Area Forecast Discussion
Issued by NWS Tucson, AZ

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039
FXUS65 KTWC 011635
AFDTWC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
935 AM MST MON FEB 1 2016

.SYNOPSIS...SCATTERED RAIN AND SNOW SHOWERS WITH OCCASIONALLY GUSTY
WINDS THIS MORNING THEN PRECIPITATION WILL DECREASE IN COVERAGE THIS
AFTERNOON. MUCH COLDER TEMPERATURES WILL ALSO OCCUR TODAY AND
TUESDAY FOLLOWED BY A WIDESPREAD HARD FREEZE TUESDAY NIGHT. DRY
CONDITIONS WITH A PRONOUNCED WARMING TREND WILL THEN PREVAIL LATER
THIS WEEK AND INTO NEXT WEEKEND.

&&

.DISCUSSION...KEMX WSR-88D DEPICTED SCATTERED 30-40 DBZ ECHOES
EXTENDING FROM CENTRAL SANTA CRUZ COUNTY EWD INTO SRN COCHISE COUNTY
AT 1625Z. SURFACE OBSERVATIONS DURING THE PAST SEVERAL HOURS HAVE
INDICATED PERIODS OF LIGHT SNOW AT THE KOLS/KALK/KFHU ASOS SITES.
SOME SNOW ACCUMULATIONS OF MOSTLY LESS THAN ONE INCH HAVE ALSO
OCCURRED IN TOMBSTONE.

OTHERWISE...IR/VISIBLE SATELLITE IMAGERY DEPICTED MOSTLY CLOUDY TO
CLOUDY SKIES ACROSS SE ARIZONA AT THIS TIME. SURFACE WINDS WERE
GENERALLY WLY AROUND 10-20 MPH WITH GUSTS OF 20-30 MPH. THESE SPEEDS
WERE CONSIDERABLY LOWER VERSUS WIND SPEEDS THAT OCCURRED LAST NIGHT.
01/12Z KTWC SOUNDING DEPICTED AN EXTREMELY IMPRESSIVE WIND
PROFILE...WITH NEARLY 150 KTS OBSERVED AS LOW AS AROUND 475 MB.

FOR SOME PERSPECTIVE...THE 73 KT SPEED OBSERVED AT 500 MB VIA THE
01/12Z KTWC SOUNDING IS THE STRONGEST SPEED RECORDED FOR A 12Z KTWC
SOUNDING FOR FEB 1. THE PREVIOUS RECORD WAS 69 KTS AT 500 MB FOR A
12Z SOUNDING FOR FEB 1.

THUS...AM NOT AT ALL SURPRISED TO SEE SOME OF THE VERY STRONG
SURFACE/MOUNTAIN WIND SPEEDS MEASURED/REPORTED SO FAR. 01/12Z UPPER
AIR PLOTS DEPICTED A 536 DM LOW CENTERED OVER NW ARIZONA WITH NORTH-
TO-SOUTH RIDGES OVER THE CENTRAL CONUS PLAINS AND OFF THE WEST COAST
ADJACENT 130W. VERY STRONG GENERALLY WLY FLOW ALOFT PREVAILED ACROSS
SE ARIZONA.

THE UPPER LOW WILL MOVE EWD TO NEAR THE FOUR CORNERS REGION AROUND
NOON TODAY...THEN CONTINUE EWD INTO NE NEW MEXICO/SE COLORADO BY
THIS EVENING. PRECIP FOR THE REST OF TODAY WILL GENERALLY BE
CONFINED TO LOCALES EAST-TO-SOUTH OF TUCSON. THE WINTER STORM
WARNING AND WINTER WEATHER ADVISORY WILL REMAIN IN EFFECT UNTIL 2 PM
MST. PLEASE REFER TO AWIPS PRODUCT PHXWSWTWC FOR DETAIL.

MEANWHILE...WINDS WILL GRADUALLY DIMINISH ESPECIALLY BY THIS EVENING
AS THE CORE OF STRONGER WINDS ALOFT MOVES WELL EAST OF THE AREA. THE
INHERITED HIGH WIND WARNING WAS RECENTLY DOWNGRADED TO A WIND
ADVISORY...AND A WIND ADVISORY FOR MUCH OF THE AREA REMAINS IN
EFFECT UNTIL 2 PM MST. PLEASE REFER TO AWIPS PRODUCT PHWNPWTWC FOR
DETAIL.

A CHANCE OF SNOW SHOWERS CONTINUES TONIGHT MAINLY ACROSS THE WHITE
MOUNTAINS. MUCH COLDER TEMPS WILL OCCUR TODAY...WITH HIGH TEMPS TO
BE NEARLY 15-25 DEGS COLDER VERSUS TEMPS ACHIEVED SUN...DEPENDING
UPON LOCATION.

