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000
FXUS65 KFGZ 192214
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
310 PM MST SUN MAY 19 2013

.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS EVENING ACROSS
NORTHEAST ARIZONA AS WEAK WEATHER DISTURBANCE MOVES THROUGH. ASIDE
FROM THIS...FAIR WEATHER IS EXPECTED ACROSS THE AREA THROUGH
TUESDAY. HIGH TEMPERATURES WILL START A WARMING TREND TUESDAY...WITH
GUSTY AFTERNOON WINDS RETURNING FROM WEDNESDAY THROUGH AT LEAST
FRIDAY.

&&

.DISCUSSION...
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
THIS EVENING NORTH OF A LINE FROM THE SOUTH RIM GCNP TO WINDOW ROCK.
THESE STORMS ARE DUE TO A WEAK DISTURBANCE ALOFT MOVING ALONG THE AZ
UT BORDER. THIS FEATURE SHOULD BE THROUGH THE FOUR CORNERS AFTER
MIDNIGHT TONIGHT.

MONDAY AND TUESDAY...COOL AND DRY NORTHERLY FLOW ALOFT MONDAY WILL
BECOME WESTERLY BY TUESDAY EVENING. TEMPERATURES WILL WARM A FEW
DEGREES STARTING TUESDAY WITH OCCASIONAL CIRRUS PASSING OVERHEAD.

WEDNESDAY...SURFACE WINDS IN NORTHERN AZ WILL BE INCREASING AS DRY
SOUTHWEST FLOW ALOFT SETS UP. MODELS ARE IN GOOD AGREEMENT SHOWING A
CLOSED LOW SETTLING OVER THE PACIFIC NORTHWEST...AND A STALLED COLD
FRONT RUNNING NE-SW FROM SW WYOMING THROUGH LAS VEGAS. CROSS
SECTIONS HERE SHOW DEEP AFTERNOON MIXING...BUT BOUNDARY LAYER WIND
SPEEDS ARE RUNNING FROM 20-30 KT. CONFIDENCE IS GROWING IN CRITICAL
FIRE WEATHER CONDITIONS BEING MET IN COCONINO COUNTY WEDNESDAY
AFTERNOON.

THURSDAY...THE UPPER LOW REMAINS OVER THE PACIFIC NW. THE LAST TWO
RUNS OF THE ECMWF HAS SHOWN A STRONG PROBLEM CHILD SHORTWAVE MOVING
THROUGH SOUTHERN NEVADA WHILE THE GFS DOES NOT. THURSDAYS WIND
FORECAST HERE BLENDS THE TWO MODELS...AND THIS FORECAST HAS
CRITICAL FIRE WEATHER CRITERIA BEING MET IN AREAS WEST OF A LINE
FROM PAGE TO FLAGSTAFF TO SHOW LOW. SHOULD THE ECMWF CONTINUE TO
SHOW THIS SHORTWAVE FEATURE...SURFACE WIND SPEEDS AND GUSTS WOULD
NEED TO BE INCREASED AROUND 5-10 MPH ACROSS THE NORTHLAND.

FRIDAY THROUGH SUNDAY...PROGS HAVE THE UPPER LOW PRESSURE SYSTEM
OVER THE PAC NW AND SURFACE PRESSURE GRADIENTS WEAKENING WITH TIME
STARTING SATURDAY.  ARIZONA REMAINS IN SW FLOW AND FRIDAY SHOULD BE
ANOTHER BREEZY DAY...THEN WIND SPEEDS DROPPING A FEW MPH EACH DAY.

&&

.AVIATION...FOR THE 00Z PACKAGE...VFR CONDITIONS EXPECTED OVER THE
NEXT 24 HRS. SCT CUMULUS WITH BASES AT OR ABOVE 14 KFT MSL NORTH OF
THE MOGOLLON RIM AND A ISOLD -TSRA/-SHRA THREAT OVER FAR NORTHERN AZ
THROUGH 01Z-03Z MONDAY. LIGHTER WINDS AND LESS CLOUDS DURING THE DAY
MONDAY. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...ONE LAST DISTURBANCE ROTATING THROUGH THE FOUR
CORNERS AREA WILL PRODUCE GUSTY WEST WINDS AND SPOTTY CRITICAL FIRE
WEATHER CONDITIONS UNTIL AROUND SUNSET. ISOLATED HIGH BASED SHOWERS
AND THUNDERSTORMS CAN BE EXPECTED NORTH OF A GRAND CANYON VILLAGE TO
WINDOW ROCK LINE THROUGH EARLY EVENING. MONDAY INTO TUESDAY DRIER
CONDITIONS CAN BE EXPECTED WITH LIGHTER WINDS. BRIEF HIGH PRESSURE
RIDGE OVER ARIZONA ON TUESDAY WILL GIVE WAY TO THE NEXT LOW PRESSURE
TROUGH MOVING THROUGH THE PACIFIC NORTHWEST.

WEDNESDAY THROUGH FRIDAY...WEDNESDAY AND THURSDAY...A STRONG LOW
PRESSURE SYSTEM WILL CONTINUE OVER THE NORTHWEST U.S. FOR NORTHERN
ARIZONA THESE TWO DAYS LOOK TO BE THE WINDIEST WITH CRITICAL FIRE
WEATHER CONDITIONS BECOMING MORE LIKELY. BREEZY AND WARM CONDITIONS
ARE EXPECTED ON FRIDAY...HOWEVER THE WINDS LOOK TO BE A FEW MILES
PER HOUR UNDER CRITICAL FIRE WEATHER CONDITIONS. MODERATE TO HIGH
HAINES FROM THE MOGOLLON RIM NORTH CAN BE EXPECTED DURING THIS TIME
PERIOD.



&&

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

&&

$$

PUBLIC.........DL
AVIATION.......TEC
FIRE WEATHER...TEC

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF