868  
FXUS64 KHGX 222336  
AFDHGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX  
636 PM CDT TUE AUG 22 2017  
   
AVIATION
 
 
ISOLATED DAYTIME SHOWERS CONTINUE TO DISSIPATE EARLY THIS  
EVENING WITH DRY CONDITIONS EXPECTED AT THE TERMINAL OVERNIGHT.  
HOWEVER, WATER VAPOR IMAGERY SHOWS AN UPPER LOW SPINNING OVER THE  
NORTHWEST GULF THIS EVENING AND IF THIS FEATURE WOBBLES FARTHER TO  
THE WEST TONIGHT AS AFTERNOON GUIDANCE INDICATED, A FEW PRE-DAWN  
SHRA OR EVEN TSRA WILL BE POSSIBLE ALONG THE COAST (POSSIBLY  
IMPACTING GALVESTON). HAVE LEFT OUT OF TAF FOR NOW DUE TO LOW  
CONFIDENCE BUT MAY NEED TO BE INCLUDED WITH THE 06Z UPDATE.  
DAYTIME HEATING WILL AGAIN RESULT IN ISOLATED TO SCATTERED  
SHRA/TSRA DEVELOPING NEAR CONROE/ THE HOUSTON TERMINALS AND POINTS  
SOUTH BY EARLY AFTERNOON, WITH AN APPROACHING FRONTAL BOUNDARY  
LOOKING TO RESULT IN A SECOND ROUND OF SHRA NEAR COLLEGE STATION  
AND HUNTSVILLE LATE IN THE TAF PERIOD. OTHERWISE, EXPECT VFR  
CONDITIONS WITH VARIABLE WINDS LESS THAN 8 KNOTS THROUGH THE  
PERIOD.  
 
HUFFMAN  
 

 
   
PREV DISCUSSION
 
/ISSUED 353 PM CDT TUE AUG 22 2017/  
 
DISCUSSION...  
NOT MUCH CONVECTIVE COVERAGE THIS AFTERNOON AS THE DRIER AIR MASS  
RESIDING OVER SOUTHEASTERN TEXAS SEEMS TO HAVE WON OUT...HIGHEST  
MOISTURE STILL REMAINS CENTERED OVER EXTREME SOUTHEASTERN TEXAS.  
WHEN AN ISOLATED SHOWER DOES FORM ALONG ONE OF THE NUMEROUS MESO-  
BREEZES IT QUICKLY BECOMES OUTFLOW DOMINANT AND FIZZES OUT.  
SURFACE ANALYSIS DEPICTS A SOUTHERN PLAINS BOUNDARY SLIDING DOWN  
INTO CENTRAL OK THIS AFTERNOON. THIS BOUNDARY IS FORECAST TO SINK  
FURTHER SOUTH INTO THE PINEY WOODS/EASTERN TEXAS BY TOMORROW  
AFTERNOON. THUS...ANOTHER FOCUS POINT FOR WHICH WARMTH-OF-THE-  
DAY SHOWERS AND THUNDERSTORMS COULD DEVELOP. OVERNIGHT MINIMUMS  
WILL NOT SURPRISINGLY FALL MUCH...INLAND MIDDLE 70S TO LOWER 80S  
ALONG THE COAST. LOW END CHANCE POPS FOR ANY SHORT LIVED -TSRA  
TOMORROW DURING THE DAY WITH THE HIGHEST PROBS OCCURRING ACROSS  
THE COASTAL AND SECOND TIER COUNTIES. MAXIMUM TEMPERATURES IN THE  
MEAN MIDDLE 90S (UPPER 90S ACROSS THE FAR INTERIOR) WILL EQUATE TO  
MAXIMUM HEAT INDICES IN THE 102 TO 106 F RANGE.  
 
