Red Flag Warning 1, NWS Phoenix, AZ

685 
WWUS85 KPSR 150215
RFWPSR

URGENT - FIRE WEATHER MESSAGE
NATIONAL WEATHER SERVICE PHOENIX AZ
715 PM MST MON JAN 14 2013

AZZ131-CAZ231-150315-
/O.CAN.KPSR.FW.W.0001.000000T0000Z-130115T0300Z/
ARIZONA FIRE WEATHER ZONE 131                                    
YUMA/MARTINEZ LAKE AND VICINITY/LOWER COLORADO RIVER VALLEY AZ-
CALIFORNIA FIRE WEATHER ZONE 231                                 
LOWER COLORADO RIVER VALLEY CA-
715 PM MST MON JAN 14 2013 /615 PM PST MON JAN 14 2013/

...RED FLAG WARNING WILL EXPIRE AT 8 PM MST /7 PM PST THIS EVENING 
FOR STRONG WINDS...LOW RELATIVE HUMIDITY AND VERY HIGH FIRE DANGER
FOR YUMA/MARTINEZ LAKE AND VICINITY AND THE LOWER COLORADO RIVER
VALLEY.

WIND SPEEDS WERE GRADUALLY DECREASING THIS EVENING ..EASING CRITICAL
FIRE WEATHER CONDITIONS.

$$

NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT

WEATHER.GOV/PHOENIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
900 PM MST SUN JAN 13 2013

.SYNOPSIS...
A VERY COLD CANADIAN AIRMASS OVER THE AREA WILL REMAIN IN PLACE
THROUGH AT LEAST TUESDAY. NEAR OR SUB-FREEZING MINIMUM TEMPERATURES
ARE LIKELY AND FREEZE WARNINGS ARE IN PLACE FOR THE LOWER DESERTS.
CONDITIONS WILL GRADUALLY WARM BY THE END OF THE WEEK AS WARMER AIR
MOVES INTO THE REGION FROM THE SOUTH.

&&

.DISCUSSION...
A WELL DEFINED AND INTENSIFYING PV ANOMALY HAS DEPRESSED INTO SRN
NEVADA CARVING OUT OF THE BASAL PORTION OF THE LONGWAVE SWRN CONUS
TROUGH. ALTHOUGH ISENTROPIC ANALYSIS INDICATES RATHER NEUTRAL
ASCENT...MID/HIGH LEVEL VORTICITY ADVECTION AHEAD OF THE SHORTWAVE
HAS BEEN MORE THAN SUFFICIENT LIFT TO PRODUCE RATHER EXTENSIVE CLOUD
COVER AT MULTIPLE LAYERS...AND AS LOW AS 10K FT OVER SERN CALIFORNIA
AND WRN ARIZONA. MODEL RH FORECASTS BETWEEN H7 AND H3 HAVE CAPTURED
THESE MULTI-LAYER FEATURES WELL...WITH PROGS INDICATING THE BULK OF
THE THICKER LAYERS ADVECTING THROUGH CNTRL (AND ESPECIALLY SRN)
ARIZONA AROUND MIDNIGHT BEFORE SHEARING EAST IN THE STRONG
DOWNSTREAM JET CORE AND LARGELY CLEARING THE FORECAST AREA.

EVEN AS THE THICKER CLOUD COVERAGE MOVES OUT OF THE CWA BY THE LATE
NIGHT HOURS...THE LARGE CONUNDRUM IS THE PRESENCE OF POCKETS OF MORE
CLOUD COVER SAMPLED UPSTREAM THAT WOULD CONCEIVABLY IMPACT LOW
TEMPERATURE FORECASTS ON A MORE LOCALIZED SCALE. BASED ON THE
CURRENT CLOUDS SERIOUSLY HAMPERING IN THE INITIAL NOCTURNAL
RADIATIONAL COOLING OVER THE WESTERN CWA...THE LIKELIHOOD OF COOLING
NEARLY STALLING THROUGH THE EASTERN PARTS OF THE FORECAST AREA IN
THE NEXT SEVERAL HOURS...AND POTENTIALLY MORE CLOUDS IMPACTING THE
REGION OVERNIGHT...HAVE MADE RATHER SIGNIFICANT REVISIONS TO BOTH
HOURLY TEMPERATURE TRENDS AND FORECAST LOWS.

STILL EXPECTING SUB-FREEZING LOWS OVER MARICOPA...GILA...AND LA PAZ
COUNTIES AS CURRENT TEMPERATURES ONLY NEED TO FALL 5F-10F TO REACH
THAT CRITERIA. HOWEVER...HAVE INCREASED LOWS IN THE YUMA AREA AS
WELL AS MUCH OF SERN CALIFORNIA TO NEAR AND ABOVE FREEZING LEVELS.
WILL KEEP FREEZE HEADLINES IN TACT...AS MANIPULATION NOW IS MORE AN
EXERCISE IN FUTILITY AND CONFUSION AS ALL PREPARATIONS HAVE ALREADY
BEEN MADE...AND TOMORROW NIGHT WILL LIKELY SEE EVEN COLDER
TEMPERATURES.

