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000
FXUS65 KFGZ 131018
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
315 AM MST THU MAR 13 2014

.SYNOPSIS...A LOW PRESSURE SYSTEM OVER SOUTHERN NEVADA WILL MOVE SLOWLY
EASTWARD ACROSS ARIZONA LATE THURSDAY BRINGING SHOWERS AND A FEW
THUNDERSTORMS. BY FRIDAY...SHOWERS AND ISOLATED THUNDERSTORMS WILL
LINGER ACROSS EASTERN ARIZONA. THIS SHOWER ACTIVITY WILL GRADUALLY
CLEAR FROM WEST TO EAST IN THE AFTERNOON HOURS AS THE LOW CONTINUES
TO MOVE EASTWARD INTO NEW MEXICO. DRY WEATHER AND ABOVE NORMAL
TEMPERATURES RETURN SATURDAY AND LAST INTO NEXT WEEK. ON
SUNDAY...EXPECT STRONG AND GUSTY NORTHERLY WINDS TO DEVELOP AS THE
RIDGE AMPLIFIES ALONG THE WEST COAST AND INTERACTS WITH A SECOND LOW
CENTER DROPPING SOUTH THROUGH COLORADO AND NEW MEXICO. DRIER AND
WARMER WEATHER CONDITIONS WITH LIGHT TO BREEZY WINDS WILL SET UP
FOR THE FIRST HALF OF NEXT WEEK.

&&

.DISCUSSION...GOES SATELLITE WATER VAPOR IMAGERY SHOWS AN ELONGATED
LOW PRESSURE REGION OVER SOUTHERN NEVADA INTO CENTRAL CALIFORNIA
THIS MORNING. THE UPPER LEVEL TROUGH AXIS IS TILTING TOWARDS THE
SOUTHWEST WHICH VERIFIES WELL WITH THE SHORT TERM MODEL FORECASTS.
AS THIS LOW MOVES SLOWLY EASTWARD INTO ARIZONA EXPECT SCATTERED
SHOWER ACTIVITY WITH ISOLATED THUNDERSTORMS THROUGH THE AFTERNOON
AND EVENING HOURS. SNOW LEVELS WILL RANGE FROM AROUND 6000 FEET NEAR
THE GRAND CANYON TO AROUND 8000 FEET IN THE WHITE MOUNTAINS THIS
EVENING. CONVECTIVE SHOWERS MAY CAUSE LOCALLY LOWER SNOW LEVELS AND
GRAUPEL SHOWERS. THE LOW CENTER MOVING THROUGH ARIZONA WILL DISPLAY
WEAK DYNAMICS AND LIGHT OROGRAPHICS...WHICH TRANSLATES TO ONLY LIGHT
PRECIPITATION AMOUNTS (BELOW ONE TENTH OF AN INCH)...LOCALLY HIGHER
AMOUNTS ARE POSSIBLE IN CONVECTIVE SHOWERS.

ON FRIDAY...THE LOW PRESSURE CENTER WILL MOVE EAST INTO NEW MEXICO.
LINGERING MOISTURE AND INSTABILITY BEHIND THE UPPER LEVEL TROUGH
WILL ALLOW CONVECTIVE SHOWERS TO DEVELOP MAINLY OVER MOUNTAIN AREAS
OF EASTERN ARIZONA (WHITE MOUNTAINS NORTHWARD TO THE CHUSKA
MOUNTAINS). ISOLATED THUNDERSTORM POTENTIAL EXISTS ALONG AND EAST OF
A LINE FROM FLAGSTAFF TO PAYSON. SHOWERS WILL GRADUALLY DIMINISH
FROM WEST TO EAST THROUGH THE AFTERNOON HOURS. SNOW LEVELS WILL
RANGE FROM 6000 TO 7000 FEET. THE HIGHEST PRECIPITATION AMOUNTS ARE
FORECAST ALONG THE NEW MEXICO BORDER REGION. WE HAVE INCREASED
CHANCES FOR SHOWERS ON FRIDAY AFTERNOON IN LINE WITH THE EUROPEAN
MODEL. OVERALL THE GLOBAL WEATHER MODELS ARE IN GOOD AGREEMENT WITH
THIS SYSTEM WITH ONLY SUBTLE DIFFERENCES IN CONVECTIVE SHOWER
POTENTIAL. THE EUROPEAN MODEL OVER THE PAST 3 DAYS HAS BEEN THE MOST
CONSISTENT AND WE CONTINUE TO USE THIS MODEL OUTPUT TO DRIVE THE
PRECIPITATION FIELDS IN OUR MORNING FORECAST GRIDS.

SATURDAY AND SUNDAY...DRIER AND WARMER WEATHER IS FORECAST FOR THE
WEEKEND AS A HIGH PRESSURE RIDGE AMPLIFIES ALONG THE WEST COAST AND
A SECOND LOW CENTER MOVES SOUTH THROUGH COLORADO AND NEW MEXICO. ON
SUNDAY MORNING...STRONG AND GUSTY NORTHEASTERLY WINDS WILL DEVELOP
MAINLY OVER THE MOGOLLON RIM (FLAGSTAFF TO THE WHITE MOUNTAINS) AND
ALONG THE SOUTHWEST FACING SLOPES. NORTHEASTERLY WIND SPEEDS WILL
RANGE FROM 18 TO 25 MPH WITH GUSTS RANGING FROM 35 TO 45 MPH.
PRESSURE GRADIENTS WILL WEAKEN RAPIDLY BY LATE AFTERNOON RESULTING
IN RAPIDLY DIMINISHING WIND SPEEDS.

MONDAY THROUGH WEDNESDAY...A WEAKENING RIDGE ALONG THE WEST COAST
WILL KEEP ARIZONA IN A DRY AND WARM WEATHER PATTERN WITH LIGHT TO
BREEZY WINDS THROUGH WEDNESDAY.

&&


.AVIATION...FOR THE 12Z PACKAGE...CLOUD COVER WILL GRADUALLY
INCREASE OVER THE NEXT 24 HOURS IN ADVANCE OF AN APPROACHING WEATHER
SYSTEM. ISOLATED -SHRA/-SHSN POSSIBLE MAINLY FROM KIGM-KFLG-KRQE
NORTHWARD THROUGH 18Z. AFTER 18Z...SCATTERED SHRA/SHSN WITH ISOLATED
THUNDERSTORMS ACROSS NORTHERN AZ...ESPECIALLY HIGHER TERRAIN AREAS.
EXPECT MAINLY VFR CONDITIONS BUT WITH ISOLD IFR/MVFR CONDITIONS IN
SNOW SHOWERS ABOVE 6500-7000 FEET ELEVATION. AVIATION DISCUSSION NOT
UPDATED FOR AMENDMENTS.

&&

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

&&

$$
PUBLIC.........BOHLIN
AVIATION.......MCCOLLUM

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF