Area Forecast Discussion
Issued by NWS Phoenix, AZ

Home | 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 271736
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1035 AM MST TUE JAN 27 2015


.SYNOPSIS...
A LOW PRESSURE SYSTEM EXITING THE REGION WILL BRING A FEW LINGERING
SHOWERS TO HIGH TERRAIN AREAS MAINLY BEFORE NOON. HIGH PRESSURE WILL
BRIEFLY TAKE OVER ALLOWING FOR A RETURN TO WARMER WEATHER THROUGH
THURSDAY. ANOTHER LOW PRESSURE SYSTEM WILL BRING ADDITIONAL MOISTURE
AND RENEWED HIGHER CHANCES FOR PRECIPITATION THURSDAY NIGHT THROUGH
POSSIBLY SATURDAY.

&&

.DISCUSSION...
LAST ROUND OF SHOWERS FOR TODAY NOW MOVING THROUGH FAR NORTHEAST
MARICOPA COUNTY AND SOUTHERN GILA COUNTY. HOWEVER...SOME ISOLATED
VERY WEAK ECHOES HAVE REDEVELOPED OVER CENTRAL PIMA COUNTY. WITH THE
MAIN UPPER TROUGH AXIS CONTINUING TO MOVE NORTHWARD...IT WILL BE
HARDER FOR THOSE PIMA COUNTY SHOWERS TO SUSTAIN THEMSELVES AND THUS
WILL HOLD OFF ON INTRODUCING POPS FOR THE AFTERNOON OVER PINAL/NE
MARICOPA COUNTIES...JUST SOME LINGERING SLIGHT CHANCES OVER SOUTHERN
GILA. SATELLITE IMAGERY SHOWS LINGERING FOG/STRATUS OVER PORTIONS OF
SOUTHEAST CALIFORNIA...MAINLY EAST OVER RIVERSIDE COUNTY WEST OF
BLYTHE WHERE WE HAVE NO SURFACE OBS. THIS SHOULD BREAK UP BY 19Z.
NEXT SYSTEM TO AFFECT OUR AREA WILL BE APPROACHING FROM FAIRLY LOW
LATITUDES AS THIS ONE HAS BUT WILL STALL OUT OVER THE SOUTHWEST AND
WEAKEN BEFORE BEING PUSHED BACK SOUTH ON SUNDAY. WINDOW OF PRECIP
OPPORTUNITY WITH THIS NEXT SYSTEM LOOKS TO BE THURSDAY NIGHT THROUGH
SATURDAY WITH THE MAIN EMPHASIS BEING LATE THURSDAY NIGHT THROUGH
FRIDAY. MORE LATER.

&&

.PREVIOUS DISCUSSION ISSUED 305 AM MST/205 AM PST...
THE UPPER LOW CENTER CONTINUES TO MOVE NORTHWARD ALONG THE
CALIFORNIA COASTLINE WITH A TRAILING TROUGH AXIS MOVING NORTHWARD
THROUGH CENTRAL ARIZONA AND SOUTHEAST ARIZONA. CURRENT WATER VAPOR
IMAGERY SHOWS DRIER AIR WORKING INTO ARIZONA FROM THE SOUTH AND THIS
WILL EVENTUALLY ALLOW FOR SOME GRADUAL CLEARING SKIES TODAY AND THE
END OF ANY RAIN CHANCES BY EARLY AFTERNOON. LOW LEVEL MOISTURE WILL
STAY IN PLACE AT LEAST INTO WEDNESDAY...BUT ANY LOW CLOUDS TODAY
SHOULD CLEAR OUT BY EARLY TONIGHT.

WEDNESDAY LOOKS TO BE THE MOST PLEASANT WEATHER DAY OF THE WEEK AS
WE SEE A RETURN TO WARMER TEMPERATURES AND MOSTLY CLEAR SKIES UNDER
RIDGING ALOFT. HOWEVER...THE NEXT WEATHER SYSTEM MOVING ACROSS THE
PACIFIC WEST OF BAJA WILL START TO STREAM IN MOISTURE IN THE MID AND
UPPER LEVELS BY LATE WEDNESDAY AND ESPECIALLY BY EARLY THURSDAY.
THIS WILL LEAD TO A FAIRLY THICK CLOUD DECK DEVELOPING FOR THURSDAY
AND A FEW DEGREE DECREASE IN HIGH TEMPERATURES...BUT WARMER
OVERNIGHT LOWS FOR WEDNESDAY NIGHT AND THURSDAY NIGHT.

