Area Forecast Discussion
Issued by NWS Phoenix, AZ

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000 FXUS65 KPSR 271129 AFDPSR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 429 AM MST FRI MAR 27 2015 .UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS... && .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... 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...MO CLIMATE...MO AVIATION....KUHLMAN FIRE WEATHER...KUHLMAN

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