AFDBRO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 401 AM CDT TUE APR 19 2011 .SHORT TERM /TODAY THROUGH WEDNESDAY/...MAIN FORECAST QUESTION IS HOW HIGH THE WINDS ALONG THE COAST WILL REACH TODAY. SIGNIFICANT PRESSURE GRADIENT SETTING UP BETWEEN LOW PRESSURE IN THE WESTERN VALLEY AND DOMINANT SFC RIDGE ACROSS THE NORTHERN GULF. WILL NEED TO WAIT FOR MORNING SOUNDING TO VERIFY IF VWP IS INDEED CORRECT IN INDICATING 60KT WINDS AT 2KFT. ON THE OTHER HAND...THE SFC LOW AND ASSOCIATED DRYLINE WILL ENTER INTO THE WESTERN VALLEY THIS AFTERNOON...BRINGING ALMOST CALM WINDS GENERALLY WEST OF US 281. IF MORNING SOUNDING DOES COME BACK WITH 50KT WINDS ALOFT...THEN WESTERN COUNTIES WOULD EASILY SEE 20 TO 25 KNOTS SUSTAINED...WITH QUICK DECREASE IN WINDS STILL EXPECTED THE FURTHER WEST YOU GO. IN EITHER CASE...DRY SOUTH WINDS ALONG THE COAST WILL BRING TEMPS INTO THE LOWER 90S...WHILE THE DRYLINE WILL BRING IN DESERT AIR...ALLOWING TEMPS OUT WEST TO JUMP QUICKLY TO 100 TO 105. BREEZY CONDITIONS WILL CONTINUE THROUGH THE NIGHT TONIGHT...WITH GENERALLY OVERCAST SKIES AND LOWS GENERALLY WITHIN 2 DEGREES OF DAILY RECORD HIGH MINIMUM TEMPERATURES IN THE MID TO UPPER 70S. WEDNESDAY WILL BE SIMILAR TO TODAY EXCEPT FOR LESSER EFFECTS OF THE DRYLINE MOVING INTO THE WESTERN VALLEY...RESULTING IN TEMPS A COUPLE DEGREES LOWER THAN TODAY. .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...NEARLY ZONAL FLOW TO PREVAIL ACROSS THE SOUTHERN UNITED STATES WEDNESDAY BEFORE A BROAD 500MB TROUGH DEVELOPS ACROSS THE WESTERN U.S. THURSDAY. LOW PRESSURE IS PROGGED TO DEVELOP ON THE LEE SIDE OF THE ROCKIES THURSDAY AND MOVE EASTWARD FRIDAY. THIS WILL RESULT IN VERY WARM AND HUMID CONDITIONS ACROSS SOUTH TEXAS THROUGH THE REST OF THE WEEK WITH RAIN CHANCES REMAINING WELL TO THE NORTH OF THE AREA. THE 00Z ECMWF HINTS AT SOME CONVECTION DEVELOPING ACROSS THE MEXICAN PLATEAU SATURDAY BUT THE ATMOSPHERE WILL LIKELY REMAIN CAPPED INTO THE WEEKEND. THE TROUGH ACROSS THE WESTERN U.S. IS PROGGED TO DEEPEN SUNDAY AND THIS WILL RESULT IN THUNDERSTORMS DEVELOPING ACROSS NORTHWEST TX. OUTFLOW BOUNDARIES FROM THESE STORMS MAY ERODE THE CAP ENOUGH FOR CONVECTION TO DEVELOP FURTHER SOUTH ESPECIALLY AS THE TROUGH MOVES EASTWARD TOWARDS THE END OF THE FORECAST PERIOD. AM RELUCTANT TO MENTION RAIN CHANCES SUN NIGHT THROUGH MONDAY AS CONFIDENCE IN THE STRENGTH AND TIMING OF THIS SYSTEM LOW AT THIS TIME. && .MARINE...SMALL CRAFT ADVISORY FOR THE GULF WATERS WILL BE PULLED WITH THE NEXT UPDATE AS 20KT WINDS APPEARED FOR 1 HOUR EARLIER THIS EVENING AND PROMPTLY DECREASED AGAIN. ADVISORIES ARE STILL IN EFFECT FOR THE LAGUNA MADRE FOR THE DAY TODAY AS WINDS WILL STILL INCREASE TO 20 KNOTS AFTER SUNRISE. WINDS ACROSS THE GULF WILL REMAIN IN THE 15 TO 20 KNOT RANGE...WITH SEAS 4 TO 5 FEET. MODELS SHOW ANOTHER INCREASE IN WINDS OVERNIGHT TONIGHT...BUT HAVE BUSTED 2 OF THE PAST 3 NIGHTS...SO WILL BE VERY HESITANT TO FORECAST THIS AGAIN TONIGHT. WEDNESDAY WILL AGAIN BE BREEZY NEAR THE COAST...AND WILL HAVE TO MONITOR FOR MORE ADVISORIES FOR THE LAGUNA. WEDNESDAY NIGHT THROUGH SATURDAY...MODERATE TO STRONG SOUTHEAST WINDS WILL CONTINUE WED NIGHT THROUGH THE REST OF THE WEEK INTO THE BEGINNING OF THE WEEKEND AS THE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE WESTERN GULF OF MEXICO THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 90 76 89 77 / 0 0 0 10 BROWNSVILLE 91 75 91 76 / 0 0 0 10 HARLINGEN 95 76 96 76 / 0 0 0 10 MCALLEN 95 76 96 76 / 0 0 0 10 RIO GRANDE CITY 101 76 100 75 / 0 0 0 10 SOUTH PADRE ISLAND 83 77 81 77 / 0 0 0 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY FOR WINDS FROM 10 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR GMZ130-132-135. SMALL CRAFT ADVISORY UNTIL 7 AM CDT THIS MORNING FOR GMZ150-155- 170-175. && $$