000
FXUS65 KTWC 020957
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
257 AM MST MON MAR 2 2015

.SYNOPSIS...A STRONG LOW PRESSURE SYSTEM NEAR CENTRAL AND SOUTHERN
CALIFORNIA WILL BRING WINDY CONDITIONS AS WELL AS PERIODS OF VALLEY
RAIN AND MOUNTAIN SNOW BY MID DAY TODAY THROUGH TONIGHT.
PRECIPITATION CHANCES WILL LESSEN CONSIDERABLY FOR MIDWEEK WITH DRY
CONDITIONS AREAWIDE AND WARMER TEMPERATURES BY THE END OF THE WEEK.

&&

.DISCUSSION...WATER VAPOR IMAGERY SHOWS THE UPPER LOW EXPECTED TO
BRING WIDESPREAD VALLEY RAIN AND MOUNTAIN SNOW TO THE REGION IS
CURRENTLY SPINNING JUST OFFSHORE OF THE EXTREME SOUTHERN CALIFORNIA
COAST. PLENTY OF MOISTURE IS STREAMING TO THE NORTHEAST AHEAD OF
THIS SYSTEM ACROSS MUCH OF THE DESERT SOUTHWEST. SATELLITE DERIVED
BLENDED TOTAL PRECIPITABLE WATER IMAGERY SHOWS VALUES RANGING FROM
NEAR A HALF INCH ACROSS THE EXTREME EASTERN PARTS OF MY FORECAST
AREA NEAR THE NEW MEXICO BORDER...TO NEAR AN INCH AT YUMA. IN
ADDITION...PW`S OF NEAR 1.4 INCHES CAN BE SEEN OVER SOUTHERN SONORA
MEXICO. THE LATEST RADAR MOSAIC LOOP SHOWS NUMEROUS SHOWERS
SPREADING NORTHWARD...GENERALLY ALONG THE COLORADO RIVER BASIN AND
EXTENDING INTO SOUTHERN NEVADA. ISOLATED TO SCATTERED SHOWERS CAN BE
SEEN NORTH OF THE PHOENIX AREA FROM AROUND NEW RIVER TO FLAGSTAFF.
CLOSER TO HOME...MY FORECAST AREA REMAINS VOID OF PRECIPITATION
ECHOES AT THIS TIME.

MODELS INDICATE THAT THE LOW WILL LIFT TO THE EAST NORTHEAST TODAY
WITH THE BATCH OF SHOWERS CURRENTLY SEEN ACROSS WESTERN ARIZONA
SWEEPING THROUGH THE STATE THIS AFTERNOON AND THROUGHOUT THE
EVENING. INHERITED A COUPLE OF WINTER WEATHER HEADLINES...INCLUDING
A WINTER STORM WARNING FOR THE WHITE MOUNTAINS OF GRAHAM AND
GREENLEE COUNTIES AND THE PINALENO AND GALIURO MOUNTAINS OF
SOUTHWEST AND SOUTH CENTRAL GRAHAM COUNTY. IN ADDITION...A WINTER
WEATHER ADVISORY IS IN EFFECT FOR THE SANTA CATALINA AND RINCON
MOUNTAINS OF EASTERN PIMA COUNTY ABOVE 6500 FEET. THESE WINTER
WEATHER PRODUCTS TAKE EFFECT AT 11 AM MST THIS MORNING THROUGH 1 AM
MST TUESDAY. SNOW TOTALS FOR THE WHITE MOUNTAINS...PINALENO AND
GALIURO`S RANGING FROM 10 TO 14 INCHES...WITH AMOUNTS FOR THE
CATALINAS AND RINCONS RANGING FROM 6 TO 8 INCHES. VALLEY RAINFALL
AMOUNTS EXPECTED TO RANGE FROM 0.25 TO 0.60 INCHES...WITH ISOLATED
AMOUNTS AROUND 0.75 INCHES...ESPECIALLY TO THE NORTH.

WIND WILL BE A CONCERN FOR TODAY WITH BREEZY TO WINDY CONDITIONS
AREA WIDE...WITH THE STRONGEST WINDS ACROSS MUCH OF SANTA CRUZ...
COCHISE AND SOUTHEAST PIMA COUNTY. FOR NOW IT LOOKS LIKE WINDS
SHOULD REMAIN JUST BELOW ADVISORY CONDITIONS FOR ELEVATIONS BELOW
5000 FEET. HOWEVER...FOR ELEVATIONS ABOVE 5000 FEET A WIND ADVISORY
WILL BE NEEDED SINCE SUSTAINED WINDS OF 30 TO 40 MPH WITH GUSTS TO
AROUND 50 TO 55 MPH WILL OCCUR OVER THE HIGHER TERRAIN.

