FXUS64 KBRO 262038 AFDBRO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 238 PM CST TUE NOV 26 2013 .SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...A MID LEVEL TROUGH SLIDING EAST IS NOW ALL BUT HISTORY FOR THE CWA AS HIGH PRESSURE PUSHES SOUTH FROM THE PLAINS IN FRONT OF A BUILDING RIDGE OVER THE WEST. PARTLY CLOUDY SKIES WILL BECOME MOSTLY CLEAR TONIGHT...WITH SOME UNSEASONABLY COLD WEATHER ON TAP...WITH NEAR RECORD LOW TEMPS POSSIBLE. LIGHT NORTHWEST WINDS MAY BE JUST ENOUGH TO TRIGGER A WIND CHILL ADVISORY...BUT IT WILL BE VERY BORDERLINE...AND OPTED TO HOLD OFF ON PULLING THE TRIGGER FOR NOW. NEXT SHIFT CAN WATCH WIND AND TEMPERATURE TRENDS BEFORE MAKING A FINAL DECISION. LOW TEMPERATURES WILL BE MAINLY IN THE 30S FOR MOST INLAND AREAS TONIGHT. STUCK WITH THE INHERITED FORECAST FOR THE MOST PART...WHICH MIRRORED GUIDANCE. TEMPS WILL WARM INTO THE 50S TO NEAR 60 ON WEDNESDAY...WITH A VERY NICE DAY OTHERWISE IN STORE UNDER MOSTLY SUNNY SKIES. WEDNESDAY NIGHT WILL ALSO BE UNSEASONABLY COLD...WITH VERY LITTLE THAT WILL BE MUCH DIFFERENT IN THE OVERALL WEATHER PATTERN. WINDS WILL BE LIGHTER THAN TONIGHT THOUGH...AND THERE WILL BE A THREAT OF A FREEZE IN THE RURAL AREAS WITH LOW TEMPERATURES POSSIBLY DIPPING BELOW FREEZING FOR A FEW HOURS BEFORE DAWN. .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... WEDNESDAY NIGHT INTO THURSDAY A WEAK UPPER RIDGE OVER THE CENTRAL PLAINS WILL HELP STRETCH SURFACE HIGH PRESSURE SOUTHWESTWARD OVER DEEP SOUTH TEXAS. CONVERGENCE ALOFT WILL COUPLE WITH CONTINUED NORTHEAST WINDS TO KEEP CONDITIONS DRY...BOTH FROM A HUMIDITY AND A PRECIP STANDPOINT. SOME MIDDLE AND HIGH CLOUD COVER IS EXPECTED AND THE ONGOING COOLER AIR ADVECTION SHOULD HELP KEEP HIGHS IN THE LOWER TO MID 60S. THURSDAY INTO FRIDAY THAT SURFACE RIDGE SHIFTS EASTWARD AND OUR LOW LEVEL FLOW BECOMES MORE ONSHORE AND EASTERLY. THE GULF AIRMASS IS PRETTY WORKED OVER SO DEWPOINT/MOISTURE RECOVERY WILL TAKE A WHILE BUT EXPECT DEWPOINTS WILL HAVE STARTED AN UPWARD TREND BY LATER IN THE DAY AND A FEW CU WILL PROBABLY START TO BUBBLE IN THE AFTERNOON WITH HIGHS WARMING INTO THE LOWER 70S. DATA FROM A RECENT MODIS POLAR ORBITING SATELLITE PASS AND NEARSHORE TEMPERATURE OBSERVATIONS SHOW THE FRONT AND PERSISTENT NORTH WINDS HAVE DRASTICALLY REDUCED THE TEMPERATURE OF THE NEARSHORE GULF OF MEXICO DUE TO UPWELLING. THE SATELLITE SUGGESTS THE MORE DRASTIC DEPARTURE IS WITHIN 5 TO 15 MILES OF THE COASTLINE...WHICH IS FAIRLY TYPICAL. WITH EASTERLY WINDS PROJECTED TO FLOW OVER THE GRADIENT OF RELATIVELY WARM...76F ACCORDING TO BUOY 20...OFFSHORE WATER...TO THE RELATIVELY COLD NEARSHORE WATER...A SETUP FAVORABLE FOR SEA ADVECTION FOG EXISTS. ADDED FOG TO THE OVERNIGHT GROUP THURSDAY NIGHT INTO FRIDAY...BUT IN LOCALIZED AREAS THE TIME OF DAY MAY NOT MAKE A SIGNIFICANT DIFFERENCE REGARDING FOG