AP-TX--PHX-TX Area Forecast Discussion, TX

000

FXUS65 KPSR 151229 CCA

AFDPSR

AREA FORECAST DISCUSSION...CORRECTED

NATIONAL WEATHER SERVICE PHOENIX AZ

530 AM MST WED JUL 15 2015

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

&&

.SYNOPSIS...

MOSTLY DRY CONDITIONS WILL CONTINUE FOR THE LOWER DESERT ELEVATIONS

WITH AFTERNOON SHOWERS MAINLY IN AFFECTING THE FOOTHILLS AND HIGHER

TERRAIN OF EASTERN ARIZONA. BY FRIDAY...MOISTURE LEVELS WILL RAMP UP

SIGNIFICANTLY AND BRING IN CLOUDINESS AND COOLER

TEMPERATURES...ALONG WITH A GOOD CHANCE FOR RAIN SHOWERS AND

THUNDERSTORMS OVER THE WEEKEND.

&&

.DISCUSSION...

DEBRIS CLOUDS WERE HOLDING OVER THE CORNERS OF MARICOPA COUNTY AND

ACROSS PORTIONS OF THE PINAL COUNTY THIS AM...WITH CONTINUED STORM

CLOUDS OUT EAST AND CLEAR SKIES FROM THE CO RIVER WESTWARD. SERIES

OF OUTFLOW INTRUSIONS INTO THE LOWER AZ DESERTS BOOSTED DEWPOINTS

LAST EVENING BACK INTO THE UPPER 50 TO LOW 60 RANGE...KEEPING

MORNING TEMPERATURES FAIRLY WARM WITH MANY SITES STILL IN THE UPPER

80S TO NEAR 90 AT 3 AM. MUCH DRIER CONDITIONS NOTED OUT WEST...WITH

SFC DEWPOINTS IN THE 30S AND 40S...AND EVEN DRIER ALOFT WITH 850MB

AND 700MB TDS 3C AND 0C RESPECTIVELY ON THE EVENING 1Y7/YPG BALLOON.

TWO AREAS OF STORM ACTIVITY CONTINUED OVERNIGHT AND ARE STILL FIRING

OFF PLENTY OF CG AND CLOUD FLASH LIGHTNING. THE FIRST LOCATED NEAR

SAFFORD AND THE MUCH LARGER...MORE ORGANIZED CONVECTIVE COMPLEX OVER

SONORA. EVENING ML/UL STREAMLINE ANALYSIS CONTINUES TO DEPICT A

SOMEWHAT STATIONARY IT IN THAT AREA...HELPING PERSIST THAT STORM

ACTIVITY THIS MORNING.

CONVECTIVE PICTURE LATER TODAY AND INTO THIS AFTN LOOKS SIMILAR TO

THE SET-UP FROM TUESDAY...WITH THE MOST FAVORABLE MOISTURE BOUNDARY

SUPPORTING LARGE AREAS OF STORMS ACROSS SOUTHEAST AND EASTERN AZ AND

POTENTIALLY SENDING SEVERAL OUTFLOWS DOWN INTO THE LOWER DESERTS.

THE INTERSECTION AND INTERACTION OF THOSE OUTFLOWS WILL LIKELY BE

THE INITIAL TRIGGERS FOR ANY SHOWERS/STORMS ACROSS THE LOWER DESERT

ELEVATIONS...INCLUDING THE I-8/I-10 CORRIDOR...GILA BEND AND THE

PHOENIX AREA. LOCAL AND REGIONAL HI-RES GUIDANCE TRIGGER CONVECTION

SOMETIME AROUND 15/21Z WITH SOME OF THE LARGER CONSOLIDATED OUTFLOWS

MOVING IN FROM THE SOUTHEAST POSSIBLY DURING THE NEW Z-DAY...OR

AFTER 5 PM LOCAL.

BY THE THURSDAY-FRIDAY TIMEFRAME THE PERSISTENT UPPER TROUGH THAT

HAS KEPT LESS THAN FAVORABLE SOUTHWESTERLY FLOW ALOFT AND HOSTED THE

MIGRATORY DRYLINE OVER THE SOUTH-CENTRAL AZ DESERTS...WILL

EVENTUALLY WEAKEN AND GIVE WAY TO A RETURN OF MORE SOUTHERLY FLOW

AROUND THE EXPANDING WESTERN PERIPHERY OF THE UL RIDGE. ALONG WITH A

RETURN OF MORE MONSOONALLY-ORIENTATED FLOW A SIGNIFICANT MOISTURE

SFC...COURTESY OF TROPICAL CYCLONE DOLORES...WILL TRANSITION INTO

THE AREA FROM THE SOUTH RESULTING THE SKIES CLOUDING UP AND

REMAINING MOSTLY CLOUDY TO OVERCAST BEGINNING DURING THE DAY FRIDAY

THROUGH THE COMING WEEKEND. MODEL FORECAST TRACKS FOR THE CIRCULATION

REMAIN MOSTLY CONSISTENT...SLIDING THE TC W-SW OF BAJA BUT

EVENTUALLY WORKING 1.5 TO 2 INCH PWAT READINGS INTO THE FORECAST

AREA OVER THE WEEKEND.

