Severe Thunderstorm Warning 52, NWS Glasgow, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
155 PM MDT FRI JUL 30 2004

.SHORT TERM...FOR NORTHEAST MONTANA TONIGHT THROUGH SUNDAY...A
NORTH-SOUTH ORIENTED WARM FRONT WAS MOVING EAST ACROSS THE CWA THIS
AFTERNOON. BREEZY DRY CONDITIONS EXISTS OVER CENTRAL PORTIONS OF THE
STATE WITH THE AIRMASS BEING WARMED BY DOWNSLOPE AND STRONG JULY
SUNSHINE. NOT A LOT OF WEATHER TO SPEAK OF ASSOCIATED WITH THE WARM
FRONT OTHER THAN SCATTERED HIGH-BASED CUMULUS CLOUDS AND A
TEMPERATURE/WIND DIFFERENCE.

A WEAK COLD FRONT WAS MOVING SOUTH THROUGH SOUTHERN ALBERTA AND INTO
NORTH-CENTRAL MONTANA THIS AFTERNOON. SOME CONVECTION HAS BROKEN OUT
NEAR THE TRIPLE POINT OF THESE TWO FRONTS OVER SW SASKATCHEWAN AND
IS MOVING TO THE SOUTHEAST TOWARD THE NORTHEAST ZONES.

MODELS WERE IN GENERAL AGREEMENT THROUGH THE SHORT TERM...BUT
COULDN/T TIME THE VORT MAXES IN A FAST WEST-NORTHWEST JET OVER THE
REGION. THE ETA LOOKED MUCH STRONGER WITH THIS EVENING/S CONVECTION
AND THEREFORE QPF TONIGHT FOR THE CWA. HOWEVER...THE BEST
INSTABILITY AND MOISTURE SHOULD REMAIN ACROSS SASKATCHEWAN. MET
GUIDANCE SUGGESTING TO RAISE POPS ACROSS THE CWA...BUT DO NOT SEE
SUPPORTING EVIDENCE FOR THIS TO HAPPEN. INHERITED SLIGHT CHANCE TO
CHANCE POPS ACROSS THE NORTHERN ZONES LOOKS GOOD.

MODELS SHOWING THAT A SURFACE LOW DEVELOPS ON THE THIS COLD FRONT
TOMORROW...WHERE IT THEN MOVES INTO THE DAKOTAS. SPC SWODY2 HAS THE
NE ZONES ON THE WESTERN EDGE OF A SLIGHT RISK AREA. GIVEN THE TIMING
INCONSISTENCIES OF THE MODELS...WILL DECLINE TO MENTION ANY SEVERE
WEATHER AT THIS POINT.

UPPER FLOW BACKS A BIT THROUGH THE PERIOD WITH A WESTERN UPPER RIDGE
BUILDING INTO THE AREA FROM THE SOUTHWEST. THIS COULD LEAD TO
POTENTIALLY HOT AND DRY CONDITIONS...BUT LOW LEVEL EASTERLY FLOW
SHOULD KEEP FIRE WEATHER CONDITIONS IN CHECK. A WEAK DISTURBANCE
SCOOTING ACROSS SOUTHERN SASKATCHEWAN COULD BRING SOME CLOUDS TO THE
NORTHERN ZONES...BUT PRECIPITATION IS NOT EXPECTED WITH THE SHALLOW
MOISTURE.  JAMBA

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
OVERALL MODEL AGREEMENT LOOKS GOOD NEXT WEEK WITH FAIRLY TYPICAL
WEATHER FOR THE FIRST WEEK OF AUGUST. THE SUBTROPICAL RIDGE WILL
BUILD NORTH WITH 500H HEIGHTS IN THE 580S AND THICKNESS VALUES WELL
INTO THE 570S. LIKELY THAT THERE WILL BE AT LEAST A FEW 90+ DEGREE
DAYS. AN UPPER TROUGH IN WESTERN CANADA AND THE NORTHEAST PACIFIC
MAY PUSH INTO THE NORTHERN ROCKIES LATE IN THE WEEK WHICH WOULD PUSH
THE RIDGE AXIS EAST OF THE AREA AND ALLOW SOUTHWEST FLOW TO DEVELOP
AROUND THE PERIPHERY OF THE HIGH. THE PATTERN LOOKS RELATIVELY DRY
THROUGH THE MIDDLE OF THE WEEK WITH AN INCREASING CHANCE OF
CONVECTION TOWARD THE END OF THE WEEK.

SUNDAY NIGHT & MONDAY...THE EXTENDED PERIOD BEGINS WITH NEARLY ZONAL
FLOW ACROSS THE AREA ON THE EDGE OF NORTHERN JET AND PERIPHERY OF
THE SUBTROPICAL HIGH. THERE MAY BE SOME WEAK DISTURBANCES IN THE
NORTHERN BRANCH...BUT APPEARS THE BEST CHANCE OF SHOWERS WILL REMAIN
NORTH OF THE BORDER.  TEMPERATURES SHOULD BE CLOSE TO SEASONAL
AVERAGES.

TUESDAY & WEDNESDAY...THE SUBTROPICAL RIDGE CONTINUES TO BUILD TO
THE NORTH WITH THE RIDGE AXIS ACROSS EASTERN MONTANA. 850H
TEMPERATURES ARE PROGGED BY BOTH THE GFS AND ECMWF TO GENERALLY BE
IN THE 25-28C RANGE EACH AFTERNOON. TEMPERATURES SHOULD TOP OUT IN
THE 90S EACH AFTERNOON. WILL TWEAK UP TEMPERATURES JUST A DEGREE OR
TWO...BUT DOWN THE ROAD MAY NEED TO CONSIDER RAISING MAXIMA A BIT AS
IT COULD GET WELL INTO THE 90S AT THE USUAL HOT SPOTS.

THURSDAY & FRIDAY...THE RIDGE AXIS SLOWLY GETS NUDGED TO THE EAST AS
AN UPPER TROUGH PUSHES EAST. ALWAYS POSSIBLE WITH A STRONG
SUBTROPICAL RIDGE THIS TIME OF YEAR THAT IT HANGS ON FOR ANOTHER DAY
OR TWO INTO THE WEEKEND. IT IS POSSIBLE THAT IF THE TROUGH MAKES
STRONG INROADS INTO THE PACIFIC NORTHWEST THAT SOUTHWEST FLOW WILL
SET UP AND A COLD FRONT WILL WORK ACROSS THE AREA BY LATE FRIDAY OR
FRIDAY NIGHT INCREASING THE CHANCE OF CONVECTION BY THEN. CONSENSUS
OF SURROUNDING OFFICES IS TO KEEP IT DRY FOR NOW AS IT IS TOWARD THE
TAIL END OF THE EXTENDED PERIOD. TEMPERATURES SHOULD CONTINUE TO BE
QUITE WARM/HOT THROUGH THE END OF THE WEEK. CB

&&

CLIMO...SO FAR THE AVERAGE TEMPERATURE AT KGGW THIS MONTH IS 69.0
DEGREES...WHICH IS 1.1 DEGREES BELOW AVERAGE. PRECIPITATION MONTH TO
DATE IS EXACTLY AT THE 30 YEAR AVERAGE OF 1.69 INCHES. TEMPERATURES
THIS MONTH HAVE RANGED FROM A LOW OF 48 DEGREES ON THE 9TH AND
29TH...TO A HIGH OF 100 DEGREES ON THE 18TH. CB

&&

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

&&