Severe Thunderstorm Warning 22, NWS Great Falls, MT

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
230 AM MDT SUN JUL 1 2001

.SHORT TERM...THE ETA/MESO-ETA SOLUTION IS PREFERRED THIS MORNING IN
SPITE OF THE INITIALIZATION PROBLEMS OVER THE SOUTHWEST AS REFERRED
TO IN THE LATEST MODEL DIAGNOSTIC DISCUSSION. SATELLITE COMPARISONS
TO MODEL FEATURES SHOWS THE ETA MODEL IS CLOSER TO THE POSITION OF
THE SHORTWAVES SO IT WILL BE THE PREFERRED MODEL FOR THIS SOLUTION.

SHORTWAVE CONTINUES TO MOVE THROUGH NORTHWEST MONTANA...GENERATING
SCATTERED SHOWERS AND A FEW THUNDERSTORMS AS IT DOES. SHORTWAVE
WILL CONTINUE TO MOVE NORTHWEST AND INTO SOUTHERN CANADA BY MORNING.
EXTRAPOLATION OF THE RAIN AREA INDICATES IT WILL CLIP PARTS OF
THE ROCKY MOUNTAIN FRONT. MODELS DO INDICATE ANOTHER SHORTWAVE THAT
PASSES THROUGH THE CENTRAL AND NORTHERN ZONES THIS MORNING REACHING A
POSITION BETWEEN GTF AND HVR BY 12Z BEFORE MOVING OUT. MESO-ETA IS
THE STRONGEST WITH THIS WAVE WHILE THE AVN SEEMS TO ALMOST IGNORE IT.
WAVE APPARENT ON WATER VAPOR AT THIS TIME IN EAST CENTRAL IDAHO.
SURFACE HIGH PRESSURE OVER SOUTHERN MANITOBA WILL PROVIDE GOOD LOW
LEVEL UPSLOPE AND GOOD DIRECTIONAL SHEER THIS MORNING. MINIMAL
POPS LOOK GOOD FOR CENTRAL ZONES WITH BETTER CHANCES ACROSS THE HIGH
LINE WHERE THE BEST DYNAMICS ARE.

MODELS HOLD ONTO PRECIP A LITTLE LONGER OVER THE NORTH CENTRAL AND
EAST CENTRAL ZONES THIS MORNING AND WILL WORD ACCORDINGLY. THE
AFOREMENTIONED SURFACE HIGH MOVES INTO MINNESOTA LATE IN THE DAY
AND FLOW BECOMES A BIT MORE DOWNSLOPE LATE IN THE DAY. INSTABILITY
LINGERS OVER THE SOUTHERN AND EASTERN ZONES WITH LIFTED INDICES
AS HIGH AS -3 AND CAPES IN EXCESS OF 1000 J/KG. FEEL A MENTION OF
CONVECTION WARRANTED FOR THE AFTERNOON BUT IT SHOULD BE RESTRICTED
TO THE HIGHER TERRAIN.

RIDGE BEGINS TO BUILD IN EARNEST TONIGHT AND MONDAY FOR CLEAR SKIES.
WILL REMOVE MENTION OF THUNDERSTORMS MONDAY OVER THE SOUTHWEST. AS
FAR AS TEMPS GO THICKNESS RIDGE BUILDS OVER THE AREA FROM THE SOUTH
SETTING THE STAGE FOR A WARM DAY. THICKNESS RIDGE IS KNOCKED DOWN A
BIT ON MONDAY BUT WITH STRONG INSOLATION...WILL KEEP TEMPS PRETTY
CLOSE TO SUNDAYS READINGS.

.EXTENDED...MODELS CONTINUE TO BE IN GOOD AGREEMENT. A STRONG H5
RIDGE WILL DOMINATE EARLY IN THE PERIOD FOR A DRY NORTHWEST FLOW
ALOFT. AVN TRIES TO BRING A FEW WEAK SHORTWAVES THROUGH THE
RIDGE...MAINLY ACROSS THE SOUTH. WITH THE LACK OF MOISTURE AND NO
REAL DYNAMICS WILL GO DRY FOR DAYS 3 THROUGH 5. FLOW TURNS MORE
SOUTHWEST ON DAYS 6 AND 7 WITH A MORE SIGNIFICANT SHORTWAVE FOR
FRIDAY AFTERNOON SO WILL CONTINUE CHANCE OF SHOWERS. RIDGE AXIS
SHIFTS EAST ON DAY 7 FOR A DEEPER SOUTHWEST FLOW AND MORE AERIAL
COVERAGE OF THUNDERSTORMS. TEMPS WILL REMAIN SEASONABLY WARM WITH
SLIGHTLY COOLER READING FOR DAYS 6 AND 7.

GOUDSWARD

CCF NUMBERS
GTF BB 084/052 082/050 085 05200
CTB BB 079/050 078/050 082 05300
HLN BB 087/055 086/050 089 05100
BZN BB 086/052 086/048 087 05110
WEY BB 084/040 084/042 085 05110
DLN BB 085/050 086/050 089 05110
HVR BB 088/056 088/052 088 05310
LWT BB 080/052 082/049 080 05210=