Area Forecast Discussion
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FXUS64 KEPZ 250312 AAA
AFDEPZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EL PASO TX/SANTA TERESA NM
811 PM MST WED DEC 24 2014

.SYNOPSIS...
AN APPROACHING LOW PRESSURE SYSTEM WITH A COLD FRONT WILL BRING
WINDY AND WARMER WEATHER TO SOUTHERN NEW MEXICO AND WEST TEXAS ON
CHRISTMAS DAY. THE STORM SYSTEM WILL THEN PASS THROUGH THE REGION
CHRISTMAS NIGHT AND FRIDAY CAUSING COOLER BELOW NORMAL
TEMPERATURES ALONG WITH A FEW RAIN AND SNOW SHOWERS. SEVERAL
INCHES OF SNOW ARE POSSIBLE OVER THE HIGHER MOUNTAINS THURSDAY
NIGHT AND FRIDAY. FOR THE COMING WEEKEND THE WEATHER SHOULD REMAIN
CHILLY WITH LIGHT RAIN OR SNOW FALLING ON VERY ISOLATED LOCATIONS.
MONDAY AND TUESDAY SHOULD BE DRY WITH NEAR NORMAL TEMPERATURES
BEFORE MUCH COLDER AIR INVADES THE BORDERLAND NEW YEARS EVE.

&&

.UPDATED DISCUSSION...
HAVE UPDATED WIND ADVISORY TO INCLUDE ZONES ALONG THE EAST SLOPES OF
THE FRANKLIN AND ORGAN MOUNTAINS (NORTHEAST EL PASO AND WHITE SANDS
HDQTRS). WINDS AT LOCAL MOUNTAIN TOP LEVELS BEGIN INCREASING
THURSDAY MORNING AHEAD OF THE INCOMING PACIFIC FRONTAL SYSTEM.
MOUNTAINS SHOULD ENHANCE THESE WINDS ALONG EASTERN SLOPES AND
THROUGH GAPS. I`VE STARTED THE NEW ADVISORY AT 8AM BUT DOWNSLOPE
WINDS COULD EVEN START EARLIER. LATEST GFS/NAM SHOW WINDS FROM JUST
OFF THE SURFACE UP WELL ABOVE MOUNTAIN TOPS INCREASING TO 35 TO 55
MPH. THESE AREAS WON`T GET MUCH HELP FROM THE PRESSURE GRADIENT
THURSDAY BUT DOWNSLOPE WINDS AND ACCELERATION THROUGH GAPS SHOULD
BRING WINDS UP TO ADVISORY LEVEL. ALSO KEPT THIS NEW AREA RUNNING
LONGER THAN THE OTHER ADVISORY AREAS SINCE PROG SOUNDINGS SHOW
STRONG MOUNTAIN TOP LEVEL WINDS PERSISTING INTO FRIDAY
MORNING...ALONG WITH A MINOR MID LEVEL INVERSION.

17/HEFNER

.PREVIOUS DISCUSSION...
RATHER ACTIVE AND CHALLENGING WEATHER SCENARIO INDICATED THROUGH
NEXT WEEK. AN UPPER WAVE WAS LOCATED ALONG THE NORTHWEST COAST
EARLY THIS AFTERNOON WILL DIG/AMPLIFY AS IT MOVES TO THE SOUTHEAST
AS SYSTEM HAS A 130 KT JET STREAK IN ITS WESTERN QUADRANT.
CONSEQUENTLY SYSTEM WILL HAVE AN ASSOCIATED CLOSED LOW OVER UTAH
BY CHRISTMAS AFTERNOON WITH TRAILING TROUGH AXIS AXIS MOVING
EASTWARD ACROSS ARIZONA. APPROACH OF SYSTEM WILL INDUCE INCREASING
SOUTHWEST WINDS ACROSS SOUTHERN NEW MEXICO AND WEST TEXAS ON
THURSDAY WITH WIND SPEEDS AROUND 50 KT NEAR THE 700 MB MIXING
HEIGHT LEVEL. THUS EXPECT A WINDY CHRISTMAS ALL AREAS WITH SPEEDS
AROUND ADVISORY LEVELS WESTERN AND HIGH MOUNTAIN ZONES. SOUTHWEST
FLOW WILL ALSO ADVECT WARM DRY AIR WITH TOMORROW`S HIGH
TEMPERATURES HIGH TEMPERATURES A LITTLE ABOVE NORMAL.

