AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
900 PM MST MON MAY 20 2013
.SYNOPSIS...
THE EARLY EVENING SHOWERS WITH ISOLATED THUNDERSTORMS NEAR THE FOUR
CORNERS REGION HAVE DIMINISHED. A WEAK HIGH PRESSURE RIDGE WILL
BRING WARM AND DRY CONDITIONS TO ARIZONA ON TUESDAY. ON WEDNESDAY A
SEASONABLY STRONG LOW WILL MOVE INTO THE PACIFIC NORTHWEST AND
BECOME NEARLY STATIONARY. THIS LOW WILL PRODUCE STRONGER WINDS
ACROSS NORTHERN ARIZONA AND START A MULTIPLE DAY CRITICAL FIRE
WEATHER PATTERN WHICH WILL LAST INTO THE UPCOMING MEMORIAL DAY
WEEKEND.
&&
.DISCUSSION...
A WEAK HIGH PRESSURE RIDGE WILL MOVE THROUGH THE SOUTHWEST REGION ON
TUESDAY AS A LARGE LOW MOVES INTO THE PACIFIC NORTHWEST. DRY AND
WARM WEATHER CONDITIONS ARE FORECAST UNDER SCATTERED HIGH CIRRUS
CLOUD COVER. THE PACIFIC NORTHWEST LOW WILL SETTLE IN OVER THE
PACIFIC NORTHWEST THROUGH THE WEEKEND...BRINGING AN EXTENDED PERIOD
OF CRITICAL FIRE WEATHER CONDITIONS WITH STRONG GUSTY WINDS AND DRY
HUMIDITY LEVELS FROM WEDNESDAY ONWARD. IN THE SHORT TERM...A FIRE
WEATHER WATCH HAS BEEN ISSUED FOR WEDNESDAY AND THURSDAY ACROSS MOST
FIRE ZONES IN NORTHERN ARIZONA. SEE PRODUCT RFWFGZ FOR DETAILS.
WEDNESDAY AND THURSDAY...TODAYS 12Z MODELS ARE IN BETTER AGREEMENT
FOR THESE DAYS. LOOK FOR INCREASING SOUTHWEST FLOW OVER AZ AS A
CLOSED LOW SETTLES OVER THE PACIFIC NORTHWEST. BOTH THE ECMWF AND
GFS HAVE A STALLED COLD FRONT RUNNING NE-SW FROM SW WYOMING THROUGH
LAS VEGAS...AND BOTH NOW SHOW TWO SHORTWAVES MOVING ALONG THE
FRONTAL ZONE...ONE WEDNESDAY AND #2 ON THURSDAY. THIS IS A VERY GOOD
PATTERN FOR STRONG WINDS ACROSS NORTHERN AZ. THIS AFTERNOONS
FORECAST HAS SOUTHWEST WIND ON WEDNESDAY 20-30 MPH WITH GUSTS TO 40
MPH...AND ABOUT 5 MPH FASTER ON THURSDAY. FASTEST WINDS ALONG AND
NORTH OF THE MOGOLLON RIM. WINDS THURSDAY MORNING SHOULD GET AN
EARLY START AS SHORTWAVE #2 MOVES THROUGH SOUTHERN NEVADA.
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED. A WIND ADVISORY IS
PROBABLE THURSDAY FOR AREAS ALONG AND NORTH OF THE MOGOLLON RIM.
FRIDAY THROUGH MONDAY...DRY...WINDY AND WARM. THE LOW PRESSURE
SYSTEM IS SHOWN TO REMAIN OVER THE PACIFIC NORTHWEST THROUGH THIS
PERIOD. SOUTHWEST FLOW ALOFT WILL PERSIST ACROSS ARIZONA. CONFIDENCE
IS GROWING THAT ALL FOUR CRITICAL FIRE WEATHER CONDITIONS WILL BE
MET FRIDAY AND SATURDAY AFTERNOONS ALONG AND NORTH OF THE RIM.
CURRENT INDICATIONS ARE FOR SLOWER WINDS SUNDAY AND MONDAY.
&&
.AVIATION...FOR THE 06Z PACKAGE...VFR CONDITIONS EXPECTED OVER THE
NEXT 24 HRS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FIRE WEATHER...A RIDGE WILL DEVELOP ACROSS THE SOUTHWEST ON TUESDAY
BRINGING WARM TEMPERATURES AND LIGHT WINDS.
WEDNESDAY AND THURSDAY...A STRONG TROUGH WILL DEVELOP ALONG THE WEST
COAST. SOUTHWEST WINDS WILL BECOME STRONG AND GUSTY AND WILL COMBINE
WITH VERY LOW RELATIVE HUMIDITIES TO CREATE CRITICAL FIRE WEATHER
CONDITIONS ACROSS MUCH OF NORTHERN ARIZONA. A FIRE WEATHER WATCH IS
IN EFFECT FOR WEDNESDAY AND THURSDAY.
FRIDAY AND SATURDAY...A TROUGH WILL REMAIN OVER THE SOUTHWEST
BRINGING PERIODS OF STRONG AND GUSTY WINDS ALONG WITH VERY LOW
RELATIVE HUMIDITIES. CRITICAL TO NEAR-CRITICAL FIRE WEATHER
CONDITIONS ARE EXPECTED TO CONTINUE.
EXTENDED FORECAST...STRONG WINDS AND LOW RELATIVE HUMIDITIES WILL
CONTINUE THROUGH EARLY NEXT WEEK.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH WEDNESDAY AFTERNOON THROUGH THURSDAY EVENING FOR
FIRE WEATHER ZONES AZZ104>117-138>140.
&&
$$
PUBLIC.........BOHLIN/DL
AVIATION.......BOHLIN
FIRE WEATHER...DB
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF
