FXUS64 KEWX 271741
AFDEWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1141 AM CST FRI NOV 27 2009
.AVIATION...
VFR CONDITIONS WILL CONTINUE THIS AFTERNOON AND EVENING WITH BKN-
OVC LAYER AT 8-10 KFT OR HIGHER. ISOLATED SPRINKLES AND DRIZZLE
ARE EXPECTED ACROSS THE REGION THROUGH THIS AFTERNOON BUT ARE NOT
ANTICIPATED TO IMPACT TAF SITES SO HAVE LEFT MENTION OUT. A LOWER
CLOUD DECK IS EXPECTED TO DEVELOP OVERNIGHT WITH MVFR CIGS
POSSIBLE AT ALL SITES BY 12-13Z. COULD SEE SOME LIMITATIONS TO
VSBYS DUE TO FOG AT KSSF AROUND THE SAME TIME BUT ATTM NOT
EXPECTING MUCH LOWER THAN 4-5 SM. CIGS COULD LOWER TO IFR AT KDRT
AND KSSF AFTER 14-15Z HOWEVER CONFIDENCE IS MODERATE AT BEST AT
THIS TIME. S-SELY SFC WINDS OF 5-10 KTS WILL GENERALLY PREVAIL THIS
AFTERNOON WITH LIGHT SE WINDS EXPECTED OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 1120 AM CST FRI NOV 27 2009/
UPDATE...
TWEAKED AFTERNOON TEMPERATURES UPWARD A FEW DEGREES BASED ON CURRENT
TRENDS..OTHERWISE CURRENT FORECAST LOOKS FINE.
DISCUSSION...
PREV DISCUSSION... /ISSUED 532 AM CST FRI NOV 27 2009/
DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION BELOW.
AVIATION...
INCREASING CIGS AT 15-20 KFT AGL WILL LIMIT MIXING AND WIND SPEEDS
THROUGH THE WEEKEND. AN ISOLATED SPRINKLE OR TWO IS EXPECTED IN
THE AREA, BUT NOT ENOUGH FOR A SIGNIFICANT IMPACT ON THE
TERMINALS. THE BEGINNING OF LOW CLOUDS IS EXPECTED AFTER DAYBREAK
SATURDAY IN THE SAT AREA, BUT LOW CIGS MAY STILL BE LIMITED BY THE
DENSE MID LEVEL CEILINGS ABOVE.
PREV DISCUSSION... /ISSUED 427 AM CST FRI NOV 27 2009/
DISCUSSION...
THE LATEST WATER VAPOR SATELLITE IMAGERY SHOWS AN UPPER TROUGH
OVER NW MEXICO PROGRESSING EAST TOWARD OUR AREA. MOISTURE IN THE
MID AND UPPER LEVELS OF THE ATMOSPHERE WILL BE ON THE INCREASE
TODAY AS THE UPPER TROUGH GETS CLOSER. THE LATEST KDFX VAD WIND
PROFILE IS POPULATING DATA BETWEEN 20-27K FT...WHICH INDICATES
MOISTURE AT THAT LEVEL. MOISTURE ADVECTION WILL WORK DOWN THE
COLUMN WITH TIME...WITH STRATIFORM PRECIPITATION DEVELOPING. THE
LATEST KDFX REFLECTIVITY IMAGES SHOW 20-24DBZ WEST OF THE RIVER ON
THE EDGE OF THE RADAR UMBRELLA MOVING ENE. HOWEVER...DRY AIR IN
THE LOWER LEVELS OF THE ATMOSPHERE WILL PREVENT MUCH OF THE RAIN
FROM REACHING THE GROUND INITIALLY. WILL MENTION LIGHT RAIN FOR
MUCH OF THE AREA TODAY...BUT VERY LITTLE MEASURABLE PRECIPITATION
IS EXPECTED.
GULF MOISTURE WILL RETURN IN EARNEST SATURDAY INTO SUNDAY AHEAD OF
THE NEXT COLD FRONT AND UPPER TROUGH. MOISTURE ADVECTION IN THE
LOWER LEVELS OF THE ATMOSPHERE SATURDAY NIGHT WILL LIKELY RESULT
IN ADVECTION-TYPE FOG. THIS SCENARIO HAS SUPPORT FROM BOTH THE
LATEST NAM AND GFS MOS BULLETINS. THE COLD FRONT IS FORECAST TO
PUSH THROUGH LATE SUNDAY AFTERNOON AND SUNDAY EVENING...WITH
STRONG COLD AIR ADVECTION BEHIND IT. ISENTROPIC UPGLIDE...WITH A
PACIFIC MOISTURE TAP...WILL CONTINUE BEHIND THE FRONT THROUGH
MONDAY. RAINFALL AMOUNTS LATE SUNDAY THROUGH MONDAY WILL GENERALLY
RANGE FROM ONE HALF TO ONE INCH...ALTHOUGH AMOUNTS NEAR TWO INCHES
WILL BE POSSIBLE ACROSS OUR EASTERN-MOST COUNTIES.
BOTH THE 00Z GFS AND ECMWF SOLUTIONS BRING A 550-555DAM 500MB LOW
INTO WEST TEXAS ON TUESDAY AND ACROSS OUR AREA TUESDAY NIGHT. THE
ECMWF IS A TAD SLOWER AND DEEPER WITH THE LOW...WHICH WOULD BE
MORE SNOW FAVORABLE...AND FOR A GREATER PORTION OF OUR AREA.
FORECAST SOUNDINGS FROM THE 00Z GFS40 SHOW A CLASSIC "SNOW
SOUNDING" FOR POINTS IN THE NORTHERN HILL COUNTRY AND EDWARDS
PLATEAU LATE TUESDAY NIGHT AS THE UPPER LOW MOVES OVERHEAD. THE
THEME HERE IS INCREASING CONFIDENCE IN OUR FORECAST OF FROZEN
PRECIP TUESDAY INTO WEDNESDAY FOR PORTIONS OF OUR AREA.
THERE IS CONSIDERABLE DIFFERENCES BETWEEN THE 00Z GFS AND ECMWF
SOLUTIONS BEYOND 12Z WEDNESDAY OF NEXT WEEK...WITH THE ECMWF MUCH
COLDER GIVEN A LARGE UPPER TROUGH OCCUPYING THE EASTERN HALF OF
THE CONUS...CLEARING THE WAY FOR COLD AIR TO SPILL SOUTH DOWN THE
PLAINS. FOR NOW...WE'LL STICK WITH THE WARMER GFS FORECAST AND
WAIT FOR MORE RUN-TO-RUN CONSISTENCY BEFORE TRENDING COLDER.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 69 49 72 61 71 / - - - 10 30
AUSTIN BERGSTROM INTL AIRPORT 67 48 72 58 72 / - - - 10 30
NEW BRAUNFELS MUNI AIRPORT 68 49 71 58 73 / - - 10 10 30
BURNET MUNI AIRPORT 66 51 68 60 68 / - - 10 10 40
DEL RIO INTL AIRPORT 66 50 72 58 71 / 10 - - - 20
GEORGETOWN MUNI AIRPORT 68 49 71 60 70 / - - - 10 40
HONDO MUNI AIRPORT 66 48 71 59 72 / - - 10 10 30
SAN MARCOS MUNI AIRPORT 67 48 72 59 72 / - - 10 10 30
LA GRANGE - FAYETTE REGIONAL 69 49 72 61 72 / - 10 - 10 30
SAN ANTONIO INTL AIRPORT 67 49 71 60 72 / - - 10 10 30
STINSON MUNI AIRPORT 67 49 71 60 73 / - - 10 10 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
02/25
