Severe Thunderstorm Warning 45, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
925 AM MST TUE JUL 27 2004

.SYNOPSIS...NORTHERN ARIZONA WILL SEE ANOTHER DAY OF WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS...SOME WITH HAIL AND STRONG WINDS.
STARTING TOMORROW A DEVELOPING WESTERLY FLOW ALOFT WILL BRING DRIER
AIR INTO THE STATE. THIS WILL RESULT IN A DOWNWARD TREND IN STORM
ACTIVITY FROM WEST TO EAST DURING THE WEEK.

&&

.DISCUSSION...THE HIGH PRESSURE RIDGE AXIS HAS MOVED WELL SOUTHWEST
OF THE STATE...ALLOWING FOR WEAK SHORTWAVE FEATURES TO AFFECT
NORTHERN AZ. THE MAIN ONE WE ARE WATCHING TODAY IS CURRENTLY OVER
CENTRAL NV AND WESTERN UT. JET STREAK OF AROUND 50KT STRETCHED FROM
NEAR DESERT ROCK NV TO FLAGSTAFF AND THIS LIKELY RESPONSIBLE FOR
ONGOING CONVECTION OVER WESTERN COCONINO COUNTY. LOW LEVEL WINDS
SHOW GOOD VEERING WITH HEIGHT THIS MORNING AS SEEN ON KPSR
SOUNDING (WIND DATA FROM 12Z KFGZ SOUNDING WAS UNAVAILABLE). MODEL
SOUNDINGS TREND THE SHEAR TOWARD MORE UNIDIRECTIONAL LATER
TODAY...BUT WITH STRONG FLOW FOR THIS TIME OF YEAR AT THE JET STREAM
LEVEL. LOW LEVEL MOISTURE HAS DECREASED FROM THE MOGOLLON RIM
NORTHWARD COMPARED TO YESTERDAY...BUT STEEP LAPSE RATES SHOULD MAKE
UP FOR THIS DRYING. THE SHORTWAVE OVER NV IS FORECAST TO MOVE INTO
FAR NW AZ BY MID-LATE AFTERNOON...THEN SOUTHEASTWARD ACROSS NE AZ
THROUGH THE NIGHT. INCREASED INSTABILITY WITH THE SHORTWAVE...ALONG
WITH BETTER WIND SHEAR POINT TO THE POSSIBILITY OF A FEW SEVERE
THUNDERSTORMS THIS AFTERNOON AND EVENING...MAINLY FROM THE MOGOLLON
RIM NORTHWARD. SCATTERED SHOWERS AND STORMS SHOULD LAST LATE INTO
THE NIGHT OVER NE AZ...SO WILL BE INCREASING POPS FOR THAT PERIOD.
SOUTHEAST YAVAPAI AND NORTHERN GILA COUNTIES WILL HAVE TO DEPEND ON
OUTFLOW FROM THE RIM CONVECTION AS THE STEERING FLOW IS TOWARD THE
SOUTHEAST. ONGOING STORMS MOVING INTO YAVAPAI ARE MOVING INTO AN
INCREASINGLY UNSTABLE ENVIRONMENT SO THESE WILL HAVE TO BE WATCHED.
DOWNWARD TREND IN CONVECTION STILL COMING FOR WEDNESDAY THROUGH MUCH
OF THE EXTENDED. WILL COVER THIS IN AFTERNOON DISCUSSION.

FYI...18Z SOUNDING SHOULD BE AVAILABLE FROM KFGZ DUE TO AN EQUIPMENT
TEST.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&

JOHNDROW

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
240 PM MST TUE JUL 27 2004

AZZ004>018-037>040-281400-
WESTERN MOGOLLON RIM-GRAND CANYON COUNTRY-YAVAPAI COUNTY MOUNTAINS-
YAVAPAI COUNTY VALLEYS AND BASINS-OAK CREEK AND SYCAMORE CANYONS-
MARBLE AND GLEN CANYONS-KAIBAB PLATEAU-COCONINO PLATEAU-
NORTHEAST PLATEAU AND MESAS HWY 264 NORTHWARD-
NORTHEAST PLATEAU AND MESAS SOUTH OF HWY 264-
CHINLE VALLEY-CHUSKA MOUNTAINS AND DEFIANCE PLATEAU-
BLACK MESA AREA-LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY-
LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY-
LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY-
EASTERN MOGOLLON RIM-WHITE MOUNTAINS-NORTHERN GILA COUNTY-
240 PM MST TUE JUL 27 2004

...SEVERE THUNDERSTORM WATCH FOR YAVAPAI AND NORTHERN GILA COUNTIES
UNTIL 7 PM MST...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR APACHE...COCONINO...NORTHERN
GILA...NAVAJO...AND YAVAPAI COUNTIES IN NORTHERN ARIZONA.

.DAY ONE...TODAY

A WEAK UPPER LEVEL DISTURBANCE AND ASSOCIATED JET STREAM WILL MOVE
ACROSS NORTHERN ARIZONA THIS AFTERNOON THROUGH TONIGHT...INCREASING
THE THREAT OF SEVERE WEATHER. SCATTERED THUNDERSTORMS HAVE
DEVELOPED THIS AFTERNOON...WITH SOME BECOMING SEVERE ACROSS YAVAPAI
COUNTY. THUNDERSTORMS ARE EXPECTED TO CONTINUE SPREADING SOUTHWARD
ACROSS MUCH OF YAVAPAI AND NORTHERN GILA COUNTIES THROUGH EARLY
EVENING WITH A FEW OF THESE BEING SEVERE. ELSEWHERE ACROSS NORTHERN
ARIZONA...SCATTERED THUNDERSTORMS WILL CONTINUE INTO THE EVENING. SOME
OF THESE STORMS WILL CONTAIN SMALL HAIL AND WIND GUSTS NEAR 50 MPH.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A DRYING TREND IS EXPECTED TO DEVELOP ON WEDNESDAY...ESPECIALLY OVER
THE WESTERN PORTIONS OF THE STATE RESULTING IN ONLY ISOLATED SHOWERS
AND THUNDERSTORMS. FARTHER SOUTH AND EAST...MOISTURE WILL REMAIN IN
PLACE FOR A CONTINUATION OF SCATTERED SHOWERS AND THUNDERSTORMS.
THURSDAY THROUGH SATURDAY...THE DRYING TREND WILL EXPAND EASTWARD TO
ENCOMPASS MOST OF NORTHERN ARIZONA. MOISTURE AND STORMS SHOULD BEGIN
TO INCREASE AGAIN TOWARD THE BEGINNING OF NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

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

JJ