Area Forecast Discussion
Issued by NWS Flagstaff, AZ

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623
FXUS65 KFGZ 151617
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
930 AM MST FRI MAY 15 2015

.SYNOPSIS...COLD CONDITIONS AND WIDESPREAD RAIN AND SNOW SHOWERS
WITH ISOLATED THUNDERSTORMS ARE EXPECTED THROUGH SATURDAY. SNOW
LEVELS WILL BE LOW ENOUGH TO SEE SOME ACCUMULATIONS OVER THE RIM
COUNTRY. AFTER SOME IMPROVEMENT SUNDAY...A CHANCE FOR RAIN SHOWERS
RETURNS MONDAY AND TUESDAY.

&&

.DISCUSSION...LOOKING AT THE RADAR THIS MORNING SCATTERED SNOW AND
RAIN SHOWERS WERE CONTINUING ACROSS THE MOGOLLON RIM WITH SHOWER
ACTIVITY MORE ISOLATED ACROSS THE REMAINDER OF THE AREA. ANOTHER
IMPULSE WILL MOVE ACROSS ARIZONA TODAY INTO SATURDAY WITH NUMEROUS
SHOWERS DEVELOPING ACROSS MOST OF NORTHERN ARIZONA THROUGH SATURDAY
MORNING. CURRENT FORECAST IN GOOD SHAPE BUT MAKE SURE AN CHECK BACK
FOR UPDATES.

A LARGE LOW PRESSURE SYSTEM WAS ROUGHLY CENTERED OVER THE GREAT
BASIN THIS MORNING...WITH TWO DISTINCT CIRCULATION CENTERS EVIDENT
ON WATER VAPOR IMAGERY. THE FIRST AREA...LOCATED NEAR LAS
VEGAS...BROUGHT SOME CONVECTIVE SHOWERS TO OUR AREA EARLIER IN THE
NIGHT...AS WELL AS STRATIFORM PRECIPITATION ALONG A FRONTAL BOUNDARY
JUST WEST OF THE I-17 CORRIDOR. THE SECOND AREA IS NOW APPROACHING
SAN DIEGO AND WILL AFFECT CENTRAL ARIZONA LATER THIS MORNING AND
INTO THE AFTERNOON.

SNOW LEVELS ALREADY HAVE...OR WILL FALL NATURALLY TO AROUND 7000
FEET...BUT MAY BE FORCED DOWN AS LOW AS 6000 FEET IN THE STEADIER
PRECIPITATION AREAS. SNOWFALL RATES HAVE BEEN IMPRESSIVE FOR THIS
TIME OF YEAR...WITH AS MUCH AS TWO INCHES ALREADY IN BAND NEAR
BELLEMONT. EFFICIENCY WILL DROP WHEN THE SUN COMES UP...THE BEST
CHANCES FOR ACCUMULATING SNOW WILL BE THROUGH MID-MORNING AND
THEN AGAIN THIS EVENING.

THIS LOW PRESSURE SYSTEM WILL MOVE AWAY FROM THE AREA SATURDAY.
SOME INSTABILITY SHOWERS WILL LINGER THROUGH THE DAY...ESPECIALLY
OVER THE NORTHERN ZONES. MODELS CONTINUE TO SHOW PERSISTENT LOW
PRESSURE AFFECTING THE WEST INTO NEXT WEEK. TWO MORE TROUGHS WILL
BRING CHANCES OF SHOWERS MONDAY OR TUESDAY AND THEN AGAIN LATER
IN THE WEEK. AT THIS TIME...THE NEXT LOW PRESSURE SYSTEMS ARE NOT
AS DEEP AND PRECIPITATION SHOULD BE MORE SHOWERY IN NATURE AND
ALL RAIN.

&&

.AVIATION...FOR THE 18Z PACKAGE...SCT SHRA/SHSN WILL INCREASE IN
COVERAGE THIS AFTERNOON AND TONIGHT WITH ISOLD TSRA. EXPECT
WIDESPREAD IFR CONDITIONS OVER MOUNTAIN REGIONS DUE TO LOW CEILINGS
AND PERIODS OF LOW VISIBILITIES IN SNOW SHOWERS. SNOW LEVELS WILL
RANGE FROM 6500-7000 FT MSL ALONG AND WEST OF A KPGA-KPAN LINE
TODAY...TO ABOVE 7000 FT MSL EAST OF THIS LINE. SCATTERED MVFR/IFR
CONDITIONS ELSEWHERE WITH PERIODS OF MODERATE TO HEAVY RAIN SHOWERS.
IMPROVING CONDITIONS ARE NOT ANTICIPATED UNTIL AFTER 15Z SATURDAY.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...A LARGE TROUGH OF LOW PRESSURE OFF THE CALIFORNIA
COAST WILL MOVE EAST AND CONTINUE TO BRING INCREASING MOISTURE
OVER ARIZONA THROUGH SATURDAY. EXPECT SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS...WELL BELOW NORMAL DAYTIME
TEMPERATURES...AND BREEZY TO WINDY CONDITIONS.

SUNDAY THROUGH TUESDAY...A FEW LINGERING SHOWERS ARE EXPECTED
SUNDAY WITH WARMER TEMPERATURES AND LIGHTER WINDS. ANOTHER TROUGH
WILL BRING INCREASING WINDS ON MONDAY WITH A CHANCE OF SHOWERS
RETURNING LATE MONDAY INTO TUESDAY.

&&

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

&&

$$

PUBLIC...MCCOLLUM/PETERSON
AVIATION...MCS/MAS
FIRE WEATHER...MAS



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