Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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000
FXUS65 KFGZ 271708
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1008 AM MST MON JUL 27 2015

.SYNOPSIS...DRY SOUTHWEST FLOW WILL LIMIT MOST MONSOON ACTIVITY TO
THE WHITE MOUNTAINS TODAY. EXPECT A RETURN TO A MORE TYPICAL
MONSOON PATTERN BY THE MIDDLE AND LATER PARTS OF THE WEEK.

&&

.DISCUSSION...
LOCALLY BREEZY SOUTHWEST WINDS WILL CONTINUE INTO THE
AFTERNOON...WITH THE POTENTIAL FOR SHOWERS GENERALLY LIMITED TO
THE WHITE MOUNTAINS TODAY. MAKING SHORT TERM EDITS TO INCREASE
WIND GUST SPEEDS TODAY...BUT FORECAST LOOKS IN GOOD SHAPE
OTHERWISE.

&&

.PREV DISCUSSION /335 AM MST/...A SEASONABLY STRONG LOW PRESSURE
SYSTEM CURRENTLY OVER THE PACIFIC NORTHWEST WILL MOVE INTO
MONTANA LATER TODAY...WITH A TROUGH AXIS EXTENDING INTO THE GREAT
BASIN. GUSTY SOUTHWEST FLOW WILL DEVELOP OVER CENTRAL AND NORTHERN
ARIZONA IN RESPONSE TO THIS TROUGH AND THE DRY LAYER BELOW ABOUT
550MB WILL PERSIST. THE BOUNDARY LAYER IS ALSO QUITE DRY AND
DEWPOINTS TO OUR WEST AND SOUTHWEST OFFER NO IMPROVEMENT TODAY AND
PROBABLY MOST OF TOMORROW. A SHALLOW SURGE UNDERWAY IN THE FAR
SOUTHERN PORTIONS OF THE STATE WILL NOT MAKE IT THIS FAR NORTH AND
WILL LIKELY MIX OUT LATER THIS MORNING.

ALL THIS MEANS THAT THE ATMOSPHERE IS TOO DRY AND STABLE TO
CONVECT OVER MOST OF THE CWA. THE EXCEPTION BEING OVER ZONE
17...WHICH IS CLOSEST TO SOME HIGHER BOUNDARY LAYER MOISTURE FOUND
IN WESTERN NEW MEXICO.

MUCH OF TUESDAY WILL FEATURE THE SAME AIRMASS...BUT CHANGES WILL
BE STARTING LATER IN THE DAY AS THE TROUGH MOVES EAST. A
BUILDING MID-LEVEL HIGH WILL THEN FORM OVER NEW MEXICO INTO
WEDNESDAY...WITH LOWER LEVEL FLOW BECOMING MORE SOUTHERLY AND
EVEN EASTERLY AS WE HEAD THROUGH THE WEEK. THIS WILL ALLOW DEEPER
MOISTURE TO MOVE INTO THE AREA. IT WILL ALSO ALLOW BOUNDARY LAYER
MOISTURE TO INCREASE AS THUNDERSTORM/COMPLEX ACTIVITY INCREASES.
ALL THIS WILL LEAD TO A MORE FAVORABLE CIRCULATION PATTERN AND
MOISTURE PROFILE BY LATER THIS WEEK...LEADING TO AT LEAST A LOW
GRADE...PERHAPS MODERATE GRADE...MONSOON PATTERN FROM WEDNESDAY
ONWARD.

&&

.AVIATION...FOR THE 18Z PACKAGE...VFR CONDITIONS ARE EXPECTED AT
ALL TAF SITES IN NORTHERN ARIZONA THROUGHOUT THE NEXT 24 HOURS.
ISOLD -SHRA/-TSRA 19-02Z POSSIBLE SOUTH OF A KSJN-KRQE LINE. GUSTY
SW WINDS THIS AFTERNOON. AVIATION DISCUSSION NOT UPDATED FOR
AMENDMENTS.

&&

.FIRE WEATHER...A TROUGH OF LOW PRESSURE MOVING THROUGH THE GREAT
BASIN WILL BRING BREEZY SOUTHWEST WINDS TO MOST OF THE AREA
TODAY. ISOLATED THUNDERSTORMS ARE POSSIBLE IN SOUTHERN APACHE
COUNTY. MOISTURE WILL BEGIN TO MOVE NORTHWARD ON TUESDAY WITH A
CHANCE FOR SHOWERS AND THUNDERSTORMS IN SOUTHERN APACHE AND NAVAJO
COUNTIES.

WEDNESDAY THROUGH FRIDAY...EXPECT A RETURN TO MORE TYPICAL SUMMER
MONSOON CONDITIONS. INCREASING COVERAGE OF STORMS FARTHER NORTH
AND WEST IS EXPECTED WITH EACH PASSING DAY. NEAR AVERAGE
TEMPERATURES ARE EXPECTED WITH INCREASING AFTERNOON HUMIDITY
LEVELS.

&&

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

&&

$$

PUBLIC...KD/PETERSON
AVIATION...TC
FIRE WEATHER...MAS

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF


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