FXUS64 KMAF 282247
AFDMAF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX
447 PM CST SAT NOV 28 2009
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW.
&&
.AVIATION...
NO MAJOR AVIATION CONCERNS...AS VFR CONDITIONS EXPECTED THRU THE
FORECAST PERIOD. CIGS PROGGED TO LOWER OVER THE NEXT 24 HRS AS
BAROCLINIC LEAF INTENSIFIES AHEAD OF TROUGH OVER SOCAL...BUT STILL
REMAIN VFR.
&&
.PREV DISCUSSION... /ISSUED 333 PM CST SAT NOV 28 2009/
DISCUSSION...
THE MAIN FOCUS FOR THIS FORECAST PACKAGE WILL CONTINUE TO CENTER ON
A WINTER STORM THAT WILL LIKELY IMPACT WEST TEXAS AND SOUTHEAST NEW
MEXICO LATE SUNDAY NIGHT...AND CONTINUING THROUGH MONDAY AND
TUESDAY.
LATE AFTERNOON WATER VAPOR IMAGERY SHOWS THE ADVERTISED UPPER LEVEL
LOW DIGGING ACROSS SOUTHERN CALIFORNIA. THIS FEATURE WILL SLOWLY
MOVE SOUTHWARD TO NEAR THE CA/AZ BORDER BY EARLY SUNDAY MORNING. THE
FLOW ALOFT WILL BECOME SOUTHWESTERLY ACROSS OUR FORECAST AREA LATE
TONIGHT...AS THE BROAD UPPER TROUGH CONTINUES TO CARVE ACROSS THE
SOUTHWESTERN CONUS. A SHORTWAVE IMPULSE WITHIN THE SOUTHWEST FLOW
ALOFT WILL LIFT NORTHEASTWARD ACROSS NORTHERN MEXICO AND FAR WEST
TEXAS/SOUTHERN NEW MEXICO LATE TONIGHT. SCATTERED RAIN SHOWERS WILL
DEVELOP ACROSS THE NORTHWESTERN HALF OF THE CWFA WITHIN THE FAVORED
REGION OF LIFT TONIGHT...MAINLY AFTER MIDNIGHT. ELEVATED INSTABILITY
WILL BE MARGINAL OVERNIGHT...BUT ENOUGH WILL BE PRESENT TO KEEP
MENTION OF ISOLATED THUNDERSTORMS ACROSS THE GUADALUPE MOUNTAINS AND
SOUTHEAST NEW MEXICO PLAINS.
MODELS ARE THEN IN GOOD AGREEMENT THAT THE UPPER LOW WILL CONTINUE
TO DIG/SLOWLY MOVE ACROSS NORTHERN BAJA/SONORA MX SUNDAY AND SUNDAY
NIGHT. MEANWHILE...A FAST MOVING SHORTWAVE TROUGH WILL CLIP ACROSS
THE CENTRAL PLAINS SUNDAY...AND WILL SEND A STRONG COLD FRONT
SOUTHWARD THROUGH THE SOUTHERN PLAINS...INCLUDING MUCH OF OUR
FORECAST AREA DURING THE DAY SUNDAY. MUCH COOLER TEMPERATURES WILL
RETURN ACROSS THE NORTHERN CWFA BEHIND THIS FRONT SUNDAY AFTERNOON.
TEMPERATURES WILL BE LUCKY TO REACH THE MID 50S TO NEAR 60 BEFORE
THE FRONT PASSES ACROSS MOST LOCATIONS. ADDITIONAL LIFT WILL BE
PROVIDED BY ADDITIONAL SHORTWAVE IMPULSES WITHIN THE SOUTHWEST FLOW
AND ALSO ALONG THE FRONTAL BOUNDARY SUNDAY. THUS...A CHANCE OF RAIN
SHOWERS WILL CONTINUE ACROSS THE FORECAST AREA THROUGH THE
DAY...WITH A FEW THUNDERSTORMS ALSO POSSIBLE ACROSS SOUTHERN
SECTIONS OF THE CWFA. COLDER AIR WILL CONTINUE TO FILTER ACROSS THE
CWFA SUNDAY NIGHT. MID LEVEL FLOW WILL BECOME NEARLY SOUTHERLY
ACROSS WESTERN PORTIONS OF THE REGION SUNDAY NIGHT...AS A DIFLUENT
PATTERN DEVELOPS AHEAD OF THE UPPER LEVEL STORM SYSTEM. THIS WILL BE
A FAVORABLE PATTERN FOR PRECIPITATION DEVELOPMENT...ESPECIALLY WEST
OF THE PECOS RIVER...WHERE WE HAVE INCREASED GRIDDED POPS TO THE
LIKELY CATEGORY. FORECAST SOUNDINGS ARE IN GENERAL AGREEMENT THAT
PRECIPITATION SHOULD REMAIN IN THE FORM OF RAIN BEFORE MIDNIGHT...