ONCE THIS SYSTEM MOVES TO THE EAST A SECONDARY SYSTEM MOVING ACROSS
ARIZONA AND NORTHERN MEXICO WILL KEEP A SMALL THREAT FOR SHOWERS IN
THE FORECAST FOR TUESDAY THROUGH WEDNESDAY BEFORE DRY WEATHER
RETURNS LATE IN THE WEEK AND INTO THE WEEKEND AS HIGH PRESSURE
BUILDS ACROSS THE WEST COAST AND DRY NORTH TO NORTHWEST WINDS
PREVAIL ACROSS THE SOUTHWEST.

FOR TUCSON...HIGH TEMPERATURES GENERALLY 6 TO 10 DEGS BELOW NORMAL
TODAY THROUGH THURSDAY...BUT THE COOLEST DAYS WILL OCCUR TUESDAY AND
WEDNESDAY. NEAR NORMAL HIGHS FOR FRIDAY...THEN SEVERAL DEGREES ABOVE
NORMAL FOR THE WEEKEND. LOW TEMPS AROUND 3 TO 5 DEGS BELOW NORMAL
TUESDAY THROUGH THURSDAY MORNINGS...THEN NEAR NORMAL
FRIDAY...FOLLOWED BY LOWS 2 TO 4 DEGS ABOVE NORMAL FOR THE WEEKEND.

&&

.AVIATION...VALID THRU 03/12Z.
AN APPROACHING STORM SYSTEM WILL BE IMPACTING THE AREA THRU THIS
EVENING.  EXPECT SCT CUMULUS NEAR 4-6K FT AGL WITH BKN-OVC LAYERS
ABV THROUGH 25K FT...THEN AFT 02/18Z BECOMING BKN-OVC 4-6K FT WITH
MULTIPLE LAYERS ABV AND IFR/MVFR CONDS OVER MTNS AND NEAR SHOWERS.
ISOLD SHOWERS THIS MORNING WILL BECOME WIDESPREAD THIS AFTERNOON.
CLOUDS AND SHOWERS DIMINISHING FROM THE WEST BEHIND THE COLD FRONT
WHICH WILL BE NEAR KTUS 02/23Z AND KDUG NEAR 03/05Z.  SFC WINDS S
8-16 KTS THEN INCREASING TO 15-25 KTS WITH HIGHER GUSTS TO 40 KTS IN
ADVANCE OF APPROACHING COLD FRONT.  STRONG SOUTHERLY JET TODAY WITH
WINDS 30-50 KTS 5-10K FT MSL.  AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.

&&

.FIRE WEATHER...A SLOWLY APPROACHING STORM SYSTEM GENERATE STRONG
WINDS TODAY INTO THE EARLY EVENING...ESPECIALLY ACROSS THE
MOUNTAINS.  WINDS WILL EASE BEHIND THE COLD FRONT WHICH WILL BE NEAR
TUCSON AROUND 4 PM THIS AFTERNOON AND THEN MOVE INTO NEW MEXICO
AROUND 10 PM.  A FEW LIGHT SHOWERS ARE EXPECTED THIS MORNING THEN
BECOMING WIDESPREAD THIS AFTERNOON.  THE SHOWERS WILL DIMINISH
BEHIND THE COLD FRONT.  THEN WITH AN UPPER LEVEL LOW IN THE AREA
EXPECT VARIABLE CLOUDS AND A CHANCE OF SHOWERS NOW AND AGAIN THROUGH
WEDNESDAY.  DRY AND WARMER THURSDAY ONWARD.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
     WINTER STORM WARNING 11 AM MST THIS MORNING TO 1 AM MST
     TUESDAY ABOVE 6500 FEET FOR AZZ510-511.

     WINTER WEATHER ADVISORY 11 AM MST THIS MORNING TO 1 AM MST
     TUESDAY ABOVE 6500 FEET FOR AZZ514.

     WIND ADVISORY UNTIL 8 PM MST THIS EVENING ABOVE 5000 FEET FOR
     AZZ512>515.

&&

$$

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