&&

.AVIATION...VALID THRU 02/18Z.
SCATTERED TO NUMEROUS -SHRA/-SHSN WILL PREVAIL MAINLY EAST-TO-SOUTH
OF KTUS INTO THIS AFTERNOON. THIS PRECIPITATION WILL OCCUR
ESPECIALLY IN THE VICINITY OF KOLS/KFHU/KALK WITH CEILINGS BELOW
3000 FEET AND VSBYS LESS THAN 3SM. SCATTERED MAINLY MOUNTAIN -SHSN
WILL THEN OCCUR THIS EVENING INTO EARLY TUESDAY MORNING MAINLY NE OF
KSAD.

OTHERWISE...CLOUD DECKS INTO THIS AFTERNOON WILL GENERALLY BE AROUND
5-9K FT MSL THEN DECREASING CLOUDS FROM WEST-TO-EAST THIS EVENING.
EXPECT SCATTERED CLOUDS MAINLY ABOVE 10K FT MSL LATE TONIGHT INTO
TUESDAY MORNING. SURFACE WIND WILL GENERALLY BE WLY AT 15-30 KTS
WITH GUSTS OF 30-45 KTS INTO EARLY THIS AFTERNOON. WIND SPEEDS WILL
DECREASE TO 10-20 KTS WITH GUSTS OF 20-30 KTS LATE THIS AFTERNOON
INTO THIS EVENING. AVIATION DISCUSSION NOT UPDATED FOR TAF
AMENDMENTS.

&&

.FIRE WEATHER...SCATTERED TO NUMEROUS VALLEY RAIN AND MOUNTAIN SNOW
SHOWERS WILL CONTINUE THIS MORNING...WITH PRECIPITATION ENDING FROM
WEST TO EAST THIS AFTERNOON. STRONG AND GUSTY SOUTHWEST TO NORTHWEST
WINDS WITH SPEEDS OF 25 TO 35 MPH AND GUSTS TO 55 MPH WILL CONTINUE
THROUGH THE AFTERNOON HOURS. ISOLATED TO SCATTERED SNOW SHOWERS WILL
CONTINUE MAINLY ACROSS THE WHITE MOUNTAINS TONIGHT INTO TUESDAY. DRY
CONDITIONS WITH TERRAIN DRIVEN WINDS MAINLY LESS THAN 15 MPH WILL
THEN PREVAIL AREA-WIDE TUESDAY NIGHT INTO THIS WEEKEND. MUCH COLDER
TEMPERATURES WILL OCCUR TODAY INTO WEDNESDAY FOLLOWED BY A
PRONOUNCED WARMING TREND THURSDAY INTO NEXT WEEKEND.

&&

.PREV DISCUSSION /315 AM MST/...A STORM SYSTEM CONTINUED TO BRING
VERY STRONG WINDS AND WIDESPREAD SHOWERS TO THE AREA EARLY THIS
MORNING. VARIOUS WARNINGS AND ADVISORIES FOR WIND AND SNOWFALL
REMAINED IN EFFECT THROUGH EARLY THIS AFTERNOON. LATEST MODELS TRACK
THIS SYSTEM EAST OF THE AREA THIS AFTERNOON WITH IMPROVING WEATHER
CONDITIONS ANTICIPATED BY THIS EVENING. WILL LIKELY SEE SOME
LINGERING SHOWERS IN THE WHITE MOUNTAINS THROUGH TONIGHT BUT OVERALL
SKIES WILL BE CLEARING FROM WEST TO EAST TODAY. PLEASE REFER TO THE
FOLLOWING PRODUCTS FOR DETAILS ON THE HEADLINES...AWIPS HEADER
PHXNPWTWC OR WMO HEADER WWUS75 FOR WIND...AND AWIPS HEADER PHXWSWTWC
OR WMO HEADER WWUS45 FOR SNOW. MUCH COLDER AIR WILL SPREAD INTO THE
AREA TODAY WITH FREEZING TEMPERATURES IN THE LOWER DESERTS EXPECTED
TONIGHT AND TUESDAY MORNING. EVEN COLDER TEMPERATURES CAN BE
ANTICIPATED TUESDAY NIGHT AND WEDNESDAY MORNING WITH A WIDESPREAD
HARD FREEZE LIKELY FOR THE LOWER DESERTS. LATER SHIFTS WILL LIKELY
POST A HARD FREEZE WARNING ONCE THE STORM SYSTEM CLEARS THE AREA
TODAY. OTHERWISE...MODELS SHOWED A RIDGE OF HIGH PRESSURE ALOFT
BUILDING OVER THE REGION BY THURSDAY WHICH WILL BRING A WARMING
TREND AFTER TUESDAY.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
   WINTER STORM WARNING UNTIL 2 PM MST THIS AFTERNOON FOR AZZ510
     ABOVE 5000 FEET.

   WINTER WEATHER ADVISORY UNTIL 2 PM MST THIS AFTERNOON FOR
     AZZ507>509-511>514 ABOVE 4500 FEET.

   WIND ADVISORY UNTIL 2 PM MST THIS AFTERNOON FOR AZZ503-504-
     506>515.

&&

$$

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