Area Forecast Discussion
Issued by NWS Brownsville, TX

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KBRO 292336
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
636 PM CDT FRI AUG 29 2014

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...A COMPLEX OF SHRA AND TSRA MOVING ESE CURRENTLY
THROUGH C/E HIDALGO COUNTY TOWARD CAMERON COUNTY. XPECT IMPACTS TO
HRL FROM 0000-0100Z AND AT BRO 0030-0300Z. XPECT TSRA WITH FRQ LTG
AND HEAVY RAIN. WINDS GUSTS TO 30 KNOTS POSSIBLE AS WELL. AFTER
THIS COMPLEX MOVES THROUGH...A LULL IN ACTIVITY XPECTED THROUGH
REST OF THE EVENING BUT REDEVELOPMENT POSSIBLE AFT 09Z ESPECIALLY
ALONG THE COASTAL COUNTIES AND HRL/BRO. THIS ACTIVITY WILL
DECREASE BY MID MORNING BUT DIURNAL TSRA EXPECTED IN THE MID/UPPER
VALLEY AND INCLUDING MFE SATURDAY MIDDAY THROUGH LATE AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 320 PM CDT FRI AUG 29 2014/

SHORT TERM.../NOW THROUGH SATURDAY NIGHT/...LATEST RADAR AND
SATELLITE IMAGERY SHOW THE WEAK LOW PRESSURE NE/EAST OF PORT
MANSFIELD. DUE TO THE EARLIER CONVECTION MOST OF THE ACTIVITY
DIMINISHED FOR A FEW HOURS BY MID MORNING. HOWEVER...AS THE HIGH
LEVEL CLOUDS CONTINUE TO BREAK MORE SHOWER ACTIVITY WILL BEGIN TO
INITIATE ALONG THE COASTAL WATERS AND EAST OF HWY 77. 12Z KBRO
SOUNDING CONTINUES TO SHOW PRECIPITABLE  VALUES OF 2.5 INCHES IN THE
AREA AND 1000 TO 500 MB RH AROUND 70 TO 80 PERCENT. CONDITIONS ARE
FAVORABLE FOR MORE ISOLATED CONVECTION TO DEVELOP LATER THIS
AFTERNOON. HIGH TEMPERATURES WILL BE LOWER COMPARED TO PREVIOUS DAYS
ONLY WARMING INTO THE MID TO LOW 90S ALONG THE COAST AND IN THE
HIGHER END TOWARDS THE WESTERN ZONES DUE TO LESS CLOUD COVER.

TONIGHT INTO SATURDAY...GFS/NAM AND ECMWF CONTINUE TO SHOW THIS
LOW/MCV DEVELOPING INTO A MORE INVERTED TROUGH GRADUALLY MOVING
WESTWARD TONIGHT AND INTO EARLY SATURDAY. PRECIPITABLE VALUES STILL
MAINTAIN HIGH VALUES ABOVE 2.4 INCHES INITIATING ANOTHER ROUND OF
CONVECTION AFTER MID NIGHT OVER THE COASTAL COUNTIES. THE UPPER
TROUGH OVER THE CENTRAL PLAINS WILL PROGRESS EASTWARD OVER THE AREA
AND SHEAR ALL THE DEEP MOISTURE NORTHEAST SHIFTING UPPER LEVEL FLOW
TOWARDS THE WESTERN COUNTIES MORE NW TO W LIMITING THE CONVECTION
FOR THE WESTERN ZONES. LEAN TOWARDS HIGHER POPS OVERNIGHT ESPECIALLY
FOR EASTERN HIDALGO AND ALONG AND EAST OF HWY 77 AND THE COASTAL
WATERS. WITH THE ABUNDANCE IN MOISTURE AVAILABLE IN THE ATMS...
EXPECT THESE SHOWERS TO MOVE SLOWLY AND DEVELOP HEAVY DOWNPOURS
WHICH COULD CAUSE LOCALIZED FLOODING OF URBAN AND POOR DRAINAGE
AREAS. RAINFALL ACCUMULATIONS COULD SEE 1 TO 3 INCHES WITH THE
STRONGEST DOWNPOURS. THIS SHOULD PREVAIL THROUGH THE DAY FAVORING
THE COASTAL COUNTIES WITH BETTER POTENTIAL OVER THE LOWER AND MIDDLE
VALLEY.

SATURDAY NIGHT...ANOTHER WEAK TROPICAL WAVE MOVES INTO THE CWA WITH
ABUNDANT MOISTURE AVAILABLE IN THE AREA. INCREASE THE POPS EARLY SUN
MORNING AS THE WEAK LOW DEVELOPS OVER THE AREA FAVORING THE EASTERN
SIDE OF THE LOW OVER THE COAST. TEMPERATURES THROUGH SATURDAY WILL
REMAIN IN THE MID TO UPPER 90S AND OVERNIGHT IN THE MID TO UPPER
70S.

LONG TERM/SATURDAY NIGHT THROUGH FRIDAY/...RAIN CHANCES CONTINUE
LOW TO MODERATE THROUGH THE EXTENDED AS WE ENTER INTO SEPTEMBER
OUR CLIMATOLOGICAL BEST MONTH FOR RAIN.

