Area Forecast Discussion
Issued by NWS Phoenix, AZ

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000
FXUS65 KPSR 271548
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
850 AM MST FRI MAR 27 2015

&&

.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL LEAD TO AFTERNOON TEMPERATURES
REACHING THE LOWER AND MIDDLE 90S THROUGH THE WEEKEND. AN AREA OF
WEAK LOW PRESSURE WILL MOVE INTO THE SOUTHWEST EARLY NEXT
WEEK...BRINGING INCREASED CLOUDINESS AND SLIGHTLY COOLER
TEMPERATURES. HOWEVER...TEMPERATURES WILL STILL REMAIN WELL ABOVE
NORMAL NEXT WEEK.

&&

.DISCUSSION... AFTER A VERY WARM AFTERNOON YESTERDAY...WHICH SAW
HIGHS NEAR...OR SLIGHTLY ABOVE 90 DEGREES AT MANY LOWER DESERT
LOCATIONS...CLEAR SKIES AND A VERY DRY AIRMASS ALLOWED TEMPERATURES
TO FALL SHARPLY LAST NIGHT AND EARLY THIS MORNING AT MANY RURAL
LOCATIONS ACROSS SOUTH CENTRAL ARIZONA. SOME OF THE COOLER
LOCATIONS...SUCH AS CASA GRANDE...COOLIDGE...AND THE MORE REMOTE
AREAS OF THE SE VALLEY SAW LOWS FALL INTO THE LOW 50S...ALMOST 40
DEGREES BELOW YESTERDAY/S HIGHS. TODAY STILL LOOKS LIKE IT WILL BE
EVEN WARMER THEN YESTERDAY...WITH 500MB HEIGHTS NEAR 585DM AND 850MB
TEMPS IN THE 19-22C RANGE SUPPORTING HIGHS IN THE MID TO UPPER 90S
ACROSS THE LOWER DESERTS. THUS...OTHER THAN SOME MINOR ADJUSTMENTS
TO REFLECT CURRENT HOURLY TRENDS IN THE TEMP/DEWPOINT/WIND
GRIDS...INHERITED FORECAST PRODUCTS ARE LOOKING VERY GOOD...AND NO
UPDATES ARE PLANNED.

&&

.PREVIOUS DISCUSSION... NORTH AMERICAN PATTERN AMPLIFICATION HAS
BECOME MAXIMIZED EARLY THIS MORNING AS A PERVASIVE DRY ANTI-CYCLONIC
CIRCULATION CENTER ESTABLISHES ITSELF OVER SRN NEVADA PER WV
IMAGERY. 00Z REGIONAL SOUNDING DATA MEASURED H5 HEIGHTS IN A 582-
584DM RANGE WITH THE FORECAST AREA ALREADY WELL WITHIN THE GRIPS OF
NORTHEASTERLY FLOW ALOFT AND LARGE SCALE SUBSIDENCE. FORECAST
CONFIDENCE THROUGH THE WEEKEND REMAINS EXCELLENT WITH ALL MODEL
SUITES SUGGESTING H5 HEIGHTS FREQUENTLY TOUCHING 585DM BEFORE
DAMPENING SOMEWHAT SUNDAY IN RESPONSE TO A WEAK SHORTWAVE EJECTING
EAST FROM ITS CURRENT LOCATION NEAR 27N 140W. BOTTOM LINE IS HIGH
TEMPERATURES IN THE LOWER AND MIDDLE 90S WILL BE COMMON THE NEXT
SEVERAL DAYS (EVEN A FEW LOCATIONS FLIRTING WITH 100 DEGREES) LIKELY
COMING CLOSE TO OR ECLIPSING RECORD HIGHS (SEE CLIMATE SECTION
BELOW).

