Flash Flood Warning 21, NWS Flagstaff, AZ

094 
WGUS75 KFGZ 290100
FFSFGZ

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
600 PM MST SUN JUL 28 2013

AZC005-290109-
/O.CAN.KFGZ.FF.W.0021.000000T0000Z-130729T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
COCONINO AZ-
600 PM MST SUN JUL 28 2013

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL COCONINO
COUNTY...

GRAND CANYON PARK OFFICIAL INDICATE FLASH FLOODING HAS ENDED ON GARDEN 
CREEK...THUS THE FLASH FLOOD WARNING HAS BEEN CANCELLED. 


LAT...LON 3610 11214 3610 11209 3606 11210 3606 11213

$$

41

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
355 PM MST SUN JUL 28 2013

.SYNOPSIS...MONSOON MOISTURE WILL CONTINUE TO BRING A GOOD CHANCE OF
THUNDERSTORMS TODAY...A FEW CAPABLE OF PRODUCING HEAVY RAIN.
STARTING MONDAY...DRIER AIR WILL MOVE INTO NORTHERN ARIZONA WITH A
DECREASE IN STORM ACTIVITY.

&&

.DISCUSSION...A WEAK SHORTWAVE OVER SOUTHERN NEVADA WHICH WAS
EVIDENT ON WATER VAPOR/IR THIS MORNING HAS PUSH A BOUNDARY SOUTHWARD
RUNNING FROM NORTHWEST OF PRESCOTT...NORTH OF FLAGSTAFF AND EASTWARD
OUT OVER THE LITTLE COLORADO RIVER VALLEY NORTH OF WINSLOW THIS
AFTERNOON. THIS BOUNDARY IS HELPING TO PROVIDE WEAK UPWARD
VERTICAL MOTION ALONG WITH CONVERGENCE AND THIS WILL CONTINUE TO BE
THE FOCUS FOR THUNDERSTORMS PRODUCING HEAVY RAIN AND POSSIBLY
TRAINING ACTIVITY LEADING TO POSSIBLE FLASH FLOODING.

ANOTHER FEATURE MOVING INTO WESTERN ARIZONA IS AN UPPER LEVEL
SHORTWAVE WITH WEAK TO MODERATE FORCING...EVIDENT AT AT 300 MB ON
THE GFS AND IN THE DIVQ FIELDS FROM 500-300 MB. THIS WILL BE MOVING
INTO WESTERN SECTIONS OF OUR FLASH FLOOD WARNING AREA THIS EVENING.
THIS FEATURE WILL TRACK ACROSS WESTERN ARIZONA AND NW COCONINO
COUNTY. THIS FEATURE WILL ALSO PROVIDE LIFT IN ASSOCIATION WITH
UPPER LEVEL VORTICITY ADVECTION. THE SHEAR OVER ARIZONA IS IN
RESPONSE TO THE INCREASED HEIGHT GRADIENT OVER THE SOUTHWEST U.S. AS
THE SOUTHWEST SITS BETWEEN A HIGH TO THE EAST AND A TROUGH OF LOW
PRESSURE ALONG THE CALIFORNIA COAST. THE BEST SHEAR IS AT ANVIL
LEVEL WHICH WILL HELP SUPPORT A FEW ORGANIZED THUNDERSTORMS MAYBE
STRONG ENOUGH TO PRODUCE LARGE HAIL AND HEAVY RAIN NORTHWEST OF A
KPRC TO KRQE LINE. THE BEST PW IN THE FORECAST AREA IS ALONG AND
NORTH OF THE I-40 CORRIDOR THIS AFTERNOON AND EVENING. THERE IS THE
POSSIBILITY OF MAYBE A FEW TRAINING STORMS IN THE SHEARED
ENVIRONMENT THAT MAY POSE A HEAVY RAIN THREAT. STORMS WILL BE MOVING
TO THE NORTHEAST BETWEEN 10 TO 20 KTS AND GIVEN THE RAPID MOVEMENT
OF CELLS AND THE LOWER PW ENVIRONMENT WOULD NOT MAKE IT FAVORABLE
FOR NUMEROUS AREA OF HEAVY RAIN AND OR FLASH FLOODING...EXCEPT FOR
NW COCONINO COUNTY. THE SYNOPTIC LIFT COULD FAVOR AN ENVIRONMENT FOR
NUMEROUS THUNDERSTORM AND WITH THE UNIDIRECTIONAL SHEAR AN ANCHORED
LINE OF STORMS WITH TRAINING CELLS.

