Blowing Dust Advisory 1, NWS Tucson, AZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
420 PM MST SUN JAN 31 2016

.SYNOPSIS...EXPECT WIDESPREAD VALLEY RAIN...MOUNTAIN SNOW AND VERY
STRONG GUSTY WINDS TONIGHT INTO MONDAY AS A FAST MOVING STORM SYSTEM
MOVES EASTWARD ACROSS THE AREA. A CHANCE OF SNOW SHOWERS CONTINUES
MAINLY ACROSS THE WHITE MOUNTAINS MONDAY NIGHT INTO TUESDAY. MUCH
COLDER TEMPERATURES WILL ALSO OCCUR MONDAY INTO TUESDAY...AND A HARD
FREEZE APPEARS LIKELY FOR MUCH OF THE AREA TUESDAY NIGHT. DRY
CONDITIONS WITH A PRONOUNCED WARMING TREND WILL THEN PREVAIL LATER
THIS WEEK AND INTO NEXT WEEKEND.

&&

.DISCUSSION...A 536 DM LOW WAS CENTERED NEAR SAN FRANCISCO CALIF
THIS AFTERNOON WITH AN ATTENDANT COLD FRONT ARCING SWD TO JUST WEST
OF THE SRN CALIFORNIA COAST. THE UPPER LOW WILL DIG SEWD INTO NWRN
ARIZONA BY AROUND DAYBREAK MON MORNING. SCATTERED SHOWERS WILL
DEVELOP NORTH-TO-WEST OF TUCSON THIS EVENING...THEN WIDESPREAD
VALLEY RAIN/MOUNTAIN SNOW WILL OCCUR LATE TONIGHT INTO MON MORNING.

THE 31/12Z NAM/GFS/ECMWF/CMC WERE IN GOOD AGREEMENT WITH DEPICTING
THE HEAVIEST RAIN/SNOW TO OCCUR LATE TONIGHT/EARLY MON MORNING AS
THE SURFACE COLD FRONT MOVES EWD ACROSS THE AREA. THE UPPER LOW IS
THEN PROGGED TO MOVE RAPIDLY EWD INTO NE NEW MEXICO/SE COLORADO BY
MON EVENING. PRECIP WILL DECREASE FROM WEST-TO-EAST MON AFTERNOON...
THEN A CHANCE OF SNOW SHOWERS REMAINS MON NIGHT MAINLY ACROSS THE
WHITE MOUNTAINS. A SLIGHT CHANCE OF SNOW SHOWERS CONTINUES ACROSS
THE WHITE MOUNTAINS TUE WITH DRY CONDITIONS ELSEWHERE.

HERE IS A SUMMARY OF THE HEADLINE ADJUSTMENTS ASSOCIATED WITH THIS
FORECAST PACKAGE...

A WINTER WEATHER ADVISORY FOR SNOW WAS ADDED FOR THE MOUNTAINS SOUTH-
TO-SOUTHEAST OF TUCSON ABOVE 5000 FEET.

A WINTER WEATHER ADVISORY FOR SNOW WAS ADDED FOR ELEVATIONS BETWEEN
4500-5000 FEET EAST OF TUCSON.

THE WIND ADVISORY WAS UPGRADED TO HIGH WIND WARNING FOR THE SRN
PORTION OF THE UPPER SAN PEDRO RIVER VALLEY PARTICULARLY INCLUDING
THE SIERRA VISTA VICINITY.

THE ENDING TIMES FOR THE INHERITED WARNINGS/ADVISORIES WERE CHANGED
TO 2 PM MST MONDAY.

REGARDING THE NOTION OF A POTENTIAL BLIZZARD WARNING ISSUANCE...
SUSTAINED WIND SPEEDS OR FREQUENT GUSTS OF 35 MPH OR GREATER AND
CONSIDERABLE FALLING AND/OR BLOWING SNOW REDUCING VISIBILITY TO LESS
THAN ONE QUARTER OF A MILE WILL LIKELY BE ACHIEVED FROM THE
CATALINA/RINCON MOUNTAINS NEWD TO THE WHITE MOUNTAINS.

