848
FXUS65 KTWC 090916
AFDTWC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
215 AM MST TUE FEB 9 2010
SYNOPSIS
DRY WITH A BRIEF DAYTIME WARMING TREND BEFORE ANOTHER
WINTER STORM BRINGS VALLEY RAIN AND MOUNTAIN SNOW BY LATE WEDNESDAY
INTO THURSDAY. THIS NEXT STORM WILL BE COLDER THAN RECENT ONES...SO
THE SNOW LEVEL WILL BE MUCH LOWER WEDNESDAY NIGHT AND EARLY THURSDAY
WITH SIGNIFICANT ACCUMULATIONS POSSIBLE ABOVE 4000 FEET OR EVEN
LOWER. DRY AND WARMER FRIDAY INTO THE WEEKEND UNDER HIGH PRESSURE.
DISCUSSION
SHORTWAVE RIDGE PHASING EASTWARD AHEAD OF A STRONG LOW
WINDING UP NEAR SAN FRANCISCO AS IT DIGS DOWN THE CALIFORNIA COAST.
IT IS EXPECTED TO TURN THE CORNER AND KICK EASTWARD LATE TONIGHT AND
EARLY WEDNESDAY MORNING ON A TRACK ACROSS SOUTHERN CALIFORNIA AND
NORTHERN BAJA TOWARD SOUTHERN ARIZONA. TIMING IS STILL SHAKY WITH
SOME MODEL RESOLUTIONS LIKELY A BIT EARLY. EXPECT AN EXTRA WOBBLE AS
INERTIA AND BRIEF RECONSOLIDATION FROM LAST PIECE OF REINFORCING
ENERGY ULTIMATELY BRINGS THE STORM ACROSS THE AREA LATE WEDNESDAY
AND WEDNESDAY NIGHT INTO THURSDAY MORNING. THIS IS EXPECTED TO ALSO
ALLOW A BETTER MOISTURE TAP EARLIER AND FURTHER WEST FOR WIDESPREAD
PRECIPITATION (WITH THE SUBTROPICAL MOISTURE PLUME NOW REACHING
TOWARD CENTRAL BAJA COMING INTO PLAY). A COLDER AND STRONGER SYSTEM
THAN MOST RECENT STORMS...SNOW LEVELS WILL FALL TOWARD VALLEY FLOORS
ESPECIALLY IN EASTERN ZONES. SIGNIFICANT ACCUMULATIONS APPEAR LIKELY
ABOVE 4000 FEET WITH SNOW LEVELS AS LOW AS 3000 FEET...PERHAPS
LOCALLY A BIT LOWER NEAR CONVECTION. BEST MOISTURE...DYNAMICS AND
COLD AIR COME TOGETHER WEDNESDAY EVENING INTO THURSDAY MORNING.
WE THINK THE ECMWF MIGHT BE A TAD TOO AGGRESSIVE WITH THE
TIMING...AND EXPECT SOME WRAP AROUND STILL ROTATING THROUGH THE
SOUTHEAST CORNER OF THE STATE THURSDAY MORNING.
RIDGING WILL DOMINATE WESTERN STATES IN THE PATTERN SETTING UP FOR
THE END OF THE WEEK AND NEXT WEEKEND. EXPECT A STRONG WARMING TREND
TO BACK ABOVE CLIMO AFTER THE COLD AND WET PERIOD.
AVIATION
INCREASING HIGH CLOUDS FROM THE SOUTHWEST TODAY. SURFACE
WINDS ARE EXPECTED TO BE LESS THAN 15 KTS AND ADHERE TO TYPICAL
DIURNAL PATTERNS. HIGH PRESSURE WILL GIVE WAY TO A STRONG STORM
MOVING IN FROM THE WEST BY LATE WEDNESDAY. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
FIRE WEATHER
NO FIRE WEATHER CONCERNS AT THIS TIME.
TWC WATCHES/WARNINGS/ADVISORIES
WINTER STORM WATCH FROM
WEDNESDAY 3 PM THROUGH THURSDAY 11 AM ABOVE 4000
FEET AZZ019-029-030-032>035.
WEATHER.GOV/TUCSON
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