Flash Flood Warning 44, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
245 PM MST TUE SEP 3 2013

.SYNOPSIS...AN UPPER LEVEL DISTURBANCE APPROACHING FROM THE EAST WILL
INCREASE THUNDERSTORM ACTIVITY ACROSS ARIZONA TODAY AND TONIGHT. A
DRIER AIRMASS WILL RETURN TO THE AREA FOR THE LATTER HALF OF THE
WEEK. TEMPERATURES WILL WARM TO A FEW DEGREES ABOVE NORMAL BY LATE IN
THE WEEK.

&&

.DISCUSSION...HIGH PRESSURE REMAINS TO THE EAST OF AZ WITH SOUTH-
EASTERLY FLOW ACROSS MUCH OF THE STATE. THE APPROACH OF AN UPPER
LEVEL TROUGH IS EXPECTED TO ENHANCE THUNDERSTORM ACTIVITY ACROSS MUCH
OF AZ TODAY. IN ADDITION...THE TIMING OF THE TROUGH MOVING INTO NRN
AZ DURING THE EVENING HOURS WILL LEAD TO INCREASED POTENTIAL FOR
CONTINUED EVENING/OVERNIGHT ACTIVITY.

LINGERING MOISTURE WILL ALLOW SCATTERED THUNDERSTORM DEVELOPMENT
AGAIN ON WEDNESDAY BUT DRIER AND MORE STABLE AIR THEN MOVES INTO THE
AREA THURSDAY THROUGH SATURDAY. EXPECT A DECREASE IN CONVECTIVE
ACTIVITY. TEMPS WILL WARM TO A FEW DEGREES ABOVE NORMAL.

THERE IS STILL SOME UNCERTAINTY IN HOW THE FORECAST WILL PLAY OUT
FOR NEXT WEEKEND. THE ECMWF CONTINUES TO BE MORE AGGRESSIVE IN
DRAWING MOISTURE NORTH INTO AZ WHILE THE GFS TRIES TO KEEP HIGH
PRESSURE ESTABLISHED OVER THE REGION SUPPRESSING ADDITIONAL MOISTURE
SURGES. HAVE NOT MADE ANY BIG CHANGES TO THE EXTENDED FORECAST AS WE
WILL CONTINUE TO MONITOR FORECAST TRENDS.

&&

.AVIATION...FOR THE 00Z PACKAGE...SCATTERED SHOWERS AND THUNDERSTORMS
WILL CONTINUE ACROSS NORTHERN AZ THROUGH THIS EVENING...BEFORE
DIMINISHING OVERNIGHT. MVFR/IFR CONDITIONS AND WIND GUSTS TO 40 KT
POSSIBLE WITH THE STRONGER STORMS. ANOTHER ROUND OF STORMS WILL
DEVELOP AFTER 18Z WEDNESDAY. AVIATION DISCUSSION NOT UPDATED FOR
AMENDMENTS.

&&

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

&&

PUBLIC.........DB
AVIATION.......KD

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1135 AM MST TUE SEP 3 2013

AZZ004>018-037>040-040700-
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-
1135 AM MST TUE SEP 3 2013

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

.DAY ONE...TODAY

AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS NORTHERN ARIZONA TODAY.
THIS DISTURBANCE WILL COMBINE WITH MONSOON MOISTURE TO PRODUCE
SCATTERED SHOWERS AND THUNDERSTORMS. STORM ACTIVITY IS EXPECTED
TO LAST WELL INTO THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SLIGHT DRYING FROM WEDNESDAY THROUGH THE WEEKEND SHOULD BRING A
DECREASE IN THUNDERSTORM COVERAGE.

.SPOTTER INFORMATION STATEMENT...

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