Area Forecast Discussion
Issued by NWS Phoenix, AZ

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FXUS65 KPSR 282125
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
225 PM MST MON JUL 28 2014

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

&&

.SYNOPSIS...
THERE WILL BE A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS
THE FORECAST AREA THIS AFTERNOON AND EVENING...BEFORE DRIER AIR
MOVES INTO THE REGION TUESDAY THROUGH LATE WEEK. STORM CHANCES WILL
INCREASE AGAIN FRIDAY INTO THE WEEKEND AS MOISTURE MOVES BACK INTO
THE SOUTHWEST UNITED STATES.

&&

.DISCUSSION...
A GOOD DEAL OF THUNDERSTORM ACTIVITY HAS POPPED UP ACROSS NORTHERN
ARIZONA THIS AFTERNOON DUE TO A BROAD UPPER LEVEL CIRCULATION MOVING
NORTHWARD ACROSS SOUTHERN CALIFORNIA. VISIBLE SATELLITE IMAGERY ALSO
SHOWING PATCHES OF CUMULUS DEVELOPMENT ACROSS OUR CWA FROM WESTERN
MARICOPA COUNTY/GILA BEND AREA...WESTWARD ACROSS SE CALIFORNIA INTO
JOSHUA TREE NP. CONVECTION HAS BEEN SLOW TO INITIATE ACROSS OUR CWA
THIS AFTERNOON GIVEN THE LIGHTER WINDS ALOFT AND THE MORE SUBSIDENT
NATURE TO THE ATMOSPHERE. STILL...GIVEN THE AMOUNT OF PRECIPITABLE
WATER IN THE ATMOSPHERIC PROFILE...AND GOOD SURFACE HEATING...WE
WILL CONTINUE TO MAINTAIN SLIGHT CHANCES OF PRECIPITATION FOR SOME
AREAS OF OUR CWA INTO THE EVENING HOURS. THE BEST CHANCES...ALBEIT
SLIGHT WILL STILL BE ACROSS SOUTH-CENTRAL ARIZONA. PRECIPITATION
CHANCES QUICKLY DWINDLE THIS EVENING FOR SOUTHEAST CALIFORNIA...AS
ALL MODELS AGREE THAT UPPER LEVEL FLOW WILL BECOME WESTERLY AND
DRIER LATER TONIGHT.

TUESDAY THROUGH SUNDAY...A DRAMATIC DECREASE THE AMOUNT OF
CONVECTION ACROSS THE AREA...WITH THE FOCUS FOR ANY PRECIPITATION IN
THE MOUNTAINS EAST OF PHOENIX THROUGH THE MIDDLE OF THE WEEK. MEAN
BL MIXING RATIOS DROP TO AROUND 6 G/KG DURING THE MIDDLE PART OF THE
WEEK AND EVEN CLIMO POPS MAY END UP BEING TOO HIGH. WITH DRIER AIR
WORKING INTO THE AREA MID WEEK...TEMPS WILL LIKELY TAKE A RUN INTO
THE 105-109 RANGE ACROSS THE DESERTS. CONSEQUENTLY...THERE SHOULD BE
A SLIGHT DROP-OFF BY THE WEEKEND AS DEEPER MOISTURE MAKES ITS WAY
BACK INTO THE AREA. STILL ABOVE 100 BUT SOMEWHAT LOWER THAN THE MID
WEEK VALUES. MADE SLIGHT REDUCTIONS TO POPS ACROSS THE BOARD FROM
TUESDAY THROUGH THURSDAY BASED ON LATEST GUIDANCE WITH THE HIGHEST
VALUES DISPLACED WELL EAST OF THE DESERTS. THE MONSOON MOISTURE
WONT BE TERRIBLY FAR AWAY...WINDS PER THE TWO-THREE MOST RECENT
RUNS OF THE EUROPEAN AND GFS BRING INCREASED MIXING RATIOS BACK INTO
THE AREA FRIDAY AND ALMOST CERTAINLY BY THE WEEKEND. PRECIP CHANCES
ONCE AGAIN LOOK FAVORABLE FOR THE LATTER PORTIONS OF THE FORECAST
PERIOD ALTHOUGH ITS STILL DIFFICULT TO HIGHLIGHT ONE DAY VS ANOTHER
UNTIL WE GET A LITTLE CLOSER.



&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
MODEL GUIDANCE SUGGESTS THAT SHOWER AND THUNDERSTORM ACTIVITY WILL
BE LIMITED THIS EVENING...MAINLY FOCUSED ACROSS THE HIGHER TERRAIN
OUTSIDE OF THE PHOENIX AREA. HOWEVER...AN OUTFLOW BOUNDARY FROM
DISTANT CONVECTION WILL LIKELY RESULT IN A SHIFT TO EASTERLY WINDS
LATER THIS EVENING.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THERE IS A SLIGHT CHANCE OF A THUNDERSTORM AT KIPL LATE THIS
AFTERNOON AS ISOLATED CONVECTION ALONG THE BAJA SPINE PROPAGATES
INTO SOUTHEASTERN CA. OTHERWISE...NO AVIATION IMPACTS EXPECTED WITH
WINDS GENERALLY REMAINING LIGHT AND DIURNAL AT KIPL AND KBLH.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
DRIER THAN NORMAL CONDITIONS EXPECTED THROUGH THURSDAY. STORM
CHANCES WILL BE SLIGHT AND WILL BE LIMITED TO THE HIGHER TERRAIN OF
EASTERN ARIZONA. LATE IN THE WEEK AND OVER THE WEEKEND...AN
INCREASE IN MOISTURE AND ASSOCIATED HUMIDITIES IS ANTICIPATED AND
STORM CHANCES...THOUGH SLIGHT...EXPAND TO THE LOWER ELEVATIONS. HIGH
TEMPERATURES TREND DOWNWARD AS WELL.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...MEYERS/LEINS
AVIATION...HIRSCH
FIRE WEATHER...HIRSCH/AJ







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