ATMOSPHERIC MOISTURE REMAINS RATHER HIGH SATURDAY NIGHT AND SUNDAY
AND A WEAK BUT PERSISTENT UPPER TROUGH CONTINUES OVER TEXAS AND THE
WESTERN GULF OF MEXICO. GIVEN THE TIME OF YEAR AND UPTICK IN MODEL
POP GUIDANCE RAIN CHANCES HAVE BEEN BUMPED UP A BIT FOR SUNDAY.
LOOKING FOR ANOTHER ROUND OF NOCTURNAL DEVELOPMENT WITH SOME SEA
BREEZE ACTIVITY IN THE AFTERNOON AS THE HIGHER AVAILABLE MOISTURE
MOVES WESTWARD.

IF ANY DAY IN THE NEXT 5-7 DAY HAS A LOW POINT IN THE CHANCE OF RAIN
THIS WOULD BE MONDAY. MOISTURE CONTENT LOWERS EVER SO SLIGHTLY AND
THE UPPER TROUGH WEAKENS AS AN UPPER RIDGE ELONGATES OVER TEXAS.
DEEP EASTERLY FLOW RESULTS TO KEEP AT LEAST A SLIGHT CHANCE OF SOME
SEA BREEZE ACTIVITY GOING.

THE MUCH ADVERTISED TROPICAL WAVE OVER THE CENTRAL/WESTERN CARIBBEAN
HAS CHANGED LITTLE OVER THE LAST 24 HOURS. NHC CONTINUES TO MONITOR
ITS MOVEMENT AND POTENTIAL DEVELOP. CURRENT THOUGHTS ARE THAT
ATMOSPHERIC CONDITIONS IMPROVE FOR SOME DEVELOPMENT AS IT MOVES INTO
THE BAY OF CAMPECHE TUESDAY INTO WEDNESDAY. GFS REMAINS PERSISTENT
ON ITS EVOLUTION AND THE NAM IS SHOWING IN BIAS OF TROPICAL
DEVELOPMENT. OTHER GLOBAL MODELS KEEP THE SYSTEM AS A TROPICAL
WAVE. ALL MODELS DO SURGE MOISTURE INTO THE WESTERN GULF AND SOUTH
TEXAS AS EARLY AS TUESDAY WITH PLENTY OF DEEP TROPICAL MOISTURE
HANGING ON THROUGH AT LEAST THURSDAY. MODEL GUIDANCE HAS BEGUN TO
INCREASE POP VALUES AS DOES THE FORECAST ESPECIALLY WEDNESDAY AND
THURSDAY WHEN THE BULK OF THE MOISTURE MOVES OVER THE REGION. WITH
THE INCREASE POPS COMES MORE CLOUD COVER WHICH WILL KEEP
TEMPERATURES BELOW NORMAL WEDNESDAY AND THURSDAY.

FOLKS SHOULD CONTINUE WATCH THE FORECAST THIS WEEKEND FOR ANY
CHANGES IN THE TROPICAL OUTLOOK. THE ENVIRONMENT REMAINS MARGINALLY
CONDUCIVE FOR SLIGHT POTENTIAL AND TROPICAL SYSTEMS CAN AND DO
DEVELOP RAPIDLY IF THE RIGHT CONDITIONS EXIST.

MARINE...NOW THROUGH SATURDAY NIGHT...WEAK PRESSURE GRADIENT ACROSS
THE GULF IS KEEPING LIGHT TO MODERATE WINDS OVER THE GULF WATERS THE
REMAINDER OF TODAY AND CONTINUING THROUGH THE SHORT TERM PERIOD. THE
SEAS WILL REMAIN BETWEEN 2 TO 4 FEET OVER THE GULF WATERS WITH SOME
ERRATIC WINDS POSSIBLE FROM OUTFLOW BOUNDARIES FROM THUNDERSTORM
DEVELOPMENT. AT THIS TIME..THE WEAK LOW SEEN ON THE LATEST RADAR
IMAGERY IS LOCATED EAST OF PORT MANSFIELD AND IT IS EXPECTED TO
INITIATE A FEW ISOLATED SHOWERS ALONG THE COAST THE REMAINDER OF
TODAY. THIS SHOULD QUIET DOWN EARLY IN THE EVENING. HOWEVER...
ANOTHER ROUND OF HEAVY DOWNPOURS IS EXPECTED TO DEVELOP OVER THE
GULF ALONG THE COAST AFTER MIDNIGHT AND CONTINUE THROUGH MID DAY
SATURDAY.

/SATURDAY NIGHT THROUGH WEDNESDAY/... MODERATE SOUTHEAST FLOW
CONTINUES THIS WEEKEND WITH A SLIGHT SEA. PRESSURE GRADIENT IS
STILL FORECAST TO STRAIGHTEN OVER THE SOUTHEAST AND SOUTH CENTRAL
GULF OF MEXICO AS HIGH PRESSURE OVER THE NORTHERN GULF AND THE
EXPECTED TROPICAL WAVE MOVING ACROSS THE YUCATAN PENINSULA
SUNDAY/MONDAY AND INTO THE SOUTHWEST GULF TUESDAY/WEDNESDAY. DEEP
EASTERLY FLOW TO PRODUCE A SWELL TRAIN THAT WILL BE DIRECTED
TOWARDS THE LOWER TEXAS COAST. SOME SWELL COULD EXCEED 7 FEET AS
EARLY AS TUESDAY NIGHT AND CONTINUE INTO THURSDAY MORNING. SMALL
CRAFT ADVISORIES MAY BE NECESSARY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

55




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.