FXUS65 KFGZ 221654
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
940 AM MST TUE DEC 22 2009
.SYNOPSIS...A STRONG STORM SYSTEM MOVING IN FROM THE NORTH WILL
BRING SNOW AND LOWER ELEVATION RAIN ALONG WITH MUCH COLDER
TEMPERATURES TODAY. ON WEDNESDAY...SNOW SHOWERS WILL CONTINUE BUT BE
ON THE DECREASE THROUGH THE DAY. FOR THURSDAY INTO THE WEEKEND...DRY
AND COLD WEATHER IS ANTICIPATED.
&&
.DISCUSSION...
THE PREVIOUS WINTER WX ADVISORY HAS BEEN UPGRADED TO A WINTER STORM
WARNING FOR HEAVY SNOW FOR PORTIONS OF COCONINO COUNTY AND A WINTER
WX ADVISORY ISSUED FOR NORTHERN GILA COUNTY...SEE PHXWSWFGZ FOR
DETAILS.
OVERNIGHT SNOWFALL AMOUNTS INCLUDE 12 INCHES AT JACOB LAKE AND 5-8
INCHES AT THE SOUTH RIM...SNOW WATER RATIOS ARE AROUND 15:1.
OVERNIGHT PRECIP AMOUNTS WERE FORECAST BEST BY THE LOCAL WRF. OUR
FORECAST QPFS WERE MASSAGED WITH THIS MODEL...AND CHANGES INCLUDED
3-6 INCHES TONIGHT AROUND PAYSON.
PREV DISCUSSION 230 AM...THE CENTER OF A STRONG LOW PRESSURE SYSTEM
WAS CENTERED OVER THE PACIFIC NORTHWEST DURING THE MORNING
HOURS...DIVING SOUTHWARD. FOR TODAY AND TONIGHT...THIS LOW AND
ASSOCIATED COLD FRONT WILL CONTINUE TO DIG SOUTHWARD EVENTUALLY
PUSHING THROUGH ARIZONA THIS AFTERNOON AND TONIGHT. AS A
RESULT...THE CHANCE FOR RAIN AND SNOW SHOWERS WILL INCREASE THROUGH
THE DAY AS TEMPERATURES ALOFT COOL UNDER STRONG LARGE-SCALE UPWARD
MOTION AND THE AIR MASS SATURATES. THE LOW-LEVEL FLOW WILL BE FROM
THE WEST TO SOUTHWEST AT 30 TO 40 MPH LEADING TO MODEST UPSLOPE
FORCING...ESPECIALLY THIS AFTERNOON AND EVENING AS THE COLD FRONT
PUSHES ACROSS THE AREA. SNOW LEVELS WILL START OUT FROM 6000-7000
FEET THIS MORNING LOWERING THROUGH THE DAY TO AROUND 4000-5000 FEET
THIS EVENING.
ON WEDNESDAY...WRAP-AROUND MOISTURE AND COLD AIR BEHIND THE CURRENT
LOW WILL CONTINUE TO EFFECT NORTHERN ARIZONA. THE MAIN IMPACT WILL
BE BREEZY AND COLD CONDITIONS. THERE WILL BE A CHANCE OF SNOW
SHOWERS ON WEDNESDAY BUT MODELS ARE INDICATING THAT THE AIR MASS
WILL HAVE SOME TROUBLE COMPLETELY SATURATING. AS A RESULT...LIQUID
PRECIPITATION AMOUNTS AND ADDITIONAL SNOW ACCUMULATIONS WILL BE
LIMITED. THE BEST CHANCE FOR ACCUMULATING SNOW WILL BE NEAR THE
ARIZONA/NEW MEXICO BORDER.
FOR THURSDAY INTO SUNDAY...LOOKS LIKE A DRY PERIOD AS HIGH PRESSURE
MIGRATES FROM WEST TO EAST ACROSS ARIZONA. TEMPERATURES WILL REMAIN
BELOW NORMAL WITH OTHERWISE FAIR CONDITIONS.
EARLY NEXT WEEK...UNSETTLED WEATHER CONDITIONS LOOK TO RETURN TO
NORTHERN ARIZONA.
MCCOLLUM
&&
.AVIATION...FOR THE 18Z PACKAGE...SCATTERED SHOWERS WILL BECOME MORE
NUMEROUS ACROSS NORTHERN ARIZONA THIS AFTERNOON. CONDITIONS WILL
CONTINUE TO DETERIORATE AND CONTINUE THROUGH TONIGHT WITH WIDESPREAD
MVFR CONDITIONS...WITH SCATTERED IFR CONDITIONS IN SNOW ABOVE 6000
FEET TODAY...LOWERING TO 5000 FEET OVERNIGHT. OCCASIONALLY GUSTY
SOUTHWEST WINDS WILL ALSO ACCOMPANY THE STORM SYSTEM THIS AFTERNOON
AND OVERNIGHT LIMITING LOCAL SURFACE VISIBILITIES. AVIATION
DISCUSSION NOT UPDATED FOR AMENDMENTS.
&&
.FGZ WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING IN EFFECT UNTIL 9 AM MST WEDNESDAY FOR AREAS
ABOVE 6000 FEET AZZ004-006-007.
WINTER WEATHER ADVISORY FROM 9 AM TUESDAY TO 9 AM MST WEDNESDAY FOR
AZZ015-016.
WINTER WEATHER ADVISORY FROM NOON TUESDAY TO NOON MST WEDNESDAY
FOR AZZ011-039.
WINTER WEATHER ADVISORY FROM 3 PM TUESDAY TO 3 PM MST WEDNESDAY
FOR AZZ017.
WINTER WEATHER ADVISORY FROM 5 PM TUESDAY TO 9 AM MST WEDNESDAY FOR
AZZ018 ABOVE 4500 FEET.
&&
$$
PUBLIC.........DL
AVIATION.......BAK
VISIT WEATHER.GOV/FLAGSTAFF FOR NORTHERN ARIZONA WEATHER
INFORMATION.
