Flash Flood Warning 67, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1234 PM CDT SAT JUN 4 2016

.AVIATION...
Anticipating more SHRA/TSRA development across SE TX this afternoon,
maybe overnight again, and once again tomorrow afternoon as the area
remains in a mostly unstable air mass. Hard to pinpoint where best
coverage will be, so will carry lots of VCSH and associated potential
lower ceilings in the TAFS. Looks like some drier air moves into the
area from the north tomorrow, and this might keep our northern TAFs
dry while SHRA/TSRA remain possible closer to the coast. Overall
confidence in the 18Z TAFs is low.  42
&&

.PREV DISCUSSION... /ISSUED /

UPDATE...
Main thunderstorm complex that moved along the coast this
morning has pushed into coastal Louisiana, with lingering light to
moderate rain falling generally along and south of the Highway 59
corridor in its wake. 8 AM surface analysis showed a weak mesoscale
low behind this system, located near Matagorda Bay. High
resolution guidance attempts to bring this feature northeast
towards Galveston Bay later this afternoon, possibly providing
another focus for showers and thunderstorms east of Interstate 45.
Farther north, scattered showers continued to develop from the
Brazos Valley into the Piney Woods coincident with a shear axis
from a decaying upper low over South Texas. Expect this activity
to continue through the remainder of the day, slowly spreading
south and east as the upper low drops farther south and
temperatures gradually rise into the upper 70s to near 80 this
afternoon. Given the variety of focusing/forcing mechanisms for
showers and thunderstorms today, continuing mention of scattered
to numerous showers and thunderstorms across the region. Locally
heavy rainfall still remains a concern, with GPS Met data showing
precipitable water values between 1.8 and 2 inches and weak winds
(variable and less than 5 knots) through 15kft contributing to
very slow storm motions.

Huffman

PREV DISCUSSION... /ISSUED /

DISCUSSION...
Upper low seen on water vapor imagery over the Hill Country should
continue drifting southward today/tonight. Large area of
convection initiated along/south of Highway 59 overnight. Offshore
portion looking like it's becoming a bit more dominant. Matagorda
has picked up about 5" rain in the past couple hours with some
street flooding. Tide levels remain above normal so will still
need to keep an eye on rain rates as drainage will be slower than
usual. Further inland with a few exceptions, and in the short
term, rates have somewhat tapered off as offshore precip has
expanded and intensified. Still quite concerned rates could
increase again however as some guidance suggests. Like yday...expect
precip to begin waning late this morning, but threat of additional
precip will linger thru the day w/ daytime heating and diffuse
trof axis/convergent zone near the coast.

Will let the Flash Flood Watch ride for the remainder of the day.
As the upper low moves further south slightly drier air will make its
way into northern zones...and precip chances will diminish there.
But closer to the coast...mid level shear axis, 1.7-2" PW's and
sfc coastal troffiness will persist into early parts of next
week. Precip pattern should transition to more of typical
summertime norm (sct activity developing offshore late at night
and transition inland during the day w/ heating & seabreeze). By
Tue/Wed daytime coverage should further diminish as drier air
makes it further southward. Uptick in rain chances again next
weekend and fetch of deeper Gulf moisture flows back inland. 47

MARINE...
For the short-term...one of the main issues will be localized strong
wind gusts/elevated seas in/near storms along the coast. All of this
unsettled weather is due in large part to the upper low lingering in
south central TX that is drawing disturbances around it from the SW.
As this system weakens and moves off to the SW...we could see a cold
front move into the coastal waters on Sun. Light offshore winds will
be possible during the early part of next week. 41

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)      81  68  85  66  87 /  60  40  20   0  30
Houston (IAH)              80  69  85  69  88 /  80  40  40  20  40
Galveston (GLS)            79  75  84  74  85 / 100  50  40  30  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flash Flood Watch until 7 PM CDT this evening 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.

GM...NONE.
&&

Discussion...14
Aviation/Marine...42

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
747 AM CDT SAT JUN 4 2016

TXZ163-164-176>179-195>200-210>214-226-227-235>238-051300-
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-
747 AM CDT SAT JUN 4 2016

...FLASH FLOOD WATCH IN EFFECT...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT

AN UPPER LEVEL LOW PRESSURE SYSTEM CENTERED OVER THE HILL COUNTRY TEXAS
WILL SLOWLY MOVE INTO SOUTH TEXAS THIS WEEKEND. A SERIES OF UPPER
LEVEL DISTURBANCES ROTATING AROUND THIS FEATURE WILL TRIGGER
PERIODS OF SHOWERS AND THUNDERSTORMS. ON AVERAGE MOST LOCATIONS
CAN ANTICIPATE 1/2 TO 2 INCHES OF RAINFALL...BUT LOCALIZED SWATHS
OF MUCH HIGHER TOTALS BETWEEN 4 AND 7 INCHES ARE POSSIBLE WHERE
TRAINING SETS UP.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE THREAT FOR ISOLATED HEAVY RAINFALL WILL CONTINUE FOR COASTAL
AREAS INTO SUNDAY. A GRADUAL DRYING TREND WILL BEGIN FOR AREAS
WELL INLAND ON SUNDAY...BUT SCATTERED TO ISOLATED SHOWERS AND
THUNDERSTORMS WILL STILL BE POSSIBLE INTO EARLY NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE REQUESTED TO REPORT RAINFALL AND FLASH FLOODING.

GMZ330-335-350-355-370-375-051300-
COASTAL WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT
20 NM-COASTAL WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-
GALVESTON BAY-MATAGORDA BAY-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL FROM 20 TO
60 NM-WATERS FROM HIGH ISLAND TO FREEPORT FROM 20 TO 60 NM-
747 AM CDT SAT JUN 4 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL IMPACT AREAS ALONG THE UPPER TEXAS COAST
TODAY AND TONIGHT. GUSTY WINDS AND HEAVY RAINFALL MAY LIMIT
VISIBILITIES TO 1 NM OR LESS AT TIMES AND PRODUCE LOCALLY HIGH
SEAS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH THURSDAY

PERIODS OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE INTO EARLY
NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.