Severe Thunderstorm Warning 12, NWS Great Falls, MT

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
230 PM MDT SAT JUN 19 1999

SHORTWAVE MOVING THROUGH NRN AREA OF CWA WITH DEVELOPMENT OF CLOUDS OVER
THE MOUNTAINS. DRIER AIR STILL WORKING ITS WAY DOWN INTO CWA FROM CANADA
AND INHIBITING POTENTIAL OF THUNDERSTORMS. MOISTURE CONVERGENCE AND
THETA-E POTENTIAL GREATEST TO THE EAST OF THE CWA.ALL MODELS AGREE ON
SOUTHWEST FLOW ALOFT AS NEXT LOW PRESSURE SYSTEM DIGS DOWN TOWARDS PAC
COAST. GUSTY SOUTHWEST WINDS TO DIMINISH AFTER DARK AND TO PICK UP AGAIN
ON SUNDAY DUE TO TIGHTER GRADIENT ALOFT AND WINDS SHOULD HOOK UP WELL
WITH SURFACE HEATING.MODELS DIFFER WITH THE FINER DETAILS SUCH AS WHERE
AND WHEN THE SURFACE LOW WILL DEVELOP. WILL HINT AT SHOWERS ON MONDAY AS
UPSLOPE SHOULD DEVELOP...HOW MUCH AND HOW LONG AGAIN DEPENDS ON TIMING
OF COLD FRONT. TEMPERATURES SHOULD WARM UP SUNDAY AND BE A LITTLE COOLER
ON MONDAY.

EXTENDED SHOWS NEXT UPPER TROF MOVING THROUGH CWS MONDAY NIGHT AND
TUESDAY BRINGING COOLER AIR AND NOT A LOT OF MOISTURE. ZONAL FLOW AND
DRY ON WEDNESDAY AND SOUTHWEST FLOW ON THURSDAY WITH WARMING AND
INCREASE OF SHOWERS. CAMP

GTF 1112 HLN 1123 HVR 1123