Severe Thunderstorm Warning 79, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
915 AM MST WED AUG 18 2004

.SYNOPSIS...SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN DEVELOP
TODAY DURING THE LATE MORNING AND AFTERNOON HOURS OVER NORTHERN
ARIZONA. ON THURSDAY...A WEATHER DISTURBANCE WILL MOVE ACROSS
NORTHEAST ARIZONA WITH A CHANCE FOR STRONG THUNDERSTORMS. AREAL
COVERAGE OF THUNDERSTORMS WILL DECREASE ELSEWHERE ON THURSDAY AS
DRIER AIR FILTERS IN FROM THE NORTHWEST. A STORM SYSTEM WILL
DEVELOP OVER THE WESTERN U.S. BY THE MIDDLE OF NEXT WEEK BRINGING
BELOW NORMAL TEMPERATURES AND A CHANCE OF SHOWERS TO THE NORTHLAND.
&&

.DISCUSSION...NORTHERN ARIZONA IS UNDER A NORTHWEST FLOW TODAY ON
THE SOUTHWEST SIDE OF AN UPPER LOW OVER NORTHEAST UTAH. PRECIPITABLE
WATER VALUES CONTINUE A SLOW DECLINE AS THE AIR TO OUR NORTHWEST IS
SLIGHTLY DRIER. HOWEVER...THIS IS BEING OFFSET BY COOLER THAN
AVERAGE TEMPERATURES ALOFT AND STEEP MID LEVEL LAPSE RATES. AN AREA
OF SHOWERS AND THUNDERSTORMS MOVED INTO FAR NORTHERN COCONINO COUNTY
EARLY THIS MORNING INDICATING UPPER LEVEL SUPPORT FROM THE TROUGH.
THESE SHOWERS ARE DISSIPATING AND SHOULD HAVE LITTLE EFFECT ON
CONVECTION LATER TODAY. EXPECTING ANOTHER ACTIVE AFTERNOON WITH
MODIFIED CAPE VALUES AT KFGZ NEAR 800 J/KG. DEEP LAYER MOISTURE OVER
SOUTHERN YAVAPAI COUNTY IS LESS THAN YESTERDAY...AND THIS MAY
DECREASE THE CHANCE OF A REPEAT OF YESTERDAYS FLOODING RAINS IN
THAT AREA. HOWEVER...STEERING FLOW FROM THE NORTHWEST POINTS TO THE
POSSIBILITY OF TRAINING STORMS AGAIN OVER THE NW/SE ORIENTED MTN
RANGES OF YAVAPAI COUNTY. POP GRIDS FOR THIS AFTERNOON LOOK GOOD
WITH 30-40 PERCENT ALL AREAS. TROUGH AXIS WILL MOVE ACROSS FAR
NORTHERN AND NORTHEASTERN AZ LATE TONIGHT THROUGH THURSDAY. THUS
WILL LEAVE POPS IN OVERNIGHT IN THESE AREAS. SPEED AND DIRECTIONAL
SHEAR PROFILES NEAR THE 4-CORNERS THURSDAY AFTERNOON SUGGEST
POSSIBILITY OF ORGANIZED STORMS WITH ISOLATED SEVERE. FRIDAY THROUGH
SUNDAY WILL SHOW A DRYING TREND AS A DRIER SOUTHWEST FLOW DEVELOPS.
WE WILL RETAIN VERY LOW POPS FOR THIS PERIOD FROM THE RIM NORTHWARD
AS MID LEVEL TEMPERATURES REMAIN BELOW AVERAGE FOR THIS TIME OF YEAR.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...NONE.
&&

JOHNDROW

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1000 AM MST WED AUG 18 2004

AZZ004>018-037>040-191400-
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-
1000 AM MST WED AUG 18 2004

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

.DAY ONE...TODAY

THE AIRMASS ACROSS NORTHERN ARIZONA REMAINS UNSTABLE THIS MORNING. AS A
RESULT...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP OVER
THE HIGHER TERRAIN AFTER 11 AM MST. STORMS WILL MOVE INTO THE VALLEY
LOCATIONS DURING THE AFTERNOON. A FEW OF THE STORMS TODAY WILL HAVE
HAIL NEAR ONE HALF INCH IN DIAMETER AND VERY HEAVY RAIN. THERE IS
ALSO A THREAT OF TRAINING STORMS OVER YAVAPAI COUNTY THIS
AFTERNOON WITH HEAVY RAINFALL AND LOCALIZED FLOODING.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A WEATHER DISTURBANCE WILL MOVE ACROSS NORTHERN NAVAJO AND APACHE
COUNTIES THURSDAY. THIS WILL ENHANCE THUNDERSTORM CHANCES IN THIS
AREA...WITH A THREAT FOR A FEW SEVERE STORMS IN THE AFTERNOON. AREAL
COVERAGE OF THUNDERSTORMS IS EXPECTED TO DECREASE ELSEWHERE ON
THURSDAY.  THE FLOW ALOFT WILL TURN TO A DRIER WESTERLY DIRECTION
FOR FRIDAY THROUGH THE WEEKEND. ISOLATED THUNDERSTORMS ARE STILL
POSSIBLE DURING THIS TIME BUT MOST LOCATIONS WILL REMAIN DRY.

.SPOTTER INFORMATION STATEMENT...

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