Severe Thunderstorm Warning 170, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
250 PM MST TUE JUL 25 2006

.SYNOPSIS...A MOIST AND UNSTABLE AIRMASS WILL REMAIN OVER ARIZONA
FOR MUCH OF THIS WEEK...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS
CONTINUING EACH DAY.

&&

.DISCUSSION...AS A MID-LEVEL HIGH PRESSURE CENTER REMAINS ACROSS
NORTHERN ARIZONA THIS AFTERNOON...SCATTERED SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED ACROSS THE FORECAST AREA. STORMS HAVE
INITIATED ACROSS THE HIGHER TERRAIN...BUT HAVE SHOWN VERY LITTLE
STORM MOTION AND ARE REMAINING NEARLY STATIONARY. WHILE THERE WAS
EVIDENCE OF A MOISTURE SURGE ACROSS SOUTHERN PORTIONS OF THE STATE
THIS MORNING...DEWPOINTS HAVE REMAINED STEADY OR DROPPED SLIGHTLY
THIS AFTERNOON FOR MUCH OF THE NORTHERN PORTION OF ARIZONA.
REGARDLESS...A FEW STRONG STORMS CONTINUE TO DEVELOP AND AS STORMS
ARE LINGERING IN THE SAME AREAS FOR EXTENDED PERIODS OF TIME...WE
WILL NEED TO MONITOR THE POTENTIAL FOR LOCALIZED FLOODING INTO THIS
EVENING.

BY WEDNESDAY...HIGH PRESSURE BEGINS ITS SLOW DRIFT WESTWARD AND ITS
CENTER SHOULD REMAIN JUST TO OUR WEST THROUGH LATE THURSDAY. DURING
THIS SAME PERIOD...MODELS HINT AT SOME CONTINUED INTRUSION OF
MOISTURE ASSOCIATED FROM CONVECTION SPAWNED BY EMILIA. POPS FOR THIS
PERIOD ARE INCREASED FROM CURRENT LEVELS ACROSS SOUTHERN PORTIONS OF
OUR FORECAST AREA TO ACCOUNT FOR THIS.

BY LATE IN THE WEEK...RIDGE SHIFTS EASTWARD AND A MORE TRADITIONAL
MONSOON SEASON SETUP RETURNS WITH SOUTHERLY FLOW ALOFT. THIS COULD
TRIGGER A VERY MOIST AIRMASS THAT WOULD SPREAD ALL THE WAY NORTH TO
THE UTAH BORDER.

OTHERWISE...AFTERNOON TEMPERATURES WILL START TO DROP TO MORE
SEASONAL LEVELS AND NON-THUNDERSTORM WINDS WILL BE RATHER LIGHT
THROUGH THE PERIOD.

KD

&&

.AVIATION...FOR THE 00Z PACKAGE...EXPECT SCT-BKN070-090 AGL WITH
SCATTERED 5SM -SHRA/-TSRA TO PERSIST THROUGH LATE EVENING.
CONDITIONS WILL IMPROVE OVERNIGHT AS CONVECTION DISSIPATES. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1000 AM MST TUE JUL 25 2006

AZZ004>018-037>040-260700-
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 TUE JUL 25 2006

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

.DAY ONE...TODAY

A MOIST AND UNSTABLE AIRMASS WILL REMAIN IN PLACE ACROSS NORTHERN
ARIZONA TODAY. MUCH OF THE THUNDERSTORM ACTIVITY SHOULD BEGIN
INITIALLY ACROSS HIGHER TERRAIN AREAS LATER THIS MORNING AND THEN
EXPAND INTO THE LOWER TERRAIN REGIONS OF THE LITTLE COLORADO RIVER
VALLEY AND YAVAPAI AND NORTHERN GILA COUNTIES BY THIS AFTERNOON. THE
MAIN THREAT FROM THE STORMS TODAY IS ANTICIPATED TO BE HAIL
OCCASIONALLY APPROACHING AND EXCEEDING THREE QUARTERS OF AN INCH IN
DIAMETER...BUT LOCALIZED AREAS OF STRONG WINDS AND SMALL STREAM
FLOODING COULD EVENTUALLY BECOME A CONCERN AS WELL.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A CHANCE OF SHOWERS AND THUNDERSTORMS WILL CONTINUE EACH DAY AS
ARIZONA REMAINS UNDER A MOIST AND UNSTABLE AIRMASS.

.SPOTTER INFORMATION STATEMENT...

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