISTURE TO WORK WITH AND THE BEST
DYNAMICS SHOULD REMAIN TO OUR NORTH. STILL WITH A COLD FRONT WORKING
ACROSS THE AREA THIS TIME OF YEAR SOME LOW POPS FOR ISOLATED TO
SCATTERED THUNDERSTORMS LOOK GOOD. ON MONDAY THE UPPER TROUGH PUSHES
EAST THROUGH THE CANADIAN PRAIRIE WITH WEST TO SOUTHWEST FLOW ACROSS
EASTERN MONTANA. THE COLD FRONT AND REAL UNSTABLE AIR SHOULD BE
DISPLACED TO OUR EAST. 500H HEIGHTS DROP ABOUT 60-80DAM AND ALTHOUGH
NOT A TON OF COOLING IN THE WAKE OF THE FRONT IT SHOULD BE ENOUGH TO
KNOCK TEMPERATURES BACK TO SEASONABLE LEVELS FOR THE MIDDLE OF JULY.

TUESDAY INTO WEDNESDAY...THE ECMWF AND GFS BOTH GENERALLY DEPICTING
ZONAL FLOW ACROSS THE NORTHERN TIER OF THE CONUS FROM THE PACIFIC
NORTHWEST INTO THE NORTHERN PLAINS. THE GFS IS A BIT MORE
PROGRESSIVE THAN THE ECMWF AT PUSHING THE UPPER TROUGH EAST AND HAS
SLIGHTLY LOWER HEIGHTS AND THICKNESSES THAN THE ECMWF WITH NEARLY
ZONAL FLOW UNDERNEATH THE DEPARTING TROUGH. ALWAYS POSSIBLE THIS
TIME OF YEAR THAT A STRONG UPPER RIDGE WILL NOT GET KNOCKED DOWN AS
MUCH AS THE MODELS ARE SHOWING...BUT BASICALLY THEY ARE ON THE SAME
PAGE IN KNOCKING THE RIDGE DOWN SO CONFIDENCE A LITTLE ABOVE AVERAGE
THAT THE RIDGE WILL BE SHUNTED TO OUR SOUTH. INHERITED GRIDS HAVE
DRY WEATHER WITH TEMPERATURES NEAR AVERAGE BOTH DAYS WHICH LOOKS
GOOD. SHOULD THE RIDGE NOT GET PUSHED AS FAR SOUTH TEMPERATURES
COULD BE A LITTLE WARMER...BUT ON THE FLIP SIDE THE GFS HAS HEIGHTS
AND THICKNESSES A BIT BELOW AVERAGE FOR THIS TIME OF YEAR. CB

&&

.CLIMO...NO 90 DEGREE DAYS AT GLASGOW YET THIS YEAR...BUT LIKELY TO
END THIS WEEK...ONLY A DAY OR TWO SHORT OF THE LATEST FIRST 90
DEGREE HIGH OF THE YEAR EVER...WHICH WAS JULY 17, 1976. THROUGH THE
FIRST TWO WEEKS OF JULY THERE HAVE ONLY BEEN TWO DAYS WITH ABOVE
AVERAGE TEMPERATURES AT GLASGOW. THE AVERAGE TEMPERATURE OF 65.8
DEGREES IS 3.3 DEGREES BELOW AVERAGE.

&&

.GGW WATCHES/WARNINGS/ADVISORIES...NONE.

&&