AFDHGX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 346 PM CDT WED AUG 31 2011 .DISCUSSION... THE PRIMARY CONCERN IN THE FORECAST FOR THE NEXT 7 DAYS IS THE MOVEMENT AND POTENTIAL DEVELOPMENT OF THE TROPICAL WAVE CURRENTLY LOCATED OVER THE SE GULF OF MEXICO. THE MODELS ARE IN GOOD AGREEMENT ON THE HANDLING OF THIS SYSTEM THROUGH FRIDAY MORNING THEN BEGIN TO DIVERGE SIGNIFICANTLY AFTER THAT. THE MAJORITY OF THE MODELS SHOW THE TROPICAL WAVE LOCATED OVER THE CENTRAL AND NORTH CENTRAL GULF FRIDAY MORNING WITH A SURFACE LOW DEVELOPING ABOUT 250 NM SOUTHEAST OF GALVESTON. ONE THING THAT IS CERTAIN IS ANY MOVEMENT BEGINNING FRIDAY IS GOING TO BE SLOW AS THE STEERING CURRENTS COLLAPSE. AS TO THE MODEL DIFFERENCES: THE 12Z GFS TAKES THE SYSTEM EASTWARD TOWARD THE CENTRAL GULF COAST...THE 12Z NAM/CANADIAN BRING THE SYSTEM ONSHORE THE UPPER TX COAST THIS WEEKEND...WHILE THE 12Z ECMWF STALLS THE SYSTEM OUT FOR SEVERAL DAYS. ALL OF THE MODELS SHOW FAIRLY SIGNIFICANT DEVELOPMENT WITH THE LOW. HAVE IGNORED THE GFS SOLUTION. WHILE THE SYSTEM COULD CERTAINLY MOVE EAST OR NORTHEAST WITH TIME...IT SEEMS UNLIKELY TO DO THAT THROUGH SATURDAY WITH SUCH STRONG RIDGING TO THE NORTH. AFTER COORDINATION WITH SURROUNDING WFOS...HAVE LEANED TOWARD THE ECMWF SOLUTION SINCE IT HAS A BETTER HANDLE ON THE RIDGING OVER THE SOUTHERN STATES AND SHOWS THE MOST CONSISTENCY WITH PREVIOUS RUNS. A SLOW MOVING AND STRENGTHENING TROPICAL CYCLONE OVER THE NW GULF WOULD RESULT IN SEVERAL IMPACTS OVER THE AREA THROUGH THE HOLIDAY WEEKEND. A PERSISTENT EAST TO NORTHEAST FETCH WOULD RESULT IN AN INCREASE IN TIDE LEVELS OVER THE BAYS AND UPPER TX COAST. THIS COULD BE EXACERBATED BY SUNDAY/MONDAY AS A SURFACE HIGH APPROACHES FROM THE NORTH TIGHTENING THE PRESSURE GRADIENT ALONG THE COAST. SWELLS FROM THE SYSTEM COULD RESULT IN DANGEROUS RIP CURRENTS AT THE BEACHES AND THE POTENTIAL FOR BEACH EROSION. AS FAR AS THE RAIN POTENTIAL...THE ECMWF SOLUTION WOULD KEEP MOST OF THE RAIN CONFINED TO AREAS EAST OF US HIGHWAY 59 AS SE TX WOULD REMAIN ON THE SUBSIDENT SIDE OF THE SYSTEM. TROPICAL SYSTEMS TEND TO EXPAND DURING THE DAY AND CONTRACT AT NIGHT...SO BANDS OF SCATTERED CONVECTION WOULD AFFECT THE SE THIRD OF THE AREA MAINLY DURING THE DAYTIME HOURS. PLACED JUST 20 POPS IN THE FORECAST THURSDAY SE HALF AS THE ENTIRE AREA WILL REMAIN ON THE SUBSIDENT SIDE OF THE WAVE. THEN HAVE BLANKETED 30-40 POPS IN FORECAST FOR SE HALF...20S NORTHWEST FRIDAY THROUGH EARLY NEXT WEEK. IRONICALLY... THE INCREASE IN WINDS AND LACK OF RAIN OVER THE NW HALF OF THE AREA COULD ACTUALLY WORSEN THE FIRE DANGER IN THESE AREAS THIS WEEKEND. AS FOR TEMPERATURES...EXPECT THURSDAY TO BE SIMILAR TO TODAY WITH STRONG SUBSIDENCE OVER THE AREA. THE COMBINATION OF THE INCREASE IN CLOUD COVER...LOWERING 850 MB TEMPS AND SCATTERED CONVECTION WILL RESULT IN A MODERATION OF TEMPS THROUGH EARLY NEXT WEEK. PERSONS ACROSS SOUTHEAST TEXAS ARE URGED TO CLOSELY MONITOR NWS FORECASTS AND NHC FORECAST UPDATES FOR THE NEXT FEW DAYS. IF A TROPICAL CYCLONE DEVELOPS IN THE NW GULF IT WILL HAVE IMPACTS ALONG THE TEXAS AND LOUISIANA COASTS THIS WEEKEND. SIGNIFICANT CHANGES TO THE FORECAST ARE LIKELY UNTIL THE MODELS GET A GOOD HANDLE ON THIS SYSTEM. 