THE BUZZ AROUND THE RE-DEVELOPMENT OF HARVEY IS RAMPING UP TODAY  
AS CAN BE EXPECTED WITH THE DETERMINISTIC SUITE COMING INTO BETTER  
ALIGNMENT THROUGH DAYS 3 THOROUGH 5. WHILE CONFIDENCE REMAINS LOW  
UNTIL THE WAVE CROSSES BACK INTO THE BAY OF CAMPECHE TOMORROW AND  
RE-FORMS AND POSSIBLY RE-FORMS A CLOSED OFF LOW...THE SUITE ALL  
AGREE TO DEEPEN THE SYSTEM TO AT LEAST A STRONG TROPICAL STORM OR  
WEAK HURRICANE AND TRACK IT TOWARDS THE LOWER TO MIDDLE TEXAS  
COASTLINE FROM TOMORROW NIGHT THROUGH FRIDAY MORNING. ONCE THIS  
SYSTEM MAKES LANDFALL FRIDAY OR SATURDAY THE SLOW STORM MOVEMENT  
WILL PLACE HIGH RAINFALL-LEADING-TO-FLOODING THE MAIN THREAT WITH  
GUSTY (SUB)TROPICAL STORM FORCE WINDS A SECONDARY THREAT. OUR  
MESSAGE IS 4 TO 8 INCHES OF WIDESPREAD RAINFALL FROM FRIDAY  
THROUGH EARLY TUESDAY WITH LOCALIZED AMOUNTS OF BETWEEN 8 TO 16  
INCHES (DOUBLE WIDESPREAD) BEING A REASONABLE POSSIBILITY PER THE  
SLOW STORM MOVEMENT. GRANTED HARVEY IS NOT REGAINED THE SHADOW OF  
HIS FORMER SELF AS OF THIS WRITING BUT IT IS HARD IGNORE THAT  
EVERY DETERMINISTIC SOLUTION LIKES THIS "SIGNAL" OF A LANDFALLING  
TC ALONG THE TEXAS COASTLINE BY THIS WEEKEND. THE MAIN CON TO  
FORMATION...OR TO PLAY DEVIL'S ADVOCATE TO JUST JUMPING ON THE  
MODEL TRAIN...
WOULD BE THE AMOUNT OF DRY AIR THAT THE SYSTEM WILL  
BE INGESTING GOING INTO THURSDAY. W/V IMAGERY DOES SHOW QUITE A  
BIT OF MID-UPPER DRY AIR MOVING INTO THE SOUTHERN BAY OF CAMPECHE  
AND THIS COULD BE A MAJOR INHIBITOR FOR DEVELOPMENT. THE TWO MAIN  
PROS FOR HARVEY MAKING IT A BAD WEEK FOR US WILL BE THE FACT THAT  
(1) THIS WAVE IS MOVING INTO A HEIGHT AND WIND WEAKNESS CHANNEL  
CARVED OUT BY THE WESTERN GULF INVERTED TROUGH BETWEEN THE GREAT  
BASIN AND BERMUDA RIDGES AND (2) SEA SURFACE TEMPERATURES OVER THE  
WESTERN GULF ARE CURRENTLY BETWEEN 85 AND 88 F (BASED ON THE BUOY  
DATA). ALTHOUGH WE MAY WANT TO GET CAUGHT UP IN THE POTENTIAL  
SPECIFICS OF THIS STORM THIS MAY BE A GREAT TIME TO BEGIN THE  
PREPAREDNESS MESSAGE AND FOCUS ON THE IMPACTS...DO YOU HAVE YOUR  
HURRICANE PREPAREDNESS PLAN IN PLACE AND CAN YOU ENACT THIS PLAN  
WITHIN THE NEXT COUPLE OF DAYS? 31  
 
MARINE...  
LIGHT WINDS AND LOW SEAS ARE EXPECTED TO CONTINUE THROUGH  
WEDNESDAY. SHOULD BEGIN TO SEE SWELLS FROM THE TROPICAL SYSTEM  
OVER THE YUCATAN BY SLOWLY INCREASE BY LATE WEDNESDAY INTO  
THURSDAY. THERE IS CONSIDERABLE UNCERTAINTY AS TO THE DEVELOPMENT  
AND EVENTUAL LANDFALL OF THE SYSTEM. THE LATEST MODELS DEVELOP THE  
SYSTEM BACK INTO HARVEY WITH LANDFALL SOMEWHERE ON THE SOUTHERN  
TEXAS COASTLINE SOMETIME LATE FRIDAY. IF THIS SCENARIO PANS OUT,  
HIGH SEAS AND STRONG WINDS WILL AFFECT THE UPPER TEXAS COASTAL  
WATERS AT LEAST LATE THURSDAY INTO SATURDAY MORNING. TIDES ALONG  
THE COAST COULD BECOME A PROBLEM AS EARLY AS THURSDAY AFTERNOON  
AND NIGHT GIVEN THE SWELLS AND STRONG ONSHORE WINDS. THE LATEST  
MODELS SHOW THE POTENTIAL FOR ACTUAL TIDE LEVELS TO REACH OR  
EXCEED 3 FEET FOR THE HIGH TIDE TIMES EITHER THURSDAY NIGHT OR  
FRIDAY MORNING.  
 
MARINERS ARE URGED TO CLOSELY MONITOR THE LATEST FORECASTS THROUGH  
THE WEEKEND. 40  
 
COLLEGE STATION (CLL) 76 98 76 95 76 / 10 30 30 40 40  
HOUSTON (IAH) 77 95 77 94 77 / 10 30 20 40 40  
GALVESTON (GLS) 82 91 83 91 82 / 20 30 20 40 50  
 
HGX WATCHES/WARNINGS/ADVISORIES...  
TX...NONE.  
GM...NONE.  
 

 
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
COLLEGE STATION (CLL) 76 98 76 95 76 / 10 30 30 40 40  
HOUSTON (IAH) 77 95 77 94 77 / 10 30 20 40 40  
GALVESTON (GLS) 82 91 83 91 82 / 20 30 20 40 50  
 

 
   
HGX WATCHES/WARNINGS/ADVISORIES
 
 
TX...NONE.  
GM...NONE.  

 
 

 
 
DISCUSSION...45  
AVIATION/MARINE...14  
 
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