FORMATION WITH PARTS OF SOUTH PADRE ISLAND AND THE NEARSHORE WATERS POSSIBLY EXPERIENCING FOG FOR AN EXTENDED PERIOD OF TIME. SATURDAY INTO SUNDAY A SHORTWAVE TROUGH WORKS INTO THE CENTRAL PLAINS AND OUR LOW LAYER FLOW RESPONDS BY BECOMING MORE DUE SOUTHERLY. THIS HELPS FURTHER A GENERAL WARMING TREND WITH LOW LEVEL MOISTURE INCREASING. NOTED AN INCREASE IN CLOUD COVER IN THE FORECAST FOR THE WEEKEND INTO EARLY NEXT WEEK. MONDAY INTO TUESDAY THE TROUGH PASSES WELL TO THE NORTHEAST AND SIGNIFICANT RAIN CHANCES LOOK TO REMAIN TO THE NORTHEAST AS WELL. THE LACK OF A SIGNIFICANT LOW LAYER REFLECTION IS ALSO APPARENT AND KEPT THE WINDS COMING OUT OF THE SOUTHEAST AS RIDGING OVER THE NORTHCENTRAL GULF INTENSIFIES BEHIND THE UPPER TROUGH. THE END OF THE PERIOD SHOWS ANOTHER FAIRLY STRONG TROUGH DIGGING INTO THE INTERMOUNTAIN WEST BUT THE ONLY IMPACT BY TUESDAY ARE PERHAPS SOME INCREASED SOUTHERLY WINDS. BY SUNDAY INTO MONDAY SEASONABLE TEMPERATURES ARE EXPECTED WITH HIGHS IN THE UPPER 70S TO LOW 80S. && .MARINE... NOW THROUGH WEDNESDAY NIGHT...A GALE WARNING CONTINUES ON THE GULF THROUGH 6 PM...WITH GALE FORCE GUSTS VERIFYING AT THE OFFSHORE BUOY. THE GALE WARNING WILL BE REPLACED WITH A SMALL CRAFT ADVISORY THIS EVENING AT SOME POINT AS WINDS DECREASE. CONDITIONS WILL STEADILY IMPROVE TONIGHT THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE SPREADS OVER THE AREA. LIGHT NORTHEAST WINDS AND MODERATE SEAS ARE EXPECTED BY EARLY THURSDAY. WEDNESDAY NIGHT THROUGH SATURDAY... PERIODS OF SEA FOG...POSSIBLY DENSE WILL BE POSSIBLE THROUGH THE END OF THE WEEK INTO THE WEEKEND. THE MOST LIKELY PERIOD FOR FOG WILL BE FRIDAY AND SATURDAY MORNING. ASIDE FROM THE POTENTIAL FOR FOG DEVELOPMENT CONDITIONS SHOULD BE FAVORABLE FOR MARINERS. MODERATE NORTHEAST WINDS SHOULD SHIFT TO THE EAST THURSDAY INTO FRIDAY BEFORE SHIFTING MORE SOUTHERLY ON SATURDAY. LOW TO MODERATE SEAS ARE EXPECTED DURING THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 41 57 40 61 / 0 0 0 10 BROWNSVILLE 38 58 38 63 / 0 0 0 10 HARLINGEN 36 59 36 63 / 0 0 0 0 MCALLEN 40 60 38 63 / 0 0 0 0 RIO GRANDE CITY 36 60 36 62 / 0 0 0 0 SOUTH PADRE ISLAND 47 58 44 61 / 0 0 0 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ130-132- 135. GALE WARNING UNTIL 6 PM CST THIS EVENING FOR GMZ150-155-170-175. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV SHORT TERM...54 LONG TERM...68-GIBBS UPPER AIR/GRAPHICAST...MARTINEZ  FXUS64 KBRO 200859 AFDBRO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 359 AM CDT FRI JUN 20 2014 .SHORT TERM /NOW THROUGH SATURDAY/...THE 500 MB TROFFING JUST TO OUR WEST WILL LINGER THERE THROUGHOUT TODAY AND THIS EVENING AND WILL EVENTUALLY SHIFT GRADUALLY NORTH THROUGHOUT SATURDAY. THE DEEP LAYER MOISTURE ASSOCIATED WITH THIS FEATURE WILL ALSO REMAIN CONCENTRATED JUST WEST OF DEEP SOUTH TX AS 500 MB RIDGING