Flash Flood Warning 6, NWS Flagstaff, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
950 AM MST MON AUG 31 2009

.SYNOPSIS...PRECIPITATION CHANCES WILL INCREASE TODAY AND TUESDAY AS
SOUTHERLY FLOW AROUND HIGH PRESSURE NOW CENTERED OVER NEW MEXICO
BRINGS ADDITIONAL LOW LEVEL MOISTURE INTO THE NORTHLAND. EXPECT
SLIGHTLY COOLER TEMPERATURES WITH SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS OVER NORTHERN ARIZONA THROUGH MUCH OF THE WEEK.

&&

.DISCUSSION...AN INCREASED CHANCE FOR SHOWERS AND THUNDERSTORMS
APPEARS IN STORE FOR THIS AFTERNOON AND EVENING...AS MOISTURE
GRADUALLY INCREASING ACROSS THE NORTHLAND. DEWPOINTS THIS HOUR ARE
ABOUT 3 TO 6 DEGREES MORE MOIST THAN THIS TIME YESTERDAY.
STILL...MOST LOCATIONS WILL SEE NEAR TO SLIGHTLY WARMER THAN NORMAL
DAYTIME TEMPERATURES AGAIN THIS AFTERNOON. FORECAST ZONES/GRIDS
APPEAR IN GOOD SHAPE WITH NO UPDATES ANTICIPATED AT THIS TIME.

&&

.PREV DISCUSSION /330 AM MST/...LOW LEVEL MOISTURE CONTINUES TO INCH
UPWARD OVER NORTHERN ARIZONA THIS MORNING. 24H CHANGE IN SURFACE
DEWPOINTS INDICATE A COUPLE MORE DEGREES WARMER THIS AM...WITH
SATELLITE BASED IPW HOLDING AT YESTERDAYS VALUES. TODAY LOOKS LIKE
IT WILL BE QUITE WARM ONCE AGAIN...JUST A DEGREE OR TWO COOLER THAN
YESTERDAY WITH TEMPERATURES STILL AROUND 3-5 DEGREES ABOVE NORMAL
MOST AREAS. MORE FAVORABLE POSITIONING OF THE HIGH PRESSURE OVER
WESTERN NEW MEXICO WILL ALLOW FOR SLIGHTLY GREATER INSTABILITY
ACROSS THE CWA TODAY...WITH A BIT OF UPPER LEVEL COOLING AND A
CONTINUED INCREASE IN LOW LEVEL MOISTURE WHICH SHOULD ENGENDER
SOMEWHAT GREATER CONVECTIVE COVERAGE THIS AFTERNOON.

THERE IS SOME MODEL DISAGREEMENT TUESDAY THROUGH THE MIDDLE OF
THE WEEK. THE NAM IS SOMEWHAT MORE AGGRESSIVE WITH INCREASING
MOISTURE LATE TODAY AND TUE...WHILE THE 00Z GFS KEEPS NORTHERN
ARIZONA QUITE DRY. BEING AS THE OPERATIONAL GFS IS THE DRIEST
MEMBER OF THE GFS ENSEMBLE THROUGH THE WEEK...AM GOING ABOVE GFS
POP VALUES AND MORE IN LINE WITH THE TRENDS OF THE GFS ENSEMBLE
MEAN AND THE OPERATIONAL NAM. THE RESULT...A MODEST INCREASE
IN POPS THROUGH MIDWEEK IS IN ORDER AS MOISTURE CONTINUES TO
SEEP NORTHWARD INTO THE AREA.

FORECAST SOMEWHAT MORE COMPLICATED LATE IN THE WEEK AS THE
INFLUENCE OF HURRICANE JIMENA BEGINS TO IMPACT OUR WEATHER.
CURRENT GUIDANCE BRINGS THE HURRICANE NORTHWARD OVER BAJA
WEDNESDAY THROUGH FRIDAY. WHILE THIS IS A FAVORABLE SETUP FOR
A SURGE OF TROPICAL MOISTURE INTO THE STATE LATE IN THE WEEK
AND INTO THE WEEKEND...THE TIMING AND IMPACT OF ANY SURGE AND
THE REMNANT MOISTURE OF JIMENA IS FAR FROM CERTAIN...AND
HAVE CONTINUED TO NUDGE POPS UP FOR THIS TIME PERIOD.

&&

.AVIATION...FOR THE 18Z PACKAGE...WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS STILL EXPECTED TO START ALONG THE HIGHER TERRAIN AFT
18Z...THEN DRIFT DOWN INTO THE VALLEYS BY MID-LATE AFTERNOON. MOST
OF OUR TAF SITES SHOULD REMAIN DRY DESPITE CB IN VICINITY OF THE
AIRFIELDS THIS AFTERNOON. HOWEVER...KPRC AND KFLG WILL HAVE THE BEST
CHANCE FOR A BRIEF PERIOD OF RAIN. NUMEROUS OUTFLOW BOUNDARIES MAY
ALSO PRODUCE LOCALIZED VARIABLE/GUSTY WINDS ACROSS MUCH OF THE
REGION. OUTSIDE OF TSTM ACTIVITY...VFR CONDITIONS EXPECTED. STORMS
WILL DIMINISH AFT 01/02Z. AVIATION DISCUSSION NOT UPDATED FOR
AMENDMENTS.

&&

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

&&

PUBLIC..................KD
AVIATION................NP

VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
955 AM MST MON AUG 31 2009

AZZ004>018-037>040-010700-
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-
955 AM MST MON AUG 31 2009

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

.DAY ONE...TODAY

WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE ACROSS NORTHERN
ARIZONA THIS AFTERNOON AND EARLY EVENING...ESPECIALLY ACROSS THE
HIGHER TERRAIN OF THE WHITE MOUNTAINS...MOGOLLON RIM...AND YAVAPAI
COUNTY MOUNTAINS. A FEW OF THESE STORMS COULD BRING STRONG AND GUSTY
WINDS TO AROUND 50 MPH AT TIMES.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A SLOW INCREASE IN MOISTURE IS EXPECTED THROUGH THE MIDDLE OF THE
WEEK...WITH THUNDERSTORM ACTIVITY GRADUALLY BECOMING MORE LIKELY.

.SPOTTER INFORMATION STATEMENT...

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