MODELS HAVE BEEN FAIRLY CONSISTENT THE LAST DAY OR SO WITH THIS NEXT
SYSTEM BRINGING IN THE DEEPEST MOISTURE BY MID DAY THURSDAY WITH THE
OPEN WAVE NEARING THE SOUTHWESTERN UNITED STATES. DYNAMICS WILL NOT
BE VERY IMPRESSIVE OVERALL DUE TO WEAKENING JET SUPPORT...BUT THE
TROUGH DOES DEEPEN BY THURSDAY NIGHT AS IT BECOMES MORE NEUTRALLY
TILTED. THE MAIN FORCING TO SUPPORT PRECIPITATION WILL BE A BROAD
ISENTROPIC UPGLIDE SETUP WHICH WILL MOSTLY RESIDE ACROSS THE EASTERN
HALF OF ARIZONA STARTING THURSDAY AFTERNOON AND LIKELY LASTING
THROUGH FRIDAY NIGHT. THIS TROUGH SHOULD TAP INTO SOME SUB-TROPICAL
MOISTURE OVER THE NEXT COUPLE DAYS WITH SOME OF THAT MOISTURE MAKING
ITS WAY INTO OUR AREA FOR THURSDAY NIGHT AND FRIDAY. PRECIPITABLE
WATER VALUES ARE EXPECTED TO REACH NEAR ONE INCH DURING THAT TIME.

MODEL QPF AMOUNTS FROM PHOENIX EASTWARD SEEM SOMEWHAT HIGH GIVEN THE
WEAK DYNAMICS...BUT WITH DECENT RAIN CHANCES OVER ROUGHLY A 36 HOUR
PERIOD...CAN/T RULE OUT AREAS RECEIVING A STORM TOTAL OF A HALF TO
ONE INCH. HAVE INCREASED POPS FOR THURSDAY EVENING INTO THE LIKELY
CATEGORY TO THE EAST OF PHOENIX AS BOTH THE GFS AND EUROPEAN SUGGEST
A SLIGHTLY EARLIER ONSET. AM DEFINITELY NOT ANTICIPATING A
PERSISTENT RAIN OVER THE 36 HOUR PERIOD...BUT MORE ALONG THE LINES
OF INITIAL SCATTERED SHOWERS EARLY THURSDAY NIGHT WITH BEST CHANCES
OF STEADY RAIN DURING THE DAYTIME HOURS ON FRIDAY. THIS STEADY RAIN
WILL KEEP TEMPERATURES FROM RISING MUCH AT ALL ON FRIDAY
ACROSS SOUTH-CENTRAL ARIZONA AND WOULD NOT BE SURPRISED IF HIGHS
STRUGGLE TO BREAK 60 DEGREES IN SOME AREAS. FOR NOW...AREAS ACROSS
FAR SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA SHOULD BE SPARED FROM
SEEING MUCH IF ANY RAINFALL AT ALL AND THUS WILL SEE TEMPERATURES
MORE TOWARD NORMAL.

CONFIDENCE STARTS TO DIMINISH HEADING INTO THE WEEKEND AS MODELS
DIFFER SOMEWHAT ON WHEN TO SHIFT THE UPPER LOW TO THE SOUTHEAST AND
HOW QUICKLY DRY AIR SLIDES IN FROM THE NORTHWEST. THE GENERAL
CONSENSUS SHOWS THE LOW CENTER SHIFTING INTO NORTHERN MEXICO BY
SATURDAY AFTERNOON WITH A RIDGE AXIS AND DRIER AIR ENTERING
NORTHWEST ARIZONA FROM THE GREAT BASIN. SHOULD SEE SOME LINGERING
RAIN CHANCES ON SATURDAY...BUT IF THIS SOLUTION HOLDS TRUE...MOST
RAIN WILL MOVE OUT OF OUR AREA BY LATE EVENING SATURDAY. SUNDAY
LOOKS TO BE A DRY DAY WITH TEMPERATURES RISING BACK TO NEAR NORMAL
AS AN UPPER LEVEL RIDGE MOVES IN ACROSS THE STATE. WITH THE UPPER
RIDGE TAKING OVER FOR EARLY NEXT WEEK...WILL LIKELY SEE CONTINUED
DRY CONDITIONS AND HIGH TEMPERATURES BACK INTO THE 70S.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...
COPIOUS AMOUNTS OF LOW LEVEL MOISTURE WILL KEEP CIGS BETWEEN 6-7
THSD AGL THROUGH 20-21Z. FURTHER AFTN HEATING WILL BREAK CIGS TO SCT
6-7 THSD AGL AFTER 21Z. LGT AND VRBL WND AT LEAST THROUGH 03Z WED.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
THROUGH 20Z TUE...SCT TO BKN BTWN 3-5 THSD AGL. FURTHER AFTN HEATING
WILL BREAK CIGS TO SCT 5-6 THSD AGL AFTER 21Z. LGT AND VRB WND AT
LEAST THROUGH 03Z WED.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
ABOVE NORMAL TEMPERATURES AND RELATIVELY MOIST CONDITIONS WILL
PREVAIL THURSDAY AS A RIDGE PREDOMINATES ACROSS MEXICO. ANOTHER LOW
PRESSURE SYSTEM WILL RESULT IN INCREASING RAIN CHANCES AND
COOLER TEMPERATURES THURSDAY NIGHT THROUGH SATURDAY. A WARMING AND
DRYING TREND IS EXPECTED SUNDAY/MONDAY AS A RIDGE BUILDS ACROSS
CALIFORNIA.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...AJ
PREVIOUS DISCUSSION...KUHLMAN
AVIATION...VASQUEZ
FIRE WEATHER...HIRSCH





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