REMAINS IN CONTROL OVER THE WESTERN GULF OF MEX AND THE TX COASTLINE. DAYTIME HEATING LATER TODAY WILL ALSO LIKELY HELP ENHANCE THE POTENTIAL CONV OVER THE HIGHER TERRAIN OF NORTHEAST AND NORTH CENTRAL MEXICO. THIS IS NOT A GREAT SET UP FOR RAINFALL ACROSS DEEP SOUTH TX THROUGHOUT THE SHORT TERM. HOWEVER ISOLD CONV CAN NOT BE RULED OUT ESPECIALLY TODAY DUE TO THE FAIRLY CLOSE PROXIMITY OF THE 500 MB TROFFING. THE NAM GUIDANCE DOES NOT REFLECT ANY DECENT POPS THROUGHOUT THE SHORT RANGE PERIOD. HOWEVER BOTH THE GFS AND ECMWF GUIDANCE ARE SHOWING A LITTLE WETTER SCENARIO FOR TODAY AND WILL GO AHEAD AND INCLUDE SOME MENTION OF ISOLD CONV TODAY. FOR TEMPS TODAY WILL GO A LITTLE COOLER FOR HIGHS AS WITH THE CONV FIRING TO OUR WEST LATER TODAY EXPECT PLENTY OF DEBRIS CLD COVER TO SPREAD OVER THE RGV WHICH COULD LOWER TEMPS A FEW DEGREES. WILL GO A LITTLE WARMER HIGHS FOR SATURDAY AS THE 500 MB TROFFING PULLS FURTHER AWAY FROM US AND ALLOWS THE MID LEVEL RIDGING TO BUILD A LITTLE FURTHER WEST INCREASING THE 1000-500 MB THICKNESSES A BIT. WILL STILL LEAN CLOSER TO THE WARMER SIDE OF GUIDANCE FOR HIGHS. THE SHORT TERM GUIDANCE IS IN PRETTY GOOD AGREEMENT FOR MINS TONIGHT AND WILL GO WITH A MODEL CONSENSUS HERE. .LONG TERM /SUNDAY THROUGH FRIDAY/... SUNDAY AND MONDAY SHOULD CONTINUE TO BE DRY AND HOT WITH OVERALL COLUMN AND LOW LEVEL MOISTURE LACKING. MODERATE TO BREEZY SOUTHEAST WINDS WILL LOOK TO CONTINUE AS WELL. NOTABLE MODEL DISCREPANCY THOUGH BEGINS ON SUNDAY NIGHT. OVERALL THE GFS IS MORE AGGRESSIVE WITH AN UPPER TROUGH MOVING INTO THE NORTH CENTRAL AND CENTRAL GULF AND THEN STALLING. THE ORIENTATION OF THE TROUGH IS FURTHER REINFORCED WHEN ANOTHER WAVE DIGS INTO THE EASTERN U.S. BY TUESDAY NIGHT. THIS LEAVES THE MAIN WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE CENTRAL GULF AND A SFC SHEAR ZONE SETS UP AND PREVENTS A SURGE OF CARRIBEAN SOURCED LOW LEVEL EASTERLIES FROM MOVING INTO THE WESTERN GULF AND SIGNIFICANTLY INCREASING AVAILABLE MOISTURE OVER SOUTH TEXAS. THE ECMWF IS MUCH WEAKER WITH THE INITIAL TROUGH AND DOES NOT PROVIDE IT WITH A REINFORCING SURGE...PLACING THE GENERAL TROUGHINESS MORE OVER LOUISIANA AND TEXAS. THIS ALLOWS A SURGE OF DEEP EASTERLIES...WHICH HAVE BEEN PERSISTENT IN THE CARRIBEAN AND ARE VISIBLE ON THE 20.01 ASCAT PASS OF THAT AREA...TO PUMP DEEP AND RICH MOISTURE INTO THE AREA BY TUESDAY THROUGH THE REST OF THE WEEK AND THE ECMWF INCREASES PRECIP CHANCES AND QPF ACCORDINGLY. BY THURSDAY INTO FRIDAY THIS EVOLVES INTO A DRASTICALLY DIFFERENT UPPER LEVEL PATTERN BETWEEN THE GFS/ECMWF. THE GFS PRODUCES SHARP TROUGHING OVER LOUISIANA AND THE ADJACENT GULF WATERS WITH A 594 DM RIDGE CENTERED OVER NORTHWESTERN MEXICO TO OUR WEST AND A WEAKER BERMUDA HIGH OVER FLORIDA AND CUBA. THE ECMWF SLOWLY CLOSES OFF RIDGING OVER FLORIDA EMBEDDED IN A MUCH LARGER SCALE HIGH