Area Forecast Discussion
Issued by NWS Phoenix, AZ

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS65 KPSR 201215
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
515 AM MST SAT DEC 20 2014

.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS...

&&

.SYNOPSIS...
HIGH PRESSURE OFF THE WEST COAST WILL RESULT IN NEAR NORMAL
TEMPERATURES WITH VARYING AMOUNTS OF HIGH CLOUDS THROUGH MID WEEK. A
FAST MOVING STORM SYSTEM WILL MOVE THROUGH THE FOUR CORNERS LATER
THIS WEEK BUT SHOULD ONLY RESULT IN SLIGHTLY COOLER TEMPERATURES AND
INCREASED CLOUDINESS. DRY WEATHER IS EXPECTED NEXT WEEKEND WITH
BELOW NORMAL TEMPS.

&&

.DISCUSSION...
ONSHORE FLOW ACROSS NORTHERN CALIFORNIA AND THE ASSOCIATED 300-400MB
JET STREAK HAS RESULTED IN QUITE A BIT OF HIGH CLOUD COVER ACROSS
THE REGION THIS MORNING. INITIAL BAND OF CLOUDS WAS POSITIONED OVER
CENTRAL ARIZONA AS OF 08Z WITH CLEARING ACROSS SOUTHEAST
CALIFORNIA...THEN ADDITIONAL HIGH CLOUDINESS OVER CENTRAL
CALIFORNIA. SO FAR THE HIGH CLOUD COVER HAS HAD A NEGLIGIBLE IMPACT
ON TEMPERATURES AS READINGS AS OF 08Z WERE ON PAR WITH READINGS THE
PAST SEVERAL MORNINGS. MOST DESERT LOCALES WERE IN THE LOW/MID 40S
WITH LIGHT WINDS. MUCH LIKE YESTERDAY...NO FOG HAS SHOWN UP AT ANY
OF THE ASOSS OR ON ANY WEBCAMS QUITE YET BUT WITH ELEVATED
DEWPOINTS AND STEADILY DECREASING DEWPOINT DEPRESSIONS...I WILL
LEAVE A MENTION OF FOG IN THE LOCATIONS THAT SAW IT EARLY FRIDAY
MORNING.

NOT MANY CHANGES TO FORECAST THINKING FOR MUCH OF THE UPCOMING WEEK.
ONCE THE TROUGH AND ASSOCIATED ONSHORE FLOW MOVES THROUGH NORTHERN
CALIFORNIA TONIGHT...RIDGING WILL STRENGTHEN OFF THE SOUTHERN
CALIFORNIA COAST WITH ANOMALOUSLY HIGH H5 HEIGHTS FORECAST TO REMAIN
IN PLACE THROUGH AT LEAST WEDNESDAY. THIS WILL RESULT IN VARYING
AMOUNTS OF HIGH CLOUDS AND ABOVE NORMAL TEMPERATURES. A BLEND OF THE
BEST PERFORMING BIAS CORRECTED GUIDANCE SUGGESTS DAILY HIGHS FROM
65-70 EACH DAY /SLIGHTLY WARMER AROUND YUMA AND EL CENTRO/ WITH NEAR
NORMAL LOWS IN THE MID 40S.

ATTENTION TURNS TO CHRISTMAS DAY AS THERE ARE ONCE AGAIN SOME
DIFFERENCES BETWEEN THE ECMWF AND GFS MODELS. BOTH INDICATE
TROUGHING BUT THE ECMWF HAS ONCE AGAIN RETURNED TO ITS SOLUTION OF A
CLOSED CIRCULATION OVER ARIZONA WITH PRECIP DEVELOPING ACROSS THE
HIGHER TERRAIN NORTH/EAST OF PHOENIX. PARALLEL 13KM GFS IS A BIT
DEEPER WITH THE TROUGH WHEN COMPARED TO THE OPERATIONAL GFS BUT IS
LACKING MOISTURE AS IT MOVES THROUGH THE REGION. ENSEMBLES REMAIN
STEADY AND INDICATE THE OPERATIONAL GFS-TYPE SOLUTION WILL PREVAIL
BUT NOT WANTING TO DISCOUNT THE ECMWF /AND 13KM GFS/ ENTIRELY...I
INTRODUCED VERY LOW END DOUBLE DIGIT POPS NORTH/EAST OF PHOENIX ON
THURSDAY ALONG WITH SLIGHTLY COOLER TEMPERATURES. IMPACTS LOOK
MINIMAL BUT WILL NEED TO KEEP MONITORING SUBSEQUENT MODEL RUNS TO
SEE HOW THEY TREND.  REGARDLESS...A RETURN TO NORTHWESTERLY FLOW
LOOKS LIKELY LATE NEXT WEEK INTO THE WEEKEND.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...AND
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

PASSING MID TO HIGH LEVEL CLOUDS EXPECTED AT PERIODS THROUGH THE
WEEKEND...GENERATING BKN TO OVC SKIES AND REMAINING MOSTLY ABOVE
20KFT. SFC WINDS WILL REMAIN LIGHT...GNLY 8KTS OR LESS...AND FOLLOW
TYPICAL DIURNAL HEADINGS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
UPPER LEVEL RIDGING WILL DOMINATE THROUGH A GOOD PORTION...IF NOT
ALL...OF NEXT WEEK WITH ABOVE NORMAL TEMPERATURES AND SLIGHTLY DRIER
CONDITIONS. HUMIDITIES WILL REMAIN FAIRLY HIGH THROUGH THE PERIOD
WITH MINIMUM VALUES STAYING ABOVE 25 PERCENT. WINDS WILL BE LIGHT
FOR THE MOST PART THROUGH WEDNESDAY WITH THE EXCEPTION OF OCCASIONAL
AFTERNOON BREEZINESS. A PACIFIC LOW PRESSURE SYSTEM MAY AFFECT THE
REGION LATE NEXT WEEK BRINGING THE POTENTIAL FOR GUSTY
WINDS...COOLER TEMPERATURES...AND SLIGHT CHANCES FOR PRECIPITATION
ACROSS HIGHER TERRAIN AREAS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...LEINS
AVIATION...NOLTE/KUHLMAN
FIRE WEATHER...KUHLMAN







USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.