Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 251048
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
340 AM MST MON AUG 25 2014

.SYNOPSIS...SUBTROPICAL MOISTURE WILL MOVE NORTHWARD OVER NORTHERN
ARIZONA ON MONDAY AHEAD OF AN ADVANCING LOW PRESSURE TROUGH WITH
INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS.  FROM LATE MONDAY
THROUGH TUESDAY...THE PASSING TROUGH WILL BRING NUMEROUS SHOWERS AND
THUNDERSTORMS TO THE STATE. SOME STRONG THUNDERSTORMS WILL BE
POSSIBLE...ALONG WITH THE THREAT OF HEAVY RAIN. THURSDAY ONWARD...A
DRYING NORTHWEST FLOW WILL DECREASE THUNDERSTORM CHANCES.

&&
.DISCUSSION...
TODAY THROUGH WEDNESDAY...A DEEP TROUGH OF LOW PRESSURE WILL
APPROACH ARIZONA FROM THE NORTHWEST...THIS SYSTEM WILL PULL A
DEEP SUBTROPICAL AIRMASS NORTHWARD ALONG WITH THE HELP OF A
TROPICAL SYSTEM PASSING TO THE WEST OF BAJA. 1.5 INCH PW AIR IS
FORECAST TO MOVE NORTHWARD INTO SOUTHERN ARIZONA WITH UP TO 1.0 INCH
PW AIR AS FAR NORTH AS THE MOGOLLON RIM. THIS MOIST AIR MASS IS
FORECAST TO BE LIFTED OROGRAPHICALLY INTO THE YAVAPAI AND NORTHERN
GILA COUNTY MOUNTAINS...COCONINO PLATEAU...MOGOLLON RIM AND WHITE
MOUNTAINS. THE MOISTURE...LARGE SCALE LIFT...AND OROGRAPHIC LIFT IS
FORECAST TO COME TOGETHER LATE MONDAY NIGHT INTO TUESDAY MORNING AND
THEN PEAK TUESDAY AFTERNOON/EVENING...THEN DECREASE RAPIDLY EARLY
WEDNESDAY MORNING AS THE COLD FRONT MOVES EAST INTO NEW MEXICO. THE
BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BEGIN ON EARLY
TUESDAY MORNING...WINDS ALOFT ARE FORECAST TO STRENGTHEN. THE
COMBINATION OF STRENGTHENING WINDS AND INSTABILITY WILL BRING THE
THREAT OF STRONG THUNDERSTORMS...THAT COULD POTENTIALLY PRODUCE
SEVERE HAIL...STRONG WINDS...POSSIBLE ISOLATED TORNADOES...AND A
THREAT OF LOCALIZED HEAVY RAIN. THE LOCATION OF THE HEAVY RAIN
THREAT WILL LIKELY BE ALONG THE YAVAPAI AND NORTHERN GILA COUNTY
MOUNTAINS...COCONINO PLATEAU...MOGOLLON RIM...AND WHITE
MOUNTAINS...FROM VERY MOIST OROGRAPHIC UPSLOPE FLOW AND FROM
TRAINING SHOWERS AND THUNDERSTORMS IN A UNI-DIRECTIONAL FLOW
ENVIRONMENT. WE INTRODUCED HEAVY SHOWERS AND THUNDERSTORMS IN THE
FORECAST GRIDS FROM EARLY TUESDAY AND TUESDAY NIGHT. STAY TUNED THIS
WEEK TO LOCAL WEATHER FORECAST...AS THIS COULD BE A FAIRLY
WIDESPREAD WET WEATHER EVENT.

BY LATE WEDNESDAY MORNING INTO THE AFTERNOON A DRY WEST TO NORTHWEST
FLOW WILL USHER IN A RAPID TRANSITION FROM NUMEROUS SHOWERS AND
THUNDERSTORMS TO ISOLATED ACTIVITY BY THE AFTERNOON.

 THURSDAY THROUGH SATURDAY...FORECAST MODELS INDICATE A DRY
NORTHWEST FLOW WILL CONTINUE BEHIND THE WEATHER DISTURBANCE WITH
DRY CONDITIONS...AND SLIGHTLY WARMER DAYTIME TEMPERATURES.

THERE IS THE POSSIBILITY THAT ANOTHER RELATIVELY STRONG TROUGH OF
LOW PRESSURE IS FORECAST TO MOVE ACROSS THE WESTERN STATES LATE NEXT
WEEKEND WITH A A DRY AND BREEZY WEST TO NORTHWEST FLOW...MODERATE
UNCERTAINTY AT THIS TIME IS ATTACHED TO THE LATE WEEKEND STORM
SYSTEM...AS WELL AS WHETHER MOISTURE WILL INTERACT WITH THIS SYSTEM
AS IT MOVES THROUGH THE SOUTHWEST STATES.
&&

.AVIATION...FOR THE 12Z PACKAGE...EXPECT SCT-BKN HIGH CLOUDS FROM
WEST TO EAST THROUGH 16Z-18Z. AFT 18Z...SCT SC/CU WITH BASES FROM
6-8KFT AGL...WITH HIGH CLOUD COVER PERSISTING. ISOLD -SHRA SE OF
KINW AFT 20Z-22Z. -SHRA BECMG MORE NMRS AND PUSHING NW BY 23Z-01Z
WITH SCT SHRA/TSRA AND ISOLD +TSRA SE OF KGCN BY 06Z-08Z. STRONGER
STORMS MONDAY NIGHT MAY PRODUCE BRIEF MVFR CONDITIONS...ESPECIALLY
EAST OF A LINE FROM KPRC TO KFLG. AVIATION DISCUSSION NOT UPDATED
FOR AMENDMENTS.
&&

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

&&

$$

PUBLIC.........TC
AVIATION.......BP

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF









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