000
FXUS64 KBRO 281609 AAC
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1009 AM CST WED JAN 28 2015

.DISCUSSION...UPDATED FORECAST TO DROP FOG ADVISORY AND MENTION OF
MORNING FOG. NO OTHER CHANGES.

&&

.PREV DISCUSSION... /ISSUED 749 AM CST WED JAN 28 2015/

DISCUSSION...LOCALLY DENSE FOG HAS DEVELOPED ACROSS PORTIONS OF
DEEP SOUTH TEXAS. LIGHT WINDS COMBINED WITH ELEVATED LOW LEVEL
MOISTURE AND A STRONG SURFACE BASED INVERSION DUE TO GOOD
RADIATIONAL COOLING OVERNIGHT HAVE CONTRIBUTED TOWARD THE FOG
FORMATION. A DENSE FOG ADVISORY HAS BEEN ISSUED THROUGH 10 AM FOR
HIDALGO AND INLAND WILLACY AND CAMERON COUNTIES.

PREV DISCUSSION... /ISSUED 536 AM CST WED JAN 28 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...PATCHY DENSE FOG HAS DEVELOPED ON THE KBRO AND KHRL
AIRPORTS THIS MORNING. VIS WILL REMAIN LOW FOR A COUPLE HOURS
AFTER SUNRISE...BUT IS EXPECTED TO BURN OFF QUICKLY DUE TO DRIER
AIR AND BREEZIER CONDITIONS JUST OFF THE SFC. VFR CONDITIONS
THROUGH THE DAY WITH CAVU AND MODEST SOUTH WINDS. MOISTURE RETURN
FROM THE GULF MAY BRING ANOTHER ROUND OF FOG TO THE REGION AFTER
MIDNIGHT.

PREV DISCUSSION... /ISSUED 347 AM CST WED JAN 28 2015/

SHORT TERM.../NOW THROUGH THURSDAY/...CONTINUED QUIET WEATHER PATTERN
FOR SOUTH TEXAS AS H5 RIDGE REMAINS IN PLACE AHEAD OF THE LARGE
SCALE TROUGH OFF THE WEST COAST. MIDLEVEL FLOW ACROSS NORTHERN
MEXICO WILL CONTINUE TO SPREAD SOME CIRRUS ACROSS THE
REGION...ESPECIALLY TOMORROW. AT THE SFC...WEAK RIDGING FINALLY
SHIFTS TO THE EAST ALLOWING MINOR RETURN FLOW OFF THE
GULF...ESPECIALLY DURING THE DAY TOMORROW. AS HIGH TEMPERATURES WERE
ABLE TO REACH NEAR 80 YESTERDAY...HAVE UPPED TEMPS TODAY GENERALLY
INTO THE LOWER 80S. THE RETURN FLOW OFF THE GULF WILL BRING ENOUGH
MOISTURE IN TO KEEP LOW TEMPERATURE IN THE UPPER 50S.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...THE NICE WEATHER OF
LATE WILL EVENTUALLY HAVE TO COME TO AN END AS THE NEXT UPPER
LEVEL TROUGH OFF THE SOCAL/NW MEXICAN COAST MAKES ITS SLOW
EASTWARD JAUNT THROUGH THE LONG TERM PERIOD. GFS, ECMWF AND
CANADIAN ALL HAVE THE SAME IDEA BUT TIMING OF WHEN IT PUSHES EAST
OF SOUTH TEXAS WILL BE A MAIN ISSUE ISSUE AS IT WILL PERTAIN TO
WHEN AND IF RAIN CHANCES END LATE IN THE LONG TERM.

MOISTURE BEGINS TO INCREASE IN WAKE OF A WEAK FRONT THU NIGHT AND
FRIDAY AND INCREASE IN EASTERLY FLOW OFF THE GULF TO HELP
INTRODUCE A MORE HUMID FEEL. AS MENTIONED PREVIOUSLY...LIMITED
COLD AIR ADVECTION AND MOSTLY REDUCED SUNSHINE TO COMBINE TO LOWER
TEMPERATURES 5 TO 10 DEGREES FRIDAY. AS WE HEAD INTO WEEKEND
SOUTHWEST UPPER TROUGH/CLOSED LOW TAKES ITS TIME TRACKING
EASTWARD. SUBTROPICAL JET TO STRENGTHEN AS IT IS DIRECTED ACROSS
MEXICO AND INTO THE WESTERN GULF. AT THE SAME A SHARP TROUGH
ASSOCIATED WITH THE NORTHERN JET MOVES DOWN THE FRONT RANGE OF THE
ROCKIES AND TRIES TO PHASE WITH THE SUBTROPICAL JET. THE NORTHERN
TROUGH IS A BIT MORE PROGRESSIVE AND SHOOTS ACROSS TEXAS SUNDAY
PUSHING A RATHER SHARP FRONT THROUGH THE CWA SUNDAY NIGHT WITH THE
GFS AND ECMWF TIMING RATHER CLOSE THIS FAR OUT. RAIN CHANCES TO
PEAK WITH THE APPROACH OF THE FRONT WITH BRIEF DRYING TO TAKE
PLACE AS COLD AIR ADVECTION MAXIMIZES SUNDAY NIGHT AND MONDAY.
TEMPERATURES WILL BE MILD TO WARM IN ADVANCE OF THE FRONT WITH
MONDAY LOOKING LIKE THE COLDEST DAY OF THE PERIOD WITH HIGHS
ONLY IN THE 50S. TIMING OF THE EVENTUAL EASTWARD PASSAGE OF THE
UPPER TROUGH REMAINS DIFFICULT WITH IT TAKING UPWARDS OF 5 DAYS
TO MOVE FROM THE BAJA TO THE WESTERN GULF. THE DETERMINISTIC
MODELS ARE IN RATHER DECENT AGREEMENT TRACKING IT EAST OF THE CWA
LATER TUESDAY. SOME MENTION OF RAIN REMAINS IN THE FORECAST UNTIL
THE TROUGH DOES MOVE EAST OF THE AREA. A BLEND OF THE MODELS
INDICATES THIS AS WELL.

MARINE...NOW THROUGH THURSDAY...BROAD HIGH PRESSURE OVER THE
AREA WILL SHIFT SLOWLY EAST...MAINTAINING LIGHT TO MODERATE WINDS
AND LOW SEAS THROUGH THE SHORT TERM.

THURSDAY NIGHT THROUGH SUNDAY...WEAK FRONT MOVES THROUGH THURSDAY
NIGHT INTO FRIDAY. WINDS TURN NORTHEAST TO EAST BUT REMAIN BELOW
SCA AND SCEC LEVELS. HIGH PRESSURE MOVES EAST AND WINDS WINDS TURN
SOUTHEAST AS A STRONGER LOWER PRESSURE SYSTEM TAKES SHAPE OVER
WESTERN NORTH AMERICA. THE FIRST AFFECTS OF THIS SYSTEM WILL BE A
STRONG COLD FRONT LATE SUNDAY. A STRONG NORTHERLY SURGE WITH
POSSIBLE GALE FORCE GUSTS TO ACCOMPANY THE PASSAGE OF THE FRONT.
RAIN CHANCES INCREASE OVER THE WEEKEND BUT TEMPERATURES DO NOT
COOL OFF SUBSTANITALLY UNTIL THE MAIN FRONT ON SUNDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

54/68