WHAT REMAINS THE CHALLENGE IN THE FORECAST WILL BE WHAT WILL BE

AVAILABLE TO WORK ON THAT MOISTURE SURFACE TO TRIGGER SHOWER AND

THUNDERSTORM ACTIVITY THROUGHOUT THE WEEKEND. GIVEN THE ORIGIN OF

THE MOISTURE AND WARM/STABLE ML SOUNDING TRACES...IT WOULD TAKE SFC

HEATING AS ID'D IN PREVIOUS DISCUSSIONS AND ADDITIONAL

DYNAMICS/FORCING IN THE FORM OF ADDITIONAL INVERTED TROUGHING TO

HELP TRIGGER STORM POTENTIAL. STILL...POPS FOR THE WKND WERE

GRADUALLY NUDGED UPWARD AS GEFS AND DETERMINISTIC FORECAST PARAMETERS

ALL POINT TO SOME PRECIP POTENTIAL FOR MOST CWA LOCALES THROUGHOUT

THE WEEKEND PERIOD. WHERE SOME OF THE FINER PRECIP DETAILS ARE STILL

FORTHCOMING...CONFIDENCE IS MODERATE TO HIGH OF A COOLER THAN NORMAL

WEEKEND. TEMPERATURES MAY STRUGGLE TO REACH THE CENTURY MARK UNDER

THE ANTICIPATED THICK SHIELD OF CLOUD COVER.

BY EARLY NEXT WEEK...A SWIFT MOVING UPPER TROUGH WILL SKIRT THROUGH

THE GREAT BASIN TRANSITIONING WINDS BACK OUT OF TYPICAL MONSOONAL

HEADINGS AND POTENTIALLY USHERING IN SOME DRYING TO SCOUR OUT THE

DEEPLY TROPICAL AIRMASS. 1000-500MB THICKNESSES GRADUALLY CLIMB AND

AIRMASS TEMPERATURES WILL BEGIN TO WARM...RETURNING FORECAST HIGHS IN

THE COMING WEEK BACK TO NEAR NORMAL READINGS.

&&

.AVIATION...

SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...

SOUTHWEST FLOW ALOFT WILL PERSIST FOR AT LEAST ANOTHER DAY AND

PRETTY MUCH CONFINE STORMS TO AREAS SOUTH AND EAST OF PHOENIX.

CANNOT RULE OUT ELY/SELY OUTFLOW WINDS MOVING INTO THE CENTRAL

DESERTS THIS EVENING...MAINLY AFTER 7 PM...BUT CONFIDENCE TOO LOW TO

MENTION IN THE TAFS AT THIS TIME. EXPECT MAINLY SCT MID/HI LEVEL

DEBRIS DECKS THIS MORNING WITH CLEARING DURING THE DAY. POSSIBLE TO

SEE MID/HIGH LEVEL DECKS SPREAD BACK INTO THE GREATER PHOENIX AREA

THIS EVENING SHOULD CONVECTION THREATEN THE LOWER DESERTS...BUT

SHOULD THIS OCCUR MOST BASES WOULD BE AOA 11K FEET.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...

SOUTHWEST FLOW ALOFT WILL KEEP SKIES GENLY CLEAR NEXT 24 HOURS.

WINDS TO FAVOR THE SOUTH AGAIN AT KBLH WITH SOME GUSTINESS POSSIBLE

DURING THE AFTERNOON AND EARLY EVENING. AT KIPL...WINDS LIKELY TO

BECOME VARIABLE OR SELY MOST OF THE DAY BUT RETURN TO THE WEST BY

AROUND 01Z THIS EVENING. AGAIN...THERE WILL BE POTENTIAL FOR GUSTY

CONDITIONS DURING THE EVENING WITH PEAKS TO 24KT POSSIBLE AT TIMES.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...

FRIDAY THROUGH TUESDAY...

A HURRICANE MOVING NORTHWEST OFF THE COAST OF BAJA CALIFORNIA WILL

SHED SIGNIFICANT TROPICAL MOISTURE WHICH IS EXPECTED TO MOVE BODILY

INLAND AND INTO ARIZONA AND SOUTHEAST CALIFORNIA. THIS WILL LEAD TO A

SHARP INCREASE IN HUMIDITY AS WELL AS HIGHLY ELEVATED CHANCES FOR

SHOWERS AND EMBEDDED THUNDERSTORMS EACH DAY WITH THE BEST RAIN

CHANCES ON THE WEEKEND. TEMPERATURES WILL LOWER MARKEDLY WITH

HIGHS OVER THE WEEKEND FALLING INTO THE 90S OR AROUND 100 DEGREES.

SOMEWHAT DRIER AND WARMED CONDITIONS ARE POSSIBLE MONDAY INTO

TUESDAY AS MOISTURE VALUES START TO FALL OFF. BREEZY TO LOCALLY WIND

SOUTH TO SOUTHWEST WINDS ARE EXPECTED FRIDAY ESPECIALLY OVER THE

WESTERN DESERTS...WITH WINDS TO GRADUALLY TAPER OFF OVER THE

WEEKEND.

&&

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS

ACCORDING TO STANDARD OPERATING PROCEDURES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...NOLTE

AVIATION...CB

FIRE WEATHER...HIRSCH/CB

Delivered by Weather Underground Inc. Wed Jul 15 2015 8:29AM EDT