Peterson is nearly always right…

 Northern Arizona Weather  Comments Off on Peterson is nearly always right…
Nov 092008
 

So, there I am reading this morning’s forecast discussion from the National Weather Service. Suddenly, I see the word “screaming.” Instantly, I think “This sounds like Peterson.”  Sure enough, I scrolled to the bottom and found his name.  I don’t know anything about Peterson, except that his write-ups are fun to read and highly accurate. The post is pasted at the bottom of this post.

His write-up today matches with my thinking. We will get a little snow and some wind.  Welcome to winter!

If you remember, I mentioned the need for the jet stream to move farther to the  south for a pattern change.  At least this time, it looks like it will:

jet stream

jet stream

000
FXUS65 KFGZ 091015
AFDFGZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
315 AM MST SUN NOV 09 2008

.SYNOPSIS...A PACIFIC STORM SYSTEM WILL MOVE ACROSS THE REGION THIS
AFTERNOON AND TONIGHT. THIS STORM WILL BRING THE SEASONS FIRST
SNOWFALL TO MANY AREAS ABOVE 6500 TO 7000 FEET LATER TODAY AND
TONIGHT...WITH RAIN FALLING BELOW 6500 FEET. IN ADDITION TO THE RAIN
AND SNOW...EXPECT WINDY AND COLDER CONDITIONS TODAY AND MONDAY. BY
TUESDAY...CONDITIONS WILL REMAIN COOL...WITH LESS WIND...AND JUST A
SLIGHT CHANCE OF SHOWERS. HIGH PRESSURE WILL BRING A RETURN TO FAIR
AND DRY WEATHER BY MID-WEEK.

&&

.DISCUSSION...AFTER MUCH THOUGHT THIS MORNING...WE HAVE DECIDED TO
CHANGE TO FOCUS OF THE FORECAST TODAY. ALTHOUGH NOT MUCH HAS CHANGED
CONCERNING THE EVOLUTION OF THE IMPENDING STORM SYSTEM...WE FEEL
THAT THE CHANCES FOR RAIN AND SNOW WILL BE THE WEATHER HEADLINES
WITH THIS SYSTEM...AND WE WILL DE-EMPHASIZE THE WIND. IT IS MORE
IMPORTANT TO HAVE OUR "SCREAMING MESSAGE" BE THAT THIS WILL BE THE
FIRST SNOWFALL OF THE YEAR FOR MUCH OF THE HIGH COUNTRY ABOVE 6500
TO 7000 FEET LATER TODAY AND TONIGHT. NOT TO DOWNPLAY THE WIND TOO
MUCH...TODAY WILL BE A WINDY DAY...BUT MOST AREAS WILL STAY BELOW
CRITERIA.

NOW FOR THE TECHNICAL STUFF. MODELS ARE ALL NEARLY IDENTICAL WITH
PATH...SPEED...AND LOCATION OF THE UPPER LOW NOW OVER CENTRAL
CALIFORNIA. THIS LOW WILL DEEPEN SLIGHTLY THIS MORNING...AND WILL
FEATURE CLOSED HGHT CONTOURS AS IT MOVES INTO CENTRAL ARIZONA LATE
THIS AFTERNOON. THIS SYSTEM WILL HAVE A WELL-DEFINED FRONTAL BAND
THAT WILL MOVE ALONG I-40 FROM WEST TO EAST TODAY...WITH A FAIRLY
UNSTABLE AND SATURATED COLD POOL JUST BEHIND THE FRONTAL BAND. MODEL
SOUNDINGS INDICATE THAT PRECIPITATION WILL LIKELY START AS SNOW
ABOVE 7000 FEET WITH SNOW LEVELS RAPIDLY FALLING ANOTHER 500-1000
FEET SHORTLY AFTER THE ONSET OF PRECIPITATION DUE TO WET-BULBING.
THE TRAJECTORY OF THIS LOW FAVORS THE MOGOLLON RIM AND WHITE
MOUNTAINS FOR THE MAXIMUM PRECIPITATION AMOUNTS...WHICH COULD REACH
(.30-.40) INCHES WATER EQUIVALENT OVER FAVORED UPSLOPE AREAS. THE
FLAGSTAFF AREA COULD EASILY SEE A FEW INCHES OF SNOW TOWARD
SUNSET...WITH SNOW SHOWERS CONTINUING THROUGH MIDNIGHT. THE SAME
SITUATION IS LIKELY OVER THE EASTERN RIM AND WHITE MOUNTAINS LATER
SUNDAY EVENING.

THERE WILL BE A BAND OF HIGHER WINDS ALOFT AS THE FRONT APPROACHES
TODAY. HOWEVER...MIXING WILL BE HAMPERED BY CLOUD COVER AND
EVENTUALLY...PRECIPITATION. IN ADDITION...MODELS SHOW THE SURFACE
LOW FORMING RIGHT OVER CENTRAL ARIZONA...WHICH IS NOT CONDUCIVE
TOWARD A WIND EVENT. MODEL SOUNDINGS DO NOT INDICATE VERY DEEP
MIXING TODAY...WITH THE EXCEPTION OF THE FAR EASTERN ZONES.
SO...AS ALLUDED TO ABOVE...WE WILL CANCEL MOST OF THE CURRENT WIND
ADVISORY...BUT WILL KEEP IT OUT FOR A FEW EASTERN ZONES THIS
AFTERNOON.

AFTER THIS LOW MOVES THROUGH ARIZONA...MOISTURE AND COLD AIR ON THE
BACKSIDE OF THE SYSTEM WILL KEEP A FEW SHOWERS GOING MONDAY. BY
TUESDAY AND WEDNESDAY...A STRONG ANTICYCLONE WILL BEGIN TO MOVE
TOWARD THE SOUTHWEST...STAYING IN THE PICTURE THROUGH NEXT WEEKEND.
WE WILL BE ON THE EASTERN SIDE OF THIS ANTICYCLONE FOR MUCH OF THE
FORECAST PERIOD. SO...ALTHOUGH SKIES WILL CLEAR...NORTHEAST WINDS
WILL PREVENT A STRONG WARMING TREND.

&&

.AVIATION...FOR THE 12Z PACKAGE...A STORM SYSTEM WILL MOVE ACROSS
ARIZONA TODAY. EXPECT GRADUALLY LOWERING CEILINGS AND INCREASING
SOUTHWEST WINDS THROUGH THE DAY. SOUTHWEST GUSTS AS HIGH AS 40 KT
ARE ANTICIPATED BETWEEN 18Z AND 02Z. AFTER 20Z...RAIN AND SNOW
SHOWERS WILL PRODUCE SCATTERED MVFR CONDITIONS AND ISOLATED IFR
CONDITIONS OVER THE MOUNTAINS...ESPECIALLY OVER THE KAIBAB AND
NORTHEAST PLATEAUS. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS.

&&

.FGZ WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY FROM 12 PM MST
UNTIL 6 PM MST SUNDAY FOR AZ PUBLIC ZONES 013/014/017.

&&

$$

PUBLIC......PETERSON
AVIATION....MAS

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