FXUS64 KMAF 041153
AFDMAF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX
553 AM CST FRI DEC 4 2009
.DISCUSSION...
&&
.AVIATION...
SNOW CONTINUES TO FALL AT ALL TAF SITES. THE HEAVIEST SNOWFALL HAS
MOVED SOUTH OF MAF AND WAS LOCATED FROM ALPINE TO SAN ANGELO. IFR
TO LIFR CEILINGS AND VISIBILITIES AT TAF SITES EARLY THIS MORNING
WILL IMPROVE BY MIDDAY WITH VFR CONDITIONS EXPECTED BY EVENING.
&&
.PREV DISCUSSION... /ISSUED 532 AM CST FRI DEC 4 2009/
DISCUSSION...
A SHORTWAVE IMPULSE CONTINUES TO DROP ACROSS SOUTHEAST NEW MEXICO
AND WEST TEXAS EARLY THIS MORNING. IR SATELLITE IMAGERY ALSO SHOWS A
REGION OF ENHANCED LIFT ACROSS THE PERMIAN BASIN...TRANS PECOS
REGION AND THE VAN HORN CORRIDOR...WHICH FOLLOWS THE INDICATED
ENTRANCE REGION OF A 100 KNOT JET MOVING ACROSS NORTH TEXAS AND
SOUTHEAST OKLAHOMA. RADAR IMAGERY SHOWS A LARGE AREA OF LIGHT SNOW
CONTINUING ACROSS MOST OF WEST TEXAS AND PORTIONS OF SOUTHEAST NEW
MEXICO...WITH EMBEDDED HEAVIER BANDS ACROSS THE TRANS PECOS REGION
AND SOUTHERN PERMIAN BASIN. SNOWFALL ACCUMULATIONS OF 1-2 INCHES
HAVE BEEN REPORTED ACROSS THE CENTRAL AND WESTERN PERMIAN BASIN
ALREADY THIS MORNING. WE EXPECT ACCUMULATIONS TO REMAIN WITHIN
ADVISORY CRITERIA RANGE THIS MORNING ACROSS MOST AREAS...ALTHOUGH
LOCALIZED AMOUNTS APPROACHING 4 INCHES IS POSSIBLE UNDERNEATH THE
HEAVIER SNOW BANDS. SINCE SNOW WILL LIKELY BE ONGOING FOR A FEW MORE
HOURS...WE HAVE EXTENDED THE WINTER WEATHER ADVISORY TO INCLUDE ALL
BUT THE PRESIDIO VALLEY THROUGH 10 AM CST...OR 9 AM MST...AND THE
WINTER STORM WARNING FOR THE GUADALUPE MOUNTAINS THROUGH THE SAME
TIME. NORTHWESTERN PORTIONS OF THE FORECAST AREA MAY NEED TO BE
TRIMMED FROM THIS ADVISORY BEFORE 15Z. TEMPERATURES WILL BE COLD
WITH THE MODIFIED ARCTIC AIRMASS HOLDING IN PLACE TODAY. LEFT THE
PREVIOUS FORECAST HIGHS INTACT. CLOUDS ARE EXPECTED TO DECREASE
TONIGHT AND LOW TEMPERATURES WILL BE VERY COLD. PATCHY FOG IS ALSO A
POSSIBILITY TONIGHT...BUT CONFIDENCE WAS LOW ENOUGH TO PRECLUDE
MENTION IN THE GRIDS.
LITTLE CHANGE WAS MADE TO THE EXTENDED PERIOD. DRY ZONAL FLOW ALOFT
IS EXPECTED SATURDAY...WITH MODELS ALL INDICATING THE SURFACE RIDGE
OF HIGH PRESSURE SHIFTING TO THE EAST...AND LEE TROUGHING DEVELOPING
ACROSS THE PLAINS OF NORTHEAST NEW MEXICO AND SOUTHEAST COLORADO.
THIS WILL BRING INCREASED SOUTHERLY WINDS AND WARMER TEMPERATURES TO
THE REGION SATURDAY. HOWEVER...AREAS OF SNOW AND INCREASED HIGH
CLOUDS WILL TEMPER WARMING...SO HAVE KEPT FORECAST HIGHS BELOW
GUIDANCE. ANOTHER SURGE OF ARCTIC AIR WILL PUSH SOUTHWARD THROUGH
THE OKLAHOMA AND TEXAS PANHANDLES SUNDAY...BUT LATEST TRENDS KEEP
THIS AIRMASS TO THE NORTH OF OUR FORECAST AREA. THIS WILL NEED TO BE
WATCHED...BUT FOR NOW...TEMPERATURES ARE EXPECTED TO MODERATE BACK
INTO THE 50S ACROSS MOST AREAS SUNDAY AFTERNOON. A STRONG MID LEVEL
JET WILL DEVELOP ACROSS WEST TEXAS AND SOUTHEAST NEW MEXICO LATE
MONDAY INTO TUESDAY...AS AN UPPER TROUGH DEEPENS ACROSS THE
NORTHWESTERN CONUS. THE GFS MODEL SOLUTION SHOWS 700 MB WIND SPEEDS
OF 70-75 KNOTS TRANSLATING ACROSS THE REGION TUESDAY. THE ECMWF
SHOWS LOWER WIND SPEEDS...BUT LENDS SUPPORT THAT A HIGH WIND EVENT
COULD OCCUR ACROSS THE GUADALUPE AND DAVIS MOUNTAINS TUESDAY...WITH
SPEEDS POSSIBLY APPROACHING ADVISORY CRITERIA ACROSS MUCH OF THE
PLAINS AS ASSOCIATED SURFACE LOW DEEPENS IN THE VICINITY OF
NORTHWEST TEXAS. WE HAVE INCREASED GRIDDED WIND SPEEDS ACROSS THE
REGION TUESDAY. LATER SHIFTS MAY WANT TO INSERT MENTION OF STRONG
WINDS IN THE HWO IF CONTINUITY CONTINUES. ANOTHER SURGE OF COLD AIR
MAY RETURN BY MIDWEEK...AND HAVE KEPT TEMPERATURES BELOW GUIDANCE
NUMBERS.
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...WINTER WEATHER ADVISORY UNTIL 9 AM MST THIS MORNING FOR THE
FOLLOWING ZONES... CENTRAL LEA COUNTY...EDDY COUNTY
PLAINS...NORTHERN LEA COUNTY...SOUTHERN LEA COUNTY.
WINTER STORM WARNING UNTIL 9 AM MST THIS MORNING FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS OF EDDY COUNTY.
TX...WINTER WEATHER ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE
FOLLOWING ZONES... ANDREWS...BIG BEND AREA...BORDEN...
CRANE...DAVIS/APACHE MOUNTAINS AREA...DAWSON...ECTOR...
GAINES...GLASSCOCK...HOWARD...LOVING...MARFA PLATEAU...
MARTIN...MIDLAND...MITCHELL...PECOS...REAGAN...REEVES
COUNTY AND UPPER TRANS PECOS...SCURRY...TERRELL...UPTON...
VAN HORN AND HIGHWAY 54 CORRIDOR...WARD...WINKLER.
WINTER STORM WARNING UNTIL 9 AM MST THIS MORNING FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS.
&&
$$
