AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
641 AM CDT FRI JUL 8 2011

.DISCUSSION...SEE THE AVIATION SECTION BELOW FOR THE UPDATED
DISCUSSION ON THE 12Z TAF PACKAGE.

&&

.AVIATION...UPSTREAM RIDGING ALOFT AND SURFACE HIGH PRESSURE IN THE
WEST GULF ARE TEAMING UP TO PRODUCE MOSTLY CLEAR SKIES AND LIGHT
ONSHORE WINDS THIS MORNING. SMALL ISOLATED SHOWERS ARE MOVING NORTH
ALONG THE COAST AND MAY PRODUCE A SPRINKLE AT SOUTH PADRE ISLAND AND
EVEN POSSIBLY BROWNSVILLE...BUT THE SHOWERS SHOULD DISSIPATE BY MID
MORNING. GROUND MOISTURE APPEARS TO BE SUFFICIENTLY DECREASED TO
PRECLUDE THE NEED FOR ANY FURTHER OVERT MENTION OF PATCHY MORNING
FOG IN THE UPCOMING TAF PACKAGE. FEW TO SCT FAIR WEATHER CU WILL
DEVELOP DURING THE DAY...WITH VFR CONDITIONS. LOW PRECIPITABLE WATER
AMOUNTS SUGGEST VERY LIMITED SEA BREEZE POTENTIAL...THOUGH ISOLATED
BUILDUPS MAY DEVELOP BRIEFLY ALONG THE COAST IN THE EARLY
AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 334 AM CDT FRI JUL 8 2011/

SHORT TERM /TODAY THROUGH SATURDAY/...IR SATELLITE IMAGERY SHOWS A
RELATIVELY CLEAR PICTURE FOR THE WEST GULF OF MEXICO AND THE SOUTH
AND WEST PORTIONS OF TEXAS. H5 RIDGING UPSTREAM AND SURFACE HIGH
PRESSURE OVER THE WEST GULF WILL PERSIST IN THE SHORT TERM. AN
ELONGATED AREA OF LOW PRESSURE FROM THE YUCATAN PENINSULA TO THE
WEST COAST OF FLORIDA IS NOT EXPECTED TO PLAY A ROLE ON THE WESTERN
SIDE OF THE GULF. USED A MET/MAV BLEND TO NUDGE HIGH TEMPS A DEGREE
OR SO ABOVE PURE MAV GUIDANCE...WHICH WILL ESSENTIALLY BE A DEGREE
ABOVE YESTERDAY...WHICH SEEMED REASONABLE GIVEN THE FORECAST OF
AMPLE SUNSHINE AND LOWERING GROUND MOISTURE. OTHERWISE...SHOULD SEE
A FEW MORNING LOW CLOUDS...FOLLOWED BY FEW TO SCT LOW CU AND A WEAK
IF ANY SEA BREEZE GIVEN THE RELATIVELY LOW PWAT...LESS THAN 1.5
INCHES BEING FORECAST FOR TODAY. MOISTURE WILL BE SLIGHTLY HIGHER ON
SATURDAY IN PART DUE TO A WEAK FRONTAL BOUNDARY MOVING INTO THE
NORTHWEST GULF...PROVIDING A SOURCE OF MOISTURE TO BE PICKED UP BY
ONSHORE WINDS. HEAT INDEX VALUES ON SATURDAY WILL CREEP ABOVE THE
CENTURY MARK TO NEAR 105 AT SOME PLACES NEAR THE RIVER AND INLAND.
LIGHT TO MODERATE SOUTH SOUTHEAST WINDS WILL PREVAIL.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...A WEAK MID-LEVEL LOW
PRESSURE SYSTEM WILL GRADUALLY RETROGRADE FROM THE LOWER TEXAS COAST
AT THE BEGINNING OF THE PERIOD...TO THE TEXAS BIG BEND AND FINALLY
THE TEXAS PANHANDLE BY TUESDAY NIGHT. THE PASSAGE OF THIS SYSTEM...
COMBINED WITH DEEPER TROPICAL MOISTURE...FEATURING PRECIPITABLE
WATER VALUES BETWEEN 1.5 AND 2.0 INCHES...WILL PRODUCE ISOLATED
SHOWERS AND THUNDERSTORMS DURING THE DAYLIGHT HOURS LATER IN THE
WEEKEND INTO EARLY NEXT WEEK...WITH STREAMER SHOWERS DURING THE
OVERNIGHT HOURS OF THE SAME PERIOD. MID-LEVEL HIGH PRESSURE THEN
BUILDING SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY...AND THEN
WEST INTO THE LONE STAR STATE...WILL EFFECTIVELY ENFORCE DRIER
WEATHER WITHIN THE RIO GRANDE VALLEY FOR WEDNESDAY AND THURSDAY.
HOWEVER...ENOUGH DEEP TROPICAL MOISTURE WILL LINGER TO ALLOW FOR
CONTINUED STREAMER ACTIVITY AT NIGHT DURING THIS TIME. WELL ABOVE
NORMAL TEMPERATURES AT THE START OF THE LONG TERM FORECAST PERIOD
WILL GRADUALLY WARM AS THE INITIAL PRECIPITATION CHANCES WANE AND
GIVE WAY TO THE MORE OPPRESSIVE MID-LEVEL HIGH PRESSURE SYSTEM...
RESULTING IN DOWNRIGHT HOT CONDITIONS BY THE END OF THE FORECAST.

MARINE...TODAY THROUGH SATURDAY...THE LATEST OB FROM BUOY020 SHOWED
LIGHT SSE WINDS AND SEAS OF ONE TO TWO FT WITH A PERIOD OF 3 SECONDS.
THAT`S THE WAY IT WILL GO IN THE SHORT TERM WITH BROAD HIGH PRESSURE
ACROSS THE WESTERN GULF OF MEXICO. LIGHT TO MODERATE SOUTHEAST WINDS
AND LOW TO MODERATE SEAS OF ONE TO THREE FEET WILL BE THE PRIMARY
FORECAST. HOWEVER...PRESSURE FALLS OVER THE SOUTHERN HIGH PLAINS
FRIDAY NIGHT INTO SATURDAY WILL TIGHTEN THE GRADIENT SLIGHTLY...
RESULTING IN 15 TO 20 KNOT SOUTH SOUTHEAST WINDS AND EXERCISE CAUTION
CONDITIONS ON THE GULF LATE FRIDAY...BUT WITH MODERATE WINDS ON
SATURDAY.

SATURDAY NIGHT THROUGH THURSDAY...SURFACE HIGH PRESSURE OVER THE
GULF OF MEXICO WILL INTERACT MODERATELY WITH LOW PRESSURE THAT WILL
PERSIST OVER THE TEXAS BIG BEND AND EXTREME WEST TEXAS. THIS PATTERN
WILL PRODUCE LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS FOR
THE ADJACENT COASTAL WATERS OF DEEP SOUTH TEXAS THROUGH THE PERIOD.

&&

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

$$