PRESSURE SYSTEM WITH RIDGING OVER THE SONORAN DESERT REGION OF MEXICO AND ARIZONA AND PERSISTENT RESIDUAL TROUGHINESS OVER TEXAS. THE ECMWF PATTERN WOULD BRING A MUCH WETTER/SHOWERY REGIME TO THE AREA WITH MORE MODERATED TEMPERATURES WHEREAS THE GFS WOULD ALMOST CERTAINLY BE A CONTINUATION OF THE COPY PASTE HOT AND BREEZY WEATHER OF THE LAST WEEK OR SO. THE GFS SOLUTION HAS BEEN THE MOST CONSISTENT WHERE THE ECMWFS WETTER PICTURE HAS ONLY BEGUN DEVELOPING IN THE LAST 2 TO 4 RUNS...ALTHOUGH THERE IS EMERGING RUN TO RUN CONSISTENCY. FOR THE FORECAST BASED IT AROUND A SCENARIO WHERE THE GULF TROUGHINESS IS NOT QUITE AS PRONOUNCED...BUT THE DEEP 30 KNOT EASTERLY WINDS IN THE 850/700MB LAYER DO NOT GET QUITE AS CARRIED AWAY EITHER. THE WAVES IN QUESTION ARE CLEARLY PRETTY PRONOUNCED ON SATELLITE IMAGERY BUT NOT ASSOCIATED WITH MUCH PRECIP AT THE MOMENT AND AMSU/SSMI AND MODIS TOTAL PRECIPITABLE WATER IMAGERY APPEAR TO SUGGEST THERE IS NOT AS MUCH AVAILABLE MOISTURE AS THE ECMWF INITIALIZED. EVEN IF THE SYNOPTIC ECMWF SOLUTION WERE TO VERIFY THE 40 AND 50 PCT POPS PRESENTED BY ECX MOS APPEAR FAR TOO HIGH AND THUNDER WOULD BE DIFFICULT/IMPOSSIBLE IN A ZONE WITH LAPSE RATES AS POOR AS SHOULD BE IN PLACE. SO PAINTED LOW GRADE POPS/SHOWERS STARTING IN THE MORNING ALONG THE COAST WORKING INLAND THROUGH THE DAY AND INTO THE MORE FAVORED SEABREEZE ZONES BY AFTERNOON WEDNESDAY AND THURSDAY AND HUGGED BACK TOWARDS A DRIER SOLUTION ON FRIDAY. KEPT TEMPERATURES WARMER IN LINE WITH A DRIER OVERALL ENVIRONMENT BUT MODERATED SOMEWHAT BY THE FACT THE WIND DIRECTION IS MORE EASTERLY AND ONSHORE. SPEEDS ARE ALSO MORE MODERATE AND A SEABREEZE BOUNDARY MAY BE ABLE TO SET UP BY TUESDAY/WEDNESDAY. CLOUD COVER IS UP FROM WHAT WE HAVE SEEN THE LAST 4 OR 5 DAYS. /68-JGG/ && .MARINE...NOW THROUGH SATURDAY...FAIRLY PERSISTENT SURFACE RIDGING OVER THE SOUTHEASTERN U.S. WILL MAINTAIN A FAIRLY STEADY AND MODERATE S-SE SURFACE FLOW THROUGHOUT MUCH OF THE UPCOMING MARINE FORECAST PERIOD. THE MARINE CONDITIONS MAY PUSH UP CLOSE TO SCEC/POSSIBLY BORDERLINE SCA LEVELS MAINLY DURING THE AFTERNOON HOURS ACROSS THE LAGUNA MADRE. BUT NO STRONG SCA CONDITIONS EXPECTED FOR THE MOST PART. SUNDAY THROUGH TUESDAY... SUNDAY MAY APPROACH EXERCISE CAUTION OR MARGINAL ADVISORY CONDITIONS ON THE LAGUNA MADRE BUT MORE FAVORABLE MARINE WEATHER IS FORECAST THROUGH THE REMAINDER OF THE PERIOD. MODERATE SOUTHEAST WINDS ARE EXPECTED TO PICK UP A MORE EASTERLY COMPONENT MONDAY AND TUESDAY WITH LOW TO MODERATE SEAS. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 92 79 92 80 / 20 10 10 10 BROWNSVILLE 93 78 94 78 / 20 10 10 10 HARLINGEN 96 77 97 77 / 20 10 10 10 MCALLEN 98 78 99 79 / 20 20 10 10 RIO GRANDE CITY 98 77 100 77 / 20 20 10 10 SOUTH PADRE ISLAND 88 80 88 82 / 20 10 10 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 60/68/CAMPBELL