35 && .CLIMATE... THE TEMPERATURE HAS REACHED 100 DEGREES AT BOTH HOUSTON AND COLLEGE STATION THIS AFTERNOON...CAPPING OFF WHAT WILL GO DOWN AS HOTTEST MONTH OF ANY MONTH ON RECORD FOR SOUTHEAST TEXAS. FOR COLLEGE STATION...THIS IS THE 58TH DAY OF 100-DEGREE TEMPERATURES...TYING THE ALL-TIME RECORD FOR MOST IN A YEAR SET IN 1917. THE TEMPERATURE REACHED 100 DEGREES A TOTAL OF 30 OUT OF THE 31 DAYS THIS MONTH IN HOUSTON...SOMETHING THAT SEEMED ALMOST UNTHINKABLE PRIOR TO THIS MONTH. THE AVERAGE DAILY HIGH TEMPERATURE IN HOUSTON FOR AUGUST WILL EXCEED 100 DEGREES FOR THE FIRST TIME EVER FOR ANY MONTH. THE MONTHLY AVERAGE TEMPERATURE IN HOUSTON WILL END UP CLOSE TO 90.4 DEGREES...WHICH EXCEEDS THE PREVIOUS RECORD HOTTEST MONTH (AUGUST 2010) BY A WHOPPING 2.7 DEGREES. A PUBLIC INFORMATION STATEMENT WILL BE RELEASED IN THE NEXT FEW DAYS WHICH WILL DETAIL ALL OF THE HEAT RECORDS WHICH HAVE BEEN BROKEN THIS MONTH. 35 && .AVIATION... THE SLOW INCREASE OF LOW-LEVEL MOISTURE CREATING SOME MILD CONCERN FOR THE DEVELOPMENT OF SOME MVFR CIGS/VIS FOR (MOSTLY) THE SRN TAF SITES DURING THE VERY EARLY MORNING TIMEFRAME OF 09-12Z. OTHERWISE NOT TOO KEEN ON THE GFS HINTS OF TSRA FOR TOMORROW AS MOISTURE MAY STILL BE TOO LOW. OTHERWISE VFR. 41 && .MARINE... A LOT OF UNCERTAINTY REMAINS IN PLACE WITH THE UPCOMING FCST AS WE AWAIT THE POSSIBLE DEVELOPMENT OF THE TROPICAL WAVE CURRENTLY HEAD- ING INTO THE GULF. MODELS STILL SHOWING A VARIETY OF OUTCOMES WITH THIS FEATURE THROUGH THE WEEKEND BUT HAVE LEANED HEAVILY ON ECMWF/ NAM GUIDANCE AS THEY HAVE BEEN EXTREMELY CONSISTENT. BUT THAT SAID WOULD LIKE TO CAUTION EVERYONE THAT CHANGES ARE LIKELY WITH ALL OF THIS GIVEN THE NATURE OF THESE TYPES OF WEAK GULF SYSTEMS. NO ADVI- SORIES FOR OUR MARINE ZONES ATTM BUT WE SHOULD SEE THE GRADIENT BE- GIN TO TIGHTEN ACROSS THE REGION THE NEXT SEVERAL DAYS. INCREASING AND THEN SUSTAINED STRONG E/NE WIND THROUGH THE WEEKEND COULD MAKE FOR SOME TIDAL/COASTAL FLOODING ISSUES DURING THIS TIMEFRAME. OVER THE NEAR/OFFSHORE WATERS...SMALL CRAFT ADVISORIES MAY BE RAISED BY LATE FRI. ATTM NOT SURE WHEN THESE FLAGS WILL BE DROPPED...PERHAPS THE EARLY TO MIDDLE PART OF NEXT WEEK? 41 && .FIRE WEATHER... SOMEWHAT COUNTER-INTUITIVELY...THE FOCUS OF POSSIBLE TROPICAL WAVE DEVELOPMENT OVER THE CENTRAL/NWRN GULF COULD HAVE IMPACTS FOR FIRE WX INTERESTS. WHILE CLOSER TO THE COAST (ROUGHLY I-10 AND SOUTH) A TREND OF DEEPENING LOW-LEVEL MOISTURE AND INCREASING SEABREEZE ACT- IVITY SHOULD HELP TO INCREASE POPS FOR THESE LOCATIONS THROUGH THE WEEKEND. HOWEVER FURTHER NORTH THIS DEVELOPING LARGE SCALE PATTERN IS EXPECTED TO PRODUCE A FAIRLY DEEP NELY FETCH. THE RESULT SHOULD BRING MUCH DRIER AIR AND INCREASED WINDS TO THE REGION THROUGH THE WEEKEND. WITH GROUND FUELS REMAINING EXTREMELY DRY...ELEVATED FIRE WEATHER CONDITIONS ARE LIKELY. IN THE MEANTIME...WILL HAVE TO STAY AWARE OF THE SEABREEZE AGAIN TOMORROW AND ITS IMPACTS ON INCREASED S/SELY WINDS. VERY HOT TEMPS AGAIN TOMORROW AS RAIN CHANCES FALL A BIT IN THE FACE OF PERSISTENT SUBSIDENCE. 41 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 77 102 77 99 77 / 10 10 10 20 20 HOUSTON (IAH) 77 100 78 95 78 / 10 20 10 40 20 GALVESTON (GLS) 83 94 82 90 82 / 10 20 20 40 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$