Severe Thunderstorm Warning 90, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 PM MST THU OCT 4 2007

.SYNOPSIS...AN APPROACHING STORM SYSTEM WILL BRING PARTLY TO MOSTLY
CLOUDY SKIES AND A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS TONIGHT
AND FRIDAY. IT WILL ALSO BE VERY WINDY WITH THE POTENTIAL FOR
SOUTHWEST WIND GUSTS OF OVER 40 MPH EARLY THIS EVENING AND AGAIN ON
FRIDAY. OVER THE WEEKEND...A COLD FRONT MOVING IN FRIDAY NIGHT WILL
USHER IN THE COOLEST TEMPERATURES OF THE SEASON. FAIR AND MILD
WEATHER WILL RETURN FOR MUCH OF NEXT WEEK AS HIGH PRESSURES MOVES
OVER ARIZONA.

&&

.DISCUSSION...A CLOSED-LOW IN THE MID TO UPPER LEVELS WAS LOCATED
OVER THE NORTHWEST COAST OF THE UNITED STATES THIS AFTERNOON. OVER
THE NEXT 24- TO 48- HOURS THIS LOW CENTER WILL DEEPEN AND MOVE
SOUTHEASTWARD TOWARD ARIZONA AS STRONG CYCLOGENESIS CONTINUES. THIS
STRONG LOW AND COLD FRONT WILL MOVE OVER THE GREAT BASIN AND ARIZONA
FROM FRIDAY INTO SUNDAY BRINGING A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS...STRONG WINDS AND THE COOLEST TEMPERATURES OF THE
SEASON.

FOR TONIGHT...WITH STRONG PRESSURE GRADIENTS IN PLACE...EXPECT
SOUTHWEST WINDS OF 10 TO 20 MPH WITH GUSTS TO 30 MPH OVER MOST OF
THE AREA. HOWEVER...ACROSS NORTHWEST ARIZONA...INCLUDING THE GRAND
CANYON...KAIBAB PLATEAU AND THE COCONINO PLATEAU WIND GUSTS OF 45
MPH ARE ANTICIPATED UNTIL 9 PM MST AND A WIND ADVISORY WILL CONTINUE
UNTIL MID EVENING (SEE PRODUCT PHXNPWFGZ FOR DETAILS). THE THREAT FOR
SHOWERS AND STORMS WILL CONTINUE...MAINLY FROM THE MOGOLLON RIM
SOUTHWARD WHERE THE BEST MOISTURE AND OROGRAPHIC LIFT WILL BE
LOCATED.

ON FRIDAY...THE MID TO UPPER LOW WILL MOVE OVER NEVADA WITH A COLD
FRONT PUSHING TOWARD ARIZONA. AS A RESULT...EXPECT STRONG SOUTHWEST
WINDS ON FRIDAY ACROSS ALL OF NORTHERN ARIZONA. FROM MID-DAY AND
THROUGH THE AFTERNOON SUSTAINED WINDS OF 20 TO 30 MPH WITH GUSTS TO
NEAR 50 MPH ARE ANTICIPATED. A WIND ADVISORY WILL LIKELY NEED TO BE
ISSUED FOR FRIDAY. ALSO...MODELS ARE BEGINNING TO HINT TOWARD A
PRECIPITATION BAND FORMING IN ADVANCE OF THE COLD FRONT FRIDAY
AFTERNOON AND NIGHT. THE IMPACT OF THE RAIN BAND WOULD MAINLY BE
FROM A PRESCOTT...FLAGSTAFF...PAGE LINE WESTWARD WHERE WIDESPREAD
QUARTER TO HALF INCH RAINFALL TOTALS WILL BE POSSIBLE. THE COLD
FRONT AND DRIER AIR WILL PUSH ACROSS NORTHERN ARIZONA LATE FRIDAY
NIGHT.

FOR SATURDAY AND BEYOND...SUNDAY AND MONDAY MORNINGS WILL SEE THE
COLDEST LOW TEMPERATURES OF THE SEASON WITH ELEVATIONS ABOVE 6000
FEET FALLING WELL BELOW FREEZING. IN ADDITION...DAYTIME HIGHS WILL
BE THE COOLEST OF THE SEASON OVER THE WEEKEND. OTHERWISE...HIGH
PRESSURE WILL MOVE IN FROM THE WEST STARTING MONDAY WITH A RETURN TO
MOSTLY CLEAR SKIES AND MILD DAYTIME TEMPERATURES NEXT WEEK.

MCCOLLUM
&&

.AVIATION...FOR THE 00Z PACKAGE...WDLY SCT-SCT SHRA/TSRA WILL
CONTINUE TO DEVELOP THIS EVENING ACROSS THE MOGOLLON RIM AND POINTS
SW...AND WILL MOVE TOWARDS THE NE ACROSS NE AZ. CLOUD BASES WILL
GENERALLY REMAIN SCT-BKN BTWN 4-6K FT AGL. EXPECT CIGS BTWN 1K-3K FT
AGL AND VSBYS OF 1-3SM...ALONG WITH WND GUSTS UP TO 35 KT IN THE
HEAVIEST SHRA/TSRA. WDSPRD SW SFC WNDS OF 15 TO 25 KTS WITH GUSTS TO
35 KTS WILL CONTINUE THROUGH 03Z TONIGHT...THEN WILL DECREASE TO
10-15 KT. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

KETCHUM
&&

.FGZ WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 9 PM MST THIS
EVENING FOR THE KAIBAB PLATEAU...GRAND CANYON AND THE COCONINO
PLATEAU. ZONES 4/6/7.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
145 PM MST THU OCT 4 2007

AZZ004>018-037>040-050700-
KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY-
COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINS-
NORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEY-
CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
WESTERN MOGOLLON RIM-EASTERN MOGOLLON RIM-WHITE MOUNTAINS-
NORTHERN GILA COUNTY-YAVAPAI COUNTY VALLEYS AND BASINS-
OAK CREEK AND SYCAMORE CANYONS-BLACK MESA AREA-
NORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264-
145 PM MST THU OCT 4 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL
ARIZONA...NORTH CENTRAL ARIZONA...NORTHEAST ARIZONA AND WEST
CENTRAL ARIZONA.

.DAY ONE...TONIGHT

A WIND ADVISORY WILL CONTINUE UNTIL 9 PM MST FOR THE NORTHWEST
CORNER OF ARIZONA...WITH WIND SPEEDS OF 20 TO 30 MPH WITH GUSTS OF
45 MPH EXPECTED. PLEASE SEE PRODUCT PHXNPWFGZ FOR MORE DETAILS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

ON FRIDAY...WINDS WILL BE EVEN STRONGER AS A COLD FRONT APPROACHES
ARIZONA FROM THE NORTHWEST. IT IS LIKELY THAT A WIND ADVISORY WILL BE
ISSUED FOR ALL OF NORTHERN ARIZONA FOR FRIDAY.

FOR THE WEEKEND AND INTO THE MIDDLE OF NEXT WEEK...NO WEATHER
HAZARDS EXPECTED.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

MCCOLLUM