Severe Thunderstorm Warning 62, NWS Flagstaff, AZ

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 PM MST SAT OCT 07 2000

SYNOPSIS...MOISTURE WILL CONTINUE TO INCREASE ACROSS THE STATE
THROUGH SUNDAY. WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL
DEVELOP FROM EAST TO WEST OVERNIGHT...AND CONTINUE INTO SUNDAY.
SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDELY SCATTERED MONDAY
AND TUESDAY. A MUCH STRONGER SYSTEM WILL APPROACH THE STATE
WEDNESDAY...BRINGING WINDY AND COOLER CONDITIONS...ALONG WITH A
CHANCE FOR RAIN AND HIGH ELEVATION SNOW INTO THURSDAY.

DISCUSSION...MOISTURE INCREASING STEADILY ACROSS THE CWA THIS
AFTERNOON WITH ISOLATED TO SCATTERED CONVECTION NEAR THE EASTERN
BORDER. MOST CONVECTION IS DEVELOPING JUST EAST OF THE FRONTAL
BOUNDARY NEAR THE HIGHER DEWPOINTS. SATELLITE REVEALS PW-RICH PLUME
STRETCHING THROUGH SOUTHERN AND CENTRAL ARIZONA...THIS AIR LIKELY
BEING ADVECTED TO THE NORTHEAST AND OVER THE FRONTAL BOUNDARY. WILL
PROBABLY HAVE TO WAIT TIL AFTER SUNSET IN THE WESTERN CWA TO GET
ANYTHING GOING. WHEN THE SUN SETS...FRONT WILL SLIDE FURTHER WEST
AND EVER-DEEPENING MOISTURE WILL HAVE A LIFTING MECHANISM TO
UTILIZE. LOW PRESSURE SYSTEM OVER THE SOUTHERN GREAT BASIN ALSO
EXERTS ITS BEST DYNAMICS DURING THE OVERNIGHT HOURS TONIGHT. BY
SUNDAY...THE BEST MOISTURE FROM NORTHERN AND CENTRAL MEXICO SHOULD
FINALLY ARRIVE. WEAK INSTABILITY COMBINED WITH SOME DYNAMICS SHOULD
BE ENOUGH FOR LIKELY POPS IN MOST ZONES. COLDER AIR AT THE SURFACE
DUE TO THE BACKDOOR FRONT AND RAINFALL WILL LIMIT CONVECTION.
HOWEVER...CANNOT RULE OUT ELEVATED CONVECTION OVER THE TOP OF THE
COLDER AIR. THEREFORE...WILL STILL MENTION THUNDERSTORMS IN MOST
ZONES...ALTHOUGH THE PREDOMINATE SOURCE OF RAINFALL WILL BE MORE OF
A STRATOFORM-TYPE. DYNAMICS AND INSTABILITY TAIL OFF SUNDAY NIGHT
AND MONDAY. DESPITE THIS...RESIDUAL MOISTURE AND TERRAIN INSTABILITY
SHOULD BE ENOUGH TO CARRY CHANCE POPS INTO MONDAY.

FOR THE EXTENDED...NEXT TROUGH WILL BEGIN TO DIVE INTO CENTRAL AND
NORTHERN CALIFORNIA TUESDAY...WITH UPPER LEVEL DIV AND SOME MID-LEVEL
DYNAMICS ENTERING THE SOUTHWEST. ENOUGH RESIDUAL MOISTURE WILL STILL
REMAIN FOR CHANCE POPS ON TUESDAY. WEDNESDAY AND THURSDAY STILL
QUITE TRICKY. LAST NIGHTS MRF MOVED THE LOW TO A MUCH FURTHER NORTH
POSITION AND WAS STARTING TO NEGLECT A MAJOR CONTRIBUTION FROM
OLIVIA. HOWEVER...THE 12Z ETA/AVN RUNS INDICATE A VERY STRONG TROUGH
DIVING INTO THE GREAT BASIN BY EARLY WEDNESDAY WITH ITS STRONGEST JET
ENERGY STILL ON THE BACKSIDE. OLIVIA STRENGTHENED A BIT TODAY AND
ALTHOUGH IT IS NOT A HUGE SYSTEM...LOOKS LIKE SOME MOISTURE WILL BE
AROUND TO TAP. ALSO...HAVE A FEELING THAT THE DEEPEST AND MOST
WIDESPREAD MOISTURE FROM THE REMNANTS OF KEITH WILL REMAIN JUST
SOUTH OF ARIZONA AND WILL STILL BE AROUND FOR THIS TROUGH TO UTILIZE
BY WEDNESDAY. AM NOT READY YET TO GO WITH LIKELY WORDING AS MUCH
COULD CHANGE. BUT...THINK ENOUGH COLD AIR WILL SLIDE SOUTH TO AT
LAST MENTION HIGH ELEVATION SNOW BY LATE WEDNESDAY. THEREFORE...WILL
GO WITH MOSTLY CLOUDY...WINDY...AND COOLER WORDING DAY 4 AND 5 WITH
A CHANCE OF RAIN AND HIGH ELEVATION SNOW. PETERSON.

.FGZ...NONE.