Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 261709
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1000 AM MST FRI SEP 26 2014

.SYNOPSIS...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TODAY ACROSS
NORTHERN ARIZONA. A PACIFIC COLD FRONT WILL BRING NUMEROUS SHOWERS
AND THUNDERSTORMS ON SATURDAY. SOME STORMS MAY PRODUCE LARGE HAIL
AND DAMAGING WINDS. ON SUNDAY...SCATTERED STORMS SHOULD CONTINUE
ACROSS APACHE COUNTY WITH A SLIGHT CHANCE ELSEWHERE. DRY WEATHER
RETURNS SUNDAY NIGHT AND HIGH COUNTRY ELEVATIONS MAY SEE A LIGHT
FROST MONDAY AND TUESDAY MORNING.

&&

.DISCUSSION...THE THREAT FOR SEVERE WEATHER ON SATURDAY CONTINUES
AHEAD OF A SEASONABLY STRONG PACIFIC STORM FORECAST TO MOVE THROUGH
THE SOUTHWEST REGION. THIS STORM SYSTEM WILL MOVE FROM WEST TO EAST
AND INTERACT WITH A PLUME  OF DEEP TROPICAL MOISTURE. NUMEROUS
SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS NORTHWESTERN ARIZONA
ON SATURDAY MORNING...SPREADING EASTWARD TO NAVAJO AND APACHE
COUNTIES BY AFTERNOON. KEEP A WEATHER EYE OUT FOR UPDATES TO THE
FORECAST IMPACTS AND CHANGING WEATHER CONDITIONS IN YOUR LOCAL AREA.

OUR SATURDAY PUBLIC OPEN HOUSE HAS BEEN CANCELED DUE TO THE
POTENTIAL FOR SEVERE STORM ACTIVITY.

&&

.PREVIOUS DISCUSSION...

FOR TODAY...
A BROAD LOW PRESSURE SYSTEM AND COLD FRONT ARE MOVING INTO NORTHERN
CALIFORNIA. NORTHERN ARIZONA WILL INCREASING SOUTHERLY FLOW WITH
MOISTURE AND INSTABILITY RAMPING UPWARD. THERE IS A STRONG SURGE OF
MOISTURE FROM THE GULF OF CA. INTO THE DESERT SW NOW AS SFC DEW
POINTS THIS MORNING ARE IN THE MID 70S AT YUMA AND POINTS WEST OF
THERE. COOLER MID LEVEL TEMPS HERE SHOULD ALLOW SCATTERED
THUNDERSTORMS TO DEVELOP BY EARLY AFTERNOON ACROSS THE NORTHLAND.

FOR TONIGHT AND SATURDAY...SEVERAL FACTORS ARE COMING TOGETHER AND
POINT OUT THE POTENTIAL FOR SEVERE THUNDERSTORMS FROM LATE FRIDAY
NIGHT THROUGH SATURDAY. WE HAVE FAVORABLE WIND SHEAR...
INSTABILITY...A COLD FRONTAL BOUNDARY AND DYNAMIC LIFT ASSOCIATED
WITH THE UPPER LOW. THE THREATS ARE FOR HAIL GREATER THAN 1
INCH...THUNDERSTORM WINDS GREATER THAN 58 MPH AND POTENTIAL FOR
ISOLATED TORNADOES. DEEP MOISTURE LEVELS AND STRONG DYNAMICS ALOFT
ARE ALSO FAVORABLE FOR HEAVY RAIN WHICH MAY LEAD TO FLASH FLOODING.
WE EXPECT A FRONTAL BAND OF PRECIP (ALIGNED SOUTH TO NORTH) TO
ARRIVE EARLY SATURDAY MORNING IN FAR WESTERN AZ...AND BE ALONG AND
WEST OF A LINE FROM PAGE TO PAYSON BY AROUND NOON. THE FRONTAL BAND
TO MOVE SLOWLY INTO NAVAJO AND APACHE COUNTIES BY SATURDAY EVENING.
WIDESPREAD SHOWERS AND THUNDERSTORMS TO CONTINUE SATURDAY NIGHT
ACROSS THE NORTHLAND.

ON SUNDAY...THE FRONTAL BAND SHOULD STILL BE ACROSS APACHE COUNTY
SUNDAY MORNING WITH SCATTERED STORMS THERE. FURTHER WEST...A DRIER
AND STABLE SOUTHWEST FLOW IS MOVING INTO WESTERN AZ AND SPREADING
EAST THROUGH THE DAY.

MONDAY THROUGH THURSDAY...THE UPPER LOW TO MOVE THROUGH UTAH ON
MONDAY WITH DRY WESTERLY FLOW HERE. THE SENSIBLE WEATHER IS DRY WITH
BELOW NORMAL LOW TEMPERATURES. AREAS ABOVE 7000 FEET MAY SEE LIGHT
FROSTS MONDAY AND TUESDAY MORNINGS. THE ECMWF DOES BRING A FAST
MOVING SW THROUGH THE GREAT BASIN WEDNESDAY AND THIS SYSTEM BRUSHES
FAR NRN AZ. THE GFS IS DRY AND WILL KEEP THE FORECAST DRY AS WELL

&&

.AVIATION...FOR THE 18Z PACKAGE...MOISTURE WILL CONTINUE TO INCREASE
OVER THE NEXT 24 HOURS. SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP OVER NORTHERN ARIZONA THIS AFTERNOON. A STRONG STORM
APPROACHING WILL CONTINUE THE CHANCE FOR STORMS TONIGHT AND
SATURDAY. SOME OF THESE STORMS COULD BECOME STRONG TO SEVERE WITH
DAMAGING HAIL AND WIND GUSTS TO OVER 50 KTS. AVIATION DISCUSSION NOT
UPDATED FOR AMENDMENTS.

&&

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

&&

$$

PUBLIC.........BOHLIN/DL
AVIATION.......MCCOLLUM

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF











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