National Weather Service Raw Text Product

267 
FXUS64 KHGX 181556
AFDHGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1056 AM CDT MON APR 18 2016

.UPDATE...
ONGOING EXTREME FLOODING EVENT...WITH MOST OF THE CITY OF HOUSTON
EXPERIENCING RECORD LEVEL FLOODING FROM ITS REGIONAL BAYOUS AND
BASIC SHEET FLASH FLOODING. THE STRONG WEST-TO-EAST BAND OF
CONVECTION IS BACK BUILDING THROUGH THE COASTAL COUNTIES WITH
RECENT REPORTS OF HIGH RAINFALL RATES OF 1 TO 3 INCHES BEGINNING
TO DECREASE AS THE LINE BECOMES OUTFLOW DOMINANT. NUMEROUS ROADWAYS
ACROSS THE SOUTHERN SUBURBS OF HOUSTON DOWN TOWARDS (AND
INCLUDING) GALVESTON ISLAND ARE CURRENTLY EXPERIENCING FLOODING.
THE BEST ADVICE TO ANYONE ALONG AND SOUTH OF INTERSTATE 10
CORRIDOR WHO IS CONSIDERING TRAVEL IS TO STAY PUT AND DO NOT
ATTEMPT TO TRAVEL OVER THE NEXT COUPLE OF HOURS. AREAWIDE RAIN
PROBABILITIES REMAIN HIGH THROUGH THE EVENING WITH ANOTHER 2 TO 4
INCHES OF RAIN ON TOP OF WHAT WE HAVE ALREADY RECEIVED THROUGH THE
REMAINDER OF THE AFTERNOON. CURRENT THINKING IS THAT RAINFALL
RATES WILL BEGIN TO WANE IN THE NEXT FEW HOURS AND WE'LL SEE A
BREAK FROM THE HIGH RAINFALL RATES INTO THE EARLY EVENING HOURS.
THE GENERAL MODEL TREND GOING INTO EARLY TUESDAY IS FOR A POSSIBLE
SECONDARY BOUT OF RAINFALL LATTER THIS EVENING...WITH A THIRD
ROUND OF AREAWIDE RAINFALL SLATED FOR WEDNESDAY? 31

&&

.PREV DISCUSSION... /ISSUED 644 AM CDT MON APR 18 2016/ 

AVIATION...
SHRA/TSRA CONTINUE IN AND AROUND MOST OF THE SE TX TAF SITES.
HEAVIEST IMPACTED SITES CURRENTLY ARE SGR AND HOU. WITH ACTIVITY
GRADUALLY SAGGING SOUTHWARD...LBX AND GLS SHOULD BE IMPACTED SOON.
SHRA/TSRA ARE STILL POSSIBLE AT UTS AND CXO WITH THE LEAST IMPACTED
LOCATION PROBABLY CLL. NOT REALLY SURE WHAT IS GOING TO HAPPEN LATER
THIS AFTERNOON AND TONIGHT SINCE A LOT WILL DEPEND ON HOW LONG THE
CURRENT ACTIVITY LASTS. GENERALLY EXPECTING MVFR CEILINGS AND 
VISIBILITIES WITH IFR/LIFR CONDITIONS LIKELY IN AND AROUND THE
STRONGER STORMS.  42 

PREV DISCUSSION... /ISSUED 356 AM CDT MON APR 18 2016/ 

DISCUSSION...
SEVERE...HISTORIC FLOOD EVENT ONGOING. SEVERAL FLASH FLOOD
WARNINGS AND FLASH FLOOD EMERGENCIES IN EFFECT FROM SLOW MOVING
BAND OF THUNDERSTORMS. MULTIPLE HIGH WATER RESCUES REPORTED AND
STRUCTURES BEING FLOODED. UNFORTUNATELY BAND OF THUNDERSTORMS TO
IMPACT AREAS ALREADY HAVING RECEIVED HEAVY RAIN FOR POTENTIALLY SEVERAL
MORE HOURS.

WORST CASE SCENARIO AS DEEP MOISTURE ADVECTING IN OFF THE GULF
AND BEING FOCUSED ALONG E TO W BAND OF THUNDERSTORMS WITH VERY
LITTLE MOVEMENT. MODELS HAVE STRUGGLED TO CAPTURE PLACEMENT AND
TIMING OF CONVECTION AND DIFFICULT GOING FORWARD AS WELL. NOT MUCH
CHANGE IN THE PATTERN IS EXPECTED THROUGH TUESDAY. THROUGH TUESDAY
EXPECT ADDITIONAL ROUNDS OF HEAVY RAIN WHICH WILL ONLY EXACERBATE
FLOODING ALREADY ONGOING. DIFFICULT TO TIME THINGS BUT
THUNDERSTORM COMPLEXES WILL GENERALLY BE SLOW MOVING. CONCERN IS
THEY WILL OCCUR IN SIMILAR AREAS. HAVE HAD TO RAISE POPS WEDNESDAY
AS WELL AS MODELS SHOWING ANOTHER VORT LOBE PIVOTING AROUND UPPER
LOW LIKELY BRINGING MORE SHOWERS AND THUNDERSTORMS. REALLY DONT
DRY OUT UNTIL POSSIBLY FRIDAY AS MODELS SUGGEST RIDGING AT SURFACE
AND ALOFT. 46

MARINE... 
A COASTAL FLOOD WARNING REMAINS IN EFFECT FOR THE UPPER COASTAL
AREAS...GALVESTON...HARRIS...CHAMBERS. FURTHER SOUTH ACROSS BRAZORIA
AND MATAGORDA WILL HAVE A COASTAL FLOOD ADVISORY. WATER LEVELS ARE
PEAKING AROUND 4 FEET AT HIGH TIDES IN THE WARNING AREA AND AROUND
3.5 FEET IN THE ADVISORY AREA. AFTER THE AFTERNOON HIGH TIDE
PEAKING 2-3 PM WE WILL LIKELY SEE WATER LEVELS BEGIN TO SUBSIDE
SOME...ALTHOUGH STILL WELL ABOVE NORMAL.

THE SMALL CRAFT ADVISORY WILL CONTINUE TODAY AS WELL. SHOULD SEE
WINDS/SEAS SUBSIDE SOME DURING THE DAY TODAY. 33 

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      69  67  78  67  81 / 100  90  70  50  50 
HOUSTON (IAH)              71  68  77  67  82 / 100  90  80  40  70 
GALVESTON (GLS)            73  70  75  70  77 / 100  90  80  50  60 

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR THE FOLLOWING 
     ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
     COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
     HOUSTON...JACKSON...LIBERTY...MADISON...MATAGORDA...
     MONTGOMERY...POLK...SAN JACINTO...TRINITY...WALKER...
     WALLER...WASHINGTON...WHARTON.

     COASTAL FLOOD WARNING UNTIL 4 PM CDT THIS AFTERNOON FOR THE 
     FOLLOWING ZONES: CHAMBERS...GALVESTON...HARRIS.

     COASTAL FLOOD ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR THE 
     FOLLOWING ZONES: BRAZORIA...MATAGORDA.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 4 PM CDT THIS 
     AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...
     MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP 
     CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 
     20 NM.

     SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE 
     FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP 
     CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO 
     FREEPORT 20 TO 60 NM.

&&

$$

DISCUSSION...31