WITH THE EXCEPTION OF THE HIGHER ELEVATIONS OF THE GUADALUPE
MOUNTAINS...WHERE A RAIN/SNOW MIX MAY OCCUR. AFTER MIDNIGHT...
SOUNDINGS FAVOR A MIX OF RAIN/SLEET/SNOW ACROSS THE PERMIAN
BASIN...UPPER TRANS PECOS...AND MARFA PLATEAU...WHILE ALL SNOW WILL
BE POSSIBLE ACROSS THE SOUTHEAST NEW MEXICO PLAINS...AND THE
GUADALUPE/DAVIS MOUNTAINS. SNOW ACCUMULATIONS OF 1-2 INCHES WILL BE
POSSIBLE BY MONDAY MORNING...MAINLY IN THE MOUNTAINS AND THE
ADJACENT SOUTHEAST NEW MEXICO PLAINS.
DIFLUENT FLOW WILL PERSIST MONDAY...AND PRECIPITATION WILL BE LIKELY
AGAIN ALONG AND WEST OF THE PECOS RIVER. FORECAST SOUNDINGS
GENERALLY FAVOR SNOW IN THE MOUNTAINS AND A WINTRY MIX OF
RAIN...SLEET AND/OR SNOW ACROSS MUCH OF THE PLAINS MONDAY. A WINTER
WEATHER ADVISORY MAY BECOME NECESSARY DURING THE SUNDAY NIGHT/MONDAY
TIME FRAME ACROSS THE MOUNTAINS...AND POSSIBLY FARTHER EAST. THE
UPPER LEVEL LOW WILL FINALLY APPROACH WEST TEXAS MONDAY NIGHT...AND
CURRENT TRENDS ARE IN AGREEMENT THAT THIS FEATURE WILL PASS NEAR THE
I-10 CORRIDOR TUESDAY. FORECAST SOUNDINGS/PROGS INDICATE THAT
PRECIPITATION MONDAY NIGHT COULD BE A MESS OF SNOW AND POSSIBLY SOME
SLEET ALONG AND NORTH OF INTERSTATE 10...WITH A MIX OF FREEZING RAIN
AND SLEET...AND POSSIBLY SOME SNOW FLAKES ACROSS THE MARFA PLATEAU
AND BIG BEND REGION. PRECIPITATION WILL LIKELY BECOME ALL SNOW
TUESDAY NORTH OF THE PASSING UPPER LOW TUESDAY AND TUESDAY NIGHT.
CONFIDENCE IS INCREASING THAT TOTAL SNOW ACCUMULATIONS OF 2 TO 4
INCHES...WITH LOCALIZED HIGHER AMOUNTS MAY BE REALIZED ACROSS MUCH
OF THE FORECAST AREA BY TUESDAY. ALL WILL BE DEPENDENT ON THE SPEED
AND ACTUAL TRACK OF THE UPPER LOW. WE HAVE OPTED TO CONTINUE A
STRONGLY WORDED SPECIAL WEATHER STATEMENT MENTIONING ACCUMULATIONS
WITH THIS PACKAGE...AS THE HEAVIEST WINTER PRECIPITATION EVENT IS
STILL 3 DAYS OUT. A WINTER STORM WATCH MAY BECOME NECESSARY ACROSS
WESTERN PORTIONS OF THE CWFA WITHIN THE NEXT 12-24 HOURS.
THE UPPER LOW WILL PASS EAST OF THE FORECAST AREA TUESDAY NIGHT.
SOME WRAP-AROUND SNOW MAY CONTINUE ACROSS THE FORECAST AREA TUESDAY
NIGHT...BEFORE TAPERING EARLY WEDNESDAY MORNING. NORTHWEST FLOW
ALOFT AND COLD TEMPERATURES ARE EXPECTED WEDNESDAY IN THE WAKE OF
THE SYSTEM. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE END OF
THE WEEK...AS THE SURFACE RIDGE MAY BE HARD PRESSED TO MOVE EAST OF
THE FORECAST AREA.
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
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