&&

.PREVIOUS DISCUSSION...
TONIGHT AND TUESDAY...
A VERY DRY AND COLD AIRMASS CONTINUED TO FLOW SOUTH FROM WESTERN
CANADA INTO OUR REGION...AND WILL CONTINUE THIS WAY THROUGH TUESDAY
MORNING. THIS EXTRAORDINARY COLD AIRMASS WILL CONTINUE TO PRODUCE
WIDESPREAD SUB-FREEZING TEMPERATURES ACROSS THE LOWER DESERTS FROM
SOUTHEAST CA TO SOUTH CENTRAL AZ THROUGH TUESDAY MORNING. THE ONLY
CAVEAT WILL BE SOME OVERNIGHT BREEZES MONDAY NIGHT/TUESDAY MORNING
THAT COULD KEEP MINIMUM TEMPS A FEW DEGREES HIGHER...ESPECIALLY
PORTIONS OF SOUTHEAST CA AND SOUTHWEST AZ. HOWEVER...THE MAGNITUDE
OF THE BREEZES ON THE EUROPEAN MODEL IS LOWER THAN THE GFS...SO
CONFIDENCE IS TOO LOW TO CANCEL THE FREEZE WARNING ON THE SOUTHEAST
CA AND SOUTHWEST AZ DESERTS FOR MONDAY NIGHT/TUESDAY MORNING.  IN
OTHER WORDS...THE FREEZE WARNING CONTINUES FOR ALL OUR DESERTS
THROUGH TUESDAY MORNING.

WEDNESDAY THROUGH SUNDAY...
THE COLD CANADIAN AIRMASS COVER THE REGION WILL FINALLY SHIFT EAST.
WEDNESDAY WILL BE A TRANSITION DAY OF MODEST WARMING...THEN
TEMPERATURES WILL WARM CLOSE TO NORMAL THURSDAY THROUGH SUNDAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...

HIGH CLOUDS WILL STREAM ACROSS CNTRL ARIZONA OVERNIGHT...WITH MOSTLY
CLEAR SKIES MONDAY. SFC WINDS WILL REMAIN LIGHT AND GENERALLY
FOLLOW THE TYPICAL DIURNAL DIRECTIONAL TRENDS.

SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL...AND
KBLH...

MID/HIGH CIGS WILL CLEAR THE TERMINAL SITES BY SUNDAY MORNING...WITH
CLEAR SKIES FOLLOWING INTO MONDAY AFTERNOON. GREATEST AVIATION
IMPACT WILL BE STRENGTHENING AND GUSTY NORTHERLY WINDS MONDAY. WINDS
IN THE 1500-2500FT LEVEL WILL FIRST BEGIN TO INCREASE AFTER
09Z/14...THOUGH SHOULD REMAIN BELOW LLWS CRITERIA. FURTHER
STRENGTHENING WILL OCCUR THROUGH THE POST-SUNRISE HOURS...AND
MECHANICAL MIXING WILL ALLOW HIGHER GUSTS TO REACH THE SFC BY LATE
MORNING. KBLH SHOULD EXPERIENCE THE HIGHEST GUSTS...POTENTIALLY
APPROACHING 30KT BY MID AFTERNOON.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...

...GUSTY NORTH WINDS AND LOW HUMIDITIES MAY SUPPORT ISOLATED
AREAS OF CRITICAL FIRE WEATHER CONDITIONS ALONG AND WEST OF THE
COLORADO RIVER VALLEY MONDAY AFTERNOON...

TUESDAY THROUGH SATURDAY...
A LARGE UPPER TROUGH OVER THE WESTERN STATES WITH EMBEDDED WEATHER
DISTURBANCES WILL KEEP COLD AND DRY AIR IN PLACE THROUGH EARLY WEEK.
ELEVATED NORTH TO NORTHEAST SURFACE WINDS WILL LINGER ACROSS THE
FIRE ZONES TUESDAY AND WEDNESDAY AS PACIFIC RIDGING TRANSITIONS OVER
THE AREA. A WARMING TREND ALONG WITH SLIGHTLY HIGHER HUMIDITIES WILL
COMMENCE WEDNESDAY THROUGH THE END OF THE WEEK...ALLOWING DAYTIME
TEMPERATURES TO RECOVER FROM THEIR WELL BELOW NORMAL READINGS
EARLIER IN THE WEEK.

&&

.CLIMATE...

RECORDS LOWS AND COLD MAXIMUM TEMPERATURES FOR MONDAY AND
TUESDAY...JANUARY 14TH AND 15TH IN PHOENIX.

DATE       RECORD LOW/DATE        RECORD COLD MAX/DATE
----       ---------------        --------------------
JAN 14     22 IN 1963             46 IN 2007
JAN 15     23 IN 1964             50 IN 1960...1949 AND 1917

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FREEZE WARNING UNTIL 9 AM MST TUESDAY AZZ020-023-026-027.

     FREEZE WARNING FROM 5 PM SUNDAY TO 9 AM MST TUESDAY AZZ025.

     HARD FREEZE WARNING UNTIL 9 AM MST TUESDAY AZZ022-028.

     HARD FREEZE WARNING UNTIL 5 PM MST MONDAY AZZ021.

     FREEZE WARNING FROM 5 PM MONDAY TO 9 AM MST TUESDAY AZZ021.

CA...FREEZE WARNING UNTIL 8 AM PST TUESDAY CAZ031>033.

&&

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...MO
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...MO
FIRE WEATHER...NOLTE
CLIMATE...MO