000
FXUS65 KFGZ 242233
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
330 PM MST FRI MAY 24 2013

.SYNOPSIS...A BROAD LOW PRESSURE SYSTEM WILL REMAIN OVER THE PACIFIC
NORTHWEST THROUGH MEMORIAL DAY. THIS WILL PRODUCE PERIODS OF GUSTY
SOUTHWEST WINDS AND DRY CONDITIONS ACROSS NORTHERN ARIZONA. A LOW
PRESSURE SYSTEM IS FORECAST TO AFFECT THE SOUTHWEST BY TUESDAY AND
WEDNESDAY OF NEXT WEEK...WITH COOLER TEMPERATURES AND A CHANCE OF
SHOWERS OR THUNDERSTORMS.

&&


.DISCUSSION...A LARGE UPPER LEVEL CLOSED LOW OVER THE NORTHWEST U.S.
AND RIDGING ACROSS THE CENTRAL PART OF THE COUNTRY WILL KEEP AZ IN A
VERY PERSISTENT DRY AND BREEZY WEATHER PATTERN THROUGH THE UPCOMING
HOLIDAY WEEKEND. SOUTHWEST FLOW WILL PREVAIL WITH SURFACE WIND
SPEEDS EACH AFTERNOON GENERALLY RANGING FROM 15-25 MPH WITH GUSTS IN
THE 30-35 MPH RANGE. NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES AND
LOW AFTERNOON HUMIDITY ARE EXPECTED. OTHER THAN PERIODIC HIGH
CLOUDS...SKIES LOOK TO REMAIN MOSTLY CLEAR THROUGH SUNDAY. A MORE
SUBSTANTIAL INCREASE IN HIGH CLOUDS LOOKS LIKELY ON MONDAY.

TUESDAY ONWARD...CONFIDENCE DECREASES IN THE LONG TERM PORTION OF
THE FORECAST AS A RESULT OF DECREASED MODEL CONSISTENCY. THE 24/12Z
RUN OF THE ECMWF CONTINUES TO SHOW A CLOSED LOW DROPPING INTO THE
SOUTHWEST U.S. TUESDAY NIGHT AND ACROSS NORTHERN AZ ON WEDNESDAY.
HOWEVER..THE 24/12Z RUN OF THE GFS SHOWS A MORE OPEN WAVE TROUGH
MOVING THROUGH THE ROCKY MOUNTAIN REGION. IN ADDITION...THE
ENSEMBLES OF BOTH MODELS STILL SHOW CONSIDERABLE SPREAD IN
SOLUTIONS. WE WILL CONTINUE WITH A BLEND BETWEEN THE GFS/ECMWF
SOLUTIONS UNTIL CONSISTENCY IMPROVES. THIS FEATURES A TREND TOWARD
COOLER TEMPERATURES BY THE MIDDLE OF NEXT WEEK AND A CHANCE FOR
SHOWERS/THUNDERSTORMS MAINLY TUESDAY NIGHT THROUGH WEDNESDAY.

&&

.AVIATION...FOR THE 00Z PACKAGE...EXPECT VFR CONDITIONS UNDER
OCCASIONAL HIGH CLOUDS THROUGH THE 24 HOUR PERIOD. SFC WINDS WILL
RANGE FROM 15-30KTS FROM THE SW THROUGH 02Z AND WILL RESUME AFT 17Z
AGAIN ON SATURDAY. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FIRE WEATHER...A DEEP LOW PRESSURE SYSTEM WILL REMAIN OVER THE
PACIFIC NORTHWEST...BRINGING MORE BREEZY AND DRY CONDITIONS TO THE
REGION SATURDAY AND SUNDAY. ALTHOUGH CONDITIONS ARE NOT EXPECTED TO
EXCEED CRITICAL FIRE WEATHER THRESHOLDS OVER A LARGE AREA OR A
PERSISTENT AMOUNT OF TIME...SOME LOCATIONS MAY EXPERIENCE BRIEF
PERIODS CRITICAL FIRE WEATHER CONDITIONS. DAYTIME RELATIVE HUMIDITY
VALUES WILL REMAIN BELOW 10 TO 15 PERCENT...WITH ONLY MODERATE
OVERNIGHT RECOVERY.

MONDAY THROUGH WEDNESDAY...LOW PRESSURE WILL REMAIN IN PLACE ACROSS
THE WESTERN UNITED STATES AND WILL ALLOW BREEZY SOUTHWEST WINDS AND
DRY CONDITIONS TO CONTINUE ON MONDAY. THE TROUGH WILL MOVE EAST AND
APPROACH ARIZONA ON TUESDAY...BRINGING COOLER TEMPERATURES AND A
CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY.

&&

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

&&

$$

PUBLIC.........MCS
AVIATION.......PETERSON
FIRE WEATHER...PETERSON

FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF