Small Craft Advisory for Winds 30, NWS Brownsville, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1226 AM CDT THU APR 12 2012

CORRECTED TO FIX TYPO IN AVIATION SECTION.

.DISCUSSION...GOING FORECAST APPEARS SOUND AT THIS HOUR. MCS WEST
NORTHWEST OF LAREDO...AS WELL AS SOME DEVELOPING RETURNS WEST OF
ZAPATA ARE THE MAIN NEAR TERM FOCUS. AIRMASS IS WEAKLY TO
MODERATELY CAPPED AND THE BOUNDARY LAYER IS SLOWLY STABILIZING
AS THE NIGHT WEARS ON. GFS40/NAM12 SUGGEST BEST UPPER DIVERGENCE
WILL MOVE TO THE NORTH OF THE CWA AND TRENDS IN WV/IR IMAGERY AND
AVAILABLE RADAR SEEM TO SUPPORT THAT TREND. CONTINUING A SLIGHT
CHANCE OF THUNDER FOR THE NORTHWEST THOUGH WERE ENOUGH SURFACE
CONVERGENCE AND MID LEVEL AIRMASS MODIFICATION MAY OCCUR TO ALLOW
FOR A QUICK STORM OR SHOWER. WILL BE MONITORING CLOSELY. /68-JGG/

ALSO UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...DELAYED ONSET OF MVFR CIGS IN THIS MORNINGS PACKAGE.
MID LEVEL CLOUD DECK FROM CONVECTION TO THE NORTHWEST HAS
OVERSPREAD PORTIONS OF THE AREA AND SLIGHTLY SLOWED OUR SURFACE
COOLING. AREAS IN THE NORTH AND NORTHWEST WILL LIKELY GO MVFR
THROUGH THE NEXT COUPLE OF HOURS...WHILE THE TAF SITES IN THE RGV
WILL LIKELY WAIT UNTIL MID TO LATE MORNING. THERE IS AT LEAST SOME
POSSIBILITY OF REMAINING VFR...AND ALSO MVFR VISBY WITH PATCHY FOG
THROUGH PORTIONS OF SOUTH TEXAS. EXPECT CIGS TO RAPIDLY IMPROVE
THIS MORNING WITH SCATTERED MID TO LOW CLOUDS. SOUTHEAST WINDS
WILL PICK UP AND BE RATHER STRONG BY MIDDAY WITH GUSTS IN THE 25
TO 30 KNOT RANGE EXPECTED. WINDS WILL DIMINISH BY AROUND SUNSET. /68/

&&

.PREV DISCUSSION... /ISSUED 638 PM CDT WED APR 11 2012/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS DEEP SOUTH TEXAS
THROUGH THIS EVENING. MVFR CEILINGS WILL DEVELOP LATER TONIGHT AS
LOW LEVEL MOISTURE INCREASES BELOW THE THERMAL INVERSION. CEILINGS
WILL IMPROVE AFTER 15Z THURSDAY AS WINDS INCREASE WITH MIXING.
SOUTHEAST WINDS ARE EXPECTED INCREASE BY THURSDAY AFTERNOON AS THE
PRESSURE GRADIENT TIGHTENS ACROSS THE AREA.

PREV DISCUSSION... /ISSUED 211 PM CDT WED APR 11 2012/

SHORT TERM.../TONIGHT THROUGH THURSDAY NIGHT/...500MB RIDGE ACROSS
NORTHERN MEXICO AND WEST TEXAS THIS AFTERNOON WILL MOVE EASTWARD
THURSDAY ALLOWING SUBSIDENCE ACROSS THE RIO GRANDE PLAINS TO WEAKEN.
THE 12Z GFS PROGS CONVECTION DEVELOP NEAR THE BIG BEND AREA TONIGHT
AND PROPAGATING SOUTHEAST LATE TONIGHT. WILL MENTION A SLIGHT CHANCE
OF SHOWERS AND THUNDERSTORMS FOR EXTREME WESTERN PORTIONS OF THE CWA
TONIGHT. WILL ALSO MENTION A SLIGHT CHANCE FOR THE SAME AREA THURS
NIGHT AS THUNDERSTORMS WILL LIKELY DEVELOP ACROSS THE MEXICAN
PLATEAU TOMORROW NIGHT AND POSSIBLY MOVE ACROSS EXTREME WESTERN
PORTIONS OF THE RIO GRANDE VALLEY LATE TOMORROW NIGHT.

LONG TERM.../FRIDAY THROUGH WEDNESDAY NIGHT/...
UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL PLAINS WILL SLIDE EAST
FRIDAY AS A LOW PRESSURE SYSTEM OVER THE PACIFIC COAST MOVES INLAND
IN THE CALIFORNIA COAST. A LEE TROUGH/DRYLINE DEVELOPS ALONG THE
EASTERN PORTION OF NEW MEXICO STRETCHING SOUTH TOWARDS THE SIERRA
MADRE. PLENTY OF GULF MOISTURE WILL ENHANCE THUNDERSTORM ACTIVITY
FRIDAY AFTERNOON ALONG AND EAST OF THE SIERRA MADRE. A FEW ISOLATED
STORMS WILL LIKELY REACH THE NORTHWESTERN PORTION OF THE CWA FRIDAY
EVENING. THIS WILL LIKELY PRODUCE HEAVY DOWNPOURS WITH SMALL HAIL
AND GUSTY WINDS. A TIGHTER GRADIENT ALONG THE RIO GRANDE VALLEY DUE
TO A LEE SIDE TROUGH...WILL STRENGTHEN FRIDAY AFTERNOON THROUGH THE
WEEKEND INCREASING SOUTHEAST WINDS BETWEEN 15 TO 20 MPH WITH GUSTS
UP TO 25 MPH. WINDS WILL BE BELOW WIND ADVISORY CRITERIA FOR THE CWA
BUT WILL NOT RULE OUT A FEW GUSTS UP TO 30 MPH. PERTURBATIONS WITHIN
THE UPPER LEVEL LOW COULD PRODUCE SOME THUNDERSTORMS DEVELOPING OVER
THE CWA FRIDAY EVENING BUT CHANCE IS VERY MINIMAL. TEMPERATURES WILL
REMAIN ABOVE NORMAL THROUGH THE BEGINNING OF NEXT WEEK.

THE LOW PRESSURE SYSTEM OVER THE CALIFORNIA COAST STRENGTHENS OVER
THE FOUR CORNERS REGION AND CONTINUES TO MOVE NORTHEAST INTO NEXT
WEEK. A FRONT ASSOCIATED WITH THIS SYSTEM WILL MAKE ITS WAY SOUTH
ACROSS TEXAS MONDAY NIGHT INTO EARLY MORNING TUESDAY. A LINE OF
STORMS WILL LIKELY DEVELOP AHEAD OF THIS FRONTAL BOUNDARY. LOW
TEMPERATURES TUESDAY NIGHT WILL REACH THE LOW 70S WITH A FEW SPOTS
IN THE NORTHERN PORTION OF THE CWA REACHING THE MID 60S. EXPECT A
QUICK WARM UP INTO THE MID 80S QUICKLY WEDNESDAY MORNING AS CLEAR
SUNNY SKIES WILL WARM UP TEMPERATURES.

MARINE...TONIGHT THROUGH THURSDAY NIGHT...SEAS WERE NEAR 4 FEET WITH
SOUTHEAST WINDS NEAR 14 KNOTS AT BUOY020 EARLY THIS AFTERNOON.
MODERATE TO STRONG SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL
WATERS TONIGHT INTO THURSDAY AS A SURFACE TROUGH OF LOW PRESSURE
ACROSS WEST TEXAS AND A SURFACE RIDGE OF HIGH PRESSURE ACROSS THE
EASTERN UNITED STATES TIGHTENS THE PRESSURE GRADIENT ACROSS THE
WESTERN GULF OF MEXICO. WILL WORD SCEC FOR THE OFFSHORE WATERS
TONIGHT BUT SMALL CRAFT ADVISORIES MAY BE NEEDED TONIGHT AND
POSSIBLY THURS NIGHT IF WINDS ARE SLIGHTLY STRONGER THAN FORECAST.

FRIDAY THROUGH TUESDAY NIGHT...
MARINE WEATHER WILL BEGIN TO DETERIORATE BY FRIDAY AS SOUTHEAST FLOW
INCREASES BETWEEN 15 TO 20 KTS WITH A FEW HOURS IN THE AFTERNOON
GUSTING UP TO 25 KTS. NO SCA CRITERIA EXPECTED FRIDAY. HOWEVER...
WINDS AND SEAS WILL BEGIN TO INCREASE INTO SATURDAY AS LEE SIDE
TROUGH INTERACTS WITH THE SURFACE HIGH OVER THE GULF. A SCA WILL
LIKELY BE ISSUED FRIDAY EVENING INTO SATURDAY. AN UPPER LEVEL LOW
WILL MOVE EAST OVER THE FOUR CORNERS REGION AND AN ASSOCIATED FRONT
WILL MAKE ITS WAY SOUTH OVER DEEP SOUTH TEXAS BY MONDAY NIGHT INTO
TUESDAY. EXPECT A LINE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER
THE MARINE ZONES OVER THE MONDAY AFTERNOON. SOUTHEAST WINDS WILL
SHIFT NORTH/NE WITH THE PASSAGE OF THIS FRONT.

&&

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

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