HOWEVER...THE EXPECTATION AT THIS TIME IS FOR THESE CONDITIONS TO BE
BRIEF...AND ARE NOT EXPECTED TO OCCUR FOR THREE HOURS OR LONGER.
THUS...BASED ON THIS REASONING...HAVE OPTED TO MAINTAIN A
COMBINATION OF WIND ADVISORIES/WARNINGS WITH SNOW ADVISORIES/
WARNINGS VERSUS A BLIZZARD WARNING ISSUANCE. FOR MORE DETAILED
INFORMATION...PLEASE REFER TO AWIPS PRODUCTS PHXWSWTWC AND PHXNPWTWC.

AT ANY RATE...A HARD FREEZE WARNING FOR MUCH OF PIMA COUNTY AND
SOUTHERN PINAL COUNTY WILL LIKELY BE ISSUED WITH SUBSEQUENT FORECAST
SHIFTS FOR TUE NIGHT/EARLY WED MORNING. THEREAFTER...DRY CONDITIONS
WILL PREVAIL WED-SUN IN RESPONSE TO AN AMPLIFIED UPPER RIDGE OVER
THE WRN CONUS.

HIGH TEMPS MON WILL BE NEARLY 15-25 DEGS COLDER VERSUS TEMPS
ACHIEVED THIS AFTERNOON DEPENDING UPON LOCATION. EXPECT A FEW DEGS
OF ADDITIONAL COOLING TUE FOLLOWED BY A FEW DEGS OF WARMING WED.
MARKEDLY WARMER TEMPS ARE FORECAST TO OCCUR THUR INTO NEXT WEEKEND.

&&

.AVIATION...VALID THRU 02/00Z.
SCATTERED -SHRA WILL DEVELOP WEST-TO-NORTH OF KTUS THIS EVENING
FOLLOWED NUMEROUS VALLEY -SHRA AND MOUNTAIN SHSN LATE TONIGHT INTO
MONDAY MORNING. SCATTERED VALLEY -SHRA AND MOUNTAIN -SHSN WILL THEN
OCCUR MAINLY EAST OF KTUS MONDAY AFTERNOON. EXPECT MVFR CONDITIONS
AND OCCASIONAL IFR CONDITIONS ASSOCIATED WITH THIS PRECIPITATION.
OTHERWISE...CLOUD DECKS ABOVE 20K FT MSL THIS EVENING WILL LOWER TO
AROUND 5-9K FT MSL LATE TONIGHT AND CONTINUE INTO MONDAY AFTERNOON.
SURFACE WIND WILL GENERALLY BE SWLY/WLY AT 15-30 KTS WITH GUSTS OF
30-45 KTS INTO EARLY MONDAY AFTERNOON...THEN WIND SPEEDS WILL
DECREASE TO 10-20 KTS WITH GUSTS OF 20-30 KTS MONDAY AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...WIDESPREAD VALLEY RAIN AND MOUNTAIN SNOW WILL OCCUR
INTO MONDAY MORNING...THEN PRECIPITATION WILL DECREASE FROM WEST-TO-
EAST MONDAY AFTERNOON. EXPECT STRONG AND GUSTY SOUTHWEST TO
NORTHWEST WINDS THROUGH MONDAY AFTERNOON. ISOLATED TO SCATTERED SNOW
SHOWERS WILL CONTINUE MAINLY ACROSS THE WHITE MOUNTAINS MONDAY NIGHT
INTO TUESDAY. DRY CONDITIONS WILL THEN PREVAIL AREA-WIDE TUESDAY
NIGHT INTO NEXT WEEKEND. MUCH COLDER TEMPERATURES WILL OCCUR MONDAY
INTO WEDNESDAY FOLLOWED BY A PRONOUNCED WARMING TREND THURSDAY INTO
NEXT WEEKEND.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
   WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 2 PM MST
     MONDAY FOR AZZ510 ABOVE 5000 FEET.

   WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM MST
     MONDAY FOR AZZ507>509-511>514 ABOVE 4500 FEET.

   HIGH WIND WARNING FROM 10 PM THIS EVENING TO 2 PM MST MONDAY FOR
     AZZ507-511>514.

   WIND ADVISORY FROM 10 PM THIS EVENING TO 2 PM MST MONDAY FOR
     AZZ503-504-506>510-515.

&&

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