FOR MONDAY THROUGH WEDNESDAY...A WEAK LOW PRESSURE SYSTEM WILL BRUSH
THE PACIFIC NORTHWEST MOVING FROM WEST TO EAST. IN RESPONSE...HIGH
PRESSURE WILL BE SUPPRESSED TO THE SOUTH AND EAST OF ARIZONA. THE
SHIFT IN THE HIGH WILL ALLOW A SLIGHTLY DRIER AND MORE STABLE AIR
MASS FROM OVER THE EASTERN PACIFIC TO MOVE ACROSS NORTHERN ARIZONA.
AS A RESULT...SHOWERS AND STORMS WILL BECOME MORE ISOLATED DURING
THIS TIME PERIOD.

FROM THURSDAY INTO NEXT WEEKEND...MODELS INDICATING A FAVORABLE
REPOSITIONING OF THE SUBTROPICAL HIGH BACK TO THE EAST OF ARIZONA
WITH AN INCREASING MOIST SOUTHERLY FLOW COMING BACK INTO NORTHERN
ARIZONA. THUNDERSTORMS CHANCES WILL BE TRENDING UPWARD DURING THIS
PERIOD.
&&

.AVIATION...FOR THE 00Z PACKAGE...SCT-NMRS TSRA/SHRA WITH MVFR/IFR
CONDITIONS. CONVECTIVE ACTIVITY SLOWLY DIMINISHING OVERNIGHT. AFT
29/18Z...ISOLD-SCT -TSRA/-SHRA. AVIATION DISCUSSION NOT UPDATED FOR
AMENDMENTS.

&&

.FIRE WEATHER...A MOIST AND UNSTABLE AIRMASS WILL REMAIN OVER THE
AREA TONIGHT PRODUCING HEAVY RAIN SHOWERS AND THUNDERSTORMS. THE MAIN
THREATS WILL CONTINUE TO BE LOCALIZED FLASH FLOODING AND LIGHTNING. A
SLIGHT DECREASE IN MONSOON MOISTURE IS FORECAST ON MONDAY AND TUESDAY
WITH LOWER CHANCES FOR STORM ACTIVITY.

WEDNESDAY THROUGH FRIDAY...A DOWNWARD TREND IN THUNDERSTORM ACTIVITY
WILL CONTINUE ON WEDNESDAY. EXPECT INCREASING CHANCES FOR
THUNDERSTORMS OVER NORTHEASTERN ARIZONA ON THURSDAY AND FRIDAY.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH UNTIL 10 PM MST
THIS EVENING FOR AZZ004>007.

&&

PUBLIC.........TC/MCCOLLUM
AVIATION.......DB
FIRE WEATHER...DB

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
403 PM MST SUN JUL 28 2013

AZZ004>018-037>040-291330-
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-
403 PM MST SUN JUL 28 2013

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

MONSOON MOISTURE WILL REMAIN OVER NORTHERN ARIZONA. AN UPPER LEVEL
WEATHER SYSTEM WILL HELP LIFT THE ATMOSPHERE WITH NUMEROUS STORMS FROM
FLAGSTAFF NORTHWEST. THE MAIN THREAT FROM THE STORMS WILL
CONTINUE TO BE HEAVY RAIN...ESPECIALLY OVER NORTHWEST COCONINO
COUNTY NORTH AND NORTHWEST OF FLAGSTAFF. A FLASH FLOOD WATCH WILL
CONTINUE UNTIL 10 PM MST.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

FROM MONDAY THROUGH WEDNESDAY...DRIER AIR WILL MOVE OVER THE AREA
WITH THUNDERSTORM AND SHOWER ACTIVITY BECOMING ISOLATED. FOR
THURSDAY AND THE END OF THE WEEK...SOUTHERLY FLOW AND MONSOON
MOISTURE WILL RETURN TO NORTHERN ARIZONA.

.SPOTTER INFORMATION STATEMENT...

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