MEDIUM RANGE MODELS ARE GENERALLY CONVERGING ON A SOLUTION EARLY
NEXT WEEK PREVIOUSLY OFFERED BY THE ENSEMBLE MEAN AND ALREADY
ACCEPTED IN THE FORECAST PROCESS. A WEAK NEGATIVE HEIGHT ANOMALY
WILL PROPAGATE FROM THE EAST PACIFIC THROUGH NRN SONORA MONDAY
SPREADING MOISTURE ABOVE THE H7 LAYER INLAND. THE OPERATIONAL GFS
HAS TRENDED LESS INTENSE WITH THIS SHORTWAVE WHILE THE ECMWF
INCORPORATES BETTER CYCLONIC DEFINITION. REGARDLESS...WITH DEEP
BOUNDARY LAYER MIXING RATIOS BARELY REACHING 4 G/KG...LIMITED
MIDLEVEL LAPSE RATES...NOTABLE CINH...AND SYNOPTIC SCALE ASCENT WELL
REMOVED FROM THE CWA...CHANCES FOR ANY PRECIPITATION WITHIN THE
FORECAST AREA BOUNDS ARE MINIMAL. HIGHEST ENSEMBLE PROBABILITIES AND
CONCEPTUAL MODELS SUGGEST SHOWERS DEVELOPING OVER THE WHITE
MOUNTAINS INTO FAR SERN ARIZONA...BLOSSOMING MORE SO THROUGH SRN NEW
MEXICO AND SWRN TEXAS MONDAY NIGHT AND TUESDAY.

THE FLOW PATTERN FOR THE MAJORITY OF NEXT WEEK STILL APPEARS TO
REMAIN IN A QUASI-ZONAL STATE WITH A COUPLE NOTABLE SHORTWAVES
PROGRESSING THROUGH UTAH/COLORADO. AS A RESULT...SUBSEQUENT POST
FRONTAL SFC PRESSURE RISES OVER THE GREAT BASIN WILL PERIODICALLY
CAUSE AN INCREASED GRADIENT AND GUSTY WINDS OVER RIDGE TOPS AND DOWN
THE LOWER COLORADO RIVER VALLEY. DETAILS WITH RESPECT TO MAGNITUDE
AND TEMPORAL EXTENT OF STRONGER WIND GUSTS ARE STILL
LIMITED...THOUGH DIRECT IMPACTS AND THOSE ON TEMPERATURES WILL
CERTAINLY BE POSSIBLE. NEVERTHELESS...TEMPERATURE ANOMALIES ON THE
ORDER OF 5F-10F ABOVE NORMAL STILL APPEAR LIKELY FOR THE MAJORITY
(IF NOT TOTALITY) OF NEXT WEEK.

&&

.CLIMATE...

RECORD HIGHS THIS WEEKEND...

CITY         MARCH 28      MARCH 29
----         --------      --------
PHOENIX     95 IN 1986     95 IN 1971
YUMA        97 IN 1893    100 IN 1879

&&

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

STRONG HIGH PRESSURE OVER THE REGION WILL RESULT IN CONTINUED CLEAR
SKIES AND LIGHT WINDS. WIND DIRECTIONS WILL FOR THE MOST PART FOLLOW
TYPICAL DIURNAL SWINGS...BUT QUITE A GOOD AMOUNT OF VARIABILITY IS
LIKELY. NO AVIATION IMPACTS THROUGH AT LEAST SATURDAY.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
SUNDAY THROUGH THURSDAY...

ABNORMALLY WARM TEMPERATURES AND LOW HUMIDITIES WILL BE SEEN THROUGH
THE PERIOD UNDER PERSISTENT HIGH PRESSURE ALOFT. HIGH TEMPERATURES
ACROSS THE DESERTS SHOULD REACH INTO THE LOW TO MID 90S FOR SUNDAY
THROUGH TUESDAY...BEFORE COOLING SLIGHTLY STARTING WEDNESDAY.
MINIMUM HUMIDITIES ACROSS THE DESERTS WILL DIP TO BETWEEN 6-11
PERCENT EACH AFTERNOON. WINDS WILL REMAIN FAIRLY LIGHT OVERALL...BUT
AFTERNOON BREEZINESS IS POSSIBLE EACH DAY. HIGHER WIND SPEEDS ARE
LIKELY ON TUESDAY AND AGAIN ON THURSDAY WITH AFTERNOON GUSTS
APPROACHING 20-25 MPH. NO BIG CONCERNS AS FAR AS MEETING CRITICAL
FIRE WEATHER THRESHOLDS ON ANY PARTICULAR DAY AS WINDS WILL REMAIN
WELL BELOW THRESHOLDS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.

&&

$$

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

DISCUSSION...PERCHA/MO
CLIMATE...MO
AVIATION....KUHLMAN
FIRE WEATHER...KUHLMAN


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