PRIMARY VORTICITY AXIS ASSOCIATED WITH THE TROUGH ALONG WITH AN
ASSOCIATED COLD FRONT WILL MOVE ACROSS THE CWA THURSDAY
NIGHT/EARLY FRIDAY WITH ASSOCIATED LIFT RATHER STRONG AS THE CWA
WILL BE IN THE RIGHT REAR QUADRANT OF AN 130 KT UPPER JET MAX
WHILE EXPERIENCING SIGNIFICANT DIFFERENTIAL PVA. IN ADDITION A
SECONDARY VORTICITY WILL MOVE ACROSS THE REGION LATER FRIDAY.
THE UPWARD FORCING SHOULD THUS INDUCE AREAS OF PRECIPITATION WHICH
WILL SPREAD WEST TO EAST THURSDAY NIGHT AND FRIDAY. DYNAMIC
COOLING ALOFT COMBINED WITH LOW LEVEL COLD AIR ADVECTION WILL
CAUSE SNOW LEVELS TO FALL WITH SEVERAL INCHES OF SNOW POSSIBLE
OVER SOME MOUNTAIN AREAS ABOVE 6000 FEET WITH MOSTLY RAIN OR A
RAIN/SNOW MIX LOWER ELEVATIONS. YET ANOTHER VORTICITY CENTER WILL
MOVE ACROSS THE CWA ON SATURDAY PRODUCING LIGHT RAIN/SNOW OVER A
FEW AREAS WITH HIGH TEMPERATURES FALLING TO AROUND 10 DEGREES
BELOW NORMAL.

FLOW BECOMES ZONAL BY SUNDAY AFTERNOON WITH WEST TO SOUTHWEST
WINDS ALOFT CONTINUING MONDAY THROUGH TUESDAY. THUS SUNDAY THROUGH
TUESDAY WILL BE MOSTLY DRY WITH WARM AIR ADVECTION SUPPORTING A
GRADUAL WARMING TREND.

LONGER RANGE OUTLOOK/MODEL DATA INDICATE DEEP UPPER LOW MOVING
INTO THE SOUTHWESTERN UNITED STATES LATER NEXT WEEK WHILE ARCTIC
AIR ENTERS THE CWA FROM THE NORTHEAST. IF THIS WEATHER PATTERN
DOES OCCUR THEN EXPECT VERY COLD TEMPERATURES AND CHANCES FOR SNOW
AFTER TUESDAY.

&&

.AVIATION...VALID 25/00Z- 26/00Z...
P6SM FEW-SCT150 SCT-BKN200-250 THRU 18Z...THEN SCT-BKN120-150. LIGHT
SOUTH TO SOUTHWEST WINDS THRU 15Z...THEN SHIFTING TO THE SOUTHWEST
AND INCREASING TO 20-30G40KTS AT ALL TERMINALS. AREAS OF 1-3SM BLDU
AFT 18Z.

&&

.FIRE WEATHER...
A BRIEF WARMUP IS EXPECTED FOR CHRISTMAS DAY AHEAD OF A DEEPENING
UPPER LOW MOVING THROUGH THE FOUR CORNERS REGION. WINDS WILL BE ON
THE INCREASE TOMORROW AS WELL WITH SOUTHWEST WINDS TO 20 TO 35 MPH
WITH GUSTS OVER 45 MPH LIKELY. MINIMUM RELATIVE HUMIDITIES WILL BE
RUNNING JUST ABOVE 15 PERCENT FOR THE LOWLANDS WITH 20S IN THE
MOUNTAINS. AS THE SYSTEM PASSES ALONG THE COLORADO BORDER...SOME
MOUNTAIN SNOWS AND VALLEY RAIN SHOWERS ARE POSSIBLE FRIDAY. A FEW
INCHES OF SNOW ARE POSSIBLE IN THE MOUNTAINS ABOVE 6000 FEET. BREEZY
CONDITIONS WILL CONTINUE AS WELL FRIDAY BEHIND A COLD FRONT WHICH
WILL DROP HIGHS ABOUT 10 TO 15 DEGREES. DRY CONDITIONS AND BELOW
NORMAL TEMPERATURES ARE EXPECTED FOR THE WEEKEND WITH ANOTHER QUICK
WARMUP AHEAD OF A POSSIBLY VERY COLD ARCTIC AIRMASS ENTERING THE
REGION THE MIDDLE OF NEXT WEEK.

&&

.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...WIND ADVISORY FROM NOON TO 7 PM MST THURSDAY FOR NMZ401>409.

     WIND ADVISORY FROM NOON THURSDAY TO MIDNIGHT MST THURSDAY NIGHT
     FOR NMZ414>416.

TX...NONE.
&&

$$

05 ROGASH/26 GRZYWACZ







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